633 
 
 FERTILIZERS: 
 
 THEIR 
 
 Source, Purchase 
 
 BY 
 
 CARROLL B. SMITH 
 
 SECOND EDITION
 
 THE LIBRARY 
 
 OF 
 
 THE UNIVERSITY 
 OF CALIFORNIA 
 
 LOS ANGELES
 
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 FLRTIL1ZLR5: 
 
 Their- 
 
 Source, Purchase, and Use 
 
 Written for the Use of Farmers 
 
 and Fruit Growers, With Special 
 
 Reference to Citrus Culture. :: :: 
 
 By 
 
 CARROLL B. 5MITH 
 
 SECOND EDITION 
 
 Revised and ELnlarged 
 
 REDLANDS. CALIFORNIA: 
 CITROGRAPH BOOK PRESS 
 
 1911
 
 COPYRIGHTED 1911 
 
 BY 
 CARROL.L. B. SMITH
 
 633 
 
 TO THE READER. 
 
 This work is designed expressly for those 
 who are forced to use fertilizers and yet have 
 not the time to investigate the subject as they 
 would like to. It is intended to be brief and 
 suggestive of thought to the reader rather 
 than complete and final. 
 
 Technicalities are avoided and illustrations 
 simplified as much as possible. 
 
 All the facts and deductions contained are 
 based on the highest authorities on the sub- 
 jects mentioned, and largely on the results of 
 actual experience in California. 
 
 The author hopes that the matter here given 
 will aid the farmer to choose and purchase his 
 fertilizers most wisely, and help him to get the 
 best possible results from their use. There is 
 no final authority in Nature. Every farmer's 
 problems are his own and he must do his own 
 thinking. The author has tried to present 
 only the well established facts and general 
 PRINCIPLES. A fuller knowledge of these, 
 properly applied, will lead to better results 
 and larger profits. 
 
 CARROLL B. SMITH. 
 Redlands, California. 
 
 579459
 
 NOTE : This book has cross references throughout ; 
 that is, when a number in parenthesis follows a 
 sentence or paragraph it refers to some other para- 
 graph or sentence having the same number, and 
 treating of the same subject. Any phase of the 
 Fertilizer question can thus be followed throughout 
 the book.
 
 FERTILIZERS: 
 
 Their Source, Purchase and Use 
 
 SOMETHING ABOUT PLANTS. 
 
 CIRCULATION. 
 
 1. The higher plants (Fruit and Forest trees) have 
 a well defined circulatory system. Beginning with 
 the absorption by the root , hairs of soil moisture, 
 containing dissolved plant food, one set of tissue 
 termed xylem carries this moisture or sap upward 
 into the leaves and is there lost. In the leaf 
 the sap is transformed or elaborated largely by sun- 
 light, according to the plant's nature and needs, and 
 returned to the branches and trunk of the tree and 
 its fruit, by another distinct set of tissue termed 
 phloem. Both these sets of tissue are, roughly 
 speaking, found in the "Cambium" or sap layer of 
 the bark. They are between the real bark and the 
 wood of the tree. Wood is built up on one side and 
 bark on the other. In a cross section of a limb or 
 trunk of a tree these different tissues might be illus- 
 trated, as in Fig. 1. 
 
 The life of the tree is in the cambium. When we 
 bud or graft it is cambium layer contact we want in 
 both stock and scion. If the cambium is severed 
 completely around the tree it dies. All of the soil 
 derived plant foods enter the tree through its xylem 
 tissue, found in the cambium layer.
 
 6 FERTILIZERS 
 
 RESPIRATION. 
 
 2. Plants have a respiratory system. They ab- 
 sorb oxygen and give off carbonic acid, mostly at 
 night, but during the day more oxygen is given off 
 and carbonic acid absorbed. The leaves and some of 
 the green bark are the respiratory system. Carbon 
 and oxygen thus enter the plant directly from the air 
 as well as by water from the roots. 
 
 FIGURE 1 
 TRANSPIRATION. 
 
