zq< 
 
 Criteria for the Diagnosis of Nutrient Status and Guid- 
 ance of Fertilization and Soil Management Practices 
 
 HOMER D. CHAPMAN 
 
 WBm 
 
 NHp 
 
 -:-/. : ;.y: : y^;:z--y / y;.-;,:. 
 
 :■;■. W':'y> '■■■■■ "'■;■':;-':■ V : '-' ; - 
 
CONTENTS 
 
 The purpose of leaf and soil analyses 1 
 
 Initial orchard appraisal 2 
 
 Means for diagnosing nutritional status 2 
 
 Leaf analysis standards 2 
 
 Methods of leaf sampling 5 
 
 Methods of analysis 7 
 
 Soil analysis standards 8 
 
 Methods of soil sampling and handling 8 
 
 Time schedule for leaf and soil analyses 12 
 
 Method of recording results 12 
 
 Methods of controlling and correcting mineral deficiencies and excesses . . . . 12 
 
 Summary 12 
 
 Acknowledgments 13 
 
 Literature cited 49 
 
 THIS MANUAL is one of a series published by the University of California Division of Agri- 
 cultural Sciences and sold for a charge based on returning only a portion of the production 
 cost. By this means it is possible to make available publications which, due to relatively high 
 cost of production or limited audience, would otherwise be beyond the scope of the Division's 
 publishing program. 
 
LEAF and SOIL ANALYSIS 
 in CITRUS ORCHARDS 
 
 ERRATA 
 
 Page 3; Column 2; Line 5 should read "(see 
 table 7)" instead of "table 8." 
 
 Page 6; Column 2; Line 21 should read "(see 
 second U, page 7)" instead of ". . . page 6." 
 
 Pages 23 and 24; Table 2; Columns 2 and 3 
 captions should read "table 7" instead of 
 "table 8." 
 
 Page 38; Table 5; Column 2, last section, 
 should read "Water-soluble P by Bingham 
 (1949) method in ppm extract" instead of 
 ". . . dry soil." 
 
 Page 45; Table 7; column 3; last entry at bot- 
 tom of page should read ". . . correction by 
 use of magnesium nitrate spray at the rate 
 of 10 lbs/100 gal" instead of ". . . 10 per 
 cent magnesium nitrate foliar spray." 
 
 Page 48; Table 7; column 3; at top of page 
 should read "...magnesium nitrate at 10 
 lbs/100 gal" instead of "...10 per cent 
 concentration. . . ." 
 
 Man. 25 
 
 Criteria for the Diagnosis of 
 Nutrient Status and Guidance 
 of Fertilization and Soil 
 Management Practices 
 
 HOMER D. CHAPMAN 
 
 UNIVERSITY OF CALIFORNIA DIVISION OF AGRICULTURAL SCIENCES 
 
 Agricultural Experiment Station — Extension Service 
 
 LIBRARY 
 
 UNIVERSITY OF CALIFORNIA 
 DAVIS 
 
can now be taken out of citrus fertilization by systematic use of leaf anal- 
 yses supplemented by appropriate soil tests and such other information 
 as may be obtained from visual symptomology, general knowledge of 
 soils, past fertilizer and management practices, and composition of irri- 
 gation waters. 
 
 This manual was prepared in order to: ( 1 ) Provide the commercial 
 laboratory operator with the soil and plant analysis standards or criteria 
 currently available for assessing the nutrient status of citrus orchards and 
 the detailed methods of sampling and handling which must be followed 
 to assure results of satisfactory accuracy. (Also included are methods of 
 correcting mineral deficiencies and excesses.) (2) Inform citrus growers, 
 extension service workers, and others as to the present status of these 
 diagnostic tests and methods of control. (3) Reveal to the research man 
 the many blind or uncertain spots in existing information. 
 
 No attempt has been made to discuss the theoretical basis for soil 
 and plant analysis. Appropriate references to published work covering 
 these aspects are given in the text. 
 
 THE AUTHOR 
 
 Homer D. Chapman is Professor of Soils and Plant Nutrition, and Chemist, University of 
 California Citrus Experiment Station, Riverside, California. 
 
 JANUARY 1960 
 
THE PURPOSE OF LEAF AND 
 SOIL ANALYSES 
 
 The successful use of leaf and soil analyses 
 requires proper sampling and handling 
 techniques, the use of accurate methods of 
 analysis, periodic leaf analysis for some, 
 although not all, constituents and periodic 
 soil analyses. 
 
 In starting a program of nutritional eval- 
 uation and fertilizer guidance, an initial 
 orchard appraisal is useful. After this, a 
 complete check-up need be made only at 
 five-year intervals, or longer, but annual 
 leaf analyses for some constituents will be 
 desirable at least at the outset. 
 
 Rule-of-thumb fertilizer practices or gen- 
 eral recommendations are not only of little 
 value in citrus orchard fertilization today 
 but may produce soil problems hard to over- 
 come, decrease yields, and increase fertilizer 
 costs. Experience has shown that no set 
 program is good for all time in any given 
 orchard. Change is one of the immutable 
 laws of nature and it applies to soil-manage- 
 ment practices as well as to anything else 
 in this world. 
 
 The tree must secure an adequate 
 amount of 14 mineral elements from the 
 soil. This in itself is not always easy to 
 provide for and a further complication is 
 that either because of improper balance 
 initially, or because of wrong fertilizer prac- 
 tices, and/or the use of certain irrigation 
 waters, some constituents accumulate in 
 amounts sufficient to be toxic, or unbal- 
 ance takes place in which the solubility or 
 absorbability, or transport, or use within 
 the plant is interfered with. In addition to 
 all this, plant growth is affected by many, 
 if not all, the chemicals, other than the afore- 
 mentioned 14, in the root zone; the nutrient 
 requirements of various citrus species are 
 variable, as is the foraging power or ab- 
 sorptive ability of different rootstock -scion 
 combinations, plus which climate, soil tem- 
 perature, moisture, aeration, and biological 
 factors impose many other complications 
 and qualifying circumstances. 
 
 Realizing all of these complex problems, 
 students of soil fertility diagnosis began to 
 recognize many years ago that soil analysis 
 alone could not provide adequate fertilizer 
 guidance for citrus, and began to study the 
 
 possibility of using plant analysis and visual 
 symptoms as auxiliary aids. Independent 
 research began in several parts of the world 
 more than thirty years ago with the result 
 that both in South Africa and California, 
 a system of leaf analysis and tentative leaf- 
 analysis standards and techniques of re- 
 markable similarity came into being (Bath- 
 urst, South Africa, 1943, 1944, \9\4a; Chap- 
 man et ah, California, 1943; 1944; 1946; 
 1949; 1950). 1 Based on more recent research 
 and experience in Florida, Reuther and 
 Smith (1954; 1954a) likewise developed a set 
 of standards somewhat similar to those of 
 Bathurst and Chapman. More recently Reu- 
 ther, Embleton, and Jones (1958) have pub- 
 lished a table of standards similar in general 
 to those published previously by Reuther 
 et al. Meanwhile, some of the large citrus 
 estates in South Africa have been putting 
 leaf analysis to work (private conversations 
 with Dr. Jaap deVilliers, of Zebediela Es- 
 tates, and Dr. C. J. Naude, of the Crocodile 
 Valley Estates); and foliar diagnosis along 
 with other criteria has come into commer- 
 cial use with other crops such as sugar cane 
 and pineapples. 
 
 In Japan, Sato (1952) has made extensive 
 studies of leaf analysis not only for citrus 
 but also for many other fruit trees. Many 
 other students of soil problems have con- 
 tributed information and experience. 
 
 Everyone who has studied the problem 
 agrees that leaf analysis is an extremely 
 valuable tool. Even so, an adequate system 
 of fertilization and soil management must 
 also take advantage of information derived 
 from the soil, of visual symptomology, and 
 such other information as can be brought 
 to bear on the problem. 
 
 The purpose of this publication is to: 
 (1) suggest a system of initial orchard eval- 
 uation; (2) present stich leaf and soil an- 
 alyses criteria as currently exist; (3) give 
 detailed directions for sampling and sample 
 handling prior to analysis; (4) suggest a sys- 
 tem of recording results; (5) suggest a time 
 schedule for the continuing plant and soil 
 analyses; and (6) outline methods for con- 
 trolling nutrient deficiencies and excesses. 
 Detailed methods of chemical analyses for 
 plants, soils, and waters are being published 
 
 1 See "Literature Cited" for citations listed accord- 
 ing to author and date. 
 
 [i] 
 
separately in a companion manual under 
 the authorship of Chapman and Pratt 
 (1960). This and other standard works on 
 soil and plant analysis can be consulted for 
 analytical procedures. 
 
 The theoretical and research background, 
 upon which leaf analysis rests, has been pre- 
 sented in previous publications by Goodall 
 and Gregory (1947), Chapman and Brown 
 (1950), Ulrich (1948), Reuther and Smith 
 (1954<7), and many others. The reader is re- 
 ferred to these writings for greater detail 
 and background on these aspects. 
 
 INITIAL ORCHARD APPRAISAL 
 
 Prior to beginning a leaf and soil analysis 
 program, an initial orchard, soil, and soil- 
 management appraisal should be made in 
 order to secure data on orchard condition, 
 yield performance, special fruit and fruit- 
 quality problems, and prevailing soil con- 
 ditions. On the basis of this information, a 
 decision can be reached as to whether a leaf 
 and soil analysis program is worth the costs 
 involved and if so, what initial analyses 
 should be made, the extent and periodicity 
 of continuing analyses and, as well, addi- 
 tional information of value with respect to 
 other aspects of orchard management. 
 
 A suggested form for recording and 
 summarizing this preliminary information 
 is outlined in table 1. It will be immediately 
 evident that not all of this information is 
 needed for nutrient-appraisal purposes, but 
 with very little extra effort much of it can 
 be obtained and will be valuable in helping 
 explain problems of yield, fruit quality, and 
 tree condition, as well as providing a much 
 better background for deciding on the ex- 
 tent of leaf and soil analysis required. The 
 owner or manager will be able to supply 
 niudi of this information, and data on soil 
 characteristics can be obtained in the course 
 of soil sampling. Tin's information corre- 
 sponds to the case history of a human pa- 
 tient which, as is well known, is often the 
 most important part of a medical examina- 
 tion and frequently leads to a positive diag- 
 nosis, thus reducing the number of labora- 
 toi y tests required. 
 
 Note: Tables 1 to 7, inclusive, begin 
 on page 14. 
 
 MEANS FOR DIAGNOSING 
 NUTRITIONAL STATUS 
 
 Before presenting the leaf and soil analy- 
 sis standards for evaluating nutrient status, 
 there are listed in table 2 the criteria now 
 available for diagnosing both the early and 
 more acute stages of nutrient deficiencies 
 and excesses. Reference to table 2 shows that 
 in the case of magnesium, manganese, iron, 
 and zinc deficiencies, visual leaf patterns are 
 usually sufficient for accurate diagnosis (this 
 assumes, of course, familiarity with the simi- 
 larity and differences between these differ- 
 ent patterns). In other cases, positive diag- 
 nosis or indications can be had only by a 
 combination of plant and soil analysis, or 
 plant and soil analysis coupled with con- 
 firmatory tests using foliar sprays 2 or soil 
 applications, or the combination of visual 
 symptoms coupled with plant analysis and, 
 in some cases, soil analysis as well. 
 
 LEAF ANALYSIS STANDARDS 
 
 On the basis of the various leaf-analysis 
 standards and data developed by workers in 
 several parts of the world, plus such other 
 data as bear on this problem, table 3 has 
 been prepared, showing for each element a 
 range of values indicating deficiency, low 
 range, satisfactory range, high range, and 
 excess range. 
 
 The data on which table 3 rests are pre- 
 sented in table 4 as a means of not only 
 giving proper credit to the many people 
 who have contributed significantly to the 
 development of present standards, but more 
 important to reveal the similarities and 
 differences in the leaf values as found by 
 various workers associated with different nu- 
 tritional states. The data also reveal the 
 gaps in current information and some of the 
 uncertainties still present. In the author's 
 first tabulation of suggested leaf-analysis cri- 
 teria (Chapman 1919), three ranges were 
 given: (1) Those values associated with or 
 suggestive of deficiency; (2) range and aver- 
 age in high performance orchards; and (3) 
 values associated with or suggestive of excess 
 
 ■deVilliers in South Africa (private correspond- 
 ence) finds thai dipping single leaves in a spray 
 solution and tagging the leal is a rapid method of 
 detecting responses. 
 
 21 
 
or nutrient unbalance. Reuther and Smith 
 (1954) and later Reuther, Embleton, and 
 Jones (1958) published tables of tentative 
 standards in which five ranges are listed: 
 deficient, low, optimum, high, and excess. 
 The author has adopted this latter system 
 in the present publication since it provides 
 for a better characterization of leaf values; 
 although, as may be readily seen from tables 
 3 and 4, there are uncertainties about the 
 exact limits of each range and a degree of 
 arbitrariness in the ranges chosen for table 3. 
 
 In using table 3, three points need empha- 
 sis: (1) the need for proper leaf sampling, 
 handling, and analytical techniques (to be 
 described in the section that follows); (2) 
 realization that these standards are tenta- 
 tive, and based on leaves of known age; and 
 (3) realization that the values found at any 
 one time represent only current status. If 
 there is a deficiency of zinc, or copper, or 
 boron, or any other element, and this is 
 corrected, then the values for this as well as 
 for other elements will often change. This is 
 one reason why the leaf-analysis operation 
 needs to be continued from year to year in 
 order to alter, step by step, the nutritional 
 status and bring the tree into a balanced 
 state. Mention should be made of the fact 
 that even where there are no changes in 
 fertilization or soil management, leaves of 
 the same age will show, from year to year, 
 small up and down fluctuation in values. 
 This is a further reason why it is necessary 
 to continue the leaf-analysis program on a 
 more or less regular basis. In this way an 
 idea of the magnitude of normal orchard 
 fluctuation becomes possible and affords, as 
 stated, a continued check on the changes 
 which one is trying to achieve. 
 
 There is substantial evidence that range of 
 leaf values shown under the "satisfactory" 
 heading in table 3, is consistent with top 
 performance, but does not guarantee it be- 
 cause many factors besides nutrition affect 
 yield and quality. If values for one or more 
 constituents are consistently higher or lower 
 than those regarded as satisfactory, fertiliza- 
 tion or suitable soil-management changes 
 should be initiated to achieve the desired 
 changes. It may require several years to ac- 
 complish these changes through soil applica- 
 tions, particularly with calcium, potassium, 
 and magnesium. Because of the danger of 
 
 fertilizer burn, it is unwise to try to increase 
 the potassium or the magnesium content 
 too rapidly. Recently Embleton and Jones 
 (1959) have shown that the latter can be 
 corrected by foliar sprays (see table 8). With 
 those elements where foliar sprays are espe- 
 cially satisfactory such as boron, zinc, man- 
 ganese, copper, molybdenum, and nitrogen 
 (urea), correction can be achieved quickly. 
 Where soil applications of boron, molybde- 
 num, nitrogen, and sulfur are employed, a 
 significant increase in leaf content can be 
 readily obtained. Where phosphorus is defi- 
 cient, it has been our experience that correc- 
 tion can be achieved in one growing season 
 from broadcast applications of soluble phos- 
 phates such as superphosphate, or ammo- 
 nium phosphate with rates of from 5 to 10 
 pounds P 9 5 per tree. More discussion of 
 control methods will be found later in this 
 paper. 
 
 In initiating a program of fertilizer guid- 
 ance by leaf analysis, it is important to make 
 analyses initially for the first 14 of the con- 
 stituents shown in table 3. Analyses for the 
 remaining 19 elements need be made only 
 if there are reasons to suspect some special 
 soil condition, or contamination from water, 
 fertilizer, or air pollution. As leaf analysis 
 data accumulate for a given orchard, the 
 number of analyses each year can be reduced 
 until, in time, yearly analyses will not be 
 required. 
 
 In the case of deficiencies of magnesium, 
 manganese, iron, and zinc, respectively, leaf 
 patterns are distinctive and readily recog- 
 nized by most qualified people, and there 
 appears to be no need for supplemental leaf 
 analysis unless one is in doubt about the 
 diagnosis. Apparently fruit production and 
 quality are influenced little, if any, in the 
 stage where a minor degree of leaf pattern 
 can be seen, but the presence of a few such 
 leaves here and there in an orchard is suf- 
 ficient to indicate an incipient deficiency 
 which should be corrected. 
 
 Some discussion of the range of values for 
 each element is called for. 
 
 Calcium. Virtually no data are available 
 regarding excess calcium but when values in 
 4- to 7 -month-old leaves from fruiting termi- 
 nals are over 6 per cent it may mean that 
 potassium and magnesium are lacking, or 
 low, or that some other upset in nutritional 
 
 [3] 
 
balance is present. On the deficient side, 
 there is some evidence that values below 2.0 
 per cent should be regarded with suspicion, 
 and trials with calcium sulfate or nitrate 
 additions to the soil should be initiated, or 
 foliar spray applications be made, using 10 
 pounds Ca(OH) 2 per 100 gallons of water. 
 (See table 7.) 
 
 Magnesium. As with calcium, not much is 
 known about magnesium excess but values 
 over 0.70 per cent might suggest low potas- 
 sium or calcium, or other nutrient unbal- 
 ance. Analysis of leaves showing typical de- 
 ficiency patterns usually shows values in the 
 0.05 per cent to 0.15 per cent range; values 
 somewhat higher or lower than the 0.30 to 
 0.60 per cent range may well be consistent 
 with top performance, but more experience 
 is needed. 
 
 Nitrogen. There is considerable evidence 
 that with some citrus varieties in some loca- 
 tions, values as low as 1.90 per cent N may 
 be sufficient, and on the other side, values 
 of 2.5 per cent and above may not be con- 
 sistent with best quality in certain climatic 
 zones. More data and local experience relat- 
 ing nitrogen levels in leaves to yield, qual- 
 ity, size, regreening, and other factors, are 
 needed. 
 
 Phosphorus. Excess phosphorus in the soil 
 (amounts sufficient to bring on copper and 
 zinc deficiencies), may not show up by leaf 
 analysis; hence, on the excess end leaf an- 
 alysis is not a satisfactory indicator. 
 
 On the low side, phosphate-deficient trees 
 almost always show leaf values under 0.10 
 per cent, but values of 0.08 per cent and 
 higher may not necessarily denote phospho- 
 rus deficiency. In short, as with most of the 
 other elements, the satisfactory range may 
 be wider than indicated. 
 
 Potassium. Yield is not much affected un- 
 til leaf values fall below 0.40 per cent in the 
 experience of the author, but sizes can prob- 
 ably be increased some when leaf values well 
 below 1 .0 per cent are brought to values well 
 above the 1 per cent level provided magne- 
 sium, zinc, or manganese deficiencies are not 
 induced. When potassium is on the low side, 
 magnesium sulfate or dolomite should be 
 added along with the potassium to forestall 
 magnesium defi< ieiuy, and any zinc or man- 
 ganese defn ieiHy brought on, eorrected with 
 foliai sprays. 
 
 Sulfur. Excess sulfate produces a leaf pat- 
 tern somewhat similar to boron excess, and 
 the combined use of leaf pattern and leaf 
 analysis is helpful in diagnosing excess sul- 
 fate conditions. No field data are available 
 regarding sulfur deficiency, and the values 
 given are based on limited evidence. How- 
 ever, lack of sulfur produces a yellowing of 
 foliage similar to nitrogen deficiency. Leaf 
 values for sulfur will be low and nitrogen 
 high, when sulfur is deficient. The converse 
 is true when nitrogen is lacking. 
 
 Sodium and Chloride. The usual levels of 
 these in citrus leaves where salinity is not a 
 problem are under 0.10 per cent. When the 
 levels are at 0.20 per cent and above, soil 
 salinity should be checked. 
 
 Boron. Some data show that total boron 
 above the deficient range, i.e., higher than 
 25 ppm may not always be a sure indication 
 of ample boron. deVilliers and Beyers, in 
 South Africa, found that despite leaf values 
 higher than 25 ppm total boron, certain tree 
 and fruit disorders not hitherto recognized 
 as boron deficiency, are apparently due to 
 lack of this element and were corrected by 
 boron applications. In all such cases, they 
 found that water-soluble boron in the leaves 
 was low (under 8.0 ppm boron in the dry 
 matter). From this is would appear desir- 
 able, where total boron is between the 25- 
 40 ppm range, to make a determination of 
 water-soluble boron. 
 
 Copper. Some excellent orchards have 
 been found in which leaf levels of copper 
 are as low as 2 ppm 3 (Bradford and Hard- 
 ing, 1957), with no sign of copper deficiency 
 symptoms. Nonetheless, when copper levels 
 are under 4.0 ppm, it is desirable to in- 
 clude copper in nutritional sprays. Insuffi- 
 cient data are at hand to establish Cu excess 
 levels. 
 
 Iron. Leaf patterns appear to be satisfac- 
 tory for diagnosing moderate to acute iron 
 deficiency but the very early stages may not 
 show leaf patterns and in this case leaf an- 
 alysis may reveal an incipient deficiency. 
 Nothing is known about the levels indicat- 
 ing iron excess. 
 
 Manganese. Leaf analysis is useful in over- 
 all evaluation even though exact limits for 
 excess are not yet well worked out. There 
 
 :1 As determined by spectrographs analysis. 
 
 141 
 
are definite leaf patterns associated with ex- 
 cess manganese and leaf analysis will serve 
 as a double check on visual diagnosis. 
 
 Molybdenum. Not enough data are avail- 
 able to clearly establish levels indicating in- 
 cipient deficiency or excess. The satisfactory 
 range may be wider than indicated. 
 
 Zinc. The zinc excess range is not defi- 
 nitely known. As with manganese and iron, 
 leaf patterns are usually sufficient to indicate 
 mild and acute deficiency, although there 
 are reports in which responses to zinc have 
 been obtained even though no distinctive 
 patterns are evident. Leaf analysis is there- 
 fore valuable for evaluation purposes. 
 
 Other Trace Elements. More experimen- 
 tal data are needed to evaluate the signifi- 
 cance of varying quantities of the many 
 other trace elements found in citrus leaves. 
 Spectrographic and other analyses of leaves 
 from high -producing orchards (Bradford 
 and Harding, 1957), suggest that the range 
 for each element in the "satisfactory" col- 
 umn is consistent with good performance. 
 
 From this brief discussion it is evident 
 that some uncertainty exists as to interpreta- 
 tions of leaf analysis. However, the values in 
 the "deficient" range are, in general, quite 
 reliable; the levels in the "satisfactory" range 
 are consistent with satisfactory performance, 
 although the ranges may be broader than 
 those indicated. In any case, significant in- 
 formation of great value can be obtained, 
 and when followed by such soil tests as may 
 be required, much of the guesswork in fer- 
 tility management can be removed. More- 
 over, trends toward deficiency or excess can 
 be detected and corrected before they occur, 
 thus assuring better over-all performance. 
 
 METHODS OF LEAF SAMPLING 
 
 The success or failure of leaf analysis 
 hinges on satisfactory sampling, handling, 
 cleaning, and analysis techniques. Errone- 
 ous results and conclusions are likely if care- 
 less or improper methods are used at any 
 stage of this process. Quick-test procedures 
 and a hasty grab sample of leaves are likely 
 to be a complete waste of time. 
 
 A number of investigators have studied 
 one or more phases of the sampling 
 and/or cleaning and analysis phase of citrus 
 leaf analysis: Smith, Reuther, and Specht 
 
 (1950), Chapman and Brown (1950;, Cam- 
 eron, Mueller, and Wallace (1952), Wallace, 
 Mueller, and Squier (1952), Monselise and 
 Herschberg (1953), and Steyn (1957, 1959;. 
 The latter has made an exhaustive investi- 
 gation of all phases of citrus leaf sampling, 
 handling, cleaning, and preparation. 
 
 The procedure to be followed will depend 
 on the objectives. Where the purpose is only 
 to confirm a visual symptom diagnosis, ioi 
 example, to distinguish whether a leaf pat- 
 tern is due to boron or sulfate excess, or 
 sodium and chloride injury, or to confirm 
 a tentative copper, boron, zinc, manganese, 
 and molybdenum deficiency, the procedure 
 then is simply to collect 100 to 200 of the 
 leaves showing the particular visual symp- 
 tom it is wished to confirm, follow the 
 handling, cleaning, and analysis techniques 
 outlined hereinafter, and make the analyses 
 by methods of acceptable accuracy. 
 
 However, when leaf analysis is to be used 
 for purposes of continued fertilizer guid- 
 ance, a more careful sampling system must 
 be followed. At the outset it will be desirable 
 to establish in large, apparently uniform 
 blocks (10 to 50 or more acres), whether 
 one sampling unit will suffice, or whether 
 it is necessary to establish within the block 
 several permanent sampling locations. This 
 problem will be discussed in the section 
 which follows. 
 
 Preliminary Survey of Orchard and Selec- 
 tion of Initial Sampling Units. Quite often 
 soils are variable and one part of an or- 
 chard may be very different in slope, tex- 
 ture, depth, and color from another part of 
 the orchard. Moreover, plantings in one sec- 
 tion may be on a different rootstock or a 
 different top-rootstock combination than an- 
 other. Obviously, for proper evaluation and 
 fertilizer guidance, the whole orchard must 
 be broken down into units which assure 
 homogeneity with respect to: (1) top-root- 
 stock combination; (2) soil; and (3) visual 
 tree homogeneity within these subdivisions. 
 There may be scattered trees within these 
 units which depart substantia llv from the 
 general average (e.g., trees showing scaly 
 bark, or gummosis, or iron chlorosis, or 
 otherwise obviously off-type tree). Clearly, 
 leaves from such trees should not be com- 
 posited with those representing the average 
 condition. Rather, if the cause of this ran- 
 
 [5] 
 
dom departure is to be ascertained, a sep- 
 arate sample, as stated, should be taken. It 
 may be that the entire block, on the other 
 hand, is virtually uniform as to variety/or 
 rootstock, soil, growth, and appearance. In 
 this case, such blocks, if more than five acres 
 in extent, should be broken down into five- 
 acre units for the initial sampling. 
 
 Steyn (1957) has data to show that what- 
 ever the size unit, no less than 20 per cent 
 of the trees should be sampled. A five-acre 
 block might contain 400 to 600 trees. This 
 means that 80 to 150 trees should be sam- 
 pled. While this represents considerable 
 work it must be borne in mind that even 
 more effort will go into the final analytical 
 job. With experience, a person can select the 
 proper leaves from a given tree in about two 
 minutes. Thus, an average of two to three 
 five-acre units can be sampled in one day. 
 
 Selection of Leaves, and Handling. (Note: 
 The following directions apply to all ele- 
 ments except fluorine. In case of this ele- 
 ment, see under "Methods of Analysis," 
 Chapman and Pratt (1960), for special sam- 
 pling and handling.) 
 
 The leaf analysis standards shown in table 
 3 are based on 4- to 10-month-old spring 
 cycle leaves selected from fruit-bearing ter- 
 
 OLDER GROWTH 
 
 SPRING CYCLE GROWTH 
 
 Leaves 1, 2, and 3 are spring or bloom cycle leaves 
 and any one of them suitable for sampling; leaves 
 4, 5, 6, 7, and 8 are older cycle leaves and should 
 NOT be picked for leaf sample. 
 
 minals. Some investigators, notably Reuther 
 and Smith (1954), base their standards on 
 four- to seven-month-old spring cycle leaves 
 from nonfruit-bearing terminals. There ap- 
 pears to be little difference in leaf analysis 
 criteria whether the leaves come from fruit- 
 bearing or nonfruit-bearing terminals. The 
 author suggests the use of leaves from fruit- 
 bearing terminals (see figure) on the grounds 
 that it is simpler in practice to make leaf 
 selections from this type terminal and be 
 sure of leaf age than to identify with certain- 
 ty the age of leaves from nonfruiting termi- 
 nals. deVilliers (private correspondence) is 
 of the same opinion. Though there are oc- 
 casional years when fruit production is very 
 low and one has to search for fruit, it is 
 almost always possible to find enough such 
 terminals, considering the number of trees 
 (80 to 150) from which leaves should be 
 taken. deVilliers (see second ^[ p. 6) suggests 
 taking only two leaves per tree. Seldom, if 
 ever, will citrus yields be so low that an 
 average of at least two fruits per tree cannot 
 be readily found. The South African work- 
 ers have also standardized on fruit-bearing 
 terminals, but use 10- to 1 1 -month-old leaves. 
 
 Since in the present state of knowledge 
 it appears to make little or no difference 
 whether the four- to seven-month-old spring 
 cycle leaves are from fruit-bearing or non- 
 fruit-bearing terminals, the matter can rest 
 with the preference of the individual in 
 charge of the leaf analysis program. 
 
 The sketch shows a bearing twig with 
 several leaves which emerged with the flower. 
 Any one of these leaves may be selected but 
 the sampler should be sure that the leaf 
 is not from an older cycle of growth. Se- 
 lect four leaves per tree, depending on size, 
 around the periphery in a band from about 
 1 to 7 feet from the ground. Pick average- 
 sized leaves to represent the prevailing con- 
 dition of this age leaf. If there are occasional 
 leaves which show moderate or extreme iron 
 chlorosis, or zinc deficiency, or other leaf 
 patterns or abnormalities, avoid including 
 these in the sample. On the other hand, if 
 there is a prevailing leaf mottle condition 
 such as subacute manganese deficiency, one 
 cannot avoid picking this type of leaf. Since 
 the main purpose of leal analysis is to guide 
 Fertilizer and soil -management practices, 
 particularly to pick up conditions which are 
 
 [61 
 
incipient, one must choose leaves that repre- 
 sent average foliage conditions which pre- 
 vail for this particular cycle of growth. 
 
 A somewhat less time-consuming method 
 is employed by deVilliers (private corre- 
 spondence) on the Zebediela Estates in South 
 Africa. A two and one-half acre block — 
 near the center of a 1,600-tree block — is 
 chosen as the permanent sampling unit. One 
 sampler starts in on the S.W. corner and 
 picks two leaves from every tree on a di- 
 agonal across to the N.E. corner; another 
 picker simultaneously picks on a diagonal 
 from the S.E. to the N.W. corner. The two 
 samples are combined. The two leaves per 
 tree are picked alternately from the south 
 and west and the north and east sides of 
 the trees. Thus equal numbers come from 
 all sides of the trees. Their planting dis- 
 tances are such that about 80 trees are sam- 
 pled per two and one-half acre block, the 
 sample consisting of 160 leaves. Tests of 
 reproducibility showed, in six composites 
 picked in this manner, the following range 
 in leaf values: N per cent 2.374 to 2.536; 
 P per cent 0.090 to 0.097; K per cent 0.614 
 to 0.706; Ca per cent 4.210 to 4.705; Mg 
 per cent 0.430 to 0.548; Fe (ppm) 119 to 133; 
 Mn (ppm) 56 to 63; Cu (ppm) 3.6 to 4.0; 
 Total B (ppm) 46 to 58; Water Sol. B (ppm) 
 28 to 36; Mo (ppm) 0.27 to 0.33. (Mo is high 
 because of a preceding spray.) These figures 
 represent single analytical determinations. 
 deVilliers estimates that their total cost per 
 sample, which includes picking, cleaning, 
 and analysis for N, P, K, Ca, Mg, Fe, Mn, 
 Cu, total B, water-soluble B, and Mo, at 
 about $14 each, or about $14 a year for each 
 sampling unit. This sampling unit repre- 
 sents 1,600 trees. If the analysis did no more 
 than cut nitrogen usage from L% to \i/ 2 
 pounds per acre per tree per year, they save 
 more than twice the cost of the analysis. 
 
 Steyn (1957) recommends that the freshly 
 picked leaves be placed in porous cloth bags 
 (not polyethylene bags) transported to the 
 laboratory the same day, then transferred to 
 polyethylene bags and immediately placed 
 in a refrigerator pending leaf cleaning; or, 
 as an alternative, a portable refrigeration 
 chest could be carried to the field and the 
 leaf sample (in this case picked into a 
 polyethylene bag), placed immediately in 
 the ice chest following collection, and when 
 
 brought to the laboratory, placed in a re- 
 frigerator. 
 