 3. Plants give off water (Transpiration) at all 
 times of day and night. The water escapes at cer- 
 tain pores, called Stomata, of the leaf contained also 
 in very young bark. Water carries the plant food 
 into the plant by way of the roots. The plant foods, 
 changed and elaborated, are retained in the tissue as 
 new growth while the water passes off through 
 the leaves as a vapor. When transpiration exceeds 
 the supply from the roots the plant wilts. If the air 
 is saturated with moisture, plants give off less, but
 
 FERTILIZERS 7 
 
 on hot days give off more. The leaves of fruit trees 
 may be made large or small by an adequate or inad- 
 equate supply of moisture. ',The larger and healthier 
 the leaves, the more plant food]is>laborated^and the 
 better the growth and the crop. So the transpira- 
 tion system and its healthy activities are very 
 directly connected with the production of fruit. 
 
 4. Any serious or prolonged check to the process 
 of transpiration necessitates a long time for full 
 recovery, frequently several years. A severe wilting 
 will show for a year, but a slight wilting usually 
 fully recovers after watering. Thus the importance 
 of a regular and sufficient supply of water is evident. 
 
 Water is the common carrier of all the plant's food, 
 whether the food is derived from the air or from the 
 soil (13), the only positively known exceptions being 
 the absorption of carbon and oxygen by respiration. 
 
 The whole movement of water from the root hairs 
 to the leaf and back to other parts of the plant and 
 fruit, is confined to the cambium layer in which are 
 contained the xylem (upward flow) and phloem 
 (downward flow) tissue. 
 
 LEAVES. 
 
 5. A good leaf is essential to the best results. 
 Leaves put the plant in communication with sun- 
 light, under which influence sap is changed and many 
 products, incident and essential to growth, are 
 manufactured. It is believed that all of the plant 
 food brought into the 'tree by water, undergoes 
 some change in the leaf (digestion) before it is finally 
 added to the various tissue of the plant. If the leaf 
 has been stunted or impaired by drought, frost or 
 fire, it manufactures less of the products essential
 
 8 FERTILIZERS 
 
 to growth. Less water can come into it ; therefore, 
 less water and less food enter the plant. Less sun- 
 light can act on it, and all of the activities of the 
 plant are so reduced that the result is a small crop 
 of undersized fruit. Consequently, a good leaf is 
 essential to the best results. 
 
 BARK. 
 
 6. What has been said of the function of leaves is 
 true, to some extent, of green bark. Old, corky bark 
 may be regarded as the armor or shield to the cam- 
 bium layer. But young, tender bark can carry on 
 the process of respiration of carbon and oxygen, and 
 of transpiration of moisture, and to that extent the 
 transformation of the sap and plant food. Although 
 these activities in bark are very limited, they are 
 sufficient to continue the life of the tree should it 
 ever become defoliated for purposes of transplanting 
 or on account of disease or frost. Under the young 
 bark's continued activity new leaves may start, 
 until finally the plant renews its full health and 
 vigor. 
 
 ROOTS. 
 
 7. The distribution of plant food throughout the 
 soil influences directly, and, with water, the entire 
 development of the root. The absorptive power of 
 the root is in the young, tender rootlets or fibres, 
 by means of root hairs invisible to the eye. These 
 root hairs are distributed along the length of the 
 tender, growing fibre. The end of the fibre has a cap 
 which protects it as it develops and crowds its way 
 between the smallest soil particles. The very tips of 
 roots and fibres cannot absorb moisture or food.
 
 FERTILIZERS 9 
 
 FIBROUS ROOTS. 
 
 8. If the soil is poor, the roots are very long and 
 develop very few fibres and root hairs. But in a 
 rich soil they are short and well branched, often 
 forming a perfect mat of fibres. Under such fertile 
 conditions the root hairs are more numerous and the 
 plant's contact with the soil and its feeding powers 
 are much greater. Consequently, roots develop 
 where the food is. Fertilizers should be applied as 
 deep as possible, so that root development will not 
 be encouraged near the surface. (63) (79). 
 