 Washing. The samples should be removed 
 one at a time from the refrigerator and 
 handled as outlined and as quoted from 
 Steyn (1957): "Take 5 polyethylene dishes 
 (about 6-inch deep and 12 inches in diam- 
 eter) and place about 750 ml of a 0. 1 per cent 
 detergent solution (Dreft or Teepol, or a 
 sudsy Ivory soap solution) in the first, 750 ml 
 deionized or distilled water in the second 
 and third, and 750 ml deionized or distilled 
 water in the fourth. The fifth dish is used 
 to collect the wet leaves. Sponge each leaf 
 thoroughly with cotton wool in the deter- 
 gent solution, wiping both sides, then rinse 
 well in the three sets of water, and finally 
 rinse each leaf in fresh, deionized water. 
 Shake off drops of water and place in the 
 fifth dish. When the complete sample has 
 been washed, drain off the water as com- 
 pletely as possible, and place the leaves on 
 a large sheet of Whatman drying paper. 
 Then place the leaves in a suitable-sized 
 muslin bag, tie shut with a rubber band, 
 and suspend inside a forced draft oven set 
 at 65° C. Dry for 48 hours and then grind 
 the sample in an agate ball mill, ensuring 
 that the jar is at least half filled with the leaf 
 sample. After grinding, place the powder in 
 a clean screw-capped bottle, leave open in 
 the forced draft oven for 24 hours at 65° C, 
 and seal tightly while still warm. Store in a 
 cool dry place and carry out the analyses 
 within a two-month period." 
 
 METHODS OF ANALYSIS 
 
 Details of procedures are being published, 
 as previously stated, in a separate volume 
 (Chapman and Pratt, 1960). 
 
 At the present time quick-test methods, 
 as previously stated, are not recommended. 
 The uncertainties attached to interpretation 
 are such that it is desirable to employ accu- 
 rate analytical procedure. Most investigators 
 and laboratories have their own particular 
 methods of analysis. 
 
 Where large numbers of determinations 
 are to be handled on a commercial basis and 
 equipment is available, it is recommended 
 that flame photometer methods be employed 
 for Ca, Mg, Na and K, and the speetograph 
 for B, Cu," Zn, Li, Mn, Mo, Cr, Pb, Ni, Ag, 
 
 [7] 
 
Sr, Sn, Ti, V and Zr. For all other elements, 
 methods outlined in Chapman and Pratt 
 (1960) or in other standard works on soil 
 and plant analysis, will be found satisfactory. 
 
 SOIL ANALYSIS STANDARDS 
 
 Neither soil nor plant analyses alone are 
 sufficient to provide all of the information 
 needed for fertilizer guidance. Plant analysis 
 indicates current nutrient status but reveals 
 little about total reserve in the soil. Soil 
 analysis alone has limitations also. As is well 
 known, the total supply of a given element 
 often bears little relation to that portion 
 available for plant use; nor has any extrac- 
 tant ever been devised that can imitate the 
 feeding action of plant roots, plus which 
 variability among plants, variable nutrient 
 needs at different stages of growth, micro- 
 biological effects, and climatic interrelations, 
 to name some of the complications, all make 
 the results of soil analysis difficult of inter- 
 pretation. However, soil tests will provide 
 useful information as to whether the total 
 or so-called available supply is high or low, 
 whether salt is high or low and these data 
 added to those provided by plant analysis, 
 will add immeasurably to the whole picture. 
 Results relating nutrient supply in the soil, 
 as measured by one or more methods, to 
 citrus tree performance are incomplete, and 
 for this reason, in working up tentative val- 
 ues, the standards outlined in table 5 are 
 those arrived at by investigators working 
 with a variety of other crops. 
 
 For most constituents or soil conditions, 
 remarks as to meaning and interpretation 
 have been included in the table and there 
 is no need to elaborate on them here. 
 
 Details of the actual methods to be used 
 in determining the various constituents can 
 be sought in the original literature citations 
 given and/or various compendiums of meth- 
 ods for soil, plant, and water analyses. 
 
 METHODS OF SOIL SAMPLING 
 AND HANDLING 
 
 The success or failure of soil analysis as 
 an aid to fertilizer guidance hinges on se- 
 curing a representative soil sample plus all 
 subsequent handling operations including 
 analysis. 
 
 The sample finally weighed for any de- 
 termination is the resultant of several oper- 
 ational steps: (1) taking and mixing a series 
 of cores from the area to be sampled; (2) sub- 
 sampling this original sample one or more 
 times; (3) air-drying, grinding, sieving, and 
 mixing. The greatest element of error, as- 
 suming proper subsampling, drying, grind- 
 ing, and sieving techniques, is in securing a 
 representative composite sample. 
 
 Having established for leaf sampling 
 the units which are to be regarded as the 
 permanent sampling areas, a pattern of soil 
 sampling within these units needs to be 
 established. 
 
 Many studies of soil sampling techniques 
 have been made (Cline, 1944; Reed and 
 Rigney, 1947; Barker and Steyn, 1956; Mc- 
 Kenzie, 1955; Hausenbuiller, 1957; and 
 Hemingway, 1955). The following princi- 
 ples are well established: (1) a series of 
 cores taken according to some systematic 
 grid layout of the area of equal diameter 
 and comparable depth (volume) must be 
 composited; (2) separate soil cores should 
 be analyzed or replicate sets of composites 
 so as to determine statistical significance of 
 analytical results on the composite; (3) the 
 number of soil cores to be composited will 
 depend on the variability of the soil, the 
 degree of accuracy desired, and the particu- 
 lar element or elements it is desired to de- 
 termine, and the general over-all purpose, 4 
 (4) cultivated soils are generally more varia- 
 ble than virgin soils, and saline and alkali 
 soils are extremely variable; (5) separate 
 composite samples representing different seg- 
 ments of the soil profile or root zone should 
 be taken; (6) contamination from soil sur- 
 face materials (crop residues, manures, ferti- 
 lizers, et cetera) should be avoided, as also 
 contamination of one soil depth with that 
 of another; and (7) in areas that are to be 
 sampled at successive intervals, it is impor- 
 tant to make a map showing initial sampling 
 
 1 In one study of this question, Steyn (1957) found 
 that, in one of three ^4 -acre pl° ts °f apparently uni- 
 form virgin soil, it would require for potassium 80 
 cores taken in a uniformly distributed grid pattern 
 (o show a significance at the 5 per cent level in 
 sample difference, exceeding 10 per cent of the mean. 
 With the two other plots, it would require 28 to 20 
 cores, respectively. For nitrogen, on the other hand, 
 it required only 20, 16, and 12 cores for the same 
 degiee of significance in these three plots. 
 
 »1 
 
points and take subsequent samples at points 
 somewhat removed from the preceding. 
 
 Directions for Sampling Furrow-Irrigated 
 Citrus Orchards. Furrow-irrigated orchards 
 are especially variable and a soil-sampling 
 scheme suitable for these likely will be suita- 
 ble for any other type citrus planting. Hence 
 a suggested soil-sampling method for this 
 situation is outlined in the following para- 
 graphs. 
 
 In most furrow-irrigated orchards, two 
 distinct soil conditions prevail: the soil 
 which has been, and continues to be wet 
 with irrigation water; and the soil in be- 
 tween the irrigated spaces which, except 
 when the orchard was young, is no longer 
 irrigated. The area wet by irrigation water 
 must be adequately sampled. Harding of our 
 staff has shown that marked differences in 
 salt levels exist in all parts of the soil profile 
 as between the furrow closest to the tree 
 (tree furrows), and the furrows in the middle 
 farthest from the trees. He (1954) and others 
 have shown that there are usually substan- 
 tial salt and nitrate accumulations in the 
 furrow crests, so any sampling procedure 
 which seeks to determine mean composition 
 should take equal numbers of soil cores from 
 the furrow crests and furrow bottoms. There 
 may be differences between the tree furrows 
 on the sun side of the tree and the shadow 
 side of the tree so equal numbers of cores 
 should be taken from these positions. It goes 
 without saying that various depths repre- 
 senting most of the root zone should be 
 composited separately and it has been a 
 standard practice from a depth point of 
 view to sample the surface cultivated zone 
 (0 to 6 inches), the second 6 inches (6 to 12 
 inches), and then separate foot horizons 
 down to a depth of from 4 to 6 feet. The 
 importance of taking the deeper horizons 
 is that salt accumulation and per cent 
 sodium in both the soluble and exchange- 
 able form often increase with depth, and 
 it is important to know what the situation 
 is in these lower horizons. 
 
 On the basis of these considerations, the 
 authors suggest a sampling grid as repre- 
 sented on page 10. With an assumed block 
 of 400 trees at planting distances of 18' x 18' 
 or 20' x 20' or, comparable, the total area 
 represented would be about 5.0 acres. In 
 this diagram, four furrows between tree 
 
 rows are visualized but variations from this 
 are unimportant. What is important is that 
 eight sampling zones are set up (designated 
 as X 1S , X ish , X 2S , X 2Sh , X., s , X., Kh , X 4S , X, .). 
 Two sampling zones are located near the 
 head of the irrigation run, two near the ends 
 of the irrigation run, and the others at ap- 
 proximately 1/3 and 2/3 the distance from 
 the irrigation stands. At each sampling zone, 
 4 cores should be taken, one in the tree fur- 
 row, one in the furrow crest adjacent to the 
 tree furrow, and comparable cores in the 
 furrow and crest at a point midway between 
 the tree rows. A further variation is that the 
 X x and X 4 samples will be taken on 
 a straight line between the tree trunks, 
 whereas the X 2 and X 3 sample will be 
 taken in a comparable line midway between 
 the trees. Another variation is that the X ]S , 
 X 2S , X 3S , and X 4S samples will begin in the 
 tree furrow on the sunny side of the tree, 
 whereas the X lsh , X 2Sh , X 3Sh and X 4Sh sam- 
 ples will start in the furrow located on the 
 shady side of the tree. Under this system, 
 equal numbers of samples from both the 
 sunny and shady tree furrows, equal num- 
 bers from furrow crests and furrow bottoms, 
 equal numbers from the middles farthest 
 from the tree and equal numbers closest to 
 the tree will be taken. This sampling plan 
 involves the removal of 32 cores of soil for 
 each soil depth. 
 
 It is apparent that this plan can be con- 
 tracted or expanded to cover a larger or 
 smaller area but to include equal numbers 
 of cores representing the variations men- 
 tioned, the same number of cores (32) must 
 be taken. 
 
 In taking the initial set of soil samples, 
 some idea of soil variability throughout the 
 entire block can be obtained by compositing 
 separately the four cores from each of the 
 X locations, and taking a subsample (i/ 2 ) 
 of each of these composites for separate 
 analysis. The other i/ 2 portions of each of 
 these four-core composites will, of course, 
 be composited into the main sample rep- 
 resenting the block as a whole. From these 
 data one can calculate the error of the block 
 mean for each soil constituent, and deter- 
 mine whether differences found in future 
 samplings are real or sampling error. 
 
 In situations where localized salt ac- 
 cumulations are suspected, it is suggested 
 
 [9] 
 
Row No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 
 
 Irrigation 
 
 stand OOOOOOOOOOOOOOOOOOOO 
 
 Tree No. 
 
 1 
 
 2 • • • • • *| s • • • • • • • • • • Hsh * * * * 
 
 3 
 
 4 
 
 5 
 
 7 
 
 8 
 
 9 
 
 10 
 
 1 1 • • • • •••••• •••••••••• 
 
 12 
 
 X 3s X 3sh 
 13 
 
 14 
 
 15 
 
 16 
 
 17 
 
 18 
 
 .v X 
 
 19 *4sh 4* 
 
 20 
 
 "F South 
 
 Suggested soil sampling system for furrow-irrigated citrus orchard. Four cores to 
 be taken at each of x locations. See diagram on page 11. 
 
 Y . Sampling Zone (4 cores) on N-S line be- ^ -v Sampling Zone (4 cores) along N-S line 
 18 tween tree trunks beginning in tree fur- 2S [ in centers between tree squares beginning 
 1 ) row on shade side of tree 3S ) in tree furrow on sun side 
 
 Y Sampling Zone (4 cores) along N-S line Y > Sampling Zone (4 cores) along N-S line 
 1 h ( between tree trunks beginning in tree v 2Sh > in centers between tree squares beginning 
 
 " ' h ) furrow on shade side of tree ;!S, 'J in tree furrow on shade side 
 
 I 10] 
 
CROSS SECTION 
 
 36 to 48" 
 
 -> South 
 
 Location of core sampling sites in an X 1S or X 4S zone; X lsh and 
 X 4Sh similar except on north side of tree. 
 
 that samples from the furrow crest and the 
 furrow bottoms all by horizons, of course, 
 be composited separately and analyzed. The 
 mean salt concentration in the soil mass as 
 a whole may not reveal local areas of high 
 salt concentration, yet these latter may be 
 very significant in terms of tree performance. 
 The tool with which soil cores are ob- 
 tained will depend on the soil. When the 
 soil is suitable, a ^- to 1-inch soil tube is 
 recommended. Where the soil is too stony, 
 gravelly, sandy, or dry, jaw-type posthole 
 diggers, barrel-(bucket) type soil augers, or 
 a spade must be used. Whatever the method, 
 it is obviously important to take from each 
 sampling point and horizon the same vol- 
 ume of soil. Where large sampling tools are 
 used, it will be necessary to take a subsample 
 of the core obtained. A series of large, heavy 
 paper or canvas bags, properly marked as 
 to horizon, can be used. When sampling is 
 complete, a subsample can be taken and 
 the rest discarded. This is easily accom- 
 plished by spreading the sample out on a 
 large piece of canvas or rubberized cloth, 
 breaking up the lumps or borings by hand, 
 
 thoroughly mixing by rolling in two direc- 
 tions, and taking a suitable-sized subsample 
 (about two quarts) for laboratory drying, 
 pulverizing, sieving, and final analysis. 
 
 Samples should be brought to the labora- 
 tory as soon as possible, spread out on paper 
 to dry (it will often save much time to 
 crumble the moist soil cores by hand and 
 pass the moist sample through a 6 mm sieve, 
 discarding the coarse stones and pebbles, but 
 not soil clods) in a dust-and fume-free loca- 
 tion. When air-dry, the soil should then be 
 worked through a 2 mm screen, again dis- 
 carding small gravel but not soil crumbs. 
 The use of a rubber stopper to help work 
 the soil through the screen, or a mortar and 
 rubber-tipped pestle, or wood roller to 
 pulverize soil clods and aggregates is the 
 usual means of reducing particle size so as 
 to pass it through the 2 mm screen. After 
 screening, the soil should be thoroughly 
 mixed by rolling on an appropriate sized 
 piece of rubberized cloth. 
 
 A one-quart sample of soil will suffice for 
 all of the chemical tests. We have found it 
 convenient to store soils, under California 
 
 [in 
 
climatic conditions, in one-quart cardboard 
 cartons. Glass jars are commonly used and 
 in some cases press top tin cans. 
 
 TIME SCHEDULE FOR LEAF AND 
 SOIL ANALYSIS 
 
 The table below shows a suggested time 
 schedule for the plant and soil analyses. 
 The initial orchard evaluation involving 
 both leaf and soil analyses represents the 
 longest and most expensive part of the 
 operation. Following this, far less extensive 
 plant and soil analyses are called for, and 
 in the second and succeeding years, rela- 
 tively few analyses will be needed. 
 
 Suggested Schedule of Observations, Measure- 
 ments, and Operations 
 
 Initial orchard 
 evaluation 
 
 1. Appraise orchard as outlined in table 1. 
 
 2. Make complete leaf analysis, taking leaf samples in 
 September or October (northern hemisphere) pref- 
 erably. 
 
 3. Determine pH and salinity status and such other 
 soil determinations as may be suggested by results 
 of leaf analysis. 
 
 4. Initiate such fertilizer, irrigation, and other soil and 
 orchard management practices as may be indicated 
 by analyses and orchard appraisal. 
 
 First year 
 fallowing 
 change in 
 practice 
 
 1. Leaf analysis: Take leaf sample at same date as 
 initially (preferably September or October, northern 
 hemisphere), and make analyses for Ca, Mg, K, N, 
 P, and such additional elements as shift in fertilizer 
 practices may suggest as necessary. 
 
 2. Soil analysis: If initial samples showed excess salts, 
 resample and analyze to determine effectiveness of 
 leaching and/or other practices initiated. 
 
 3. Check visual symptomatology at same time as ini- 
 tially. 
 
 Succeeding 
 years 
 
 1. Make such leaf and soil analyses as may be indi- 
 cated by results of initial and first-year results and 
 the changes in fertilizer and management practices 
 inaugurated. In general, if changes in nutrition are 
 being sought, yearly leaf analyses should be made 
 until the desired changes have been achieved. 
 
 METHOD OF RECORDING 
 RESULTS 
 
 Id using plant and soil analyses as a guide 
 to soil-management and fertilizer practices 
 it is important to maintain a running record 
 showing yearly leaf analysis values, fertilizer 
 
 and soil-management practices, pest- and 
 disease-control treatments, together with a 
 record of yield, sizes, fruit quality, and 
 visual symptoms. A suggested method of 
 recording all these results in tabular form 
 is shown in table 6. 
 
 METHODS OF CONTROLLING 
 
 AND CORRECTING MINERAL 
 
 DEFICIENCIES AND 
 
 EXCESSES 
 
 Having diagnosed either acute or sub- 
 acute, or suspected malnutrition due to 
 mineral deficiencies or excesses, the question 
 of how to control, correct, or begin to 
 ameliorate the condition arises. To provide 
 tangible guidance on this problem, table 
 7 has been prepared showing for each con- 
 dition the method or methods found useful 
 in correcting deficiencies and excesses so 
 far as is known. Supplementary remarks are 
 included in the table and require no further 
 elaboration. 
 
 SUMMARY 
 
 By means of leaf analysis visual symptoms 
 and soil analysis, either singly or more often 
 in combination, it is now possible to posi- 
 tively diagnose not only the moderate to 
 acute stages of mineral deficiencies or ex- 
 cesses, but in most cases, secure positive 
 indications of early stages of these or trends 
 in this direction. 
 
 Such leaf and soil analysis criteria as are 
 currently available are presented in this 
 paper, together with detailed directions for 
 plant and soil sampling, handling, and 
 methods for initiating the programs, record- 
 ing the results, and, finally, control pro- 
 cedures. 
 
 It is emphasized repeatedly that the most 
 important precaution to observe is proper 
 sampling techniques and analyses. A lew 
 leaves or one or two cores of soil as samples, 
 or the use of quick-test chemical methods are 
 likely to yield completely unreliable results. 
 
 Not only is proper sampling and analysis 
 important, but some continuation of the 
 leaf-analysis program is called for as a check 
 on the effects of corrective treatments. 
 
 The initial costs for orchard evaluation 
 and soil and plant analysis will be the 
 
 I 121 
 
greatest; in succeeding years the costs will 
 diminish. 
 
 Increased tree yields and decreased ferti- 
 lizer costs resulting from such a program, 
 and the knowledge that soil-management 
 practices were going in the right, rather than 
 
 the wrong direction, will in the long run 
 pay dividends. 
 
 As research and experience progress, bet- 
 ter criteria and methods will emerge, thus 
 increasing the accuracy of diagnosis and de- 
 creasing the costs. 
 
 ACKNOWLEDGMENTS 
 
 The author is indebted to Dr. Jaap deVil- 
 liers, Horticulturist of Zebediela Estates, 
 Northern Transvaal, Union of South Africa, 
 for critically reviewing this publication and 
 making many valuable suggestions. He is 
 also indebted to Mr. Edward Curran, Man- 
 ager of the Fruit Growers Service Labora- 
 tory, Santa Paula, California, for similar 
 assistance; and to a considerable number of 
 other reviewers who have made many valu- 
 able suggestions. 
 
 In addition, a great deal of basic data, 
 upon which current leaf and soil standards 
 rest, have emerged from the research of 
 colleagues in the Department of Soils and 
 Plant Nutrition, and the Department of 
 
 Horticulture of the Citrus Experiment Sta- 
 tion, as well as the research of many other 
 investigators throughout the world. The 
 source of all of this information is indicated 
 and credited in the various tables and in 
 the text, but special mention of it is made at 
 this point, for the reason that a publication 
 such as this would not have been possible 
 except for the enormous amount of research 
 and experience which has been devoted to 
 this subject by many people. The author is 
 indebted to Miss Harrietann Joseph, Senior 
 Laboratory Technician of the Department 
 of Soils and Plant Nutrition for the line 
 drawings. 
 
 [13] 
 
TABLE 1. — Suggested Form for Use in Recording and Summarizing Data of 
 
 Initial Orchard Appraisal. 
 
 I. LOCATION: 
 
 Owner 
 
 Address 
 
 Manager_ 
 
 Address 
 
 Location of orchard 
 
 MAP OF LOCATION 
 Show nearest crossroads, towns, and 
 other locational data 
 
 DETAIL OF SOIL AND LEAF SAMPLING AREA 
 Field No. Block No. 
 
 Legend: x = tree;(x) = tree sampled; 
 o = irrig. stand; Q= windbreak tree 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 II. ORCHARD DATA : 
 Age 
 
 Previous cropping history 
 
 Species, variety_ 
 
 Top-worked 
 
 Ac rea ge 
 
 Roots tock 
 
 Sandwich 
 
 Size trees 
 
 Pruning history_ 
 Fol iage densi ty_ 
 Dieback 
 
 Source nursery trees_ 
 
 No. mature trees 
 
 C r owd i n g 
 
 Gi rdl ing history_ 
 Fol iage color 
 
 Abnormal leaf drop_ 
 
 When 
 
 Periodic leaf patterns 
 
 Season of appearance_ 
 
 Deficiencies or excesses, or other abnormalities indicated_ 
 
 Frost damage history_ 
 
 Wind damage history 
 
 Heat damage history 
 
 Other damage history_ 
 Other information 
 
 I ii I 
 
TABLE 1. — Continued 
 
 III. DISEASE INDICATIONS : 
 
 Gummos i S 
 
 Scaly bark_ 
 
 Root rot 
 
 Quick dec] ine__ 
 
 Other virus disease indications 
 
 Other bark or root troubles 
 
 Stubborn disease 
 
 Control measures used for disease 
 
 Hormone sprays 
 
 Other sprays 
 
 Kind and amount 
 
 Soil fumigation_ 
 Other treatments 
 
 IV. INSECT PROBLEMS : 
 Sever i ty 
 
 Major pests_ 
 
 V. Y 
 
 Control practices used in past several years 
 
 
 
 
 IELD AND QUALITY PERFORMANCE: 
 
 \ 
 
 Acreage 
 
 Yield 
 
 Pack out data 
 
 Year 
 
 Field 
 boxes 
 
 Packed 
 boxes 
 
 Weight 
 
 Peak sTTes 
 
 % 1st 
 grade 
 
 % 2nd 
 grade 
 
 % 3rd 
 grade 
 
 % By- 
 products 
 
 % 
 cul Is 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 I 
 
 
 Special fruit problems: 
 
 Small sizes 
 
 Creasing 
 
 Granulation 
 
 Rind texture 
 
 Color problems 
 
 Internal quality 
 
 P re-harvest disease_ 
 
 Post-harvest disease 
 
 Maturity problems 
 
 Other problems 
 
 [15] 
 
TABLE 1. — Continued 
 
 VI. CLIMATE: 
 
 Annual average rainfall_ 
 
 Seasonal distribution 
 
 Mean annual temperature_ 
 Absolute maximum 
 
 Effective rainfal 
 Character of rain 
 
 Absolute minimum 
 
 Frequency and periods when temperature exceeds 100° F. 
 
 Frost hazard 
 
 Humidity and climate: Desert 
 Mean annual humidity (% rel.) 
 
 Are fogs common 
 
 % Rel. humidity, A.M. av. 
 
 Orchard heating practice_ 
 Intermediate 
 
 Coastal 
 
 % Rel. humidity, P.M. av._ 
 % maximum 
 
 Sunshine, hours annual_ 
 
 No. months when temperatures suitable for vegetative growth_ 
 
 Are nights predominantly cool 
 
 Damaging winds, frequency 
 
 Character and season of winds 
 
 Prevai I ing winds_ 
 
 Other significant climatic character istics 
 
 VII. SOIL CHARACTERISTICS : 
 Soil series and type_ 
 
 Soil profile characteristics: Depth to rock or hardpan__ 
 
 Homogeneous S t ra t i f i ed C I ay I ayers 
 
 Plowsole 
 
 Hardpan_ 
 
 Compactness 
 
 Desc ription of profile characteristics: 
 
 
 1st 
 horizon 
 
 2nd 
 horizon 
 
 3rd 
 horizon 
 
 4th 
 horizon 
 
 5th 
 horizon 
 
 6th 
 horizon 
 
 Depth 
 
 
 
 
 
 
 
 Texture 
 
 
 
 
 
 
 
 Gravel, stones 
 
 
 
 
 
 
 
 Color 
 
 
 
 
 
 
 
 Granulation 
 
 
 
 
 
 
 
 Concretions 
 
 
 
 
 
 
 
 Shells 
 
 
 
 
 
 
 
 Mottl inq 
 
 
 
 
 
 
 
 Other 
 
 
 
 
 
 
 
 Soil drainage characteristics: 
 Depth to permanent water table_ 
 Does water table fluctuate 
 
 Good 
 
 medium 
 
 poor_ 
 
 Does soil take water readily 
 
 Do lower horizons stay wet unduly after rain or irrigation_ 
 Other characteristics 
 
 Topography: Flat- 
 
 slope (% approx.) 
 
 terraced 
 
 , undulating^ 
 
 evidence of erosion 
 
 contour 
 
 Soil information available or applicable: 
 Known or obvious chemical characteristics 
 
 Microbiological information available 
 
 16 1 
 
TABLE 1. — Continued 
 
 VIII. IRRIGATION: 
 
 Is orchard irrigatcd_ 
 
 Source of water 
 
 Ana lysis of water: 
 
 How many years irrigated 
 
 Conductivity ECxlQ° at 
 
 25° C. 
 
 j>H_ 
 
 Total dissolved solids, ppro 
 
 Boron (B) , ppm 
 
 Fluoride (F) , ppm 
 
 Bicarbonate (HCO3) , ppm 
 Chloride (Cl), opm 
 
 Sulfate (SO4) , ppm 
 
 Nitrate (NO 3), ppm 
 
 Calcium (Ca) , ppm 
 Magnesium (Mg) , ppm 
 
 Sodium (Na) , ppm 
 
 Potassium (K) , ppm 
 
 Per cent Na Na x 100 
 
 Na+K+Ca+Hg 
 
 (Expressed 
 in me/1) 
 
 Residual sodium carbonate 
 (Ca+Mg) - (HCO3+CO3) - RSC 
 (Expressed in me/I) 
 
 Remarks on water 
 
 Method of irrigation: Basin, furrow, sprinkler_ 
 
 Length of runs, if furrow 
 
 Frequency 
 
 Amount per irrigation 
 
 Other data on irrigation 
 
 IX. CULTIVATION : 
 Cul tivated 
 
 Noncul ti vat ion 
 
 Frequency, 
 How long_ 
 
 Method 
 
 Weed control materials 
 
 Is organic matter used. 
 
 Surface mulching 
 
 Other information 
 
 Kinds_ 
 
 Materials 
 
 Amounts 
 
 X. FERTILIZER PRACTICES DURING PAST 5-10 YEARS : 
 
 N i t rogen : Annua 1 arooun ts 
 
 Manure and organic materials: 
 When applied 
 
 Frequency_ 
 
 Green manure practice: Kinds, 
 
 Mixed fertilizers: Kinds 
 
 History of use 
 
 Kinds_ 
 
 Amounts 
 
 How app I i ed_ 
 
 Kinds 
 
 Tonnage produced. 
 Amounts used 
 
 Fol iar sprays : 
 Frequency_ 
 Amendments : 
 
 Kinds 
 
 Lime 
 
 Gypsum_ 
 Other 
 
 Other information on fertilizer practices 
 
 Amounts, 
 Amounts, 
 Amounts 
 
 [H] 
 
TABLE 1. — Continued 
 
 XI. CONCLUSIONS REGARDING CLIMATE . SOIL . AND ORCHARD : 
 
 Climate 
 
 Are recurring climatic extremes a serious problem Heat 
 
 Cold Wind Hai1_ " 
 
 Humi d i ty Hurr i canes 
 
 Is growing season too short for maximum varietal performance (yield, size, quality) 
 
 Can top performance orchards be found in the area 
 
 Are climatic handicaps too great for economical citrus production. 
 
 Can climatic handicaps be overcome to some extent by proper management. 
 
 Soil 
 
 Is soil suitable for citrus, considering climatic situation and availability of 
 
 water 
 
 Does soil texture impose special management problems 
 
 Do profile characteristics pose water penetration, aeration, drainage, or salinity 
 p rob 1 eras 
 
 What are probable fertility problems based on general knowledge of soils, past and 
 present fertilizer practices, irrigation water composition 
 
 Is present fertilizer practice going in right or wrong direction as near as can be 
 ascertained 
 
 I rrigation 
 
 Is sufficient water available 
 
 Is salinity build-up a potential threat 
 
 Is irrigation practice satisfactory Periodic stresses. 
 
 Should tensiometers be installed 
 
 Is water penetration a problem 
 
 Are there periods when soil is too wet 
 
 Disease 
 
 Is disease incidence or threat such that orchard should be completely replanted, 
 or individual trees replaced 
 
 Insect 
 
 Is there an insect problem and are handicaps so large and costly that, considering 
 climatic and soil handicaps, citrus should be replaced by another crop 
 
 General conclusions as to reasons for orchard condition 
 
 Recommended soi 1 and plant anal yses 
 Initial appraisal 
 
 Continuing program 
 
 [18] 
 
XII. SOIL ANALYSIS DATA SHEET. 
 
 TABLE 1. — Continued 
 
 Dates sampled 
 Area 
 
 
 Horizon and depth 
 
 Measurement 
 
 1 
 
 2 
 
 3 
 
 k 
 
 5 
 
 Average 
 
 Depth represented 
 
 
 
 
 
 
 
 Texture 
 
 
 
 
 
 
 
 Color 
 
 
 
 
 
 
 
 + pH: 1:2.5 suspension 
 
 
 
 
 
 
 
 + Conductivity of saturation extract 
 ECx103 at 25° C. 
 
 
 
 
 
 
 
 * Calcium (Ca) (me/I) 
 
 
 
 
 
 
 
 * Magnesium (Mg) (me/1) 
 
 
 
 
 
 
 
 * Potassium (k) (me/1) 
 
 
 
 
 
 
 
 * Sodium (Na) (me/l) 
 
 
 
 
 
 
 
 * Sulfate (SO^) (rae/1) 
 
 
 
 
 
 
 
 * Nitrate (NO3) (roe/I) 
 
 
 
 
 
 
 
 * Carbonate (CO3) (me/1) 
 
 
 
 
 
 
 
 * Bicarbonate (HCO3) (me/1) 
 
 
 
 
 
 
 
 * Chloride (CI) (me/1) 
 
 
 
 
 
 
 
 * Boron (B) (me/1) 
 
 
 
 
 
 
 
 Other 
 
 
 
 
 
 
 
 * Total soluble solids in 
 ppm saturation extract 
 
 
 
 
 
 
 
 * Exchange capacity, me/100 g soil 
 
 
 
 
 
 
 
 * Phosphorus: 
 
 Total P in ppm dry soil 
 
 
 
 
 
 
 
 O.SM Na Bicarbonate soluble 
 in ppm dry soi 1 
 
 
 
 
 
 
 
 Water soluble in ppm dry soil 
 (Binqham, method) 
 
 
 
 
 
 
 
 * Potassium: 
 
 Total K in ppm dry soil 
 
 
 
 
 
 
 
 Exchangeable, me/100 g 
 
 
 
 
 
 
 
 Exchangeable in % exch, cap. 
 
 
 
 
 
 
 
 * Magnesium: 
 
 Total Mg in ppm dry soil 
 
 
 
 
 
 
 
 Exchangeable, me/100 g 
 
 
 
 
 
 
 
 K:Mg ratio 
 
 
 
 
 
 
 
 * Calcium: 
 
 Total Ca in ppm dry soil 
 
 
 
 
 
 
 
 Exchangeable, me/100 g 
 
 
 
 
 
 
 
 * Sodium: 
 
 Exchangeable, me/100 g 
 
 
 
 
 
 
 
 % Exch. Na Na 
 
 
 
 
 
 
 
 Ca+Mg+Na+K 
 
 
 * Organic matter, % 
 
 
 
 
 
 
 
 * Nitrogen, total % 
 
 
 
 
 
 
 
 * Nitrate prod, capacity 
 
 
 
 
 
 
 
 + These determinations highly desirable. 
 