 SHALLOW WORK. 
 
 9. If the application of fertilizers and water is 
 limited to the top foot the most of the fibres are de- 
 veloped there, and deep ploughing and cultivation 
 become questionable policy. Thick \vater conserv- 
 ing mulch becomes impossible, (see frontispiece). 
 This is the actual condition where impervious strata 
 or "hard pan" lies near the surface. 
 
 DEEP WORK. 
 
 10. In open, deep soils where water can go down 
 easily, the plant food is more widely distributed and 
 likewise the fibrous roots. Here, deep work and a 
 deep mulch are possible, and in case of water short- 
 age, would be found a great advantage, as there is a 
 better reserve supply in the sub-soil. 
 
 APPLY FERTILIZER DEEPLY. 
 
 11. Present practice applies all fertilizer between 
 the surface and the bottom of the plow furrow. 
 This is unavoidable, even in open soils where the 
 water is easily absorbed. Methods of effecting
 
 10 FERTILIZERS 
 
 deeper applications without serious root disturbance 
 are unknown. As a result roots are encouraged 
 near the surface, and this fact is the best argument 
 advanced for the use of the most water soluble forms 
 of fertilizer obtainable, as they are more widely dis- 
 tributed by the movement of water. (77) (79). 
 
 SOILS AND ROOTS. 
 
 12. The permeable character of the soil influences 
 the root development, aside from the question of 
 plant food. In clay or adobe soils there is a limited 
 root development and a resultant smaller tree. 
 "Hard pans" near the surface have the same limit- 
 ing influence. In such soils, more trees can be 
 planted to the acre. 
 
 Open, free loams or gravelly, sandy loams permit 
 a larger root development and trees should be 
 placed further apart. These are usually local ques- 
 tions, but should be considered by the intending 
 planter. The mechanical or physical nature of the 
 soil should be known to a considerable depth. (20- 
 22).
 
 FERTILIZERS 1 1 
 
 SOMETHING ABOUT SOILS. 
 
 13. Of more than seventy elements known to 
 chemistry, fourteen have been found to be essential 
 to plant life. Ten of these are soil derived, and four 
 are derived from the air : 
 
 Air Derived. Soil Derived. 
 
 Carbon Calcium 
 
 Oxygen Silicon 
 
 Hydrogen Iron 
 
 Nitrogen Magnesium 
 
 Manganese 
 Sulphur 
 Chlorine 
 Sodium 
 Potassium 
 Phosphorus 
 
 These fourteen elements, in varying portions, are 
 peculiar to all plants so far as different species have 
 been examined. 
 
 14. All soils, for convenience, may be considered 
 as composed of various portions of: 
 
 Rock Powder } f Sand 
 
 Silt I j 
 
 Clay > or simply Clay 
 
 Humus ) | 
 
 Plant food j" Humus 
 
 Sand is rock powder and may or may not contain 
 silt. Clay is a chemical compound and a very im- 
 portant element of soils, as it retains large amounts 
 of moisture. If too abundant, the soil is intractable
 
 12 FERTILIZERS 
 
 and hard to manage, and bakes easily and while 
 sand alone is too porous to retain moisture, the 
 addition of a little clay with sand makes the proper 
 balance for retaining moisture and for friability. 
 
 15. Humus, decayed organic matter, is absolutely 
 essential as it is the source of the necessary nitrogen. 
 It is a fundamental truth in connection with this sub- 
 ject that there is no fertility without humus. It also 
 influences favorably, as nothing else will, the soil's 
 mechanical condition and moisture content, besides 
 supplying essential plant foods. 
 
 The humus which plants contribute to the soil 
 not only furnishes all of the soil nitrogen, except 
 that artificially added, but gives life to numerous 
 forms of bacterial life, with which every healthy soil 
 is teeming. We cannot discuss this subject here (86- 
 89), but it will suffice to say that, without the 
 contribution made by plants to the soil, the micro- 
 scopic forms of life could not exist and they are now 
 regarded as essential to fertility. Indeed, it is pos- 
 sible to inoculate soils with beneficial bacteria, and 
 improve their fertility. 
 