 * These determinations necessary only when it is desired to confirm visual or 
 analysis indications of excesses br deficiencies. 
 
 leaf 
 
 [19] 
 
TABLE 1. — Continued 
 
 XII. SOIL ANALYSIS DATA SHEET (cont.) 
 
 1 — 1 
 
 Horizon and depth 
 
 Measurement 
 
 1 
 
 2 
 
 3 
 
 k 
 
 5 
 
 Average 
 
 * Sulfur: 
 
 Total S in ppm dry soil 
 
 
 
 
 
 
 
 Water sol. SOl (sat. extract) 
 
 
 
 
 
 
 
 * Boron: 
 
 Total B in ppm dry soil 
 
 
 
 
 
 
 
 Water sol .Bin soi 1 
 
 (NcClunq Dawson (1950) method) 
 
 
 
 
 
 
 
 * Copper: 
 
 Total Cu in ppm dry soil 
 
 
 
 
 
 
 
 1 N-HC1 extract in ppm dry soil 
 
 
 
 
 
 
 
 * Manganese: 
 
 Total Mn in ppm dry soil 
 
 
 
 
 
 
 
 Exchangeable 
 
 
 
 
 
 
 
 Easily reducible 
 
 
 
 
 
 
 
 * Zinc: 
 
 Total Zn in ppm dry soil 
 
 
 
 
 
 
 
 Ammonium ace tate-d i thi zone 
 
 extract in ppm dry soil (Shaw* 
 and Dean (1952) method) 
 
 
 
 
 
 
 
 * Molybdenum: 
 
 Total Mo in ppm dry soil 
 
 
 
 
 
 
 
 Ammonium oxalate extractable 
 in ppm dry sol 1 
 
 
 
 
 
 
 
 Other soil constituents: 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 Evaluation, based on soil analysis: 
 
 
 
 
 
 + These determinations highly desirable. 
 
 * These determinations necessary only when it is desired to confirm visual or leaf 
 analysis indications of excesses or deficiencies. 
 
 I 20 1 
 
TABLE 1. — Continued 
 
 XII 
 
 INITIAL LEAF ANALYSIS DATA SHEET 
 
 Orchard designation 
 Field No. " 
 
 Block No. 
 
 Age of leaves 
 
 Sampling Unit 
 
 No. trees sampled 
 
 Date sampled 
 
 Per cent of total trees in sampling unit from which leaves were taken 
 
 
 Sampl ing Uni t 
 
 E 1 emen t 
 
 1 
 
 2 
 
 3 
 
 k 
 
 5 
 
 6 
 
 7 
 
 
 Per cent in dry matter of leaf 
 
 + Calcium (Ca) 
 
 
 
 
 
 
 
 
 + Magnesium (Mg) 
 
 
 
 
 
 
 
 
 + Nitrogen (N) 
 
 
 
 
 
 
 
 
 + Phosphorus (P) 
 
 
 
 
 
 
 
 
 + Potassium (K) 
 
 
 
 
 
 
 
 
 + Sulfur (S) 
 
 
 
 
 
 
 
 
 + Sodium (Na) 
 
 
 
 
 
 
 
 
 + Chloride (CI) 
 
 
 
 
 
 
 
 
 
 In ppm dry matter of leaf 
 
 + Boron (B) 
 
 
 
 
 
 
 
 
 + Copper (Cu) 
 
 
 
 
 
 
 
 
 + Iron (Fe) 
 
 
 
 
 
 
 
 
 + Manganese (Mn) 
 
 
 
 
 
 
 
 
 + Molybdenum (Mo) 
 
 
 
 
 
 
 
 
 + Zinc (Zn) 
 
 
 
 
 
 
 
 
 * Aluminum (Al) 
 
 
 
 
 
 
 
 
 * Antimony (Sb) 
 
 
 
 
 
 
 
 
 * Arsenic (As) 
 
 
 
 
 
 
 
 
 * Barium (Ba) 
 
 
 
 
 
 
 
 
 * Bromine (Br) 
 
 
 
 
 
 
 
 
 * Chromium (Cr) 
 
 
 
 
 
 
 
 
 * Cobalt (Co) 
 
 
 
 
 
 
 
 
 * Fluorine _(F} 
 
 
 
 
 
 
 
 
 * Indium fin) 
 
 
 
 
 
 
 
 
 * Iodine (1) 
 
 
 
 
 
 
 
 
 * Lead (Pb) 
 
 
 
 
 
 
 
 
 * Lithium (Li) 
 
 
 
 
 
 
 
 
 * Nickel (Ni) 
 
 
 
 
 
 
 
 
 * Silver (Aq) 
 
 
 
 
 
 
 
 
 * Strontium (Sr) 
 
 
 
 
 
 
 
 
 * Tin (Sn) 
 
 
 
 
 
 
 
 
 * Ti tanium (Ti) 
 
 
 
 
 
 
 
 
 * Vanadium JV) 
 
 
 
 
 
 
 
 
 * Zi rconium (Zr) 
 
 
 
 
 
 
 
 
 * Other: 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 Evaluation based on leaf analysis: 
 
 
 + These determinations should all be made initially. 
 
 * These determinations need be made only if some unusual condition is suspected, e.g., 
 nature of soil, water, or air pollution possibilities, unusual fertilizer or pest control 
 practices, etc. 
 
 [21] 
 
TABLE 1. — Continued 
 
 XIV. RECOMMENDED CHANGES IN ORCHARD MANAGEMENT BASED ON INITIAL FINDINGS 
 
 Tree changes: 
 
 Pruning 
 
 Gi rdl ing 
 
 Top-working 
 
 Other 
 
 Di sease control : 
 
 Insect control 
 
 Cul ti vation: 
 
 Organic matter use: 
 
 Irrigation practice: 
 
 Fertilizer management: 
 
 Other: 
 
 I 22 1 
 
TABLE 2. — Means by Which Nutrient Status of Citrus Can Be Determined 
 
 Condition 
 
 Early stage 
 
 (See tables 3 and 4 for leaf and soil analysis criteria 
 
 and table 8 for control methods) 
 
 Moderate-to-acute stage 
 
 (See tables 3 and 4 for leaf and soil analysis criteria 
 
 and table 8 for control methods; 
 
 Boron 
 
 Deficiency 
 
 1. Leaf analysis for total and water-soluble boron supple- 
 mented by soil analysis for water-soluble boron will 
 give indications. 
 
 2. Confirmation by foliar spray trials or soil applications 
 of boric acid or borax usually necessary. 
 
 1. Leaf analysis and visual symptoms usually sufficient 
 
 2. In case of doubt make soil analysis for water- 
 soluble boron. 
 
 3. Confirm if necessary by foliar sprays or soil applica- 
 tion of boric acid or borax. 
 
 
 Excess 
 
 1. Leaf pattern, confirmed by leaf analysis, usually suffi- 
 cient. 
 
 1. Leaf pattern confirmed by leaf analysis. 
 
 Calcium 
 
 Deficiency 
 
 1. Leaf analysis supplemented by soil tests for pH and 
 possibly exchangeable Ca in soils will give indications 
 but 
 
 2. Confirmation by application of calcium compounds to 
 soil necessary. 
 
 1. Leaf analysis coupled with visual symptoms and 
 
 2. Confirmed by soil applications of soluble calcium 
 compounds. 
 
 
 Excess 
 
 1. Leaf analysis coupled with soil analysis for soluble 
 calcium (little data exist as to specific toxicity of cal- 
 cium; hence considerable uncertainty surrounds this 
 condition and its diagnosis). 
 
 1. Leaf analysis coupled with soil analysis for soluble 
 soil calcium (little data exist as to specific toxicity 
 effects of soluble calcium). 
 
 Copper 
 
 Deficiency 
 
 1. Leaf analysis and soil tests for total and 0.1 N HCI 
 soluble Cu in soil will give indications. 
 
 2. Confirmation by use of foliar sprays usually necessary. 
 
 1. Visual symptomatology usually sufficient. 
 
 2. If confirmation required, make leaf analysis. 
 
 3. For further confirmation (not usually needed; try 
 foliar sprays. 
 
 
 Excess 
 
 1. Leaf and root analysis supplemented by 
 
 2. Soil analysis for total and 0.1 N HCI soluble copper. 
 
 1. Leaf and root analysis supplemented by 
 
 2. Soil analysis for total and 0.1 N HCI soluble copper. 
 
 Iron 
 
 Deficiency 
 
 1 . Leaf pattern usually sufficient but leaf analysis can be 
 used to confirm. 
 
 2. Further confirmation can be had with foliar spray of 
 iron sulfate or iron chelate. 
 
 3. Soil examination for pH, lime, and heavy metals and 
 moisture status may be useful in indicating cause. 
 
 1. Leaf patterns sufficient but confirmation can be 
 had by leaf analysis and 
 
 2. Foliar sprays using iron sulfate or iron chelates. 
 
 3. Soil examination may be useful in indicating cause. 
 
 
 Excess 
 
 No data available. 
 
 No data available. 
 
 Molybdenum 
 
 Deficiency 
 
 1. Leaf analysis, supplemented by 
 
 2. Soil analysis for total and ammonium oxalate extract- 
 able Mo and 
 
 3. Confirmed by foliar sprays or soil analysis. 
 
 1. Leaf patterns confirmed by leaf analysis, and trials 
 with foliar sprays or soil applications of sodium 
 molybdate. 
 
 2. Soil analysis for total and ammonium oxalate ex- 
 tractable Mo (not usually necessary). 
 
 
 Excess 
 
 1. Insufficient information on effects. Leaf and soil 
 analysis may be indicative. 
 
 1. Insufficient information on effects. Leaf and soil 
 analysis may be indicative. 
 
 Nitrogen 
 
 Deficiency 
 
 1. Leaf analysis for total N indicative but 
 
 2. Soil analysis for nitrate, or nitrate-producing capacity 
 can help confirm. 
 
 1. Leaf color confirmed by leaf analysis for total N. 
 
 
 Excess 
 
 1. Leaf analysis supplemented by soil analyses can give 
 indications. 
 
 1. Leaf analysis supplemented by soil analyses. 
 
 Phosphorus 
 
 Deficiency 
 
 1. Leaf analysis supplemented by 
 
 2. Soil analysis for 0.5M Na bicarbonate soluble P, and 
 confirmed by 
 
 3. Trials with phosphorus fertilizer added to the soil. 
 
 1. Leaf analysis, visual symptomatology and confirmed 
 by 
 
 2. Soil analysis for 0.5M sodium bicarbonate soluble P. 
 
 3. Application of phosphate fertilizer to soil will provide 
 further confirmation. 
 
 
 Excess 
 
 1. No clear-cut criteria, but soil analysis for 0.5M Na 
 bicarbonate P will provide some indications. 
 
 1. No clear-cut criteria but soil analysis for 0.5M Na 
 bicarbonate P plus leaf analysis may give indications. 
 
 Chlorine 
 
 Deficiency 
 
 No critical data established. 
 
 No critical data established. 
 
 
 Excess 
 
 1. Leaf analysis supplemented by 
 
 2. Soil analysis for water-soluble chloride in saturation 
 or other water extract. 
 
 1. Leaf analysis and visual symptoms supplemented by 
 
 2. Soil analysis for water-soluble chloride in saturation 
 or other water extract. 
 
 [23] 
 
TABLE 2. — Continued 
 
 Condition 
 
 Early stage 
 
 (See tables 3 and 4 for leaf and soil analysis criteria 
 
 and table 8 for control methods) 
 
 Moderate-to-acute stage 
 
 (See tables 3 and 4 for leaf and soil analysis criteria 
 
 and table 8 for control methods) 
 
 Magnesium 
 
 Deficiency 
 
 1. Leaf patterns supplemented if need be by 
 
 2. Leaf analysis. 
 
 3. Soil analysis useful in indicating reasons for defi- 
 ciency. 
 
 1. Leaf patterns usually sufficient. 
 
 2. Leaf analysis will provide confirmation. 
 
 3. Soil analysis useful in indicating reasons for defi- 
 ciency. 
 
 
 Excess 
 
 1. Soil analysis for water-soluble Mg in saturation ex- 
 tract indicative; determinations of total magnesium 
 in soil and tests for presence or absence of magnesium 
 carbonates and basic carbonates. 
 
 2. Leaf and root analysis may provide further indications. 
 
 1. Soil analysis for water-soluble Mg in saturation ex- 
 tract useful; determination of total magnesium in 
 soil and tests for presence or absence of magnesium 
 carbonates or basic carbonates. 
 
 2. Leaf and root analysis will give further indications. 
 
 3. Excess magnesium may bring about iron chlorosis 
 leaf patterns. 
 
 Manganese 
 
 Deficiency 
 
 1. Leaf patterns usually sufficient. 
 
 2. Leaf analysis will provide further confirmation. 
 
 3. Can further confirm with foliar sprays with manganese 
 sulfate. 
 
 4. Soil analysis can be made but leaf patterns and analy- 
 sis are sufficient for positive diagnosis. 
 
 1. Leaf patterns sufficient generally. 
 
 2. Leaf analysis will provide further confirmation. 
 
 3. Can further confirm with foliar sprays of manganese 
 sulfate. 
 
 
 Excess 
 
 1. Leaf analysis supplemented by 
 
 2. Soil analysis for total and easily reducible manganese. 
 
 1. Leaf patterns supplemented by leaf analysis. 
 
 2. Soil analysisfor total and easily reducible manganese. 
 
 Potassium 
 
 Deficiency 
 
 1. Leaf analysis supplemented by 
 
 2. Soil analysis for exchangeable K and 
 
 3. Confirmed by soil fertilizer tests. 
 
 1. Leaf analysis supplemented by 
 
 2. Visual symptomatology usually sufficient. 
 
 3. Soil analysis for exchangeable K, confirmed by soil 
 fertilizer tests, will provide confirmation. 
 
 
 Excess 
 
 1. Leaf analysis supplemented by 
 
 2. Soil analysis for exchangeable and water-soluble K 
 will give indication, but exact criteria lacking. 
 
 1. Leaf analysis supplemented by 
 
 2. Soil analysis for exchangeable and water-soluble K. 
 
 Sulfur 
 
 Deficiency 
 
 1. Leaf analysis supplemented by 
 
 2. Soil analysis for total S and soluble sulfate and 
 checked by 
 
 3. Field fertilizer tests. 
 
 1. Leaf analysis and visual symptomatology supple- 
 mented if need be by 
 
 2. Soil analysis for total S and soluble sulfate. 
 
 3. Further confirmation can be had from field fertilizer 
 tests. 
 
 
 Excess 
 
 1. Soil analysis for sulfates and 
 
 2. Leaf analysis for total sulfur. 
 
 1. Soil analysis for sulfates and 
 
 2. Leaf analysis for total sulfur. 
 
 Zinc 
 
 Deficiency 
 
 1. Leaf patterns are usually sufficient; can confirm if 
 necessary by 
 
 2. Leaf analysis and spray trials. 
 
 1. Leaf pattern and other symptoms are clear-cut; 
 hardly ever necessary to confirm by leaf analysis or 
 spray trials. 
 
 
 Excess 
 
 1. Soil analysis for total and 0.10N HCI soluble zinc in soil 
 and supplemented by 
 
 2. Leaf analysis. 
 
 1. Soil analysis for total and 0.10N HCI soluble zinc 
 in soil and supplemented by 
 
 2. Leaf analysis. 
 
 Salinity 
 
 Excess 
 
 1. Soil analysis of saturation extract for soluble salts in 
 various horizons of root zone coupled with 
 
 2. Leaf and root analyses. 
 
 1. Soil analysis of saturation extract for soluble salts in 
 various horizons of root zone coupled with 
 
 2. Leaf and root analyses. 
 
 Trace elements not 
 essential for plant 
 growth, such as 
 lithium, nickel, 
 cobalt, etc. 
 
 Excess 
 
 1. Leaf and root analysis, and/or 
 
 2. Visual symptoms, and/or 
 
 3. Soil analysis will provide indications as to status; posi- 
 tive in some cases, inconclusive in others. 
 
 1. Leaf and root analysis, and/or 
 
 2. Visual symptoms, and/or 
 
 3. Soil analysis will provide indications as to status. 
 
 |24 1 
 
TABLE 3. — Leaf Analysis Standards for Assessing Current Nutrient Status of 
 
 Citrus Trees 
 
 (Based on 4- to 10-month-old spring cycle leaves from fruit-bearing terminals) 
 
 Element 
 
 Calcium (Ca). . 
 Magnesium (Mij 
 Nitrogen (N) . . . 
 Phosphorus (P) . 
 Potassium (K).. 
 
 Sulfur (S) 
 
 Sodium (Na) . . . 
 Chloride (CI) . . . 
 
 Deficient range Low range 
 
 Satisfactory range. High range Excess range 
 
 in per cent of dry matter of leaf 
 
 <2.0 
 0.05 0.15 
 0.60 1.90 
 
 <0.07 
 0.15-0.30 
 0.05-0.13 
 
 2.0 2.9 
 0.16 0.20 
 1.90 2.10 
 0.07-0.11 
 0.40-0.90 
 0.14-0.19 
 0.01-0.06 
 
 3.0^.0 
 0.30 0.60 
 2.20 2.70 
 0.12-0.18 
 1.00-1.70 
 0.20-0.30 
 0.01-0.15 
 0.02-0.15 
 
 6.1 6.9 
 0.7CM.0 
 2.80 3.50 
 0.19 0.29 
 1.8(M.90 
 0.40 0.49 
 0.20 0.25 
 0.20 0.30 
 
 >7.0? 
 
 >1.0? 
 
 ^3.60? 
 
 ^0.30? 
 
 >2.00? 
 
 >0.50 
 
 >0.25 
 
 >0.40 
 
 in ppm dry matter of leaf 
 
 Boron (B) 
 
 Copper (Cu) 
 
 Iron (Fe) 
 
 Manganese (Mn) . 
 Molybdenum (Mo) 
 
 Zinc (Zn) 
 
 Aluminum (Al) . . . 
 
 Arsenic (As) 
 
 Barium (Ba) 
 
 Bromine (Br) 
 
 Chromium (Cr)f. . 
 
 Cobalt (Co) 
 
 Fluorine (F) 
 
 Gallium (Ga) 
 
 Indium (In) 
 
 Iodine (I) 
 
 Lead(Pb)t 
 
 Lithium (Li) 
 
 Nickel (Ni)t 
 
 Silver (Ag)t 
 
 Strontium (Sr) 
 
 Tin(SN)t 
 
 Titanium (Ti) 
 
 Vanadium (V)f. . . 
 Zirconium (Zr) 
 
 <15.0 
 <4.0 
 <40.0 
 5.0-20.0 
 0.01-0.05 
 4.0-15.0 
 
 15.0-40.0 
 
 4.1-5.0 
 
 40.0-60.0 
 
 21.0-24.0 
 
 0.06-0.09 
 
 15.0-24.0 
 
 6.0-20.0 
 
 <1.0 
 
 5.0-20.0 
 
 ? 
 
 Tr.-0.20 
 
 <0.4 
 
 < 1.0-5.0 
 
 <1.0 
 
 <1.0 
 
 <0.5 
 
 <0.5 
 
 <0.5 
 
 <0.05 
 
 30.0-90.0 
 
 >1.0 
 
 0.3.30 
 
 1.5-3.0 
 
 ? 
 
 50.0-200.0 
 
 5.1-15.0 
 
 60.0-150.0 
 
 25.0-100.0 
 
 0.10-3.0 
 
 25.0-100.0 
 
 6.0-30.0 
 
 <1.0 
 
 5.0-49.0 
 
 ? 
 Tr.-0.50 
 Tr.-0.4 
 
 < 1.0-20.0 
 <1.(M.O 
 
 <1.0 
 
 <1.0 
 0.5-0.9 
 <0.5-1.0 
 
 < 0.5-0.7 
 30.0-90.0 
 
 >1.0 
 
 0.3-3.0 
 
 1.5-3.0 
 
 ? 
 
 200.0^250.0 
 
 15.0-20.0? 
 
 > 150.0 
 
 100.0^200.0 
 
 4.0-100.0 
 
 110.0-200.0 
 
 40.0-200.0 
 
 >1.0 
 
 50.0-200.0 
 
 200.0-1000.0 
 
 1.0-? 
 
 ? 
 
 25.0-100.0 
 
 5.0-10.0 
 
 1.0-2.0 
 
 2.0-20.0 
 1.0-5.0 
 1.(M.0 
 0.1-4.0 
 100.0-1000.0 
 4.0-12.0 
 4.0-20.0 
 
 ? 
 
 ? 
 
 > 250.0 
 >20.0? 
 
 ? 
 300.0-1000.0? 
 >100? 
 >200? 
 
 ? 
 >5.0 
 
 ? 
 1000.(M0OO.0 
 
 ? 
 
 ? 
 
 > 100.0 
 
 ? 
 
 ? 
 
 ? 
 
 12.0-200.0 
 8.0-up 
 ? 
 ? 
 ? 
 ? 
 ? 
 ? 
 
 * There is no evidence that these elements are essential for higher plants; nonetheless, they influence plant behavior. 
 
 t Low levels of these elements in leaves may not necessarily denote absence of harmful amounts in the soil; some of these exert toxic effects on 
 root tissue and decrease growth, but are not appreciably transported to leaves. 
 
 ? Indicates that doubt exists regarding the values, but is the best current estimate available. 
 
 [25] 
 
CO 
 
 CD 
 
 a 
 c 
 
 03 
 
 CO 
 
 75 
 OC 
 
 Chapman and Vanselow (1955) 
 
 CD 
 
 •s- 
 
 O 
 
 c 
 
 CS 
 
 E 
 
 Q. 
 CS 
 
 JC 
 
 o 
 
 B thurst (1958) as quoted by De Villiers et 
 al. (1958) 
 
 00 
 CO 
 CD 
 
 iC 
 
 CO 
 
 CO 
 
 CO 
 
 "C 
 
 l_ 
 
 o 
 
 ■a- 
 in 
 
 Oi 
 
 JC 
 
 E 
 
 CO 
 
 ■o 
 c 
 
 CS 
 i_ 
 CD 
 
 J= 
 
 *■! 
 
 3 
 03 
 
 OC 
 
 00 
 
 in 
 cs 
 
 CO 
 S3 
 
 c 
 o 
 -1 
 
 ■o 
 c 
 
 CS 
 
 C 
 
 © 
 
 03 
 
 -C 
 
 E 
 UJ 
 
 uT 
 
 03 
 
 £ 
 
 3 
 03 
 
 OC 
 
 De Villiers and Beyers, as quoted from De 
 Villiers etal. (1953) 
 
 Reyneke and Joubert, as quoted from De 
 Villiers et al. (1958) 
 
 De Villiers and Beyers, as quoted from De 
 Villiers et al. (1953) 
 
 De Villiers and Beyers, as quoted from De 
 Villiers et al. (1953) 
 
 en 
 
 S3 
 
 ^* 
 
 c 
 es 
 E 
 a. 
 es 
 JE 
 
 ° 
 
 "en 
 « 
 
 JT3 
 
 3 
 B. 
 C 
 3 
 
 C 
 O 
 
 a. 
 
 es 
 
 To 
 
 co 
 
 u 
 
 CD 
 
 > 
 CD 
 
 Q 
 
 > 
 
 JZl 
 
 "CJ 
 CD 
 
 C 
 3 
 
 a 
 
 09 
 
 es 
 
 CO 
 
 in 
 
 CT3 
 
 "a. 
 
 tm 
 3 
 £ 
 
 7c 
 oa 
 
 c? 
 in 
 cn 
 
 Reyneke and Joubert (1958) as quoted from 
 De Villiers et al. (1953) 
 
 in 
 
 CJ3 
 
 I 
 
 CO 
 
 ■o 
 c 
 es 
 
 CD 
 
 JE 
 
 3 
 CD 
 
 OC 
 
 00 
 
 in 
 cn 
 
 09 
 CD 
 
 c 
 o 
 
 "1 
 
 •o 
 c 
 es 
 
 tf 
 o 
 
 CD 
 
 15 
 E 
 
 UJ 
 
 t-7 
 
 09 
 JZ 
 
 3 
 03 
 
 OC 
 
 03 
 
 S 
 
 CO 
 CO 
 
 eo 
 CJ 
 X 
 
 Id 
 
 o 
 o 
 o 
 
 CN 
 
 V 
 
 o 
 o 
 o 
 
 OJ 
 
 
 
 o 
 o 
 r-«. 
 
 CM 
 
 A 
 
 o 
 
 O 
 t>- 
 CM 
 
 A 
 
 
 
 
 
 o 
 
 
 
 
 O 
 
 A 
 
 c 
 
 o 
 l>J 
 
 A 
 
 s 
 oa 
 c 
 
 OS 
 
 l_ 
 
 J= 
 
 at 
 
 if 
 
 : 
 
 o 
 o 
 
 o 
 
 A 
 
 
 o 
 o 
 
 CO 
 CM 
 
 o 
 
 O 
 CC 
 
 o 
 o 
 
 CO 
 CM 
 
 o 
 o 
 
 CO 
 
 o 
 o 
 m 
 
 CM 
 
 q 
 o 
 
 o 
 
 
 o 
 o 
 
 00 
 
 A 
 
 in 
 
 in 
 
 
 
 a 
 ■ri 
 
 A 
 
 
 en 
 
 co 
 
 CO 
 
 iri 
 
 en 
 
 CO 
 
 CO 
 
 iri 
 
 >. 
 i- 
 o 
 
 •"-' cc 
 
 ■S 5 
 
 CO es 
 
 — fc. 
 CS 
 
 CO 
 
 o 
 o 
 
 o 
 
 »■■ 
 
 o 
 o 
 co 
 
 o 
 o 
 
 o 
 
 o 
 o 
 
 CM 
 
 o 
 o 
 
 o 
 
 o 
 in 
 
 p 
 o 
 
 CM 
 
 A 
 
 O 
 O 
 
 m 
 
 o 
 m 
 
 o 
 
 C5 
 
 w 
 
 o 
 o 
 m 
 
 o 
 
 o 
 
 o 
 
 a 
 
 CO 
 
 o 
 
 CO 
 
 o 
 o 
 
 00 
 
 p 
 
 in 
 
 ■0 
 
 iri 
 
 o 
 
 CO 
 
 m 
 iri 
 
 o 
 
 CO 
 
 
 o 
 iri 
 in 
 cm' 
 
 CO 
 
 oi 
 
 A 
 
 m 
 iri 
 
 o 
 
 CO 
 
 m 
 iri 
 
 o 
 
 CO 
 
 CD 
 
 en 
 
 c 
 
 es 
 
 i_ 
 
 1 
 
 
 p 
 in 
 
 
 o 
 o 
 >s- 
 
 p 
 
 CM 
 
 o 
 a 
 
 a 
 
 CM 
 
 a 
 o 
 
 CO 
 
 p 
 in 
 
 
 o 
 iri 
 
 p 
 
 CO 
 
 a 
 
 CO 
 
 
 
 in 
 
 CM* 
 
 o 
 cm' 
 
 
 CD 
 
 oi 
 
 CO 
 
 cn 
 
 oi 
 
 i 
 
 09 
 
 Cg CD 
 •— O) 
 
 S c 
 
 «= e5 
 
 cd 2 
 
 a 
 
 o 
 in 
 
 CM 
 p 
 
 o 
 cm' 
 
 
 o 
 in 
 
 o 
 o 
 
 CM 
 
 V 
 
 O 
 
 o 
 
 CM 
 
 V 
 
 p 
 in 
 
 V 
 
 
 p 
 
 CO 
 
 V 
 
 ■a 
 
 CM 
 
 V 
 
 C^. 
 
 <33 
 
 O 
 
 p 
 cm" 
 
 V 
 
 
 IO 
 
 p 
 
 V 
 
 CD 
 
 £ 
 J 
 
 ■Is 
 
 o 
 
 a. 
 
 J- 
 '5 
 
 i 
 
 -E jo 
 
 CO « 
 
 > cz 
 
 CD E 
 
 Is 
 
 £ -z: 
 
 t. rt 
 
 — CD 
 
 co .a 
 
 CO 
 
 E 73 
 © c 
 
 * E 
 
 > 2 
 -= c 
 £ 53 
 
 O) .C 
 CZ J, 
 
 "£ 2 
 
 CO i 
 
 
 
 
 
 E _» 
 2 g 
 
 CO E 
 
 > CD 
 
 CD ** 
 
 If 
 
 CJ ■•-> 
 
 E 5 
 
 ° t 
 
 S § 
 
 CD C 
 
 E <o 
 
 £ g 
 
 CO E 
 
 ^ <S 
 
 CD *" 
 
 I.E 
 
 o *- 
 
 E I 
 
 i i 
 
 03 C 
 
 CO 
 
 E 73 
 o c 
 
 -E 
 
 > £ 
 
 CD C 35 
 — C 
 
 ^i 
 
 CJ Co 
 " 03 
 C3) J2 
 C J, 
 
 ^ 1 
 
 CO i 
 
 E -i 
 2 £ 
 
 v^ - — 
 
 . E 
 co i- 
 
 > CD 
 
 — ^^ 
 
 CC CD 
 
 o .E 
 
 C3 CS 
 
 CD 
 
 CJ] ^3 
 
 C J, 
 
 lg 
 
 CO i 
 
 CO 
 
 E « 
 o cz 
 
 > £ 
 
 Jr c 
 
 « s 
 
 CJ) X3 
 C J, 
 
 fe I 
 
 CO i 
 
 CO 
 
 E 75 
 o c 
 
 £ £ 
 
 CD g 1 
 
 ^'1 
 " CD 
 cn jZ: 
 C J, 
 
 ^1 
 
 eo i: 
 
 co 
 
 E 73 
 
 o = 
 
 * E 
 
 CO CD 
 
 > — 
 
 • s 
 
 n 
 
 oi jz: 
 
 C J, 
 
 '^1 
 
 CO Jz 
 
 
 
 
 
 CO 
 
 E 75 
 o cz 
 
 •t E 
 
 £ £ 
 
 _ C 
 
 ^'i 
 
 cj eo 
 
 " 03 
 
 cn jcj 
 
 C J, 
 
 co i 
 
 E £ 
 
 2 g 
 
 «i E 
 
 * CD 
 
 CD *" 
 
 If 
 
 CJ «-< 
 
 E 2 
 
 9 "^ 
 
 i § 
 
 00 cz 
 
 E _^ 
 
 2 g 
 
 09 I 
 ^ CD 
 
 CD ** 
 
 1.E 
 E 2 
 
 ° t: 
 
 i » 
 
 00 c 
 
 
 CO I CO 
 
 I 
 
 x' 
 
 o £ 
 
 *- a. 
 a. 
 
 •5 
 
 
 1 
 
 1 
 "3- 
 
 o 
 
 1— 
 
 o 
 
 o 
 
 a 
 
 1 
 CO 
 
 in 
 
 o 
 
 o 
 
 i 
 •el- 
 
 I 
 
 75 
 
 es 
 
 > 
 
 CO 
 
 1 
 5 
 
 "3 
 
 > 
 cs 
 
 cz 
 
 ■c 
 c 
 
 es 
 03 '^ 
 
 c ® 
 
 |5 
 
 "CD 
 > 
 CS 
 
 e 
 
 -c 
 c 
 es 
 CS 
 CD 1 
 
 c 2 
 
 JS CS 
 
 o> 
 
 *es 
 
 CD '« 
 
 01 S 
 c £ 
 
 CS CS 
 
 <D 
 IC 
 'o 
 
 CD 
 
 Q. 
 
 CO 
 
 s 1 
 
 § si 
 
 o > 
 
 03 
 
 a 
 
 cz 
 
 CS 
 
 PS 
 CD '" 
 
 c 2 
 
 CS CS 
 
 o> 
 
 > 
 
 cs 
 
 c 
 
 ■a 
 c 
 
 CS 
 CS 
 
 5 1 
 
 c 2 
 es cs 
 
 6> 
 
 CD 
 JC 
 
 'cj 
 CD 
 
 o. 
 
 CO 
 
 CD | 
 C31 C 
 
 M 
 
 O ? 
 
 > 
 es 
 
 c 
 
 ■o 
 c 
 
 CS 
 CS 
 
 ■ £ 
 
 c £ 
 
 CS CS 
 
 6> 
 
 "3 
 
 > 
 
 CS 
 
 c 
 
 ■CJ 
 
 c 
 
 CS 
 CS 
 
 s 1 
 
 cz 2 
 es cs 
 
 6 > 
 
 CD ^ 
 l> 
 
 s « 
 
 o £ 
 
 > 
 es 
 
 c 
 
 03 
 
 cn 
 
 c 
 
 es 
 
 i~ 
 
 o 
 
 03 1 
 
 cn cz 
 
 es cs 
 
 'es 
 03 1 
 
 cn S. 
 c J» 
 
 es cs 
 
 o> 
 
 CD 
 
 cn 
 c 
 cs 
 
 L. 
 
 O 
 
 "es 
 cb 'S 
 =" E 
 
 c _03 
 
 CS CS 
 
 6 > 
 
 c 
 
 CD 
 
 E 
 
 CD 
 
 D 
 
 k 
 
 E 
 c >> 
 
 — 2- 1 
 i B j 
 
 73 cz ~ 
 
 1 
 
 
 
 
 
 
 
 
 
 cz 
 o 
 
 c 
 o 
 
 JZ) 
 JD 
 
 2 
 
 _3 
 O 
 
 co 
 fa 
 
 03 
 
 re 
 
 E * 7 
 .2 c 1 
 
 CJ CD <« 
 
 75 " « 
 Ski 
 
 cd a 
 
 £ °- Z 
 O cz J 
 
 h- - £ 
 
 s 
 > 
 
 5 
 
 I 
 
 | 
 
 
 
 
 
 
 
 
 I *i I 
 

 CN 
 
 to 
 
 CO 
 T3 
 03 
 
 ■_ 
 CB 
 
 I 
 
 ■a 
 c 
 
 CB 
 
 ea 
 
 CO 
 
 o 
 7s 
 
 CO 
 
 03 
 
 CB 
 CO 
 
 t_ 
 ce 
 
 > 
 
 CD 
 
 Q 
 
 E 
 
 o 
 
 1^ 
 
 T3 
 03 
 
 O 
 3 
 O" 
 CO 
 
 cB 
 
 CO 
 US 
 
 cn 
 
 ' c? 
 
 03 lO 
 "D CB 
 
 3 r" 
 
 03 
 
 z 
 
 CO 
 
 c 
 
 03 
 
 E 
 
 B. 
 
 03 
 
 f 
 
 o 
 
 E 
 o 
 
 &- 
 **- 
 
 ■a 
 
 CD 
 
 O 
 
 3 
 CT 
 
 CO 
 
 03 
 
 CO 
 
 in 
 
 cn ,— . 
 
 1— cn 
 ^ in 
 
 ^ CT> 
 
 1- T— 
 
 CD -—• 
 
 X) 
 
 "O CO 
 
 C t- 
 C3 « 
 
 CD ZZ 
 
 -* > 
 03 "^ 
 
 C 03 
 
 03 *"' 
 
 De Villiers and Beyers (1958) as quoted from 
 De Villiers et al. (1958) 
 
 03 
 
 75 
 co 
 
 b. 
 
 CD 
 
 > 
 CD 
 
 a 
 
 >. 
 
 X) 
 
 ■o 
 
 CD 
 
 O 
 3 
 C7 
 CO 
 03 
 
 CO 
 
 m 
 en 
 
 CO eo 
 
 i 2 
 
 03 S- ' 
 
 ca 
 
 in 
 
 cn 
 
 E 
 
 CO 
 
 -a 
 c 
 
 Ctf 
 03 
 
 x: 
 
 3 
 03 
 
 OC 
 
 in 
 
 CO 
 
 a> 
 
 _« 
 
 >. 
 
 CQ 
 
 3 
 
 a 
 
 ■a 
 c 
 
 03 
 
 CO 
 
 03 
 03 
 
 X 
 
 CO 
 
 m 
 
 en 
 
 n. 
 _E 
 
 !E 
 
 CO 
 
 ■o 
 c 
 
 03 
 N 
 
 '5 
 OC 
 
 00 
 
 m 
 
 i^ 
 
 CO 
 
 CD 
 
 c 
 o 
 
 ■a 
 c 
 
 CB 
 
 cf 
 o 
 "a 
 3 
 E 
 
 Ul 
 
 bT 
 
 CD 
 
 x: 
 
 3 
 CD 
 
 OC 
 
 en 
 
 03 
 
 c 
 
 03 
 
 E 
 
 Q. 
 CO 
 
 o 
 
 Carpena, Guillen, and Sanchez (1957) 
 
 Bathurst (,1958) as quoted by De Villiers et al. 
 (1958) 
 
 De Villiers and Beyers i1958) as quoted from 
 De Villiers et al. (1958) 
 
 S 
 
 x: 
 
 I 
 CO 
 
 ■c 
 c 
 
 03 
 I— 
 03 
 
 3 
 03 
 
 OC 
 
 in 
 
 in 
 
 cn 
 
 c 
 a 
 
 X 
 
 75 
 
 5 
 
 
 
 
 
 
 
 
 
 o.. 
 
 p 
 
 CO 
 CM 
 
 A 
 
 CD .— 
 
 | 1 <£ 1 o 
 
 O O (B A 
 
 6 1° /N 
 <^ >, 
 
 A ■=> 
 
 p 
 
 CO 
 CN 
 
 A 
 
 1 
 
 
 o- 
 
 o 
 eri 
 m 
 
 CN 
 
 
 
 
 
 o 
 iri 
 
 
 
 © 
 iri 
 
 CN 
 
 A 
 
 p 
 
 CN 
 
 o 
 
 
 
 p 
 
 CN 
 CN 
 
 o 
 
 
 
 o 
 o 
 
 o 
 
 CO 
 
 A 
 
 § 
 
 7 : 
 
 
 
 p 
 
 CO 
 
 A 
 
 o 
 o 
 
 '3-' 
 
 o 
 
 o 
 in 
 
 CN 
 
 o 
 tri 
 
 o 
 iri 
 
 CM 
 
 o 
 iri 
 
 o-. 
 
 p 
 
 CO 
 
 p 
 
 CD 
 
 
 
 c». 
 
 p 
 
 CO 
 
 iri 
 
 p p 
 
 o co' 
 
 O CO 
 CN i— 
 
 o o 
 
 cri r^ 
 
 r-- 00 
 
 p 
 o 
 
 o 
 
 CO 
 
 o 
 ez! 
 
 00 
 
 p 
 
 o 
 o 
 
 2 
 
 o 
 o 
 
 CM 
 O 
 
 o 
 
 CO 
 
 o .2 
 
 f*- o 
 
 CO u. 
 
 '1 
 
 
 
 
 
 
 o 
 in 
 o 
 
 CO 
 
 o 
 iri 
 p 
 
 a> 
 ■ri 
 
 
 
 CD 
 
 T 
 
 eo 
 
 CO 
 
 1 
 
 : 
 
 1 
 1 
 
 p 
 o 
 
 CO 
 
 o 
 o 
 
 CO 
 
 p 
 
 cz> 
 m 
 
 O 1 O CD CD -JJ 
 OS 00 03 CD ' CO 
 
 m co •- > o 
 
 O O TZ CO O 
 
 c§ Sisi 
 
 
 CO 
 
 en 
 o 
 
 
 O 
 
 o 
 o 
 
 z 
 
 cd 
 
 o 
 
 CO 
 
 V 
 
 
 p 
 
 p 
 
 CO 
 
 
 in 
 
 CO 
 
 V 
 
 P 
 
 o 
 m 
 
 o 
 
 CO 
 
 
 o 
 iri 
 
 CO 
 
 °. X. ° 
 co cd x: 
 i— -~^ 
 
 
 
 
 CO 
 
 E 75 
 o c 
 
 *E 
 
 > £ 
 
 co =? 
 
 « g 
 cn x 
 
 C J, 
 
 ^ 2 
 
 CO .fc 
 
 CO 
 
 E 75 
 o c 
 
 CD =? 
 
 CB X 
 C J, 
 
 co £: 
 
 CO 
 
 E -03 
 
 c 
 
 -t E 
 
 > £ 
 
 £'i 
 
 C3 03 
 " CD 
 
 01 X> 
 C J, 
 
 * 1 
 
 CO sfc 
 
 eo 
 
 E 75 
 o c 
 
 ■fc 1 
 
 CD g 1 
 
 &"i 
 
 O 03 
 " 03 
 O) XI 
 C J, 
 
 a"! 
 
 CO x: 
 
 E ra 
 2 .E 
 
 *". E 
 
 e» Jk 
 
 _> ® 
 
 CD g 1 
 
 « s 
 
 en .Q 
 
 C J, 
 
 l! 
 
 co £ 
 
 E J2 
 
 2 « 
 
 *^ . 
 
 CO E 
 
 > CO 
 
 CD ** 
 
 1.E 
 
 u *- 
 
 E S 
 
 ° *!= 
 
 -£ § 
 
 03 c 
 
 
 
 
 
 E J2 
 2 g 
 
 » E 
 
 > CB 
 
 CD ** 
 
 If 
 
 E 1 
 
 CO C 
 
 CO 
 
 E 75 
 o c 
 
 4=1 
 
 5 2 
 
 — C 
 
 O 03 
 " CD 
 
 cn xi 
 tz J, 
 
 * 1 
 co .£: 
 
 
 
 CO 
 
 E 75 
 o c 
 
 > £ 
 
 ca cn 
 — c 
 
 cj CB 
 
 " CD 
 
 cn X) 
 
 C J, 
 
 '1 = 
 co i: 
 
 CO 
 
 E 75 
 o c 
 
 * E 
 
 2 £ 
 
 cd CH 
 
 — c 
 
 ^"i 
 
 O 03 
 w CD 
 
 cn X! 
 
 C J_, 
 
 fc 1 
 
 CO i 
 
 E • 
 2 g 
 
 CO E 
 
 ^ CD 
 
 CD *" 
 
 I.E 
 
 C3 *- 
 
 E '= 
 
 5 g 
 
 CO c 
 
 
 
 
 : 1 - 
 1 
 
 1 
 
 1 o 
 CO 1 i— 
 
 o 
 
 o 
 
 1 
 
 
 
 i 
 
 i 
 
 CO 
 
 
 o 
 
 o 
 
 i^ 
 
 ^ 
 
 
 E 
 
 3 
 « 
 
 W 
 
 CD 
 
 cn 
 
 c 
 
 03 
 
 I. 
 
 o 
 
 CD 
 > 
 03 
 
 c 
 
 T3 
 C 
 03 
 03 
 CD '« 
 01 £ 
 
 c .£ 
 
 « 03 
 
 o> 
 
 CD ^-. 
 
 o S 
 
 CD 
 
 > 
 
 o" 
 
 c 
 
 •a 
 c 
 
 03 
 
 03 
 
 CD « 
 
 C « 
 03 03 
 
 6 > 
 
 "3 
 
 > 
 
 03 
 
 C 
 
 ■a 
 c 
 
 03 
 
 03 
 
 CO "5 
 
 c X? 
 JS 03 
 
 o> 
 
 03 « 
 
 2 « 
 
 o e 
 
 > 
 
 03 
 
 C 
 
 "O 
 
 c 
 
 CO 
 
 CB 
 
 CD « 
 
 c £ 
 
 03 o3 
 
 o> 
 
 cn 
 
 c 
 
 CB 
 
 L. 
 
 o 
 
 ■o 
 c 
 
 CB 
 
 H 
 
 ~ CD 
 
 O O 
 
 cn 
 
 _c 
 
 -S 
 
 CD 
 CD 
 CO 
 
 co 
 
 3 
 K. 
 
 b 
 
 'eB 
 
 to '« 
 °> H 
 
 c X? 
 
 2 5 
 o c. 
 
 CD <— , 
 
 2 « 
 o S 
 
 CD ^~. 
 |> 
 
 2 « 
 o S 
 
 "3 
 
 > 
 
 CB 
 
 C 
 
 T3 
 C 
 03 
 CB 
 CD 'p 
 
 c X? 
 
 03 03 
 
 o> 
 
 > 
 
 CB 
 
 C 
 
 ■D 
 C 
 03 
 03 
 CD "3 
 
 c _» 
 
 03 03 
 
 o> 
 
 CD 
 
 cn 
 
 c 
 
 CB 
 
 1* 
 
 O 
 
 ■a 
 c 
 
 CB 
 
 c 
 
 O 
 
 E 
 
 CD 4_, 
 
 £ S 
 
 c ® 
 2 | 
 O cn 
 
 
 
 
 
 CD 
 
 7s 
 
 E 
 
 =. is, 
 a. ^ 
 ° c 
 
 — S- o 
 03 O. c 
 
 3 
 
 i 
 
 i 
 
 
 
 
 
 
 
 
 
 03 
 
 E 
 
 >< 
 
 — 2- s 
 
 o3 Q- e 
 
 i 
 
 i 
 
 ! 
 
 
 
 
 
 
 
 z 
 o 
 c^ 
 z 
 
 o 
 Z 
 
 03 
 
 E 
 
 X) 
 03 
 
 ■c 
 c 
 
 CB 
 
 CB 
 
 ■=■3 
 
 >-S 
 
 w- 3 
 Jl 
 
 H- 03 
 
 [27] 
 
co 
 
 - 
 
 CO 
 
 « 
 
 E 
 
 a. 
 co 
 
 — 
 
 o 
 
 r-. 
 
 IO 
 
 C 
 03 
 CO 
 
 ■a 
 c 
 co 
 
 a 
 
 CO 
 O 
 
 CO 
 IO 
 CJ> 
 
 CO 
 
 a> 
 
 = 
 o 
 
 ■o 
 c 
 co 
 
 o 
 iE 
 
 E 
 
 3 
 CO 
 
 •a 
 o 
 ■o 
 
 — 
 00 
 
 ■a 
 c 
 co 
 
 c 
 
 CO 
 
 > 
 
 2 
 < 
 
 E 
 
 CO 
 
 CO 
 i_ 
 CO 
 
 £ 
 
 3 
 CO 
 
 CC 
 
 00 
 
 io 
 
 © 
 
 .a 
 E 
 uj 
 
 CO 
 
 CC 
 
 
 E 
 
 
 E 
 
 
 
 o 
 
 
 o 
 
 
 
 u. 
 
 
 
 
 
 *^ 
 
 
 «-■ 
 
 
 
 ■a 
 
 
 ■a 
 
 CD 
 
 
 
 o 
 
 3 
 CT 
 
 
 O 
 3 
 — 
 
 
 
 09 
 
 
 
 
 
 CO 
 
 
 CO 
 
 
 
 ^^ 
 
 
 co 
 
 
 
 00 
 
 
 
 
 
 IO 
 
 en 
 
 CO 
 
 00 
 
 to 
 
 en 
 
 co 
 
 
 
 to 
 
 
 IO 
 
 OS 
 
 i- 
 
 en 
 
 
 CO 
 
 CO 
 
 co 
 
 
 
 
 >, 
 
 
 
 
 ■a 
 
 
 CD 
 
 
 .d 
 
 co 
 
 "co 
 
 .Q 
 3 
 
 "ra 
 
 3 
 
 ■a 
 c 
 
 *- 
 
 O 
 
 -,--. 
 
 a. 
 
 CO 
 
 ^ 
 
 cu 
 
 c 
 
 S3 
 
 CO 
 
 ■o 
 
 </) 
 
 3 
 
 
 
 
 L. 
 
 
 CO 
 
 CO 
 
 03 
 
 CU 
 
 
 
 
 
 * 
 
 CO 
 
 31 
 
 
 31 
 
 o 
 
 ;= 
 
 > 
 
 -* 
 
 > 
 
 
 
 
 
 
 CO 
 
 > 
 
 CO 
 
 C 
 
 co 
 
 c 
 
 03 
 
 CD 
 
 a 
 
 CD 
 
 Q 
 
 > 
 
 Q 
 
 
 CC 
 
 
 en 
 rr 
 en 
 
 o3 
 E 
 
 a. 
 co 
 
 03 
 
 .O 
 3 
 £2. 
 C 
 
 C 
 O 
 
 0. 
 
 CO 
 IO 
 
 en 
 
 *""* oo 
 
 CD IO 
 
 ■o cn 
 
 3 *~ 
 
 03 "-' 
 
 CO 
 
 Q 
 
 E 
 
 o 
 
 00 
 
 cn °° 
 ?- >o 
 C- en 
 
 03 
 CO 
 
 '3' 
 IO 
 
 cn 
 
 E 
 
 CO 
 
 •a 
 c 
 
 03 
 
 3 
 CO 
 
 CC 
 
 
 
 CM 
 
 CM 
 
 IO 
 
 IO 
 
 en 
 
 cn 
 
 ^ 
 
 
 *■ — ■• 
 
 % — 
 
 co 
 
 CO 
 
 ■o 
 
 •a 
 
 OS 
 
 OS 
 
 Mm 
 
 t- 
 
 03 
 
 03 
 
 X 
 
 I 
 
 •a 
 
 ■o 
 
 c 
 
 c 
 
 OS 
 
 03 
 
 
 
 
 
 &- 
 
 Urn 
 
 03 
 
 03 
 
 -C 
 
 -C 
 
 
 
 x: 
 
 s. 
 
 CO 
 
 CO 
 
 
 
 
 
 o 
 
 o 
 
 
 
 OS 
 
 o3 
 
 CO 
 
 CO 
 
 CO 
 
 cn 
 
 CO 
 
 cn 
 
 "O 
 
 X 
 
 A 
 
 o >» •" 
 
 o i E 
 
 <? .= o 
 
 <i = a. 
 
 CM ~ E 
 
 f— >, 
 
 o 
 A 
 
 o 
 
 o 
 
 A 
 
 o 
 
 CM 
 
 CD 
 
 O 
 
 IO 
 
 A 
 
 A 
 
 CM 
 
 O 
 
 cn 
 
 o 
 cm' 
 
 cn 
 
 o 
 
 CM 
 
 O 
 IO 
 
 o 
 
 IO 
 
 o 
 A 
 
 o 
 
 <D 
 
 D 
 C 
 
 • — 
 
 ■♦- 
 C 
 
 o 
 u 
 
 CO 03 
 
 OS 
 CO 
 
 o 
 
 o 
 
 cn 
 
 O 
 
 o 
 
 CM 
 
 o 
 
 CO 
 
 o 
 
 CO 
 
 V 
 
 p 
 
 V 
 
 IO 
 
 o 
 
 o 
 
 CM 
 
 O 
 
 o 
 
 CM 
 
 o 
 
 CO 
 
 IO 
 
 o 
 
 V 
 
 CM 
 O 
 
 o 
 A 
 
 o 
 I 
 
 
 CO 
 
 < 
 
 o o 
 
 2 
 
 IO 
 
 CO 
 
 V 
 
 V 
 
 CM 
 
 O 
 
 V 
 
 IO 
 
 o 
 
 ^- 
 O 
 
 o 
 
 I 
 
 CO 
 
 o 
 a. 
 
 S.E 
 
 £ = 
 
 ■a c 
 o C 
 
 l- CD 
 
 co 1 
 
 > CD 
 
 E =. 
 
 9 t= 
 
 i ° 
 
 >. 
 c 
 
 < 
 
 a 
 
 co E 
 > I- 
 
 — CD 
 
 CD *• 
 
 If 
 
 cn '5 
 
 co 
 
 E » 
 
 P OS 
 
 9 *J= 
 
 I § 
 
 00 c 
 
 E « 
 o c 
 
 •£ E 
 
 " CD 
 
 CO £ 
 
 E * 
 
 o c 
 
 •fc I 
 
 co a? 
 
 en .a 
 co i: 
 
 E « 
 o c 
 
 * E 
 
 — .E 
 
 CO .fc 
 
 co 
 
 E * 
 
 o c 
 
 ■!= E 
 
 £ s 
 « g 
 
 cn xi 
 = Z 
 
 &1 
 
 CO i 
 
 * E 
 
 CD J2 
 
 c • 
 
 co iz 
 
 E -5 
 
 £ c 
 
 ^ E 
 
 > CD 
 
 
 _ I 
 
 I- c 
 
 Q. O 
 
 CO c 
 
 <*_ co 
 
 °*-£ 
 
 » 9 c 
 
 CO 
 
 T 
 
 CO 
 
 I 
 
 I 
 
 i 
 co 
 
 I 
 
 O 
 
 OS 
 O CO 
 
 E 3 
 
 CD lj 
 
 CD 
 
 > 
 
 c .» 
 « OS 
 O > 
 
 CO ® 
 
 OS 
 
 I- 
 
 O 
 
 CO CO 
 
 CO 
 
 O 
 
 CO 
 
 OS 
 CD "« 
 
 c ® 
 JO CO 
 
 A > 
 
 CO 03 
 £ > 
 
 os > 
 
 o £ 
 
 T3 
 C 
 OS 
 
 c *Z 
 
 CO CO 
 
 CO 
 
 > 
 
 
 
 C0 
 
 F 
 
 sT 
 
 3 
 
 co 
 
 CO 
 
 c 
 
 CO 
 
 3 
 
 *— ' 
 
 *~-^ 
 
 CD 
 
 CD 
 
 cn 
 
 at 
 
 c 
 
 c 
 
 CO 
 
 CO 
 
 K 
 
 c 
 
 O 
 
 O 
 
 CO 
 
 CD a) 
 
 a 
 
 k 
 1 
 
 CO 
 
 E . 
 >> c 
 
 c -a 8 
 
 ! il 
 
 « =>■ o 
 o c __ 
 
 CO 
 
 1 -° 
 
 ^ a- 2 
 
 5 E - 
 
 co -n *r 
 
 3 
 
 o 
 
 CD 
 
 [28 1 
 

 
 CD 
 
 
 • 
 
 CD 
 
 
 
 
 
 
 CO 
 
 
 CO 
 
 
 
 
 a 
 
 
 CO 
 
 a 
 
 
 
 
 
 
 CD 
 
 
 CO 
 
 
 
 
 >, 
 
 
 CD 
 
 >i 
 
 
 
 
 
 
 — 
 
 
 ^^ 
 
 
 
 
 x» 
 
 
 CO 
 
 X5 
 
 
 
 
 
 
 > 
 
 
 > 
 
 
 
 
 ■o 
 
 
 .£ 
 
 ■a 
 
 
 
 
 
 
 
 
 
 
 00 
 
 
 CO 
 
 o 
 
 
 CD 
 O 
 
 
 
 
 
 
 CD 
 
 a 
 
 CO 
 
 CD 
 
 a 
 
 
 
 
 3 
 
 
 > 
 
 3 
 C7 
 
 ed 
 
 
 
 
 'co 
 
 >. 
 
 IO 
 
 en 
 
 >. 
 
 
 T— 
 
 
 
 
 CD 
 
 CO 
 
 *r 
 
 
 CM 
 
 
 
 .o 
 
 
 x> 
 
 
 N — ^ 
 
 
 co 
 
 
 a 
 
 en 
 
 
 IO 
 
 
 *r 
 
 
 ■ 
 
 
 
 CO 
 
 
 CO 
 
 
 T - 
 
 
 en 
 
 
 o> 
 
 ■a 
 
 CD 
 
 CO 
 
 ■a 
 
 
 CD 
 
 c 
 
 
 00 
 
 
 X> 
 
 00 
 IO 
 
 ,_^ 
 
 
 
 
 *™ 
 
 CD 
 
 c 
 
 CO 
 
 *4 
 
 
 o 
 —1 
 
 •a 
 
 
 to 
 
 en 
 
 
 CD 
 
 en 
 
 to 
 
 cd 
 
 ■a 
 
 cd 
 
 
 en 
 
 o 
 
 3 
 
 er 
 
 o 
 
 — » 
 
 ■a 
 
 3 
 ZJ 
 
 co 
 
 cd 
 
 So 
 
 en 
 en 
 
 c 
 
 OS 
 
 c 
 
 
 W 00 
 
 CO «o 
 
 
 O 
 3 
 
 or 
 
 CO 
 
 CO ^, 
 fc CO 
 
 » en 
 
 c 
 
 o 
 
 CO 
 
 CO 
 
 x: 
 
 1 
 
 c 
 
 C8 
 
 03 
 
 IE 
 
 ed 
 1 
 
 c 
 o 
 
 CO 
 
 cd 
 
 c 
 cd 
 
 E 
 
 i 
 
 e 
 
 _CD 
 
 X) 
 
 E 
 
 en 
 
 T 
 
 en 
 
 3 C- 
 
 o 
 
 ~i _: 
 
 «o- 
 
 IO 
 
 OS 
 CO 
 
 in 
 
 C?5 
 
 ■a — 
 c eo 
 
 o 
 u 
 
 2 
 
 I 
 
 CO 
 
 ■a 
 
 XJ 
 
 3 
 Q. 
 C 
 3 
 
 o 
 
 JS 
 
 u 
 
 Z 
 
 00 
 IO 
 
 en 
 to 
 
 © 
 CO 
 
 E 
 
 ■o 
 
 en 
 
 — CO 
 
 s s 
 
 E C 
 
 Cd 
 
 a 
 
 ■o 
 c 
 
 LU 
 
 c 
 
 CO • 
 
 CD £ 
 
 en 
 
 — 
 
 CO ® 
 
 fe 2 
 
 := cd 
 
 T5 
 C 
 
 c 
 
 CO 
 
 s 
 
 c 
 
 fe °> 
 
 CD ,— 
 
 UJ 
 
 cd 
 
 CD 
 
 eo 
 
 E 
 
 JC CD 
 CD 1= 
 
 e3 
 
 
 eo 
 
 CD 
 
 CO 
 
 CD 
 
 cd 
 
 o _' 
 
 -= cd 
 
 CD 
 
 — 
 
 y "3 
 
 CD 
 
 3 
 00 
 
 o. 
 03 
 
 c — 
 >< > 
 
 CD "* 
 
 c 
 c 
 e 
 
 ^3 
 
 CD 
 
 3 
 CD 
 
 © 
 
 CO 
 
 CO 
 
 B 
 
 CO 
 
 "> 
 
 CD 
 
 t_ 
 
 CD *"* 
 
 5 • 
 
 3 
 CD 
 
 T3 ** 
 O • 
 
 co 
 
 C 
 
 cd 
 
 DC 
 
 o 
 
 cc 
 
 o 
 
 CQ 
 
 u 
 
 _l 
 
 DC 
 
 CO 
 
 > 
 
 -1 
 
 o 
 
 ac 
 
 a 
 
 > 
 
 to 
 
 en 
 
 E 
 co 
 
 ■o 
 c 
 ed 
 
 3 
 CD 
 
 CC 
 
 g 
 
 en 
 
 c 
 cd 
 
 X) 
 
 E 
 
 -' oo 
 
 £S 
 
 CD »~ 
 
 >> "* 
 
 CD _• 
 
 oo o: 
 
 I • 
 
 ■ 2 
 
 CO CD 
 
 t- — 
 
 CO = 
 
 = > 
 
 S Q 
 
 _ed 
 
 'eo 
 
 > 
 cd 
 
 © 
 
 ■a 
 c 
 ed 
 
 a 
 
 « 
 
 ■o 
 
 •a 
 
 CD 
 CO 
 
 cd 
 
 x 
 
 A 
 
 A 
 
 ■o 
 
 A 
 
 o 
 o 
 
 o 
 o 
 
 o 
 ed 
 
 o 
 o 
 
 A 
 
 A 
 
 
 IO 
 
 o 
 
 ed 
 
 I 
 co 
 
 CO 
 
 o 
 co 
 
 00 
 
 o 
 a 
 
 CM 
 
 A 
 
 o 
 o 
 
 o 
 o 
 
 IO 
 
 z 
 
 o 
 
 CO 
 
 o 
 
 o 
 
 o 
 
 o 
 
 CM 
 
 o 
 
 00 
 
 CN 
 
 o 
 
 
 IO 
 
 
 CM 
 
 CO 
 
 o 
 
 CN 
 
 o 
 
 CO 
 
 IO 
 <N 
 
 en 
 
 CM 
 
 en 
 
 CM 
 
 o 
 
 i 
 
 CO 
 
 CM 
 
 V 
 
 o 
 o 
 
 CO 
 
 q 
 ed 
 
 o 
 
 CO 
 
 CO 
 
 o 
 
 CO 
 
 o 
 o 
 
 V 
 
 o 
 id 
 
 q 
 ■d 
 
 q 
 id 
 
 V 
 
 o 
 
 o 
 
 ^» 
 
 V 
 
 o 
 o 
 
 o 
 
 q 
 id 
 
 
 q 
 
 V 
 
 IO 
 
 V 
 
 CO 
 
 a 
 ed 
 
 o 
 ed 
 
 to 
 
 o 
 ed 
 V 
 
 E « 
 .2 S 
 
 co e 
 
 ^ CD 
 
 CD *" 
 
 E 2 
 
 CO c 
 
 E S 
 o c 
 
 * E 
 
 o cd 
 
 " CD 
 
 C3) .Q 
 
 .E Z 
 
 co i: 
 
 CO 
 
 E 75 
 o c 
 
 * E 
 
 t £ 
 
 cj cd 
 
 " eo 
 
 en j2 
 
 co i: 
 
 ed 
 CD 
 
 .a 
 
 CO 
 
 t cd 
 
 £ .E ! _ 
 - E - E 
 
 CO 
 
 E 75 
 
 o c 
 
 co 5 
 
 o cd 
 " CD 
 
 en J3 
 
 CO £ 
 
 > S 
 
 © 
 
 o co 
 
 CD 
 
 en .n 
 c I 
 
 co .fc 
 
 CO E 
 
 > i- 
 
 — CD 
 
 eo ** 
 
 a. o 
 co c 
 
 E 75 
 o c 
 
 •*=! 
 
 | 2 
 
 d> CD 
 
 — C 
 
 CJ CO 
 CD 
 
 en ^ 
 
 CO i 
 
 E » 
 
 ° CO 
 
 co e 
 
 E 2 
 
 S 't: 
 
 I § 
 
 CO c 
 
 CO 
 
 E 75 
 o c 
 
 *■ E 
 
 fO fe 
 
 5 *^ 
 
 n £ 
 
 CO >t 
 
 S 
 
 o 
 
 l_ 
 en 
 
 C 
 _cd 
 
 Q. 
 
 E 
 
 o 
 
 E » 
 
 p ed 
 
 U5 
 
 .2 « 
 
 C -J 
 
 Q. 
 CO 
 
 co E co E 
 
 — CD I — » 
 CD ** CD 
 
 - « | "3 » 
 
 E 2 
 
 I! 
 
 00 c 
 
 en 3 
 
 a. o 
 
 CO c 
 
 T 
 
 ^r 
 
 CO 
 
 a. 
 ed 
 
 
 I 
 ^9- 
 
 I 
 
 cd c: 
 
 3 
 CO CD 
 
 > -a 
 
 : cd 
 
 ■ CO 
 
 ■o 
 
 CD 
 CO 
 
 2 
 
 co cd 
 
 CD -— v 
 
 5 g 
 
 ■o 
 c 
 ed 
 cd 
 CD '« 
 
 =» E 
 
 2 « 
 o c- 
 
 03 
 
 t- 
 
 o 
 
 2 « 
 O C- 
 
 CD 
 
 > 
 
 ed 
 
 c 
 
 ■o 
 c 
 ed 
 cd 
 
 CD '« 
 
 c * 
 
 2 « 
 
 cd 
 
 > 
 
 
 ■^-^ 
 
 
 CD 
 
 CD 
 
 en 
 
 ex 
 
 C 
 
 c 
 
 ed 
 
 cd 
 
 
 
 
 
 
 x: 
 
 ^-^ 
 
 
 CO 
 
 3 
 
 
 co 
 
 CO 
 
 
 s 
 
 c 
 
 
 v — ' 
 
 3 
 
 
 *- 
 
 ^--^ 
 
 
 3 
 
 CD 
 
 CD 
 
 L> 
 
 en 
 
 en 
 
 CD 
 
 c 
 
 c 
 
 a. 
 
 cd 
 
 cd 
 
 CO 
 
 L. 
 
 t> 
 
 E 
 
 o 
 
 O 
 
 a 
 
 to « 
 a) c 
 c ® 
 
 2 J« 
 
 CO 
 
 s 'H 
 
 en E 
 
 c _es 
 
 2 « 
 
 CD 
 
 en 
 
 c 
 
 CO 
 
 c ^ 
 eo eo 
 
 c ^ 
 
 eo co 
 
 t- «^ 
 
 CD 
 
 9 S 
 
 ii 
 
 «d ^ 
 
 cd - 
 
 ed a £ 
 £ -E - 
 
 c CO 
 CD C 
 
 •a = 
 
 xi >, 
 
 >« •- 
 
 75 ■= 
 
 E |c 
 
 _ Q. co 
 co Q. cd 
 
 PS*. 
 
 [29] 
 
<D 
 
 D 
 
 C 
 
 O 
 
 u 
 
 CO 
 < 
 
 CO 
 
 CD 
 O 
 
 c 
 
 CD 
 
 b. 
 33 
 
 % 
 
 DC 
 
 De Villiers and Beyers (1958) as quoted from 
 De Villiers et al. (1958) 
 
 Reyneke and Joubert (1958) as quoted from De 
 Villiers et al. (1958) 
 
 OS 
 
 es 
 
 ■o 
 si 
 
 3 
 
 a. 
 c 
 
 3 
 
 *-» 
 c 
 o 
 Q. 
 