 A soil may contain sand, clay and humus and yet 
 lack some essential plant food, hence the last division. 
 But as a rule, sanrl, clay and humus in proper pro- 
 portions will, for a time at least, supply all the 
 requirements of plant life. 
 
 The plant requires of the soil that it furnish the 
 ten named soil derived elements, and the soil requires 
 of the plant that it supply humus and such of the 
 air derived elements as are necessary to its own 
 health and fertility. Just what amounts of hydro- 
 gen, oxygen, carbon and nitrogen are absorbed
 
 FERTILIZERS 1 3 
 
 directly from the air, and how much is contributed 
 by plant life, is not known. But it is generally be- 
 lieved that most of these elements as found in soils 
 are derived from plants, either through the agency 
 of beneficial bacteria or from the decay of vegetable 
 tissue. 
 
 16. The character of vegetation changes with the 
 soil. Pure clay soils support very little plant life, as 
 there is no drainage, no ventilation and no yielding 
 to root penetration. The right degree of porosity, 
 due to the presence of sand and humus, allows the 
 roots to enlarge rapidly which in turn nourishes a 
 large plant. Hence the same species of plants will 
 vary in size and appearance according as the nature 
 of the soil encourages or restricts their growth. A 
 well developed root means a well developed plant 
 and vice versa. 
 
 If potassium or sodium or chlorine are in excess, 
 the soil is alkaline and tolerated by certain classes of 
 plants like the salt bushes, some of the mallows, 
 tussock grass, etc. 
 
 Peat lands, bogs and meadows have a characteris- 
 tic vegetation. Peat may contain as high as 80% 
 humus or decayed organic matter. Here, nitrogen 
 is naturally in excess and moisture plenty, so that 
 the growth is vigorous and succulent. Tall grasses, 
 and willows thrive here. 
 
 The well drained "mesa" of the arid west, sup- 
 ports another variety of vegetation and a dense 
 forest cover or leaf mould, still another, according to 
 their moisture holding powers. The various com- 
 binations of sand, clay, humus and plant food are 
 almost infinite.
 
 14 FERTILIZERS 
 
 17. Soils vary in chemical composition according 
 to depth. The surface foot or two feet usually con- 
 tains the bulk of the nitrogen, due to the fact that 
 the nitrates are water soluble and the evaporation 
 of moisture at the surface leaves the nitrates and all 
 soluble plant foods there for the benefit of young 
 plants whose roots have not gone deep. Young 
 plants must grow first, and nitrogen produces 
 growth. As the plant matures, its roots penetrate 
 lower into the region where the nitrogen is scarce 
 and where the phosphates, silicon, lime and insoluble 
 elements are more evenly distributed. There, fruit 
 production and maturing of tissue take place. 
 
 During the time growth is vigorous, fruit produc- 
 tion is limited or impossible even in the case of 
 mature trees when artificially forced to an abnor- 
 mally vigorous growth. 
 
 18. While nitrogen is the chief element of growth, 
 other elements of the soil favor fruit production. 
 Phosphorus is definitely known to be one of these. 
 (70). If the fruit producing elements of the soil were 
 abundant on the surface, and nitrogen, relatively 
 deficient there, then fruit trees would be heavily 
 laden before they were taken from the nursery. 
 There is abundant evidence of order and design in the 
 methods of nature. "First the blade, then the ear, 
 then the full corn on the ear," and the soil is so 
 arranged as to effect the order. 
 
 19. It is interesting to note briefly that the func- 
 tion of potassium is to mature the growth that 
 nitrogen produces. Where nitrogen is in excess of 
 potassium, as in bogs and peat lands, the growth is 
 soft and watery, whereas if potash is abundant and
 
 FERTILIZERS 1 5 
 
 the nitrogen supply less, the growth is hard and 
 firm. As illustration : note the strength of chap- 
 arral wood, compared with marsh land growth. 
 Nitrogen is deficient (comparatively) where the chap- 
 arral grows and the mineral or soil derived elements, 
 including potassium, relatively abundant. In a 
 word, potassium gives starch or stiffness to the 
 plant. Young peppers, acacias and eucalyptus trees 
 bend frequently to the ground because their roots are 
 in the surface soil, feeding on the excess of nitrogen 
 and water. Older trees with deeper roots have not 
 this tendency. (71). 
 