 Bathurst (1958) as quoted from De Villiers 
 etal. (1958) 
 
 Naude (1958) as quoted from De Villiers et al. 
 (1958) 
 
 w 
 
 OS 
 
 es 
 
 ■a 
 
 es 
 t- 
 es 
 
 X 
 
 •a 
 c 
 
 es 
 
 'C 
 
 es 
 SZ 
 IE 
 
 CO 
 
 o 
 es 
 CO 
 
 OS 
 
 rr 
 
 OS 
 
 c 
 es 
 
 E 
 
 a. 
 es 
 
 SZ 
 
 o 
 
 S 
 
 en 
 
 sz 
 E 
 
 CO 
 
 ■a 
 c 
 es 
 
 t- 
 
 CD 
 
 SZ 
 
 3 
 03 
 
 DC 
 
 Morris (1958) as quoted from De Villiers et al. 
 (1958) 
 
 m 
 
 «3" 
 
 os 
 
 CD 
 
 E 
 
 'CD 
 
 sz 
 c 
 
 CD 
 
 Q. 
 
 a. 
 O 
 
 00 
 
 OS 
 
 'es 
 
 r- 
 
 ■a 
 c 
 es 
 
 CO 
 
 CO 
 
 m 
 
 OS 
 
 CO 
 
 CD 
 
 C 
 
 o 
 —1 
 
 •o 
 c 
 
 CO 
 
 c 
 o 
 
 £ 
 
 S3 
 
 E 
 
 UJ 
 
 lT 
 
 CD 
 
 sz 
 
 3 
 CD 
 
 QC 
 
 De Villiers and Beyers (1958) as quoted by 
 De Villiers et al. (1958) 
 
 Reyneke and Joubert (1958) as quoted by De 
 Villiers et al. (1958) 
 
 2 
 
 •a 
 si 
 
 3 
 
 a. 
 c 
 
 3 
 
 c 
 o 
 
 Q. 
 
 Bathurst (1958) as quoted by De Villiers et al. 
 (1958) 
 
 Naude (1958) as quoted by De Villiers et al. 
 (1958) 
 
 OS 
 OS 
 
 c 
 es 
 
 E 
 
 n. 
 es 
 
 SZ 
 
 O 
 
 S 
 
 OS 
 
 r— 
 
 SZ 
 
 E 
 
 CO 
 
 ■o 
 c 
 es 
 
 Urn 
 
 CD 
 
 SZ 
 
 3 
 CD 
 
 CC 
 
 03 
 
 ea 
 c 
 
 CO 
 
 ■_ 
 
 CO 
 CO 
 CD 
 U 
 X 
 
 UJ 
 
 
 
 
 m 
 ej 
 
 A 
 
 
 
 o 
 
 lO 
 
 CO 
 
 A 
 
 o 
 
 CO 
 CO 
 
 A 
 
 
 
 
 CO 
 CO 
 
 A 
 
 
 
 
 : : 
 
 o 
 
 CO 
 
 o 
 
 cv. 
 
 o 
 
 CO 
 
 o 
 
 A 
 
 High range 
 
 2.4-2.6 
 2.6-2.8 
 
 
 m 
 
 CN 
 
 i 
 
 CO 
 
 cm 
 
 
 
 
 m 
 
 CO 
 
 q 
 
 CO 
 
 
 
 
 CM 
 CO 
 
 1 
 
 00 
 CM 
 
 CM r- 
 
 o o 
 
 I I 
 CM CM 
 
 O* O 
 
 
 
 o 
 et 
 
 
 
 OS 
 CM 
 O 
 
 o 
 
 Satisfactory 
 range 
 
 1.8 2.4 
 2.0-2.6 
 
 eo >n 
 
 CM* OJ 
 
 
 CO 
 
 cm 
 
 i 
 
 GO 
 
 p in 
 cm' cm 
 
 A A 
 
 o 
 
 CO 
 
 1 
 
 00 
 
 evi 
 
 CO 
 CO 
 
 o 
 evi 
 
 OS 
 CN 
 
 1 
 «3" 
 CM - 
 
 03 
 
 A 
 
 m 
 
 CM 
 
 CO 
 
 1 
 
 CO 
 
 CM 
 
 cm" 
 
 1 
 
 ^ , 
 cm" 
 
 CM CM 
 
 O O 
 
 I I 
 OO oo 
 o o 
 
 O CS 
 
 o 
 
 CM 
 Q 
 
 o 
 
 0.09-0.11 
 
 00 
 
 o 
 o 
 A 
 
 00 
 
 o" 
 
 OS 
 
 o 
 o 
 
 CO 
 
 p 
 
 CM 
 
 d 
 
 Low range 
 
 1.6 1.8 
 1.8-2.0 
 
 
 CO 
 
 
 
 
 CO 
 CM 
 
 cm' 
 
 
 
 
 CO 
 CM 
 
 e 
 
 cm" 
 
 00 00 
 
 o o 
 o o 
 
 V V 
 
 
 
 oo 
 
 o 
 o 
 V 
 
 
 
 o 
 
 Deficient 
 range 
 
 1.3 1.6 
 1.5 1.8 
 
 i— 1— 
 
 OS 
 CO 
 
 
 
 00 
 
 in 
 
 o 
 o 
 
 CM 
 
 V 
 
 o 
 o 
 
 CM 
 
 V 
 
 CO 
 
 V 
 
 o 
 
 CM 
 
 V 
 
 0.6-2.3 
 
 OS 
 
 V 
 
 
 
 CM 
 
 CO 
 
 o 
 o 
 
 
 
 in 
 
 o 
 o 
 
 00 
 
 o 
 o 
 V 
 
 Position on tree 
 
 Spring cycle Ivs. from 
 fruit-bearing terminals 
 
 Spring cycle Ivs. from 
 fruit-bearing terminals 
 
 
 
 Spring cycle Ivs. from 
 fruit-bearing terminals 
 
 Spring cycle Ivs. from 
 fruit-bearing terminals 
 
 
 
 Spring cycle Ivs. from 
 fruit-bearing terminals 
 
 Spring cycle Ivs. from 
 nonfruiting terminals 
 
 Spring cycle ivs. from 
 fruit-bearing terminals 
 
 
 
 Ol 
 
 c 
 'il 
 
 CO 
 CD 
 
 X3 
 i 
 
 *-» 
 
 '5 
 t. 
 **— 
 
 >- co 
 «*- — 
 
 CO g 
 
 CD .E 
 
 i i 
 
 CD •— 
 
 —i -^ 
 
 Bloom cycle Ivs. from 
 nonfruiting terminals 
 
 Spring cycle Ivs. from 
 fruit-bearing terminals 
 
 Spring cycle Ivs. from 
 fruit-bearing terminals 
 
 
 Spring cycle Ivs. from 
 fruit-bearing terminals 
 
 Spring cycle Ivs. from 
 fruit-bearing terminals 
 
 Spring cycle Ivs. 
 fruit-bearing terminals 
 
 Spring cycle Ivs. from 
 nonfruiting terminals 
 
 Age of 
 
 leaf 
 
 (months'! 
 
 o o I o 
 
 I 
 
 
 o 
 
 o o ! 
 
 1 
 
 i 
 
 CO 
 
 1 
 
 o 
 
 CM 
 
 1 
 
 00 
 
 
 i 
 
 o 
 
 o 
 
 m 
 
 o 
 
 e 
 
 i 
 co 
 
 i 
 
 Citrus variety 
 
 Orange (Valencia) 
 Orange (navel) 
 
 Orange Valencia'! 
 Orange (naveH 
 
 Orange i navel) 
 
 Orange 
 Valencia 1 ) 
 
 Orange (Valencia) 
 Orange (navel) 
 
 "is 
 
 E 
 
 3 
 (/> 
 
 "a 
 CO 
 
 CD 
 Ol 
 
 C 
 es 
 
 6 
 
 Orange 
 
 (Valencia and navel) 
 
 CD 
 Ol 
 
 C 
 CO 
 
 c 
 O 
 
 03 
 Ol 
 
 c 
 
 CO 
 
 i_ 
 O 
 
 3 
 O 
 
 E 
 cs 
 sz 
 CO 
 
 CO 
 
 Ol 
 
 c 
 
 CO 
 
 ■_ 
 
 o 
 
 sz 
 
 CO 
 
 %m 
 
 es 
 
 '5 
 &_ 
 
 B 
 a. 
 
 CS 
 
 k 
 
 C3 
 
 es to 
 
 6 > 
 
 Orange (navel) 
 Orange (Valencia) 
 
 "3 
 
 > 
 
 es 
 
 C 
 
 T3 
 
 c 
 
 es 
 
 CS 
 
 CD 'p 
 
 C • 
 
 cs es 
 
 o> 
 
 "5 
 
 > 
 
 es 
 
 C 
 
 CD 
 Ol 
 
 C 
 es 
 
 o 
 
 "eS 
 CD "5 
 
 Ol c 
 
 c £ 
 
 CS CS 
 
 o> 
 
 Orange 
 
 (Valencia and navel) 
 
 Orange 
 
 03 
 O) 
 
 c 
 es 
 
 E 
 
 o 
 
 Element 
 
 Total nitrogen 
 in per cent dry 
 
 — 
 
 I 
 
 5 
 ■ 
 
 n 
 
 E 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 Total phosphorus 
 in per cent dry 
 
 CS 
 13 
 
 ■ 
 
 o 
 
 L. 
 
 B 
 
 ■ 
 E 
 
 
 
 
 
 
 f 30 1 
 
^-*s 
 
 
 CM 
 
 
 in 
 
 
 CD 
 
 
 
 
 ^— ' 
 
 
 « 
 
 
 ■o 
 
 
 es 
 
 
 L. 
 
 
 es 
 
 
 I 
 
 ,_^ 
 
 
 ■n 
 
 ■o 
 
 rr 
 
 c 
 
 en 
 
 es 
 
 
 
 
 
 
 i_ 
 es 
 
 .E 
 
 E 
 
 
 
 x: 
 
 OJ 
 
 CO 
 
 .E 
 
 — 
 
 c 
 
 
 cd 
 
 o 
 
 o. 
 
 « 
 
 a. 
 
 CO 
 
 O 
 
 00 
 
 T 
 
 fv» 
 
 OS 
 
 c 
 es 
 
 UJ 
 
 CO 
 
 in 
 
 CO 
 
 co 
 
 - 
 e 
 o 
 
 ■c- 
 c 
 
 (53 
 
 E 
 uj 
 
 3 
 
 cc 
 
 >> 
 
 CD 
 
 
 
 T 
 
 • 
 
 ! 
 
 
 
 
 
 
 
 
 
 -O 
 
 a 
 
 
 
 ca 
 
 CO 
 
 es 
 
 
 
 
 
 
 
 
 
 CD 
 
 >> 
 .o 
 
 
 
 CD 
 
 CD 
 
 CD 
 
 
 
 
 
 
 
 
 
 
 
 
 
 co 
 
 CO 
 
 CO 
 
 
 
 
 
 
 
 
 
 
 •o 
 
 
 
 
 fa. 
 
 fa. 
 
 
 
 
 
 
 
 
 
 3 
 
 CD 
 
 
 
 CD 
 
 CD 
 
 CD 
 
 
 
 
 
 
 
 
 
 er 
 
 CO 
 
 ca 
 
 O 
 3 
 
 er 
 
 
 
 > 
 
 > 
 
 > 
 
 
 
 g 
 
 CO 
 
 
 
 
 
 
 co 
 io 
 
 Oi 
 
 CO 
 
 cs 
 
 cc 
 
 
 
 CD 
 
 D 
 
 CD 
 
 a 
 
 CD 
 
 a 
 
 ■o 
 
 CD 
 O 
 
 3 
 
 er 
 
 CO 
 
 cd 
 
 
 
 E 
 o 
 
 CM 
 
 IO 
 
 
 00 
 
 co 
 
 Oi 
 
 
 
 Beyers (1 
 al. (1958) 
 
 ubert (195 
 11958) 
 
 
 
 n 
 
 CD 
 
 O 
 
 3 
 
 er 
 
 CO 
 
 ■o 
 
 CD 
 
 © 
 
 3 
 CT 
 
 co 
 
 O 
 IO 
 O 
 
 B 
 S 
 
 o 
 
 S 
 
 CD 
 
 2 
 E 
 Ul 
 
 T3 
 C 
 CS 
 
 CS 
 CS 
 
 fa. 
 
 CS 
 
 X 
 
 ■c 
 c 
 
 
 "3 
 
 C 
 CD 
 
 | 
 
 T 
 
 r«. 
 
 o> 
 
 'rt 
 
 r- 
 
 
 rs and 
 ers et 
 
 
 S? 
 
 r*. 
 rr 
 
 CS 
 
 CO 
 IO 
 
 o> 
 
 CS 
 
 00 
 IO 
 
 CO 
 
 CO 
 
 in 
 as 
 
 CO 
 
 ■a 
 c 
 
 cs 
 
 E 
 co 
 
 ■o 
 c 
 
 CS 
 fa. 
 CD 
 
 x: 
 
 CO 
 
 CD 
 
 c 
 o 
 
 —j 
 
 es 
 
 cs 
 
 x: 
 
 faj 
 CD 
 
 E 
 
 CS 
 
 E 
 
 CO 
 
 CD — 
 = > 
 > CD 
 
 CD £ 
 J* CD 
 
 CD \=. 
 
 e := 
 
 c 
 ca 
 E 
 
 Q. 
 
 
 ""' 00 
 
 cd io 
 
 ■o CO 
 
 „. oo 
 
 i_ CJ5 
 
 (O CO 
 
 I 2 
 
 e 
 
 CS 
 
 E 
 a. 
 
 fa. 
 
 CD 
 
 — 
 
 CO 
 
 CD 
 
 -E 
 
 c 
 
 CD 
 
 CD 
 
 JC 
 
 e 
 
 CD 
 
 ■o 
 c 
 
 CS 
 
 c 
 
 CS 
 
 E 
 
 a. 
 
 ^ D 
 
 2? > 
 
 CO 
 
 c 
 
 3 J- 
 
 
 es 
 
 3 
 
 3 
 
 
 a. 
 
 — 
 
 
 es 
 
 CD *"* 
 
 CD "^ 
 
 J= 
 
 < 
 
 CS ' 
 
 s 
 
 CS v "' 
 
 -C 
 
 CD 
 
 CD 
 
 
 a 
 
 S. 
 
 
 .e 
 
 Q 
 
 CC 
 
 O 
 
 Z 
 
 CQ 
 
 O 
 
 CC 
 
 CC 
 
 CO 
 
 O 
 
 o 
 
 UJ 
 
 O 
 
 
 E 
 c/> 
 
 3 
 CD 
 
 CC 
 
 f 
 
 a. 
 
 CD 
 
 — 
 es 
 
 A 
 
 o m 
 
 CM t^ 
 
 A A 
 
 cm' 
 
 A 
 
 o 
 A 
 
 cm" 
 
 A 
 
 CNJ 
 
 A 
 
 A 
 
 o 
 A 
 
 o io 
 
 IO o 
 
 CNJ 
 
 oi 
 
 M 
 
 CN 
 
 I 
 
 00 
 
 cm' 
 
 t 
 
 CO 
 
 IO 
 
 
 CM 
 
 o 
 
 O 
 
 IO 
 
 IO 
 
 v~ 
 
 ^~ 
 
 o 
 
 o 
 
 o 
 
 o 
 
 CM 
 
 o 
 
 CM 
 O 
 
 l>» IO 
 
 o o 
 
 A 
 
 A 
 
 CM 
 
 I 
 
 IO 
 
 o 
 
 CM 
 
 o 
 
 !». 
 
 O 
 CM 
 
 
 o 
 V 
 
 a 
 i 
 e*» co 
 
 a 
 
 IO 
 
 i 
 
 o 
 
 »3" 
 
 O 
 
 a 
 
 = 
 co 
 
 o 
 
 o 
 o 
 
 00 
 
 
 o 
 
 
 o 
 
 oo 
 
 o 
 
 r-. 
 
 o 
 
 o 
 
 o 
 
 
 CM 
 
 a 
 
 s 
 
 o 
 
 o 
 V 
 
 CO CO 
 
 o o 
 
 V V 
 
 a 
 V 
 
 o 
 
 V 
 
 CO 
 
 o 
 
 V 
 
 CO 
 
 o 
 
 V 
 
 V 
 
 r*. 
 
 
 
 rr 
 
 
 
 
 IO 
 
 CM 
 
 
 CM 
 
 rr 
 
 o 
 
 a 
 
 o 
 
 o 
 
 
 
 CO 
 
 CD 
 
 •a 
 c 
 
 es 
 
 es 
 
 CD 
 
 es 
 CD 
 
 E » 
 
 co c 
 
 ^ CD 
 
 CD ** 
 
 18 
 
 E E 
 
 I 1 
 
 ca c 
 
 E « 
 o c 
 
 4=1 
 
 CD X3 
 C J, 
 
 CO 
 
 E « 
 o c 
 
 4=1 
 
 en X3 
 C J, 
 
 c/5 i: 
 
 £■= 
 
 es 
 CD 
 
 X3 
 
 .E — 
 
 a, 
 C5 
 
 CO 
 
 E 73 
 o c 
 
 4=1 
 
 CO £ 
 
 — c 
 
 C31 X3 
 
 c/> i: 
 
 a. 
 
 CO 
 
 E « 
 o c 
 
 4=1 
 
 li 
 
 " CD 
 O) X5 
 C i 
 
 05 i: 
 
 E « 
 o c 
 
 4=1 
 
 • c? 
 
 w CD 
 
 en — 
 "^ 1 
 
 .E vfc 
 
 l- c 
 
 a. o 
 
 C75 c 
 
 E « 
 o c 
 
 4=1 
 
 es 
 
 CD 
 
 CO ^ 
 
 es 
 CD 
 
 CO 
 
 E "es 
 o c 
 
 4=1 
 
 > £ 
 
 cj es 
 
 " CD 
 
 en .a 
 
 E 
 
 fe £2. =• 
 
 £ cy> i 
 
 .E i 
 
 oo 
 
 I 
 
 I 
 
 CO 
 
 IV» 
 
 I 
 
 CO 
 
 i 
 
 >3- 
 
 I 
 
 co 
 
 
 
 CS 
 
 E 
 
 3 
 
 o 
 
 3 
 CO 
 
 E 
 
 es 
 
 CS 
 
 f 
 
 CO 
 
 CO 
 
 V — ' 
 
 *• — 
 
 CD 
 
 CO 
 
 en 
 
 en 
 
 c 
 
 B 
 
 CS 
 
 es 
 
 L. 
 
 ■_ 
 
 o 
 
 o 
 
 S es 
 
 2 | 
 
 a S 
 
 es cs 
 
 CD CD 
 
 « CS 
 
 > C 
 
 CS CS 
 
 k — 
 
 O O 
 
 CD CD 
 
 3 CS 
 
 > c 
 
 CD CD 
 
 en en 
 
 c c 
 
 es es 
 
 l_ L. 
 
 o o 
 
 es 
 
 o 
 
 •a 
 c 
 
 es 
 CS 
 
 c ■ 
 
 JS cS 
 
 A > 
 
 CS 
 CD « 
 
 E i? 
 es cS 
 
 o> 
 
 CS 
 
 2 'I 
 = i? 
 
 es es 
 
 CD 
 
 — 
 - 
 CS 
 
 es es 
 A > 
 
 
 
 
 
 
 
 cS 
 
 E 
 
 3 
 O 
 
 
 3 
 
 E 
 
 
 
 
 
 
 
 es 
 
 — 
 
 CD 
 
 CO 
 
 CO 
 
 CD 
 
 
 
 s 
 
 CD 
 
 CD 
 
 — 
 
 ca 
 
 c 
 
 c 
 
 CD 
 
 es 
 
 CS 
 
 In 
 
 E 
 
 o 
 
 o 
 
 - 1 i 
 
 CD CO 
 
 c § 
 
 a 5 
 
 CD 
 
 en 
 
 c 
 
 CS 
 
 i *~ 
 
 .- "o "S 
 
 CS Q) y 
 
 o » o 
 a i_ t_ 
 
 _ CD CD 
 
 « a g 
 
 O E g 
 r- ~ E 
 
 >■ 
 
 I E -S 
 
 -O CD m- 
 
 O « O 
 
 CO L. I_ 
 
 _ CD CD 
 
 s as 
 ££ I 
 
 CS 
 
 r 
 
 > 
 
 
 >, CD 
 
 B 
 
 J2~ 
 
 E 9 
 
 = 
 
 • — 
 
 .-. 
 
 > co 
 
 
 
 — 
 
 en "5 
 
 
 
 - 
 
 CD e 
 
 JZ 
 
 3 
 
 *" 
 
 -= ~ 
 
 CD 
 
 es cd 
 
 O 
 
 >■= 
 
 c 
 
 — 3 
 
 CD 
 
 cS TT 
 
 — 
 
 ȣ 
 
 > 
 
 
 .-,. 
 
 -%? 
 
 e 
 
 r- es 
 
 £. 
 
 « "3 
 
 4— 
 
 CD 
 
 
 CO 
 
 
 CS 
 
 
 X3 
 
 
 [31] 
 
D 
 C 
 
 o 
 u 
 
 < 
 
 
 CO 
 
 CD 
 U 
 
 C 
 
 ■ 
 k 
 
 9 
 "5 
 CC 
 
 00 
 CO 
 05 
 
 c 
 
 03 
 
 E 
 
 CD 
 k 
 
 iZ 
 
 ■a 
 c 
 
 03 
 
 k 
 _CD 
 
 i 
 
 C 
 
 'S 
 
 k 
 03 
 
 X 
 
 CO 
 
 3 
 
 CT> 
 
 CO 
 CD 
 
 E 
 O 
 
 "O 
 
 E 
 
 03 
 
 E 
 o 
 
 "S 
 
 £ 
 
 E 
 Ul 
 
 fcj* 
 CD 
 
 sz 
 
 3 
 CD 
 
 CC 
 
 cn 
 
 «3- 
 
 O) 
 
 c 
 
 03 
 
 E 
 
 Q. 
 03 
 JC 
 
 o 
 
 IO 
 
 CD 
 
 £ 
 I 
 
 to 
 
 ■a 
 c 
 
 03 
 k 
 CD 
 
 £ 
 
 3 
 CD 
 
 CC 
 
 oo 
 10 
 
 cn 
 
 c 
 
 03 
 E 
 CD 
 
 k 
 
 iZ 
 
 ■o 
 c 
 
 03 
 
 k 
 _JD 
 
 i 
 
 cn 
 
 B 
 
 '■5 
 
 k 
 
 03 
 
 I 
 
 Reuther, Embleton, and Jones (1958) 
 
 cn 
 
 o 
 
 r« 
 
 C 
 03 
 
 E 
 
 a. 
 
 03 
 
 £ 
 
 o 
 
 "o3 
 
 — 
 CS 
 
 £ 
 
 3 
 £3. 
 E 
 3 
 
 E 
 O 
 
 a. 
 
 Bathurst (1958) as quoted from De Villiers 
 etal. (1958) 
 
 S 
 
 cn 
 
 I 
 CO 
 
 ■o 
 
 E 
 03 
 k 
 CD 
 JE 
 
 3 
 CD 
 
 CC 
 
 00 
 CM 
 
 cn 
 
 CO 
 
 03 
 
 E 
 
 o 
 
 -Z 
 
 p- 
 
 ■o 
 
 E 
 03 
 
 CO 
 
 03 
 03 
 
 X 
 
 
 00 
 
 to 
 cn 
 
 CO 
 
 CD 
 
 E 
 O 
 "1 
 
 ■a 
 
 E 
 03 
 
 E 
 
 O 
 CD 
 
 £ 
 
 E 
 Ul 
 
 k 
 CD 
 
 E 
 
 3 
 CD 
 CC 
 
 en 
 
 cn 
 
 E 
 03 
 E 
 
 a 
 
 03 
 
 £ 
 
 o 
 
 Reyneke and Joubert (1958) as quoted by De 
 Villiers et al. (1958) 
 
 Bathurst (1958) as quoted by De Villiers et al. 
 (1958) 
 
 to 
 en 
 
 £ 
 
 E 
 
 CO 
 
 ■a 
 
 E 
 03 
 k 
 CD 
 
 £ 
 
 3 
 CD 
 CC 
 
 CM 
 IO 
 
 cn 
 
 OS 
 
 ■o 
 
 03 
 
 k 
 03 
 
 X 
 ■o 
 
 E 
 03 
 
 1m 
 
 03 
 
 E 
 
 !e 
 w 
 
 c 
 
 CO 
 
 
 CO 
 IO 
 
 cn 
 
 sz 
 
 1 
 
 CO 
 
 1 
 1 
 
 1 
 
 00 
 IO 
 
 cn 
 
 CO 
 
 CD 
 
 E 
 O 
 "1 
 
 •a 
 
 E 
 CO 
 
 E 
 
 o 
 _? 
 
 £ 
 
 E 
 Ul 
 
 k 
 
 CD 
 
 £ 
 
 m* 
 3 
 
 CD 
 
 CC 
 
 
 CD 
 
 en 
 
 c 
 
 03 
 
 k 
 CO 
 CO 
 CD 
 
 o 
 
 X 
 
 111 
 
 r-. 
 
 CO 
 
 o 
 A 
 
 IO 
 
 CM 
 
 o 
 
 A 
 
 IO 
 
 CM 
 O 
 
 p— 
 
 o 
 
 A 
 
 O 
 
 d 
 A 
 
 o 
 
 A 
 
 o 
 d 
 
 
 
 C-. 
 
 o 
 
 CO 
 
 d 
 
 A 
 
 a 
 
 o 
 
 00 
 
 d 
 
 O 
 CO 
 
 d 
 
 A 
 
 
 
 o 
 d 
 
 o 
 
 A 
 
 r— 
 
 o 
 
 d 
 
 o 
 
 CO 
 
 A 
 
 
 00 
 
 d 
 
 «k 
 O 
 
 d 
 
 o 
 
 CO 
 
 A 
 
 
 CD 
 
 oa 
 c 
 
 03 
 
 k 
 
 ca 
 
 i 
 
 
 CM 
 
 o 
 o 
 
 
 o 
 
 CO 
 
 o 
 o 
 
 o 
 
 
 o 
 
 CO 
 
 o 
 o 
 
 o 
 
 
 
 o 
 
 IO 
 
 d 
 
 A 
 
 c— 
 
 o 
 
 IO 
 
 d 
 
 C3 
 
 d 
 
 
 o 
 
 IO 
 
 d 
 o 
 
 d 
 
 
 
 p 
 d 
 
 o 
 
 d 
 
 C-. 
 
 p 
 d 
 
 o 
 
 CM 
 d. 
 
 d 
 
 
 
 p— 
 
 o 
 
 d 
 
 o 
 
 CM 
 
 O 
 
 d 
 
 
 >-, 
 
 k 
 O 
 
 _ aj 
 
 « s 
 
 .2 e 
 
 CO 03 
 
 •p. L. 
 
 03 
 CO 
 
 
 CO 
 
 o 
 
 V 
 
 o 
 
 CM 
 
 O 
 
 1 
 CM 
 
 o 
 o 
 
 o 
 
 CO 
 
 a 
 
 V 
 
 
 o 
 
 CO 
 
 o 
 
 V 
 
 o 
 
 CO 
 
 o 
 o 
 
 CM 
 
 o 
 
 d 
 
 o 
 
 IO 
 
 d 
 
 o 
 
 CO 
 
 d 
 
 o 
 
 CM 
 
 d 
 
 
 o 
 
 CO 
 
 d 
 o 
 
 CM 
 
 d 
 
 o 
 d 
 
 00 
 
 d 
 d 
 
 CM 
 
 o 
 
 CO 
 CM 
 
 o 
 d 
 
 O 
 
 d 
 
 CM 
 
 p— 
 
 o 
 d 
 
 o 
 
 5 
 
 urj 
 CM 
 
 
 
 p— 
 
 o 
 d 
 
 o 
 
 to 
 
 CM 
 
 
 CD 
 
 n 
 
 e 
 
 03 
 
 k 
 
 s 
 
 o 
 
 -I 
 
 
 
 
 
 
 
 
 
 o 
 
 d 
 V 
 
 cn 
 d 
 
 d 
 
 
 cn 
 
 d 
 
 i 
 
 d 
 
 
 
 o 
 d 
 
 CM 
 
 p 
 
 IO 
 
 O 
 
 CM 
 
 O 
 
 d 
 
 1 
 
 
 O 
 
 CM 
 
 O 
 
 <o 
 
 
 CD i_ 
 
 Q 
 
 
 
 - 
 
 
 - 
 
 p.. 
 
 CO 
 
 o 
 
 CO 
 
 a 
 d 
 
 
 CO 
 
 d 
 
 V 
 
 
 CO 
 
 d 
 
 V 
 
 o 
 
 IO 
 
 
 
 o 
 to 
 
 V 
 
 CM 
 
 cn 
 
 CM 
 
 1 
 
 CO 
 
 
 O 
 
 to 
 
 V 
 
 
 CD 
 CD 
 
 i 1 
 | 
 
 1 
 
 
 CO 
 
 E 7j 
 o c 
 
 *■! 
 
 CO fe 
 
 > -= 
 o g 
 
 E ■? 
 
 o —• 
 
 ° a 
 CO £ 
 
 CO 
 
 E 75 
 o c 
 
 * E 
 
 > £ 
 
 • i 
 
 " g 
 
 cn £ 
 
 E J, 
 
 fc I 
 
 en iz 
 
 E <o 
 
 £ 1 
 
 *- - 
 
 CO E 
 
 ± CD 
 CD ** 
 
 If 
 
 cn '5 
 
 .E -fc 
 C c 
 
 a. o 
 CO e 
 
 
 E <£. 
 
 2 g 
 
 •4- k 
 
 CO E 
 
 -2 CD 
 CD ** 
 
 11 
 
 O «- 
 
 E 2 
 
 s t= 
 -2 § 
 CO c 
 
 CO 
 
 E -5 
 o c 
 
 CO fe 
 
 > ■•= 
 
 CD g 1 
 
 " g 
 
 cn £ 
 
 C J, 
 
 co i: 
 
 
 
 CO 
 
 E « 
 
 O E 
 
 -t E 
 
 > £ 
 
 CD O 1 
 
 — c 
 
 f > CCJ 
 W CD 
 
 cn .o 
 
 E J, 
 
 i 1 
 
 co £ 
 
 E « 
 
 «5 E 
 
 ^ CD 
 
 CD ** 
 
 1.E 
 
 cn '5 
 .E i 
 
 k E 
 
 5- ° 
 
 CO E 
 
 
 
 E J2 
 
 O 03 
 i E 
 
 CO E 
 
 > CD 
 
 CD *" 
 
 If 
 
 CJ *- 
 
 E 2 
 
 § E 
 
 E i 
 
 CO 
 
 E 75 
 
 O E 
 
 -E 
 
 > £ 
 m cn 
 
 — E 
 
 o ca 
 
 " CD 
 
 cn jh 
 
 E J, 
 
 5 2 
 
 CO ^ 
 
 CO 
 
 E 73 
 
 O E 
 
 * E 
 
 > 2 
 
 CD =? 
 
 « s 
 
 cn .a 
 
 E J, 
 
 a 2 
 
 CO i 
 
 CO 
 
 E 73 
 
 O E 
 
 * E 
 
 > £ 
 
 m cn 
 
 — E 
 
 £ 1 
 
 o co 
 
 w CD 
 
 cn j2 
 
 E J, 
 
 ^ 2 
 
 CO i 
 
 CO 
 
 E 73 
 
 O E 
 
 * E 
 
 > S 
 
 CD =? 
 
 cn .a 
 c J, 
 
 & I 
 
 CO i 
 
 
 
 
 
 E » 
 
 5 s 
 
 — CO 
 CD *" 
 CJ =P 
 >< .E 
 
 o — 
 
 H 
 
 II 
 
 
 .»- ^O 
 
 g.2? 
 
 < E 
 
 o ! 
 i- i r«. 
 i i 
 
 i 
 
 CO 
 
 1 
 
 
 1 
 
 i 
 
 CO 
 
 IO 
 
 o 
 
 1 
 
 
 1 
 
 1 
 CO 
 
 o 
 
 o 
 
 V— 
 
 1 
 
 
 
 
 
 >> 
 • 
 'k 
 
 > 
 
 CO 
 
 3 
 k 
 
 5 
 
 "3 
 
 > 
 at 
 
 c 
 
 CD 
 
 cn 
 
 c 
 
 PS 
 
 k 
 
 O 
 
 're 
 
 CD "2 
 
 e» E 
 c .£ 
 
 03 03 
 
 o> 
 
 CD 
 O) 
 
 e 
 
 o 
 
 CD 
 
 cn 
 
 E 
 03 
 
 k 
 
 O 
 
 CD 
 
 cn 
 
 c 
 
 03 
 
 6 
 
 "o3 
 
 CD '£ 
 
 ■ E 
 c _0J 
 
 CS 03 
 
 CD 
 
 cn 
 
 c 
 
 03 
 
 i- 
 
 O 
 
 "3 
 
 > 
 
 03 
 
 E 
 
 CD 
 
 cn 
 
 E 
 W 
 
 i- 
 
 o 
 
 'es 
 CD '" 
 
 CS c3 
 
 o> 
 
 CD 
 
 cn 
 
 E 
 c« 
 
 k 
 
 o 
 
 'e 
 o 
 
 ---■ 
 
 CO 
 
 _J 
 
 C 
 
 o 
 E 
 
 CD 
 
 -1 
 
 CD '« 
 
 E • 
 
 o > 
 
 CD 
 
 cn 
 
 E 
 03 
 
 k 
 
 o 
 
 > 
 
 03 
 
 E 
 
 -a 
 
 E 
 03 
 03 
 
 CD "3 
 
 E J 
 03 o3 
 
 o > 
 
 "is 
 CD '« 
 
 cn £ 
 
 E -2? 
 
 ca m 
 
 o> 
 
 CD 
 
 cn 
 
 E 
 03 
 
 k 
 
 o 
 
 ■^ 
 
 CO 
 
 E 
 
 CD 
 
 cn 
 
 E 
 03 
 
 i- 
 
 o 
 
 E 
 CD 
 
 03 
 > 
 
 CD 
 
 cn 
 
 E 
 03 
 
 k 
 
 o 
 
 "cS 
 
 co o 
 
 E & 
 J? CO 
 
 O > 
 
 
 c 
 
 CD 
 
 E 
 
 CD 
 □ 
 
 !.! 
 
 c 
 1 
 
 > 
 
 i 
 
 c 
 o 
 Q 
 
 >. 1 
 
 *£ 
 
 «- CD 
 E — 
 CD ~- 
 
 u o 
 •- 1- 
 
 CD CD 
 
 a ~ 
 c « 
 ~ E 
 
 O i_ 
 
 CD 
 
 « °- 
 
 O C 
 
 . t- — 
 
 o 
 
 k 
 CD 
 
 rt 
 
 E 
 
 
 
 >■> 
 
 k 
 
 ■a 
 
 3 C 
 •»- CD 
 3 « 
 (O ■_ 
 CD 
 
 o c 
 H — 
 
 P3 
 CD 
 
 O 
 
 k 
 CD 
 
 CO 
 
 E 
 
 
 
 
 
 
 
 <D 
 
 n 
 
 03 
 
 iz 
 
 >% 
 
 03 Q. 
 o c ' 
 r- - 
 
 k 
 
 (S 
 CD 
 
 O 
 
 
 
 
 
 
 
 
 I 32 ] 
 
CM 
 
 g 
 E 
 o. 
 03 
 
 O ^ 
 
 03 ^ 
 
 la 
 
 o 2 
 
 5 I 
 
 C3) CD 
 
 _i > 
 
 a> 
 m 
 
 S 
 
 _© 
 <s 
 co 
 
 c 
 
 03 
 
 > 
 
 ■o 
 c 
 03 
 
 l_ 
 O 
 
 D3 
 
 m 
 
 03 C 
 
 "°. 1 
 
 Si 
 3 = 
 
 w 03 
 O t- 
 
 "S £ 
 co -c 
 
 5 « 
 
 > 03 
 
 
 
 
 (O 
 
 
 
 m 
 
 
 
 o> 
 
 
 
 
 
 
 vw 
 
 
 
 E 
 
 
 
 
 
 
 > 
 
 
 
 i_ 
 
 
 
 UJ 
 
 
 
 ■a 
 
 ,_^ 
 
 ,_. 
 
 E 
 
 03 
 
 03 
 
 03 
 
 
 
 03 
 
 03 
 
 a. 
 
 ■o 
 
 ■n 
 
 E 
 
 -O 
 
 S3 
 
 03 
 
 2 
 
 3 
 
 _«: 
 
 a. 
 
 B 
 
 E 
 
 c 
 
 C 
 
 3 
 
 3 
 
 a> 
 
 
 
 I 
 
 5 
 
 s 
 
 
 o 
 
 o 
 
 
 
 
 
 a> 
 
 CD 
 
 
 CO 
 
 co 
 
 CO 
 
 c 
 
 E 
 
 03 
 
 > 
 
 03 
 
 > 
 
 03 x 
 
 — O 
 
 o * 
 
 «= >, 
 
 E 5 
 CB > 
 
 IS 
 
 CD _ 
 
 "H 1 
 
 C CO 
 
 3 _ 
 
 <= E 
 *■ o 
 
 cO »*— 
 
 CO "O 
 
 ■§ ° 
 
 o .« 
 
 oi ft 
 
 > 
 
 O CO 
 
 • 3 
 
 -e a. 
 
 <S JB 
 
 2: cd 
 
 1- 
 
 c 
 
 3 £ 
 
 e w 
 
 § « 
 s: ZZ- 
 
 CD 
 
 = 1 
 
 03 -* 
 
 
 
 CO 
 
 CO 
 
 1 
 
 
 ^ 
 
 
 V— ' 
 
 v — ' 
 
 E 
 
 e 
 
 03 
 
 03 
 
 E 
 
 E 
 
 a. 
 
 a. 
 
 03 
 
 03 
 
 sz 
 
 .c 
 
 o 
 
 O 
 
 13 
 
 "a 
 
 E 
 
 c 
 
 03 
 
 03 
 
 
 
 s 
 
 s 
 
 o 
 
 o 
 
 
 
 CD 
 
 CD 
 
 CO 
 
 CO 
 
 E 
 
 E 
 
 03 
 
 03 
 
 > 
 
 > 
 
 
 
 o> 
 
 O) 
 
 
 
 S3 
 
 .O 
 
 CD 
 
 CD 
 
 _l 
 
 _l 
 
 m 
 
 03 C 
 ""= =5 
 
 i| 
 
 a. -■- 
 1? 
 
 03 
 
 I ■= 
 
 O i_ 
 
 a ° 
 
 03 i- 
 > CQ 
 
 m 
 
 ^~ 03 
 
 Cvj X 
 
 in ■*■ 
 
 o> "C 
 
 r- c 
 
 03 
 
 I "O 
 
 O i_ 
 
 "5 £ 
 
 E « 
 
 03 t- 
 
 > 03 
 
 in 
 
 CD 
 
 — O) 
 
 03 C 
 
 ' 1 
 .E 03 
 
 SI 
 
 I! 
 03 
 
 I ■= 
 
 O L- 
 
 "5 £ 
 
 E « 
 
 03 L. 
 > 03 
 
 m 
 
 i2 ™ 
 
 3 I 
 
 03 
 
 O i_ 
 
 CD £ 
 
 » "C 
 
 E « 
 
 03 l- 
 
 > 03 
 
 
 
 03 
 
 03 
 
 
 
 03 
 
 03 
 
 ■o 
 
 •a 
 
 S3 
 
 S3 
 
 3 
 
 3 
 
 a. 
 
 a. 
 
 c 
 
 c 
 
 3 
 
 3 
 
 vw 
 
 * — "" 
 
 i 
 
 S 
 
 e 
 
 o 
 
 
 
 CD 
 
 CD 
 
 CO 
 
 CO 
 
 E 
 
 c 
 
 03 
 
 03 
 
 > 
 
 > 
 
 — 
 
 3 
 
 03 
 
 > 
 
 O 
 
 ui 
 
 o 
 
 CO 
 
 A 
 
 o 
 o 
 m 
 
 A 
 
 o 
 
 
 
 o 
 
 
 
 o 
 o 
 
 
 o 
 
 *r 
 
 
 o 
 
 o 
 
 
 A 
 
 o 
 
 
 
 o 
 
 
 
 a 
 
 
 
 r " 
 
 
 
 A 
 
 o 
 o 
 
 o 
 o 
 
 A 
 
 o 
 
 CM 
 
 o 
 
 o 
 m 
 
 o 
 
 
 
 o 
 
 
 
 o 
 
 
 
 o 
 
 o 
 o 
 
 o 
 A 
 
 r>~ 
 
 o 
 
 
 
 CM 
 
 
 
 o 
 
 E> 
 
 o 
 in 
 
 «3 
 
 c4 
 
 o 
 
 o 
 
 Cvj 
 
 o 
 -a- 
 
 o 
 
 o 
 
 O 
 
 C3 
 
 o 
 
 o 
 
 o 
 
 o 
 
 T 
 
 *3- 
 
 03 
 
 E 
 
 •a 
 
 E 
 
 a. 
 
 esj 
 
 o 
 
 CO 
 
 o 
 V 
 
 o 
 in 
 
 
 o 
 
 
 
 esj 
 
 ■* 
 
 
 o 
 
 i 
 
 — 
 V 
 
 
 
 
 
 H 
 
 
 o 
 in 
 
 q 
 
 V 
 
 q 
 V 
 
 V 
 
 m 
 
 o 
 A 
 
 o 
 
 CO 
 
 A 
 
 2 
 
 CO 
 
 o 
 
 CO 
 
 o 
 
 z 
 
 CD 
 
 E 
 
 a 
 
 > 
 
 03 
 
 03 
 
 •a 
 
 03 
 
 ^5 
 
 CD 
 
 — 
 
 CO 
 
 E « 
 o c 
 
 CO fe 
 
 — c 
 
 £'i 
 
 CJ 03 
 
 " CD 
 
 CD S3 
 
 C J, 
 
 V) vt 
 
 C73 
 
 I 
 CO 
 
 in 
 
 ! 
 CO 
 
 m 
 
 I 
 
 CO 
 
 I 
 
 CO 
 
 o 
 
 1. 
 
 
 
 03 
 
 o 
 
 =r 
 
 L. 
 
 
 o 
 
 CO 
 
 -^ 
 
 CD 
 
 
 > 
 
 03 
 
 c 
 
 ^3 
 
 "■"" 
 
 c 
 
 CO 
 
 CD 
 
 CD 
 
 cx 
 c 
 
 03 
 
 03 
 
 i— 
 
 o 
 
 
 c 
 
 
 
 e 
 
 
 
 E 
 
 
 
 CD 
 
 
 
 
 
 
 ■S3 
 
 
 
 C 
 
 
 
 03 
 
 
 CD 
 
 CD 
 
 CD 
 
 O) 
 
 O) 
 
 C3) 
 
 E 
 
 E 
 
 C 
 
 03 
 
 03 
 
 « 
 
 k 
 
 L. 
 
 L. 
 
 o 
 
 o 
 
 o 
 
 CD 
 
 at 
 
 c 
 
 03 
 
 
 03 
 
 
 > 
 
 
 ■o 
 
 
 c 
 
 CD 
 
 ea 
 
 c 
 re 
 
 > 
 
 03 
 
 O 
 
 1- 
 
 CO 
 
 CO 
 
 o> 
 
 a> 
 
 c 
 
 E 
 
 
 
 
 
 
 
 3 
 
 3 
 
 U 
 
 o 
 
 c 
 
 E 
 
 o 
 
 O 
 
 E 
 
 E 
 
 CD 
 
 CD 
 
 "■ 
 
 -1 
 
 o 
 E 
 — 
 ■a 
 
 CD 
 C3) 
 
 C 
 03 
 
 CD 
 
 C 
 
 03 
 
 o 
 
 >. CD 
 
 C 
 
 
 CD 
 
 £ 
 
 CD "" 
 
 c 
 
 > on 
 
 Cfi 
 
 o»J= 
 
 «^ 
 
 CD C 
 
 03 
 
 SZ 
 
 3 ' 
 
 
 -3 ~ 
 
 CD 
 
 5 a> 
 
 U 
 
 > — 
 
 c 
 
 vt- 3 
 
 CB 
 
 rt -7; 
 
 w 
 
 »r 
 
 > 
 
 
 CD 
 
 Sg 
 
 e 
 
 h- a 
 
 ^ 
 
 * "w 
 
 H — 
 
 CD 
 
 
 CO 
 
 
 03 
 
 
 S3 
 
 
 E 
 
 3 
 E 
 
 I 
 
 _3 
 < 
 
 E 
 
 3 
 
 03 
 00 
 
 03 
 
 O 
 
 o 
 
 E 
 
 ■o 
 
 03 
 
 o 
 
 E 
 
 3 
 
 1 
 1 
 
 E 
 
 3 
 
 
 
 03 
 
 -a 1 
 
 o 
 
 c 
 
 V) 
 
 o 
 
 53 
 
 E 
 
 3 
 
 '■5 
 
 OS 
 
 c 
 
 03 
 
 > 
 
 [33] 
 
TABLE 5. — Analysis Values Useful in Evaluating 
 
 Soil 
 constituent 
 
 Method and/or fraction and 
 basis of expressing result 
 
 Range* 
 
 Deficient or un- 
 satisfactory range 
 
 Low 
 range 
 
 Ample or satis- 
 
 or 
 measurement 
 
 Extreme 
 
 Usual 
 
 factory range 
 
 Soil pH 
 
 Glass electrode on 1:2.5 soil- 
 water suspension 
 
 3.0-10.0 
 
 4.5-8.5 
 
 <4.5 
 
 4.5-5.2 
 
 5.5-7.5 
 
 Electrical conduc- 
 tivity (Ec X NPat 
 25° C.) 
 
 Ec X 10 3 at25°C.(millimhos/ 
 cm) on saturation extract of 
 soils (these determinations 
 should be made on successive 
 1 -ft. horizons of the soil to a 
 depth of 5 or 6 feet) 
 
 <0.1->20.0 
 
 0.1-10.0 
 
 t 
 
 0.2-1.0 
 
 0.2-1.9 
 
 Total soluble solids 
 
 In saturation extract ex- 
 pressed in ppm dry soil 
 
 <100.0-> 3000.0 
 
 <100.0-1500.0 
 
 t 
 
 100.0-500.0 
 
 100.0-2000.0 
 
 
 In 1-5 soil water extract ex- 
 pressed in ppm dry soil 
 
 <1 00.0-1 5,000.0 
 
 300.0-1500.0 
 
 t 
 
 50.0-250.0 
 
 50.0-850.0 
 
 Soluble salt con- 
 stituents 
 
 (1) Bicarbonate 
 (HC0 3 ) 
 
 Saturation extract expressed 
 as me/I of extract 
 
 <0.1 0-20.0 
 
 <0.1 0-5.0 
 
 t 
 
 0.10-0.50 
 
 0.10-2.50 
 
 In 1-5 soil-water extract ex- 
 pressed in ppm dry soil 
 
 <6.0->600.0 
 
 50.0-250.0 
 
 t 
 
 <6.0-50.0 
 
 < 6.0-1 00.0 
 
 (2) Carbonate 
 
 (C0 3 ) 
 
 In saturation extract ex- 
 pressed as me/I of extract 
 
 Trace->1.0 
 
 None 
 
 t 
 
 0.0 
 
 0.0 
 
 (3) Chloride 
 
 In saturation extract ex- 
 pressed as me/I of extract 
 
 <0.1->100.0 
 
 <0.1-5.0 
 
 No data available 
 as to deficient range 
 
 0.20-2.0 
 
 < 0.2-5.0 
 
 
 In 1-5 soil-water extract ex- 
 pressed in ppm dry soil 
 
 <10.0-> 2000.0 
 
 < 10.0-350.0 
 
 No data available 
 as to deficient range 
 
 < 10.0-75.0 
 
 <10.0-75.0 
 
 (4) Calcium (as a 
 salt con- 
 stituent) 
 
 In saturation extract ex- 
 pressed as me/I of extract 
 
 <0.1->150.0 
 
 <0.1-10.0 
 
 (Asa plant nutrient, 
 see elsewhere) 
 
 <0.1-1.0 
 
 1.0-10.0 
 
 (6) Magnesium 
 fas a salt con- 
 stituent) 
 
 In saturation extract ex- 
 pressed as me/I of extract 
 
 <0.2->30.0 
 
 <0.2-5.0 
 
 (Asa plant nutrient, 
 see elsewhere) 
 
 < 0.2-3.0 
 
 <0.2-5.0 
 
 (6) Sodium 
 
 In saturation extract ex- 
 pressed in me/I of extract 
 
 <0.1 -150.0 
 
 <0.1-5.0 
 
 t 
 
 <0.1-2.0 
 
 <0.1-3.5 
 
 
 In 1 -5 soil-water extract 
 expressed as ppm dry soil 
 
 <0.1 3000.0 
 
 20.0-250.0 
 
 t 
 
 <5.0 30.0 
 
 <5.0-50.0 
 
 
 Exchangeable as per cent of 
 exchange capacity 
 
 <1.0->25.0 
 
 < 1.0-5.0 
 
 t 
 
 1.0 5.0 
 
 1.0-10.0 
 
 * These are values derived from existing research sources: the wide lack of agreement between 1 5 saturation extract and Ec X 10 3 values is due to the 
 varying sources from which data were obtained. 
 t Does not apply. 
 
 I 34 ] 
 
alinity and Nutrient Status of Citrus Soils 
 
 High range 
 (Corrective 
 eatment may be 
 necessary) 
 
 8.0-8.5 
 
 Excess range 
 (Corrective 
 treatment 
 necessary) 
 
 >8.5 
 
 2.0-4.0 
 
 2000.0-3000.0 
 
 850.0-1500.0 
 
 2.5-5.0 
 
 100.0-200.0 
 
 Trace 
 
 5.0-10.0 
 
 100.0-150.0 
 
 10.0-20.0 
 
 10.0-20.0 
 
 5.0-15.0 
 
 100.0-150.0 
 
 10.0-15.0 
 
 >4.0 
 
 > 3000.0 
 
 > 1500.0 
 
 >5.0 
 
 > 250.0 
 
 Tr.-1.0 
 
 10.0-> 100.0 
 
 > 200.0 
 
 >30.0 
 
 Remarks 
 
 >15.0 
 
 > 150.0 
 
 >15.0 
 
 There is no one pH value "best" for citrus, but soils in the pH 5.5 
 to 7.5 range are often more fertile and trouble-free than those higher 
 or lower. 
 
 pH values of 5.0 or under may be indicative of both deficiencies or 
 unavailability of such elements as Ca, Mg, P, Mo, etc., or of toxicity 
 from increased solubility of Win, Zn, Al, B, and other elements. Addi- 
 tions of lime or dolomite will correct calcium and magnesium defi- 
 ciencies, overcome toxicity due to excess heavy metal solubility, and 
 may increase phosphorus and molybdenum availability. 
 
 pH values above 8.5 indicate the presence of sodium carbonate and 
 the need to treat with gypsum, sulfur, or other materials. 
 
 pH values of 8.0 to 8.5 may denote the presence of free lime; in 
 addition, manganese, zinc, copper, phosphorus, and iron are quite 
 often difficultly available. 
 
 Electrical conductivity is an indication of total soluble salt in solu- 
 tions. These values provide general guidance only; climate and the 
 particular rootstock-top combination used have an important bearing. 
 Values of Ec X 10 3 of 2.0 or over in any soil horizon of root zone should 
 be looked upon with suspicion, and irrigation practices modified so as 
 to reduce the salt concentration by further root-zone leaching. 
 
 Total soluble solids in the saturation extract is an expression of 
 total salinity or salt content of the soil. When values exceed 2000 ppm 
 in any part of the root zone, irrigation practices should be modified 
 so as to reduce the salt concentrations. 
 
 One to five soil water extracts were commonly made by earlier 
 workers to determine the salinity of soils. Some laboratories still use 
 this procedure. The same qualifications and suggestions apply as 
 under the above. 
 
 As with total soluble salts, no precise limits can be set owing to the 
 modifying influences of soil, climate, rootstock-scion, and the char- 
 acter of accompanying anions; but where values in the high and 
 excess ranges are found anywhere in the root zone, leaching should 
 be increased. 
 
 Whenever any normal carbonate is found anywhere in the root 
 zone it should be corrected by applications of gypsum, sulfur, or other 
 acid materials, and by leaching the products out of the root zone. 
 
 See comments under bicarbonate. 
 
 Little or no data are available concerning the specific toxicity of 
 calcium itself; it is the anion (S0 4 , N0 3 , or CI) associated with it 
 which is probably most important. 
 
 Not enough is known about magnesium toxicity in relation to citrus; 
 however, it is more toxic than calcium and amounts over 15-20 me/I 
 in saturation extract would suggest need for leaching. 
 
 Adverse effects on plant growth will result from too much soluble 
 sodium; not only as a direct toxicant in the plant, but because of ad- 
 verse effects on soil structure, permeability of the soil, and soil pH. 
 The degree of toxicity of soluble sodium in the soil solution will be 
 strongly influenced by the amount of soluble calcium present and the 
 character of the prevailing anions. Whenever sodium exceeds 10 per 
 cent of the exchange capacity of soils, the use of gypsum followed 
 by leaching is indicated. 
 
 Literature citations 
 
 Discussions of pH in relation to plant growth 
 may be found in nearly all textbooks on 
 soil. See: 
 
 Allaway (1957) and 
 
 Millar '1955 
 for sample discussions. 
 
 U. S. Dept. Agr. Handbook 60, L. A. Richards 
 (Ed.) (1954) 
 
 Harding and Chapman (1950) 
 
 Harding, Pratt, and Jones (1958) 
 
 Chapman and Harding (1956) 
 
 Kelley and Thomas (1920) 
 
 Harding and Chapman (1950) 
 U.S.D.A. Handbook 60 (1954) 
 
 Kelley and Thomas (1920), and Chapman, 
 Laurance, and Harding (unpub. Calif, data) 
 
 Harding and Chapman (1950) 
 
 Harding and Chapman (unpub. data) 
 U.S.D.A. Handbook 60 (1954) 
 
 Kelley and Thomas (1920), and Chapman, 
 Laurance, and Harding (unpub. data) 
 
 Harding and Chapman (1950) 
 
 Harding and Chapman unpub. data) 
 U.S.D.A. Handbook 60 (1954) 
 
 Harding and Chapman (unpub. data) 
 
 Kelley and Thomas (1920), and Chapman, 
 Laurance, and Harding (.unpub. data^ 
 
 Martin, Harding, and Murphy (,1953^ 
 
 [35] 
 

 
 
 
 
 TABLE 5.-A 
 
 
 Soil 
 constituent 
 
 Method and or fraction and 
 basis of expressing result 
 
 Range 
 
 Deficient or un- 
 satisfactory range 
 
 Low 
 range 
 
 Ample or satis- 
 factory range < 
 
 or 
 measurement 
 
 Extreme 
 
 Usual 
 
 (7) Sulfate 
 
 In saturation extract ex- 
 pressed in me 1 of extract 
 
 < 0.5-1 00.0 
 
 < 5.0-20.0 
 
 (See under sulfur as 
 a plant nutrient) 
 
 < 0.5-5.0 
 
 <5.0-20.0 
 
 
 In 1-5 soil-water extract 
 expressed as ppm dry soil 
 
 < 25.0- > 8000.0 
 
 <25.0-500.0 
 
 
 <25.0-100.0 
 
 <25.0-0.350 
 
 Potassium 
 
 In saturation extract ex- 
 pressed in me/I of extract 
 
 
 
 
 Tr.-1.0 
 
 1.0-5.0 
 
 
 Exchangeable K as per cent 
 of exchange capacity 
 
 
 
 
 
 2.0-10.0 
 
 Boron 
 
 Total boron in soil expressed 
 in ppm dry soil 
 
 <2.0-> 100.0 
 
 2.0-100.0 
 
 Tr-10.0 
 
 <10.0 
 
 
 
 Water-soluble in 1 :2 soil-water 
 suspension. Reflux method 
 of Berger and Truog (1939) in 
 ppm dry soil 
 
 
 
 0.1-0.5 
 
 0.5 
 
 
 
 Water-soluble 1:1.5 extract 
 expressed in ppm dry soil 
 
 
 
 
 
 
 
 1:2 soil-water extract ex- 
 pressed as ppm dry soil 
 
 Tr.->21.0 
 
 Tr.->21.0 
 
 
 
 Tr.-0.30 
 
 
 Soxhlet extract by method of 
 McClung and Dawson (1951) 
 
 
 
 0.03-0.37 
 
 
 
 Copper 
 
 Total copper in soil expressed 
 in ppm dry soil 
 
 < 1.0-5000.0 
 
 2.0-100.0 
 
 
 
 1 
 
 
 1N HCI extract expressed 
 in ppm dry soil 
 
 < 10.0-300.0 
 
 
 
 
 25.0 
 
 
 0.1 N HCI extract expressed 
 in ppm dry soil 
 
 
 
 0.9-1.6 
 
 
 
 
 Aspergillus niger expressed 
 in ppm dry soil 
 
 
 
 0.4-1.2 
 
 
 >2.0 
 
 Calcium 
 
 Total Ca in lime-free soils 
 expressed as ppm dry soil 
 
 860.0-20,000.0 
 
 
 
 < 1000.0 
 
 i 
 
 
 In saturation extract ex- 
 pressed in me/I of extract 
 
 <0.1->150.0 
 
 <0.1-10.0 
 
 
 <0.1-2.5 
 
 1.0-10.0 
 
 
 Exchangeable Ca as per cent 
 of exchange capacity. 
 
 5.0-95.0 
 
 50.0-85.0 
 
 <25.0 
 
 25.0^10.0 
 
 75.0-90.0 
 
 
 pH of 1 :2 soil-water sus- 
 pension 
 
 
 
 <5.0 
 
 5.0 5.5 
 
 5.5-8.5 
 
 Iron 
 
 Total iron in soil in per cent 
 dry weight 
 
 0.2^10.0 
 
 1.5-4.5 
 
 
 
 I 
 
 [ 36 1 
 
)ntinued 
 
 High range 
 Corrective 
 >atment may be 
 necessary 
 
 Excess range 
 'Corrective 
 treatment 
 necessary) 
 
 Remarks 
 
 Literature citations 
 
 20.0-30.0 
 
 >30.0->100.0 
 
 The detrimental effect of soluble sulfate is conditioned in part by 
 the dominating cation. If it is calcium, sulfate is less detrimental than 
 when sodium is the dominant cation. As with all other salt constitu- 
 ents, the degree of toxicity is dependent on soil, climate, and root- 
 stock-scion variables. Save in soils containing gypsum, high sulfate 
 values indicate a need for leaching. 
 
 Harding and Chapman unpub. data 
 U.S.D.A. Handbook 60 1954 
 
 150.0-1500.0 
 
 > 350.0 
 
 Kelley and Thomas 1920 , and Chapman, 
 Laurance, and Harding unpub. data 
 
 6.0-10.0 
 
 
 Where heavy manuring has been practiced, potassium occasionally 
 builds up to toxic levels. Precise data are not at hand, but the data 
 shown are of guidance value. 
 
 Harding and Chapman unpub. data 
 
 12.0-15.0 
 
 >15.0 
 
 Martin, Harding, and Murphy 1953 
 
 
 
 Although total boron in soils is not a good indicator of need, it gives 
 a base figure of value in indicating total reserves. 
 
 Swaine 1955 
 Whetstone et al. 1942 
 
 
 >1.3 
 
 Deficient range values are based on crops other than citrus; none- 
 theless, values in this range would provide guidance information. 
 
 Whetstone et al. 1942 
 Penman and McAlpine 1949 
 Bray 1948 
 
 
 0.73-1.72 
 
 Various citrus species showed boron toxicity leaf patterns when 
 grown in soils containing soluble boron in excess of 0.73 ppm. 
 
 Eaton and Blair 1935 
 
 
 0.50^20.0 
 
 Leaf symptoms typical of excess boron were found on citrus trees 
 where soluble boron was in excess of 0.50 ppm. 
 
 Kelley and Brown 1928 
 
 
 
 These are values for crops other than citrus but have suggestive 
 value. 
 
 Baird and Dawson 1955 
 
 
 100.0 in acid soils 
 
 As with other elements, total copperisnotareliableguideasto need, 
 but gives some idea of basic reserve supply and possible excess. 
 
 Reuther and Smith 1953 
 Swaine 1955 . Reuther 1957 
 
 
 
 Data from Florida citrus soils. 
 
 Spencer 1954 
 
 
 
 Data from apple orchards. 
 
 Bould etal. H950 
 
 
 
 Data on apple and pear soils. 
 
 Bould etal. '1953 
 
 
 
 Total calcium in soils is of chief value in indicating reserve supply; 
 soil pH and exchangeable calcium both total and as per cent of ex- 
 change capacity are far more important in indicating the status of 
 available calcium. 
 
 Millar 1955 
 
 
 
 Water-soluble calcium is chiefly useful in indicating whether there 
 is an ample supply in soil; low values do not necessarily indicate 
 deficiency. 
 
 Harding and Chapman 1950 
 
 
 
 Exchangeable calcium may be low either because of excess soil 
 acidity high exchangeable hydrogen ion» or high exchangeable so- 
 dium and or potassium. Other Ca forms and type of clay are also 
 factors. 
 
 Chapman unpub. data", Vlamis 1949 . 
 Strauss and Grizzard 1947 work on 
 peanuts by latter 
 
 
 
 Of guidance and suggestive value only. 
 
 Many investigators 
 
 
 
 So many factors influence iron availability e.g.. pH, lime content, 
 nature of iron-bearing minerals, heavy metals such as zinc and cop- 
 per, moisture, temperature, and soil organisms that few attempts 
 have been made to work out iron availability tests. 
 
 Chapman 1952 
 
 [37] 
 
TABLE 5.- 
 
 Soil 
 constituent 
 
 Method and /or fraction and 
 basis of expressing result 
 
 Range 
 
 Deficient or un- 
 satisfactory range 
 
 Low 
 range 
 
 Ample or satis- 
 factory range ^ 
 
 or 
 measurement 
 
 Extreme 
 
 Usual 
 
 Magnesium 
 
 Total Mg in nonearbonate con- 
 taining soils in ppm dry soil 
 
 200.0-13,400.0 
 
 
 < 2400.0 
 
 
 
 
 Ratio of exchangeable K:Mg 
 
 
 
 0.30-0.79 
 
 
 
 
 
 
 
 0.5(M).90 
 
 0.3-0.9 
 
 0.1-0.3 
 
 
 
 
 0.20^6.00 
 
 
 
 
 Exchangeable Mg expressed 
 as me 100 g of soil 
 
 
 
 0.04 0.20 
 
 
 
 
 Exchangeable Mg as per cent 
 of total exchange capacity 
 
 
 
 <6.0 
 
 
 
 Manganese 
 
 Total manganese in soil in 
 ppm dry soil 
 
 1.0-70,200.0 
 
 200.0-3000.0 
 
 
 
 
 
 Exchangeable Mn in ppm 
 dry soil 
 
 
 
 5.0-20.0 
 
 
 
 
 
 
 0.5 
 
 
 
 
 
 
 
 <1.5 
 
 >1.5 
 
 
 Easily reducible 0.2 r c quinal 
 in ppm dry soil 
 
 
 
 <80.0 
 
 
 
 
 
 
 
 
 > 100.0 
 
 
 Soluble in 3N NH4H2PO4— 
 ppm dry soil 
 
 
 5.0-60.0 
 
 <20.0 
 
 <30.0 
 
 30.0-60.0 
 
 Molybdenum 
 
 Total molybdenum in ppm 
 dry soil 
 
 < 0.5-200.0 
 
 
 
 
 
 
 
 0.2-5.0 
 
 
 
 
 
 
 
 <1.0 
 
 
 
 
 Ammonium oxalate extract- 
 able Mo in ppm dry soil 
 
 
 
 0.04 0.12 
 
 
 
 Nitrogen 
 
 Total nitrogen in ppm dry soil 
 
 100.0-> 10,000.0 
 
 
 
 
 
 
 Nitrate (NCh) in ppm dry soil 
 
 
 
 <5.0 
 
 
 
 Phosphorus 
 
 Total phosphorus in soil as 
 ppm 
 
 Water-soluble P by Bingham 
 1949) method in ppm dry 
 soil 
 
 < 100.0-1 0,000.0 
 
 3000.0^4000.0 
 
 < 300.0 
 
 
 
 
 
 
 <0.30 
 
 < 0.30-0.50 
 
 0.50-2.0 
 
 
 Water-soluble P in 1 5 soil- 
 water extract in ppm 
 
 Acid-soluble P by Truog '1930 
 method in ppm dry soil 
 
 <0.03 44.0 
 <30.0 900.0 
 
 <0.03 6.5 
 
 <0.03 
 
 0.03 0.30 
 
 0.30 16.0 
 
 
 <30.0 300.0 
 
 <30.0 
 
 <30.0 50.0 
 
 
 38 I 
 
)ntinued 
 
 High range 
 (Corrective 
 atment may be 
 necessary) 
 
 Excess range 
 (Corrective 
 treatment 
 necessary) 
 
 Remarks 
 
 Literature citations 
 
 
 
 Total magnesium is of very limited value in indicating available 
 supply but does give some idea of reserve in soil. 
 
 Millar (19551 
 
 
 
 These are ranges of values found in Australia citrus soils where 
 Mg deficiency patterns were studied by Parberry. 
 
 Parberry (1935) 
 
 
 
 These are values found in California citrus orchards. 
 
 Bingham et al. (1956) 
 
 
 
 These are values found in magnesium-deficient apple orchards. 
 
 Boynton (1954 1 
 
 
 
 These are values found in Florida sandy soils where citrus shows 
 Mg deficiency. 
 
 Peech (1939) 
 
 
 
 Various field and vegetable crops in New Jersey soils showed mag- 
 nesium deficiency when exchangeable magnesium constituted less 
 than 6 f " c of total exchange capacity. 
 
 Prince et al. (1947) 
 
 
 
 Total manganese is of value in indicating total reserve in soil, but 
 not with regard to availability. 
 
 Swaine (1955) 
 
 
 
 Work on citrus soils. 
 
 Connor (1954) 
 
 
 
 Work with French beans. 
 
 Fergus (1954) 
 
 
 
 Data on Florida citrus soils. 
 
 Peech (1939) 
 
 
 >500 
 
 Work with French beans. 
 
 Leeper (1935, 1947), Fergus (1954) 
 
 
 
 Field and vegetable crops. 
 
 Sherman and Harmer (1942) 
 
 
 
 Data secured on soybean soils in Ohio. 
 
 Hoff and Mederski (1958) 
 
 
 
 Total molybdenum in soils is of chief value in indicating total re- 
 serve, and, if on the very low side, suggestive of possible deficiency. 
 
 Anderson (1956) 
 
 
 
 Swaine (1955) 
 
 
 
 Walker (1948) 
 
 
 
 
 Walsh, Neenan, and O'Moore (1952) 
 
 
 
 Total nitrogen is of little value in indicating available supply, but a 
 rule of thumb figure for nitrate nitrogen is used by some commercial 
 laboratories. The figure of 5 ppm is used as a guide; if values are less 
 than this, fertilization is recommended; if more, nitrogen is withheld. 
 
 Experience of several commercial labora- 
 tories in California which carry on advisory 
 service for citrus growers. 
 
 
 
 
 
 Total phosphorus, save where it is very low, is of little value in diag- 
 nosing phosphorus state; however, Aldrich and Buchanan (1954) 
 found that many phosphorus-deficient soils showed less than 300 
 ppm P. 
 
 Chapman (1934) 
 
 Aldrich and Buchanan (1954) 
 
 
 
 Limited data on citrus soils showed that those orchards where P 
 deficiency occurred contained less than 0.30 ppm water-soluble P. 
 
 Aldrich and Buchanan (1954) 
 
 
 
 In pot culture and field trials witn citrus, fair correlations between 
 phosphorus content and response to fertilizers were obtained. 
 
 Chapman (1934) 
 
 
 
 On noncalcareous soils, phosphorus soluble in 0.002N H SO 
 (Truog, 1930) gives indications of value. 
 
 Aldrich and Buchanan (1954) 
 Chapman (1934) 
 
 [39] 
 

 
 
 
 
 
 TABLE 5.- 
 
 Soil 
 constituent 
 
 Method and or fraction and 
 basis of expressing result 
 
 Ranges 
 
 Deficient or un- 
 satisfactory range 
 
 Low 
 range 
 
 Ample or satis- 
 factory range 
 
 
 or 
 measurement 
 
 Extreme 
 
 Usual 
 
 i 
 
 Phosphorus (cont.) 
 
 0.5M sodium bicarbonate 
 extract expressed as pounds 
 Pl'Oj per acre 
 
 
 
 < 25.0-50.0 
 
 <50.0 
 
 >50.0 
 
 
 Potassium (see 
 under soluble salts 
 for toxicity point 
 of view) 
 
 Total potassium in soil ex- 
 pressed as ppm dry soil 
 
 500.0-50,000.0 
 
 500.0-30,000.0 
 
 
 
 
 
 Exchangeable potassium ex- 
 pressed in pounds/acre 
 
 
 
 <100.0 
 
 
 >200.0 
 
 
 Sulfur (see under 
 soluble salts for 
 toxicity levels of 
 sulfate) 
 
 Total sulfur in soil expressed 
 as ppm dry soil 
 
 40.0-1040.0 
 
 
 < 200.0 
 
 
 
 
 
 Morgan's Na acetate-acetic 
 acid extract in ppm dry soil 
 
 
 
 <3.0 
 
 
 
 
 Zinc 
 
 Total zinc in soil expressed 
 as ppm dry soil 
 
 <5.0-> 2000.0 
 
 10.0-300.0 
 
 
 < 100.0 
 
 
 
 
 Ammonium acetate dithizone 
 extract in ppm dry soil 
 
 
 
 <1.0 ppm in soils 
 of pH 7.0 
 and above 
 
 
 >2.0 ppm in soi 
 of pH 6.0 
 and lower 
 
 
 
 Ammonium acetate (pH 4.6) 
 extract expressed in ppm dry 
 soil 
 
 
 0.5-3.9 
 
 <1.5 
 
 
 >2.0 
 
 
 
 0.1 ON HCI extract expressed 
 in ppm dry soil 
 
 
 
 10.0 
 
 
 
 
 
 0.10N HCI extract expressed 
 in ppm dry soil 
 
 
 
 0.5-0.9 
 
 
 >1.20 
 
 
 
 0.10N MgS0 4 extract ex- 
 pressed in ppm dry soil 
 
 
 
 <1.0 
 
 
 i 
 
 
 
 
 
 
 
 
 
 
 I -10 1 
 
)ntinued 
 
 High range 
 (Corrective 
 atment may be 
 necessary) 
 
 Excess range 
 (Corrective 
 treatment 
 necessary) 
 
 Remarks 
 
 Literature citations 
 
 
 
 Values are based on field and vegetable crops; however, this 
 method gives results of considerable guidance value for citrus. 
 
 Olsen, Cole, Watanabe, and Dean (1954) 
 
 
 
 Total potassium is of little value in indicating anything about 
 available supply, save that where it is very low the likelihood of de- 
 ficiency is increased. 
 
 
 
 
 These data are based on experiments with field crops in Illinois 
 and probably apply only in a very limited way to citrus; however, 
 these figures provide some guidance value. In general, water-soluble 
 and exchangeable potassium provide only limited information. Low 
 values do not necessarily indicate deficiency; high values, however, 
 probably indicate sufficiency. 
 
 Bray (1948) 
 
 
 
 Total sulfur provides some information of value in indicating po- 
 tential supply, and if on the very low side the likelihood of a deficiency 
 developing is very real unless sufficient sulfur from fertilizers, ma- 
 nure, air pollution, rain, irrigation water, insecticides or fungicides 
 is periodically supplied. 
 
 Millar (1955) 
 
 
 
 Based on experiments with cotton, clover, and tobacco. 
 
 Jordan and Bardsley (1958) 
 
 >200.0 
 
 
 Total zinc is chiefly of value in indicating potential reserve supply 
 in soil; many factors affect availability to plants. 
 
 Swaine (1955) 
 Thorne et al. (1942) 
 
 
 
 Results were obtained on a variety of soils and crops and might 
 provide some guidance value for citrus. 
 
 Shaw and Dean (1952) 
 
 
 
 Work done on pineapple soils. 
 
 Lyman and Dean (1942) 
 
 
 
 Work on apple soils. 
 
 Bould etal. (1950) 
 
 
 
 Work on corn soil. 
 
 Wear and Sommer (1947) 
 
 
 > 100.0 
 
 Work on soy bean and cereal soils. 
 
 Berg (1947) 
 
 [41] 
 
TABLE 6. — Suggested Form for Record of Leaf and Soil Analysi* 
 
 Grove designation 
 
 
 Leaf analysis data 
 
 Visual symptoms ( 
 
 Year 
 
 Date of 
 sampling 
 
 Per cent in dry matter of leaf 
 
 ppm in dry matter of leaf 
 
 Date 
 
 Indicated deficiency \ 
 
 < 
 
 
 Ca 
 
 Mg 
 
 N 
 
 P 
 
 K 
 
 S 
 
 Na 
 
 CI 
 
 B 
 
 Cu 
 
 Mo 
 
 Mn 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 ■j. 
 
 i 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 |42 1 
 
utilizer and Pest Control Program, and Grove Performance 
 dck No Sampling unit 
 
 Soil analysis 
 
 Fertilizer program 
 
 Soil management 
 practices 
 
 Pest and disease control treatments 
 
 Yield and quality 
 
 )ate of 
 impling 
 
 Ec X 10 3 
 
 saturation 
 
 extract 
 
 Other 
 
 Date 
 
 Material applied 
 and method 
 
 Date 
 
 Pest 
 
 Materials 
 used 
 
 Field 
 
 boxes 
 
 per 
 
 tree 
 
 Peak 
 size 
 
 Qual- 
 ity 
 
 
 0-1 ' 
 1-2' 
 2-3' 
 
 4-5' 
 5-6' 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 [43] 
 
TABLE 7. — Control of Mineral Deficiencies and Excesses of Citrus 
 
 Element 
 
 Methods of control or amelioratiDn 
 
 Supplementary remarks 
 
 Soil treatment 
 
 Foliar spray 
 
 Other methods 
 
 Boron 
 deficiency 
 
 3 oz. borax /tree broadcast on 
 sandy Fla. soils. Up to 35 oz. per 
 tree used by Morris (1938) on 
 heavy soils in South Africa. One 
 application will usually last for 
 several years. 
 
 1 lb borax or boric acid to 
 100 gal water suitable; skele- 
 ton spray. 
 
 1. Acidification of neutral or 
 alkaline soils will release 
 boron. 
 
 2. Drought tends to aggra- 
 vate boron deficiency; 
 therefore, adequate mois- 
 ture will help where boron 
 is low. 
 
 1. Soil application methods prefer- 
 able but sprays useful where 
 quick tests or response desired. 
 
 2. Avoid too-heavy applications as 
 boron is very toxic to citrus. 
 
 3. Many fertilizers and most organic 
 materials contain enough boron 
 to meet citrus needs (40,000 lbs 
 of oranges, a heavy crop, re- 
 move only about 0.10 lb of boron 
 from the soil.) 
 
 4. Irrigation waters containing 0.10 
 ppm B or more will normally meet 
 citrus needs. 
 
 5. Boron is less readily absorbed by 
 sour orange roots than by some 
 other rootstocks. 
 
 Boron 
 excess 
 
 1. Excess boron can be slowly 
 leached out of soil; soil acidifi- 
 cation will make boron soluble 
 and increase rate of outgo by 
 leaching, but temporarily in- 
 crease injury. 
 
 2. Lime additions will decrease 
 boron solubility. 
 
 3. Calcium nitrate fertilizer is bet- 
 ter than other N forms where 
 high boron-containing waters 
 are used or soil is naturally 
 high in boron. 
 
 4. Acidic fertilizers such as am- 
 monium sulfate will increase B 
 solubility and produce more in- 
 jury temporarily, but will also 
 speed leaching of boron. 
 
 No data known to author, 
 but nitrogen (urea) sprays 
 might help to decrease toxicity. 
 
 Determine source of boron 
 excess and correct if possible. 
 
 1. Where excess boron is a problem 
 due to irrigation water content, 
 use of ample irrigation water and 
 good amounts of Ca(N03)2 fer- 
 tilizer will help. 
 
 2. Change to low boron content irri- 
 gation water if possible. 
 
 3. Intercrop citrus with a crop which 
 can be harvested and produces a 
 good tonnage. This will help re- 
 move boron and also aid water 
 penetration and boron outgo from 
 the soil. 
 
 Calcium 
 deficiency 
 
 Use of Ca(N03)2 fertilizer at rates 
 to supply nitrogen needs (2-3 
 lbs N/tree) should correct Ca 
 deficiency. 
 
 2. Lime at rates of 1-4 tons per 
 acre on acid soils. 
 
 3. Ca(SC>4)2 (gypsum) at rates of 
 1-5 tons per acre where Ca de- 
 ficiency is due to high sodium 
 content. 
 
 De Villiers (private corre- 
 spondence) in South Africa 
 reported that 2-3 sprays with 
 Ca(OH) 2 (10 lbs/100 gal.) 
 corrected calcium deficiency 
 of citrus. 
 
 
 1. On acid soils, lime is the best cor- 
 rective. 
 
 2. On alkaline soils (excess sodium) 
 Ca(S04)2 is the best corrective. 
 
 3. Use of calcium-containing ferti- 
 lizers is recommended to supply 
 N, and where P2O5 is needed, use 
 single strength superphosphate. 
 
 Calcium 
 excess 
 
 1. Leaching by irrigation water to 
 remove soluble salts. 
 
 2. Use of ammonium sulfate, sul- 
 fur, or other acids to solubilize 
 lime; followed by leaching; 
 practicable only where soil con- 
 tains less than 0.5 per cent 
 CaCd. 
 
 
 Excess phosphate aggra- 
 vates Cu deficiency and phos- 
 phate - containing fertilizers 
 and manures may need to be 
 discontinued. 
 
 1. Excess calcium occurs either 
 where there is alkali salt accu- 
 mulation and/or lime carbonate. 
 The former can best be removed 
 by leaching; the latter is difficult 
 to remove except by long-con- 
 tinued use of acid fertilizers and 
 leaching. 
 
 Copper 
 deficiency 
 
 Soil treatment not recommend- 
 ed for citrus in general, though on 
 acid Bands in Florida it is common 
 to recommend 1/8 to 1/2 lb of 
 CuSOi. 5H. ? per tree as a pre- 
 ventive. Others have found soil 
 applications of 1/4 lb CuSOi • 
 5HO per tree effective. 
 
 1. 3 lbs CuSOi and 4.5 lbs 
 hyd. lime to 100 gal. water 
 as a foliar spray. 
 
 2. Can be combined with 
 zinc sulfate and manga- 
 nese sulfate where Zn and 
 Mn deficiencies also occur. 
 
 3. McCleery and Stokes 
 (1929), in Australia, found 
 a 6-4-100 Bordeaux effec- 
 tive on oranges, lemons, 
 and mandarins. 
 
 Foliar sprays are best treatment; 
 sometimes two sprayings are neces- 
 sary to achieve control. Correction 
 will usually last from 1 to 3 years. 
 Spring, summer, or fall sprays usually 
 give better results than winter sprays. 
 
 [441 
 
TABLE 7. — Continued 
 
 Element 
 
 Methods of control or amelioration 
 
 Supplementary remarks 
 
 Soil treatment 
 
 Foliar spray 
 
 Other methods 
 
 Copper 
 excess 
 
 Additions of lime and/or phos- 
 phate fertilizer will reduce copper 
 solubility in soil. Iron chelates may 
 be beneficial where excess copper 
 has induced iron chlorosis. 
 
 
 
 Copper excess has developed on 
 Fla. soils from the prolonged use of 
 Bordeaux sprays. Iron chelates, su- 
 perphosphates, and where the soil is 
 quite acid, lime to correct the acidity 
 will help overcome the copper toxicity. 
 
 Iron 
 deficiency 
 
 1. Iron chelates (ethylene-diami- 
 netetraacetic acid; various iron 
 salts of). (EDTA) At 20-500 
 grams per tree on acid sandy 
 soils applied broadcast every 
 1 to 2 years very effective on 
 citrus. Cooper (1957) found 
 that 5 grams metallic Fe equiva- 
 lent of Chel. 138 H Fe, and RA 
 157 Fe were highly effective on 
 calcareous fine sandy loam soil, 
 pH 7.9, with 3-yr.-old Dancy 
 tangerines on Cleo mandarin 
 rootstock. 
 
 2. On some sandy soils, iron sul- 
 fate at rates of 1-5 lbs per tree 
 have proved successful but 
 chelates are preferred. 
 
 3. Acid peat treated with FeSCh 
 has been helpful with some 
 crops. 
 
 4. Prefumigation of soil prior to 
 planting citrus has proven 
 helpful on some soils. 
 
 FeSOi solutions with 
 spreaders are somewhat suc- 
 cessful as are chelates, but 
 there is danger of rind injury 
 to fruit and improvement in 
 foliage chlorosis is temporary. 
 Commercial practicality still 
 somewhat in doubt. 
 
 1. Careful control of irriga- 
 tion to prevent prolonged 
 overmoist condition in 
 lower root zone very often 
 effective; alternate middle 
 irrigation often helpful. 
 
 2. Leaching of soluble salts 
 where present in signifi- 
 cant amounts is often help- 
 ful. 
 
 3. Where due to heavy metal 
 solubility, liming to bring 
 pH to 6.0 or 6.5 may prove 
 helpful. 
 
 Iron deficiency ^chlorosis; in citrus 
 can be brought on by various condi- 
 tions such as: 
 
 1. Cold soil-temperatures in winter. 
 
 2. Overmoist subsoil conditions. 
 
 3. Excessive soluble salts in soil. 
 
 4. Excessive lime in soil. 
 
 5. Excesses of heavy metals such as 
 zinc, copper, nickel, chromium, 
 etc. These are often solubilized 
 when soil becomes too acid. 
 
 6. Nematodes and various patho- 
 genic soil organisms may be a 
 cause. 
 
 Correction can often be achieved 
 by eliminating or correcting the basic 
 cause or causes. 
 
 Iron 
 excess 
 
 Soil liming where due to exces- 
 sive soil acidity would be a natural 
 corrective. (See under supplemen- 
 tary remarks.) 
 
 
 
 No specific cases of excess iron on 
 citrus are known to the author ; none- 
 heless, there is no good reason to 
 suppose that this condition might 
 prevail, especially where soils are 
 very acid, or where reducing condi- 
 tions are present. 
 
 Mag- 
 nesium 
 deficiency 
 
 1. Epsom salts (MgS0 4 • 7H 2 0) 
 applied at rates of 3-30 lbs per 
 acre. 
 
 2. On acid sandy soils, 3-16 lbs 
 per tree effective. 
 
 3. Dolomite at 1-2 tons per acre 
 also effective on acid soils, par- 
 ticularly sandy soils. Amount 
 used should be such that pH of 
 soil not raised beyond pH 6.5. 
 
 1. Two to four sprays with 
 2% to 4% solutions of 
 Epsom salts are reported 
 by Herschberg (1951) and 
 others to correct Mg defi- 
 ciency of citrus. Fe, Zn, 
 and Mn added to the 
 sprays aided in the correc- 
 tion of Mg deficiency. 
 
 2. Embleton and Jones (1959) 
 have secured correction by 
 use of 10 per cent mag- 
 nesium nitrate foliar spray. 
 
 Adequate nitrogen fertiliza- 
 tion often clears up Mg defi- 
 ciency of citrus (see under 
 supplementary remarks). 
 
 1. Soil applications of magnesium 
 sulfate are preferred where defi- 
 ciency is due to excess exchange- 
 able K build-up in soil; it often 
 requires several years of repeated 
 applications to achieve correction 
 of Mg deficiency. 
 
 2. Moderately heavy nitrogen ferti- 
 lization frequently brings about 
 correction. This may be due to the 
 fact that nitrogen fertilizers tend 
 to increase amounts of Ca and Mg 
 in soil solution; the Ca may re- 
 place the K and help restore a 
 proper balance of Ca:Mg:K in the 
 exchange complex. 
 
 3. Slowness of recovery from Mg 
 applications to soil may be due to 
 slowness of absorption and or 
 movement of Mg in the plant. 
 
 [45] 
 
TABLE 7. — Continued 
 
 Element 
 
 Methods of control or amelioration 
 
 Supplementary remarks 
 
 
 
 
 
 Soil treatment 
 
 Foliar spray 
 
 Other methods 
 
 
 Mag- 
 
 1. Where due to excess soluble 
 
 
 
 Definite cases of magnesium ex- 
 
 nesium 
 
 salt, removal by leaching out of 
 
 
 
 cess on citrus (save where present as 
 
 excess 
 
 root zone is the only corrective. 
 2. Where due to excessive Mg 
 carbonate or silicates (serpen- 
 tine soils) additions of gypsum 
 and potassium salts might be 
 helpful (see under supplemen- 
 tary remarks). 
 
 
 
 a component of soluble salt excesses) 
 are unknown to author. However, in 
 controlled experiments in the green- 
 house, magnesium carbonate incor- 
 porated in a sand culture severely de- 
 pressed citrus growth. It is probable 
 that on serpentine-derived soils or 
 where magnesium carbonate is pres- 
 ent, Mg toxicity is a problem. In these 
 cases additions of soluble calcium 
 and potassium salts might prove 
 helpful. 
 
 Man- 
 
 1. 1-10 lbs manganese sulfate per 
 
 1. Sprays containing 4 lbs 
 
 1. Some decrease in Mn de- 
 
 1. Manganese deficiency can be 
 
 ganese 
 
 tree annually on sandy soils of 
 
 MnSCh • 2H 2 to 2 lbs 
 
 ficiency can often be 
 
 caused by a variety of soil condi- 
 
 deficiency 
 
 Florida are successful (Camp 
 
 Ca(OH) 2 in 100 gal. water 
 
 achieved by moderate 
 
 tions as follows: 
 
 
 and Peech, 1939). 
 
 will correct leaf patterns; 
 
 acidification of neutral or 
 
 1. Soil alkalinity. 
 
 
 2. Use of acid peat treated with 
 
 must be repeated several 
 
 slightly alkaline soils; acid- 
 
 2. Cold soil temperatures. 
 
 
 MnSOi suggested by Delap 
 
 times a year to maintain 
 
 ity should not be reduced 
 
 3. Soil organism competition for 
 
 
 (1949). 
 
 correction on citrus trees. 
 
 below pH 5.5, however. 
 
 available Mn. 
 
 
 3. Quastel et al. (1948) have 
 
 
 2. Organic matter addition to 
 
 4. Low phosphate supply. 
 
 
 found that sodium and calcium 
 
 
 soil may be helpful. 
 
 5. High potassium content or ac- 
 
 
 thiosulphate at rates of 100, 
 
 
 3. Tillage in some cases has 
 
 cumulation in soils. 
 
 
 500, and 1000 lbs per acre re- 
 
 
 improved manganese avail- 
 
 6. Excessive ammonium ion build- 
 
 
 duced manganese deficiency 
 
 
 ability, in others decreased 
 
 up in soils. 
 
 
 of oats. 
 
 
 it. 
 
 7. Oxidizing agents and condi- 
 
 
 4. There is some evidence that 
 
 
 
 tions which convert divalent 
 
 
 moderate applications of super- 
 
 
 
 manganese to higher valence 
 
 
 phosphate can increase the Mn 
 
 
 
 oxides reduce manganase avail- 
 
 
 uptake of citrus and other 
 
 
 
 ability; this condition is pro- 
 
 
 plants (Reuther et al., 1949, 
 
 
 
 duced by soil alkalinity. 
 
 
 and Bingham, 1958). 
 
 
 
 
 
 5. MnSCh and superphosphate 
 
 
 
 
 
 may be more effective than 
 
 
 
 
 
 MnSC-4 alone (Steckel, et al, 
 
 
 
 
 
 1948). 
 
 
 
 
 
 6. Soil fumigation prior to plant- 
 
 
 
 
 
 ing has been found helpful in 
 
 
 
 
 
 correcting Mn deficiency on 
 
 
 
 
 
 citrus and some other crops. 
 
 
 
 
 Man- 
 
 1. Where due to excess soil acid- 
 
 
 
 Manganese excess has been noted 
 
 ganese 
 
 ity, liming to bring pH to 6.0 or 
 
 
 
 under the following conditions: 
 
 excess 
 
 above will usually correct. 
 2. Where due to poor drainage 
 (anaerobic or partially anaerob- 
 ic conditions), better drainage 
 or irrigation practices. 
 
 
 
 1. On manganiferous soils. 
 
 2. Where soil acidity produces ex- 
 cess soluble Mn concentrations 
 in soil. 
 
 3. Under reducing conditions in 
 soils; high moisture. 
 
 4. Excess absorption from foliar 
 sprays. 
 
 Molyb- 
 
 1. 4 8 oz. sodium or ammonium 
 
 1. 2-4 oz. sodium molybdate 
 
 1. Liming acid soils will in- 
 
 Citrus appears quite tolerant to 
 
 denum 
 
 molybdate per acre (commonly 
 
 to 100 gal. water has prov- 
 
 crease Mo availability and 
 
 molybdenum, but because of toxicity 
 
 deficiency 
 
 added to other fertilizers) has 
 
 en satisfactory for the con- 
 
 in some cases has obviated 
 
 of Mo to animals rates of application 
 
 
 proven effective for correcting 
 
 trol of Mo deficiency of 
 
 the necessity for soil ap- 
 
 should in general be kept low, so as 
 
 
 and controlling Mo deficiency. 
 
 citrus. 
 
 plication of Mo. 
 
 not to build up too much Mo in the 
 soil. 
 
 [ 40 | 
 
TABLE 7. — Continued 
 
 Methods of control or amelioration 
 
 Element 
 
 Soil treatment 
 
 Molyb- 
 denum 
 excess 
 
 No cases are known of excess 
 to plants as such, but animals 
 eating plant materials high in 
 Mo are severely affected. Ad- 
 ditions of CuSO i to feed or to 
 soil have been very helpful. 
 
 Nitrogen 
 deficiency 
 
 13^ to 3 lbs N per tree per year 
 as inorganic or organic fertilizers, 
 or both, is sufficient in most cases 
 to correct and meet nitrogen needs 
 of citrus. Ample nitrogen in the 
 tree at time of bloom appears to be 
 especially important for good fruit 
 set. 
 
 Nitrogen 
 excess 
 
 Phos- 
 phorus 
 deficiency 
 
 Phos- 
 phorus 
 excess 
 
 Potassium 
 deficiency 
 
 Discontinue or apply less N fer- 
 tilizer to soil. High phosphate ferti- 
 lization decreases N effectiveness. 
 
 5-10 lbs P2O5 per tree as super- 
 phosphate broadcast or in furrows; 
 repeat applications every few years, 
 being guided by leaf and soil anal- 
 ysis. Organic manures also very 
 effective as a source of phosphorus. 
 
 1. Discontinue use of phosphorus- 
 containing fertilizers. 
 
 2. Increase use of nitrogen ferti- 
 lizer. 
 
 3. Lime application at 1-4 tons 
 per acre will decrease phos- 
 phorus availability. 
 
 1. Repeated applications of 5-10 
 lbs K2O per tree as K2SO4 or 
 KCI over a period of years. 
 
 2. Organic manures also effec- 
 tive; apply materials broadcast 
 or in furrows. Be guided by leaf 
 and soil analysis as to need for 
 repeated applications. 
 
 Foliar spray 
 
 Urea sprays containing IVi 
 lbs of urea per 100 gal. of 
 spray (urea should have no 
 more than 0.25% biuret): 
 Reuther, Embleton, and Jones 
 (1958). 
 
 Urea which contains over 
 0.25% biuret may cause leaf 
 injury of citrus, whether ap- 
 plied to the soil or as a foliage 
 spray. 
 
 Some correction can be 
 achieved using soluble phos- 
 phate fertilizers; but soil ap- 
 plications are more practical 
 in general. 
 
 Correct Cu and Zn deficien- 
 cies if they occur with appro- 
 priate sprays (see under Cu 
 and Zn). 
 
 Potassium will be some- 
 what absorbed by citrus leaves 
 from sprays containing soluble 
 potassium fertilizer, but there 
 is danger of leaf injury. Soil 
 applications are advised. 
 
 Other methods 
 
 Where legumes can be suc- 
 cessfully grown and good ton- 
 nages produced, as in young 
 orchards, N requirement can 
 be met by turning under a 
 legume crop. Chapman et al. 
 (1949). 
 
 In calcareous soils, sulfur 
 and other acid-forming mate- 
 rials will increase phosphate 
 availability temporarily. 
 
 Cover crops will bring some 
 potassium from lower hori- 
 zons to the surface, and this 
 increases availability position- 
 ally. 
 
 Supplementary remarks 
 
 Plants are not particularly sensi- 
 tive to Mo. Vanselow and Datta 
 1949; found that a several-thousand- 
 fold increase ^from 0.25 ppm Mo to 
 >500 ppm in leaf tissue of citrus 
 did not affect growth. However, ani- 
 mals feeding on such materials may 
 be severely affected. 
 
 1. Soil treatment advocated save 
 when there is need for a quick 
 nitrogen build-up in tree, e.g., 
 before or after bloom period in 
 spring. Urea spray especially val- 
 uable at that time. 
 
 2. Considerable N may be lost by 
 volatilization when ammonium 
 forms are added to alkaline soi Is. 
 
 3. There are unavoidable losses of 
 nitrogen from soil under commer- 
 cial operating conditions both by 
 leaching and by volatilization. 
 
 Excess nitrogen in some situations, 
 especially where fall and winter tem- 
 peratures are favorable for vegeta- 
 tive growth, may depress yields and 
 make fruit coarse. 
 
 Avoid excessive application of 
 phosphate as Cu, Zn, B, and N avail- 
 ability may be reduced. 
 
 1 . Phosphorus excess acts principally 
 to reduce Cu, Zn, B, and N avail- 
 ability. 
 
 2. In many soils phosphate becomes 
 less available and active as time 
 goes on; the situation will gradu- 
 ally improve if phosphorus-con- 
 taining fertilizers are discontin- 
 ued and nitrogen fertilizer appli- 
 cation increased. 
 
 Correction of K deficiency is some- 
 what slow on heavy soils, but in re- 
 peated soil applications, K moves 
 slowly downward into root zone and 
 correction can be successfully accom- 
 plished. Chapman (unpub. data 
 checked by leaf analysis the effects 
 of K fertilization on K uptake by 
 citrus on a wide variety of California 
 soils, and found in all cases that it 
 was possible to increase leaf potas- 
 sium by soil applications, though the 
 rate of change was slow in many 
 instances. 
 
 [47] 
 
TABLE 7. — Continued 
 
 Element 
 
 Potassium 
 excess 
 
 Methods of control or amelioration 
 
 Soil treatment 
 
 1. Discontinue use of organic ma- 
 nures and potassium fertilizers. 
 
 2. Add magnesium sulfate if 
 cause of Mg deficiency is too 
 much exchangeable potassium, 
 at rates of 5-10 lbs per tree for 
 several years and irrigate free- 
 ly to flush sulfate out of root 
 zone. 
 
 Sulfur 
 deficiency 
 
 Sulfur 
 excess 
 
 Zinc 
 deficiency 
 
 Zinc 
 excess 
 
 Excess 
 salts; 
 chloride, 
 sulfate, 
 s jilium. 
 carbonate, 
 bicarbon- 
 ate, etc. 
 
 Add calcium sulfate at rates of 
 500 to 1000 lbs per acre, using leaf 
 and soil analysis as a guide to fre- 
 quency required. 
 
 Where excessive soil acidity is 
 caused by sulfur, add lime to raise 
 soil pH (see under excess soluble 
 salts). 
 
 1. Not recommended on neutral 
 and alkaline soils in general, 
 but applications of ZnSOt to 
 soil under drip of tree have 
 given control; however, there 
 is danger of tree injury. 
 
 2. On acid soils, broadcast appli- 
 cations of ZnSCh are some- 
 times used. 
 
 3. Zinc chelates may have poten- 
 tial, but more data are needed 
 on safe values and methods. 
 
 1. Soil acidity may release excess 
 zinc. In this case use lime to 
 bring pH to 6.0 or 7.0. 
 
 2. Some soils are natively high in 
 zinc. Lime and phosphate will 
 be helpful. 
 
 3. Excess zinc may cause iron 
 chlorosis, and iron chelates 
 should prove helpful. 
 
 1. Leach salts out of root zone by 
 heavier than usual irrigations. 
 Drainage may be necessary if 
 water table is too high. Treat 
 soil with gypsum, sulfur, or 
 other neutralizers or soil condi- 
 tioners if necessary to get good 
 water penetration. 
 
 Foliar spray 
 
 If chief effect of excess pot- 
 ash is magnesium deficiency, 
 foliar sprays of magnesium ni- 
 trate at 10 per cent concentra- 
 tion will help correct the mag- 
 nesium deficiency. 
 
 Some leaf absorption of sul- 
 fate occurs from foliar sprays 
 but correction by this means 
 is not advocated. 
 
 1. 5 lbs ZnS0 4 , Zy 2 lbs 
 Ca(OH) 2 to 100 gal. water 
 applied in spring, summer, 
 or fall. 
 
 2. Formulations with Mn,Cu, 
 B, and other elements pos- 
 sible, as well as various 
 insecticides and fungi- 
 cides. Consult spray oper- 
 ator and insecticide manu- 
 facturer for information 
 on compatibility. 
 
 Other methods 
 
 High nitrogen fertilization 
 appears to offset injury due to 
 sulfate. 
 
 Cover crops, manures, 
 etc., have often proven 
 helpful. 
 
 Soil acidification has been 
 tried but not always suc- 
 cessful. 
 
 Supplementary remarks 
 
 1 . Excess potassium commonly pro- 
 duces magnesium and manganese 
 deficiency. Correct these by ap- 
 propriate methods (see under 
 Mg and Mn). 
 
 2. Occasionally excess soluble K is 
 found where soluble salts have 
 built up. Applications of gypsum 
 followed by leaching to remove 
 soluble salts is the proper correc- 
 tive treatment in this case. 
 
 Sulfur deficiency of citrus has not 
 been encountered in the field, but 
 should be looked for on non-irrigated 
 soils of low organic matter content 
 and high rainfall conditions; espe- 
 cially where sulfur or sulfate-con- 
 taining materials are not added in 
 the pest, disease, or fertilizer control 
 program. 
 
 See under Salinity Control where 
 excess sulfate is present. 
 
 1. In severe cases, repeated foliar 
 spraying may be necessary. 
 
 2. De Villiers (private communica- 
 tion) reports in South Africa that 
 MnS04 incorporated in zinc 
 sprays improves and speeds cor- 
 rection of zinc deficiency of 
 citrus. 
 
 3. Steyn and Eves (1956) report 
 that copper added to zinc sprays 
 decreases zinc absorption by 
 leaves. 
 
 Excess zinc in soil often produces 
 iron chlorosis of citrus (Chapman et 
 al., 1940). Similar effects on other 
 plants have been noted by many in- 
 vestigators. 
 
 Excessive salts may come from 
 irrigation water or by capillary rise 
 from saline water tables, or deposits 
 of salt in lower horizons. With irriga- 
 tion waters containing over 500 ppm 
 total dissolved solids, 5 to 15 or 
 higher per cent of water must be 
 wasted by leaching to keep salts 
 flushed out of soil. 
 
 |4«| 
 
LITERATURE CITED 
 
 Aldrich, D. G., and J. R. Buchanan 
 
 1954. Phosphorus content of soils and their par- 
 ent rocks in Southern California. Soil Sci. 
 77:369-76. 
 
 Aldrich, D. G., A. P. Vanselow, and G. R. Bradford 
 1951. Lithium toxicity in citrus. Soil Sci. 71:291- 
 95. 
 
 Allaway, W. H. 
 
 1957. pH, soil acidity, and plant growth. In Soil. 
 U.S. Dept. Agr. Yearbook 1957. Pp. 67-71. 
 
 Anderson, A.J. 
 
 1956. Molybdenum as a fertilizer. Advances in 
 Agron. 8:163-202. 
 
 Arnot, R. H. 
 
 1947. Potassium deficiency in coastal soils. A cause 
 of decline in citrus and passion fruit. Agr. 
 Gaz. N.S. Wales 58:72-74. 
 
 Baird, Guy B., and J. E. Dawson 
 
 1955. Determination of that portion of soil boron 
 available to plants by a modified Soxhlet- 
 extraction procedure. Soil Sci. Soc. Amer. 
 Proc. 19:219-22. 
 
 Barker, W. F., and W. J. A. Steyn 
 
 1956. Errors in the sampling of soils for chemical 
 analysis. S. African Jour. Sci. 52: 169-74. 
 
 Bathurst, A. C. 
 
 1943. New method for estimating the fertilizer 
 requirements of citrus trees. Farming in S. 
 Africa 18:323-27. 
 
 1944. Leaf analysis of citrus. Farming in S. Africa 
 19:325-28. 
 
 1944a. Method of sampling citrus leaves for di- 
 agnosis purposes. Farming in S. Africa 19: 
 329-30. 
 
 Berg, H. 
 
 1947. Zinc as a plant nutrient and plant poison. 
 Soils and Fertilizer XI: 116. 
 
 Berger, K. C, and E. Truog 
 
 1939. Boron determination in soils and plants. 
 Indus, and Engin. Chem., Analyt. Ed. 
 11:540-54. 
 
 Bingham, Frank T. 
 
 1949. Soil test for phosphate. California Agricul- 
 ture. 3 (8): 11,14. 
 Bingham, Frank T., and James P. Martin 
 
 1955. Effects of phosphorus on minor elements. 
 California Citrograph 40 (6): 246-49. 
 
 Bingham, F. T. 
 
 1958. Effect of phosphate on uptake of minor 
 elements. (Unpublished data.) 
 
 Bingham, F. T.,R. C. McColloch, and D. G. Aldrich 
 
 1956. Interrelation of soil potassium and mag- 
 nesium. California Citrograph 41:122,132- 
 134. 
 
 Bould, C. 
 
 1957. Iron chelates in plant nutrition. (Long 
 Ash ton Res. Sta., Bristol, Engl.) Jour. Sci. 
 Food and Agr. 8:sl-s5 (1957) Suppl. issue. 
 
 Bould, C, D. J. D. Nicholas, J. M. S. Potter, J. A. 
 H. Tolhurst, and T. Wallace 
 
 1950. Zinc and copper deficiency of fruit trees. 
 Bristol Univ., (Long Ashton) Agr. and Hort. 
 Res. Sta. Ann. Rpt., 1949, pp. 45-9. 
 
 Bould, C, D. J. D. Nicholas, J. A. H. Tolhurst, 
 and J. M. S. Potter 
 
 1953. Copper deficiency of fruit trees in Great 
 Britain. Jour. Hort. Sci. 28:268-77. 
 
 Boynton, Damon 
 
 1954. Apple nutrition. Chap. 1, in Fruit Nutrition. 
 Ed. by Norman Childers. Somerset Press. 
 Somerville, New Jersey. 
 
 Bradford, G. R., and R. B. Harding 
 
 1957. A survey of microelements in leaves of 
 forty-three high producing orange orchards 
 in Southern California. Amer. Soc. Hort. 
 Sci. Proc. 70:252-56. 
 
 Bray, Roger H. 
 
 1948. Correlation of soil tests with crop response 
 to added fertilizers and with fertilizer re- 
 quirement. Chap. 2, in Diagnostic Tech- 
 niques for Soils and Crops. The American 
 Potash Institute, Wash. 6, D.C. 
 
 Brewer, R. F., F. H. Sutherland, F. B. Guillemet, 
 and R. K. Creveling 
 1960. Some effects of atmospheric fluoride on 
 bearing navel orange trees. (Ms. for Amer. 
 Soc. Hort. Sci. Proc.) 
 Cameron, S. H., R. T. Mueller, and A. Wallace 
 1952. Influence of age of leaf, season of growth, 
 and fruit production on the size and in- 
 organic composition of Valencia orange 
 leaves. Amer. Soc. Hort. Sci. Proc. 60:42-50. 
 
 Camp, A. F., and M. Peech 
 
 1939. Manganese deficiency in citrus in Florida. 
 Amer. Soc. Hort. Sci. Proc. 36:81-85. 
 
 Carpena, O., M. G. Guillen, and J. A. Sanchez 
 1957. Iron-deficiency chlorosis of lemon trees. I. 
 (Inst. Edaphol. and Plant Physiol. Madrid) 
 Ann. edafol. y fisiol. vegetal. (Madrid) 16: 
 259-72. 
 
 Chapman, H. D. 
 
 1934. The phosphate of Southern California soils 
 in relation to citrus fertilization. California 
 Agr. Exp. Sta. Bui. 571. 
 
 1939. Absorption of iron from finely ground mag- 
 netite by citrus seedlings. Soil Sci. 48:309- 
 15. 
 
 1946. What we know and don't know about diag- 
 nosis of nutrient deficiencies and excesses of 
 citrus. California Citrograph 31(1 1):416— 17. 
 
 1949. Citrus leaf analysis. California Agriculture 
 3(11):10,12,14. 
 
 1952. Studies on the nutrition of citrus. Report of 
 the Thirteenth International Hort. Congr. 
 2:1241-56. The Royal Hort. Soc. 
 
 Chapman, H. D., and S. M. Brown 
 
 1943. Leaf analysis reveals needs. New method of 
 estimating the fertilizer needs of citrus trees. 
 
 [49] 
 
California experiments. Citrus Leaves 23 
 (11):9. 
 
 1950. Analysis of orange leaves for diagnosing nu- 
 trient status with reference to potassium. 
 Hilgardia 19(17):501-40. 
 
 Chapman, H. D., S. M. Brown, and D. S. Rayner 
 1944. Diagnosing the fertility needs of citrus trees. 
 California Citrograph 29(7): 182. 
 
 Chapman, H. D., and R. B. Harding 
 
 1956. Some effects of irrigation waters on soils. 
 California Citrograph 41(6) :206, 224-26. 
 
 Chapman, H. D., G. F. Liebig, and D. S. Rayner 
 
 1949. A lysimeter investigation of nitrogen gains 
 and losses under various systems of cover- 
 cropping and fertilization, and a discussion 
 of error sources. Hilgardia 19(3): 57-1 28. 
 
 Chapman, H. D., George F. Liebig Jr., and A. P. 
 Vanselow 
 
 1940. Some nutrient relationships as revealed by 
 a study of mineral deficiency and excess 
 symptoms on citrus. Soil Sci. Soc. Amer. 
 Proc. 4:196-200. 
 
 Chapman, Homf.r D., and Parker F. Pratt 
 
 1960. Methods of analysis for soils, plants, and 
 waters. California Agr. Exp. Sta. (In press). 
 
 Chapman, H. D., and D. S. Rayner 
 
 1951. Effect of various maintained levels of phos- 
 phate on the growth, yield, composition, 
 and quality of Washington navel oranges. 
 Hilgardia 20(1 7): 325-58. 
 
 Chapman, Homer D., and Albert P. Vanselow 
 1955. Boron deficiency and excess. California 
 Citrograph 40(1 2): 455-6, 458, 460. 
 
 Cline, Marlin G. 
 
 1944. Principles of soil sampling. Soil Sci. 58: 
 
 275-88. 
 
 Conner, Jane 
 
 1954. Effect of cultural practices on the man- 
 ganese status of soil and citrus trees under 
 irrigation. Austral. Jour. Agr. Res. 5(1): 
 31-8. 
 
 Cooper, William C. 
 
 1957. Comparison of several iron-chelating agents 
 in correcting iron-chlorosis in Dancy tan- 
 gerines in the Rio Grande Valley. Jour. Rio 
 Grande Valley Hort. Soc. 11:11-13. 
 
 Cooper, William C, and Cordell Edwards 
 
 1950. Salt and boron tolerance of Shary Red 
 grapefruit and Valencia orange on sour 
 orange and Cleopatra Mandarin rootstocks. 
 Rio Grande Valley Hort. Inst. Proc. 4:58-79. 
 
 ( ooper, William C, and Bert S. Gorton 
 
 1952. Toxicity and accumulation of chloride salts 
 in citrus on various rootstocks. Amer. Soc. 
 Hort. Sci. Proc. 59:113-6. 
 
 Cooper, William c, and Ascension Peynado 
 1954. Screening citrus rootstock seedlings for tol- 
 erance to calcareous soils. Rio Grande 
 Valley Hort. Inst. Proc. 8:100-5. 
 1056. Iron chlorosis of young Webb Red Blush 
 grapefruit trees grown in calcareous soil as 
 influenced bv rootstock and iron chelate 
 
 treatment. Jour. Rio Grande Valley Hort. 
 Soc. 10:38-42. 
 Delap, Anne V. 
 
 1949. The application of trace elements of al- 
 kaline soils. A preliminary note. Rep. E. 
 Mailing Res. Sta. for 1949(1950): 116-17. 
 DeVilliers, Jaap 
 
 1951. Citrus soils and nutrition. (Mimeo. publ.) 
 
 DeVilliers, J. I., W. Langenegger, C. J. Naude, and 
 P. C. J. Oberholzer 
 
 1958. Report of the Citrus Soils and Nutrition 
 subcommittee on Citrus Soils and Nutri- 
 tion. Union of So. Africa. (Mimeo report.) 
 
 Eaton, Frank M. 
 
 1935. Boron in soils and irrigation waters and its 
 effect on plants, with particular reference 
 to the San Joaquin Valley of California. 
 U. S. Dept. Agr. Tech. Bui. 448:1-131. 
 
 Eaton, Frank M., and George Y. Blair 
 
 1935. Accumulation of boron by reciprocally 
 grafted plants. Plant Physiol. 10:411-24. 
 
 Ellis, T. O., and E. A. Tai 
 
 1949. Report on citrus orchard analyses, 1947-48. 
 Jamaica Dept. Agr. Bui. 39. New Series. 
 
 Embleton, T. W., and W. W. Jones 
 
 1959. Magnesium deficiency of orange trees and 
 its correction. Calif. Citrograph 44:219, 236- 
 40. 
 
 Fergus, I. F. 
 
 1954. Manganese toxicity in an acid soil. Queens- 
 land Jour. Agr. Sci. 11(1): 15-27. 
 Fudge, B. R. 
 
 1939. Relation of magnesium deficiency in grape- 
 fruit to yield and chemical composition of 
 fruit. Florida Agr. Exp. Sta. Tech. Bui. 331. 
 36p. 
 
 Goodall, D. W., and F. G. Gregory 
 
 1947. Chemical composition of plants as an index 
 of their nutritional status. Imp. Bur. Hort. 
 and Plantation Crops, Tech. Commun. 17. 
 
 Haas, A. R. C, and H. J. Quayle 
 
 1935. Copper content of citrus leaves and fruit in 
 relation to exanthema and fumigation in- 
 jury. Hilgardia 9(3): 143-77. 
 
 Haas, A. R. C, and E. E. Thomas 
 
 1928. Effect of sulphate on lemon leaves. Bot. 
 Gaz. 86:345-54. 
 
 Harding, Robert B. 
 
 1954. Surface accumulation of nitrates and other 
 soluble salts in California orange orchards. 
 Soil Sci. Soc. Amer. Proc. 18:369-72. 
 1959. Salt variations in irrigated sections of citrus 
 orchards. (Unpublished.) 
 Harding, R. B., and H. 1). Chapman 
 
 1950. Progress report on a study of soil charac- 
 teristics in forty high-performance orange 
 orchards in California. Soil Sci. Soc. Amer. 
 Proc. 15:213-18. 
 
 Harding, Robert B., Marvin P. Miller, and Milton 
 Fireman 
 1958. Absorption of salts by citrus leaves during 
 sprinkling with water suitable for sin lace 
 
 I 50 | 
 
irrigation. Amer. Soc. Hort. Sci. Proc. (In 
 press.) 
 
 Harding, R. B., P. F. Pratt, and W. W. Jones 
 
 1958. Changes in salinity, nitrogen and soil re- 
 action in a differentially fertilized irrigated 
 soil. Soil. Sci. 85(4): 177-184. 
 
 Hausenbuiller, R. L. 
 
 1957. Sampling saline and alkali soils for labora- 
 tory analysis. Washington Agr. Exp. Sta. 
 Cir. 303. 
 
 Hemingway, R. G. 
 
 1955. Soil-sampling errors and advisory analyses. 
 Jour. Agr. Sci. 46(Pt.l):l-8. 
 
 Heymann-Herschberg, Lotte 
 
 1951. Magnesium deficiency of Shamouti orange 
 trees and its treatment. Palestine Jour. Bot. 
 Rehovot Ser. 8:1. 
 1954 Nitrogen and. phosphorus content of citrus 
 leaves in Israel: Frequency distribution 
 and influential factors. Agr. Res. Sta. Re- 
 hovot Ser. 87, V(l): 19-27. 
 
 Hill-Cottingham, D. G., and C. P. Lloyd-Jones 
 
 1958. Behavior of iron chelates in calcareous soils. 
 II. Laboratory experiments with some fur- 
 ther chelating agents. Plant and Soil IX: 
 189-201. 
 
 Hoff, D., and H. J. Mederski 
 
 1958. The chemical estimation of plant available 
 soil manganese. Soil Sci. Soc. Amer. Proc. 
 22:129-32. 
 
 Jordan, Howard V., and Charles E. Bardsley 
 
 1958. Response of crops to sulfur on southeastern 
 soils. Soil Sci. Soc. Amer. Proc. 22:254-6. 
 
 Kaudy, J. C, F. T. Bingham, R. C. McColloch, G. F. 
 
 Liebig, and A. P. Vanselow 
 
 1955. Contamination of citrus foliage by flourine 
 
 from air pollution in major California 
 
 citrus areas. Amer. Soc. Hort. Sci. Proc. 65: 
 
 121-7. 
 
 Kelley, W. P., and S. M. Brown 
 
 1928. Boron in the soils and irrigation waters of 
 southern California and its relation to 
 citrus and walnut culture. Hilgardia 3(16): 
 445-58. 
 
 Kelley, W. P., and E. E. Thomas 
 
 1920. The effect of alkali on citrus trees. Cali- 
 fornia Agr. Exp. Sta. Bui. 318:305-37. 
 
 Kilpatrick, D. T., and V. K. Lohmeyer 
 
 1954. Copper deficiency of citrus in South Aus- 
 tralia. Jour. Agr. South Australia 58:128-30. 
 
 Leeper, G. W. 
 
 1935. Manganese deficiency of cereals: Plot ex- 
 periments and a new hypothesis. Roval Soc. 
 Victoria, Proc. 47:225-61. 
 
 1947. The forms and reactions of manganese in 
 the soil. Soil Sci. 63:79-94. 
 
 Leonard, C. D., and Ivan Stewart 
 
 1953. Chelated iron as a corrective for lime-in- 
 duced chlorosis in citrus. Florida State 
 Hort. Soc. Proc. 66:49-54. 
 
 Levitt, E. C, and R. I. Nicholson 
 
 1941. Manganese deficiency in citrus in New- 
 South Wales coastal districts. Agr. Ga/. N. 
 S. Wales 52:283-6. 
 
 1941a. Severe manganese deficiency of citrus. Agr. 
 Ga/. N. S. Wales 52(9):447-9. 
 
 Liebig, G. F., Jr., G. R. Bradford, and A. P. Vwsli.ow 
 1959. Effects of arsenic compounds on citrus 
 plants in solution culture soil science. (In 
 press.) 
 
 Liebig, George F., Albert P. Vansi low, and H. I). 
 Chapman 
 1943. Effects of gallium and indium on the 
 growth of citrus plants in solution cultures. 
 Soil Sci. 56:173-85. 
 
 Lyman, Clarence, and L. A. Dean 
 
 1942. Zinc deficiency of pineapple in relation to 
 soil and plant composition. Soil Sci. 54: 
 315-29. 
 
 Martin, J. P., R. B. Harding, and W. S. Murphy 
 1953. Effects of various soil exchangeahle cation 
 ratios on growth and chemical composition 
 of citrus plants. Soil Sci. 76:285-95. 
 
 .Martin, J. P., G. K. Helmkamp, and J. O. Ervin 
 1956. Effects of bromide from a soil fumigant 
 and from CaBr 2 on growth and chemical 
 composition of citrus plants. Soil Sci. Soc. 
 Amer. Proc. 20:209-12. 
 
 McCleery, F. C, and W. B. Stokes 
 
 1929. Control of exanthema of citrus in New 
 South Wales. Agr. Gaz. N. S. Wales 40:523- 
 34. 
 
 McClung, A. C, and J. E. Dawson 
 
 1950. Some studies of the behavior of boron un- 
 der cropping. Soil Sci. Soc. Amer. Proc. 15: 
 
 268-72. 
 
 McKenzie, R. M. 
 
 1955. Sampling variations in the concentrations 
 of elements in soils. Austral. Jour. Agr. 
 Res. 6(5):699-706. 
 
 Millar, C. E. 
 
 1955. Soil fertility. John Wiley and Sons, Inc.. 
 New York. 
 
 Monsflise, S. P., and Lotte Heymann-Herschberg 
 1953. Influence of exposure and age on dry mat- 
 ter content, area and mineral composition 
 of Shamouti orange leaves. Amer. Soc. Sci. 
 Proc. 62:67-74. 
 
 Morris, A. A. 
 
 1937. V. The effect of differential fertilizer treat- 
 ments on the yield and quality of fruit 
 from mature bearing Valencia late trees on 
 Mazoe Citrus Estate, Southern Rhodesia. 
 Mazoe Citrus Exp. Sta. Ann. Rpt. 1936: 107— 
 53. 
 
 1938. Some observations on the effects of boron 
 treatment in the control of "hard fruit'* in 
 citrus. Jour. Pomol. and Hort. Sci. 16:1 67— 
 81. 
 
 [51] 
 
Olsen, Sterling R., C. V. Cole, Frank S. Watanabe, 
 and L. A. Dean 
 1954. Estimation of available phosphorus in soil 
 by extraction with sodium bicarbonate. U.S. 
 Dept. Agr. Cir. 939. 
 
 Oppenheimer, H. R. 
 
 1945. Leaf analyses of Shamouti oranges. Pales- 
 tine Jour. Bot., Rehovot Ser. V(I):86-95. 
 
 Oppenheimer, H. R., and K. Mendel 
 
 1938. Problems of citrus nutrition II. Studies on 
 the potash requirement of sweet lime. Had- 
 ar (Tel- Aviv) 11:177-81, 244-49. 
 
 Parberry, X. H. 
 
 1935. Mineral constituents in relation to chlorosis 
 of orange leaves. Soil Sci. 39:35-45. 
 
 Peech, Michael 
 
 1939. Chemical studies on soils from Florida cit- 
 rus grove. Florida Agr. Exp. Sta. Tech. Bui. 
 340. 
 
 Penman, F., and D. M. McAlpin 
 
 1949. Boron poisoning in citrus. Victoria (South 
 Africa) Dept. Agr. Jour. 47:181-9. 
 
 Piper, Clarence S. 
 
 1944. Soil and plant analysis. Interscience Pub., 
 Inc., New York. 
 
 Pont, J. W. 
 
 1941. The effect of mineral deficiency and excess 
 on citrus. (Unpublished manuscript, Div. 
 Horticulture, Dept. Agr. Union of So. 
 Africa.) 
 
 Prince, Arthur L., Miryam Zimmerman, and Fir- 
 man E. Bear 
 
 1947. The magnesium-supplying powers of 20 
 New Jersey soils. Soil Sci. 63:69-78. 
 
 Quastel, J. H., E. J. Hewitt, and D. J. D. Nicholas 
 
 1948. The control of manganese deficiency in 
 soils. I. The effects of sulphur and thio- 
 sulphate on crops growing on manganese- 
 deficient soils. Jour. Agr. Sci. 38:315-22. 
 
 Reed, J. Fielding, and J. A. Rigney 
 
 1947. Soil sampling from fields of uniform and 
 nonuniform appearance and soil types. 
 Jour. Amer. Soc. Agron. 39:26-40. 
 
 Reitz, Herman J., and Wallace T. Long 
 
 1952. Mineral composition of citrus leaves from 
 Indian River area of Florida. Florida State 
 Hon. Soc. Proc. 65:32-8. 
 
 Ri iiz, Herman J., and Neil F. Shimp 
 
 1953. Copper oxide as a soil amendment for cit- 
 rus. Florida Slate Hon. Sot. Proc. 66:37-42. 
 
 Ri it HER, Wali Ik 
 
 1957. Copper and soil fertility. In Soil. U.S. Dept. 
 Agr. Yearbook 1957. Pp. 128-35. 
 
 Ri i inik, Walter, Tom \V. Embleton, and Winston 
 
 W. JONES 
 
 1958. Mineral nutrition of tree crops. Ann. Rev. 
 Plan! Physiol. 9:175-200. 
 
 Rm inik. Walter, Frank e. Gardner, Paul F. 
 Smith, and Wallace R. Roy 
 191'). Phosphate fertilize! trials with oranges in 
 
 Florida. I. Effects on yield, growth, leaf 
 and soil composition. Amer. Soc. Hort. 
 Sci. Proc. 53:71-84. 
 
 Reuther, Walter, and Paul Smith 
 
 1953. Effects on high copper content of sandy soil 
 on growth of citrus seedlings. Soil Sci. 75: 
 219-24. 
 
 1954. Leaf analysis as a guide to the nutritional 
 status of orchard trees. Congr. intern, 
 boton., 8 congr. Paris 1954. Collog. analyse 
 plantes et problemes engrais mineraux, 166- 
 80. (In English.) 
 
 1954a. Leaf analysis of citrus. Chap. 7, in Fruit 
 Nutrition. Ed. by Norman F. Childers. Som- 
 erset Press, Somerville, New Jersey. 
 
 Reuther, Walter, Paul F. Smith, and Geo. K. 
 Scudder 
 
 1953. Relation of pH and soil type to toxicity of 
 copper to citrus seedlings. Florida State 
 Hort. Soc. Proc. 66:73-80. 
 
 Sato, K., M. Ishihara, and R. Harada 
 
 1952. Studies of leaf analysis of fruit trees. Bid. 
 Natl. Inst. Agr. Sci., Series E (Hort.) No.l, 
 Hiratsuka, Kanagawa, Japan. 
 
 Shaw, Ellsworth, and L. A. Dean 
 
 1952. Use of dithizone as an extractant to esti- 
 mate the zinc nutrient status of soils. Soil 
 Sci. 73:341-7. 
 
 Sherman, G. Donald, and Paul M. Harmer 
 
 1942. The manganous-manganic equilibrium of 
 soils. Soil Sci. Soc. Amer. Proc. 7:398^05. 
 
 Smith, Paul F. 
 
 1956. Effects of high levels of copper, zinc and 
 manganese on tree growth and fruiting of 
 Valencia orange in sand culture. Amer. Soc. 
 Hort. Sci. Proc. 67:202-9. 
 1956a. Relation of boron level to the production 
 of fruit quality of grapefruit and oranges. 
 Citrus Indus. 37(3):5-8, 18. 
 
 Smith, Paul F., Walter Reuther, and Alston W. 
 Specht 
 1950. Mineral composition of chlorotic orange 
 leaves and some observations on the rela- 
 tion of sample preparation technique to 
 the interpretation of results. Plant Phys- 
 iology. 25(3): 496-500. 
 
 Spencer, W. F. 
 
 1954. A rapid test for possible excesses of copper 
 in sandy soils. Florida Agr. Exp. Sta. Bui. 
 544. 12 pp. 
 
 STECKEL, Joi 1.., B. R. BtkiRAMSoN, and A. J. 
 Ohlrogge 
 1948. Manganese nutrition of plants as related to 
 applied superphosphate. Soil Sci. Soc. 
 Amer. 13:108-11. 
 
 Steyn.W.J. A., and D.J. Eve 
 
 1956. The zinc status of citrus and pineapples in 
 the Eastern Cape. South African Jour, of 
 Science. 52:270-71. 
 
 52 
 
STEYN, W. J. A. 
 
 1957. A statistical study of the errors involved in 
 the sampling and chemical analysis of soils 
 and plants with particular reference to cit- 
 rus and pineapples. (Ph.D. thesis sub- 
 mitted to the Faculty of Rhodes University, 
 Grahamstown, South Africa. October 1957.) 
 
 1959. Leaf analysis. Errors in the preparative 
 phase. Jour. Agricultural and Food Chem- 
 istry 7:344-48. 
 
 Strauss, J. L., and A. L. Grizzard 
 
 1947. The effect of calcium, magnesium and po- 
 tassium on peanut yields. Soil Sci. Soc. 
 Amer. Proc. 12:348-52. 
 
 SWAINE, D. J. 
 
 1955. The trace-element content of soils. Com- 
 monwealth Bur. Soil Sci., Rothamsted Expt. 
 Sta., Harpenden, England. Tech. Comm. No. 
 48. 
 
 Thorne, D. W., W. Derby Laws, and Arthur 
 Wallace 
 1942. Zinc relationships of some Utah soils. Soil 
 Sci. 54:463-68. 
 
 Truog, Emil 
 
 1930. The determination of the readily available 
 phosphate of soils. Jour. Amer. Soc. Agron. 
 
 22:874-82. 
 
 United States Salinity Laboratory Staff, L. A. 
 Richards, Editor 
 1954. Diagnosis and improvement of saline and 
 alkali soils. U.S. Dept. Agr. Handbook 60. 
 
 Ulrich, Albert 
 
 1948. Plant analysis, methods and interpretation 
 of results. Chap. 7, in Diagnostic Tech- 
 niques for Soils and Crops. Pub. by Ameri- 
 can Potash Institute, Washington, D.C. 
 
 Vanselow, A. P. 
 
 1952. Microelements in citrus. California Agri- 
 culture 6(1):5, 14. 
 
 Vanselow, Albert P., and Narayan P. Datta 
 
 1949. Molybdenum deficiency of the citrus plant. 
 Soil Sci. 67:363-75. 
 
 Vanselow, A. P., and George F. Liebig, Jr. 
 
 1948. Spectrochemical methods. California Agr. 
 Exp. Sta., Berkeley 4, California. 
 
 Vlamis, J. 
 
 1949. Growth of lettuce and barley as influenced 
 by degree of calcium saturation of soil. Soil 
 Sci. 67:453-66. 
 
 Walker, Richard B. 
 
 1948. Molybdenum deficiency in serpentine bar- 
 ren soils. Science 108:473-5. 
 
 Wallace, A., R. T. Mufller, and M. G. Squier 
 
 1952. Variability in orange leaves of the same 
 age and collected from a single tree. Amer. 
 Soc. Hort. Sci. Proc. 60:51-4. 
 
 Wallihan, Ellis F. 
 
 1955. Relation of chlorosis to concentration of 
 iron in citrus leaves. Amer. Jour. Bot. 42: 
 101-04. 
 
 Walsh, T., M. Neenan, and L. B. O 'Moore 
 
 1952. Molybdenum in relation to cropping and 
 livestock problems under Irish conditions. 
 Nature 170:149-50. 
 
 Wear, John I., and Anna L. Sommer 
 
 1947. Acid-extractable zinc of soils in relation to 
 the occurrence of zinc-deficiency symptoms 
 of corn: A method of analysis. Soil Sci. 
 Soc. Amer. Proc. 12:143-4. 
 Whetstone, Richard R., William O. Robinson, and 
 Horace G. Byers 
 1942. Boron distribution in soils and related data. 
 U.S. Dept. Agr. Tech. Bui. 797:1-32. 
 
 [53] 
 
In order that the information in our publications may be more intelligible it is sometimes neces- 
 sary to use trade names of products or equipment rather than complicated descriptive or chemical 
 identifications. In so doing it is unavoidable in some cases that similar products which are on the 
 market under other trade names may not be cited. No endorsement of named products is in- 
 tended, nor is criticism implied of similar products which are not mentioned. 
 
 Co-operative Extension work in Agriculture and Home Economics, College of Agriculture, University of California, and United States Department of Agriculture 
 co-operating Distributed in furtherance of the Acts of Congress of May 8, and Juno 30, 1914. George B. Alcorn, Director, California Agricultural Extension Sorvice. 
 
 5m 3,'60(A3770)MH °4«P '" 
 
▼"is BOOK «S DU r ON T HE LAST DA 
 
 By taking representative leaf and soil samples from a citrus orchard 
 and having a competent analysis made of the samples, growers may 
 remove most of the guesswork from their management practices. This 
 manual discusses the steps involved in proper sampling and analyzing, 
 and provides typical forms for surveying the orchard. 
 
 To obtain additional copies of this manual or a catalog listing other 
 manuals and free publications available, see your University of Cali- 
 fornia Farm Advisor (offices located in most California counties), or 
 write to: 
 
 Agricultural Publications 
 207 University Hall 
 2200 University Avenue 
 Berkeley 4, California 
 
 Orders of 10 or more copies of any one manual take a 20 per cent 
 discount off the list price. All manuals are shipped prepaid. 
 
 When ordering manuals, send orders and payment to the above 
 address. Make checks or money orders payable to The Regents of 
 the University of California.