 Sulphur, iron, calcium and silicon also perform 
 special parts in the building of plant tissue, but a 
 discussion of these would extend our subject unneces- 
 sarily; They are not "essential" plant foods. (23). 
 
 PHYSICAL CONDITIONS. 
 
 20. In California the mechanical or physical con- 
 dition of the soil is of greater importance than the 
 chemical composition. Especially is this true of cit- 
 rus culture, where irrigation and cultivation are so 
 frequent and thorough. The first sign of trouble is 
 usually a slight 3 r ellow color of the foliage and is 
 usually traceable to loss of humus and its conse- 
 quent nitrogen. Yet the cause may be due to the 
 roots entering a "hard pan" or coarse gravelly 
 strata, less favorable to growth. (99). In any 
 event the soil's mechanical condition should be 
 known to a depth of at least five feet, and deeper if 
 possible. The loss of humus so changes the soil's 
 condition that the trees cannot derive the benefit of 
 the water, the cultivation or the labor gives to it, 
 and the first sign is the loss of the healthy green color.
 
 16 FERTILIZERS 
 
 Applications of nitrate are helpful but not lasting 
 unless applied in organic forms, capable of making 
 humus. (86) (96). 
 
 DRAINAGE. 
 
 21. Citrus soils must be well drained. The top 
 soil may be free from gravel for a considerable depth 
 as long as it does not hold free water. The "mesa" 
 or "bench" soils of California, usually situated 
 near the foot hills, are ideal in this regard. Figure 2 
 is a photograph of a stream bank, running through 
 a "mesa." The top soil, free from rock, is here 
 about 5 feet deep, below which there is excellent 
 drainage. 
 
 HARD PANS. 
 
 22. Occasionally the best situation and soil for 
 fruit culture is underlaid at a few feet with an im- 
 pervious strata, so that orchards soon show lack of 
 vigor. These "hard pans" may be at the very sur- 
 face or at any depth below. Blasting with powder 
 or dynamite to break up the fixed condition is effec- 
 tive, but must be repeated from time to time. Per- 
 haps the best remedy where water is sufficient, is to 
 prepare it long before planting trees, by raising a 
 one or two year old stand of alfalfa, the roots of 
 which penetrate hard soils to a considerable depth. 
 Though the orchard is already established, alfalfa 
 might be grown in alternate spaces between the 
 tree rows for two years, then ploughed under and 
 the remaining spaces planted for the next two years. 
 
 " Hard pans" are usually deficient in nitrogen, but 
 may be well supplied with the other plant foods, 
 and especially with lime and iron. The latter gives a 
 very noticeable deep red tint to the orange.
 
 FIGURE
 
 FERTILIZERS 1 7 
 
 ESSENTIAL PLANT FOOD. 
 
 23. Each of the three plant foods, nitrogen, phos- 
 phoric acid and potash, are called essential ingredi- 
 ents in fertilizers, as they are the elements first 
 exhausted from the soil by plants. There are eleven 
 other elements just as essential to perfect plant 
 growth as these three, but the soil never becomes 
 depleted of them, and it is not necessary to supply 
 them, except in rare cases. Sometimes lime is sup- 
 plied to the soil, though not regularly, to set free 
 nitrogen, phosphoric acid and potash, when they 
 are known to be in the soil in insoluble condition 
 and large amounts. But, as lime adds no necessary 
 ingredient, its continued use alone will exhaust a 
 soil. If a soil is known to lack iron, this may be 
 added to make green foliage and to deepen the color 
 of oranges. 
 
 If a soil becomes unproductive under conditions of 
 good tillage and water, it is usually because one or 
 more of the essential plant foods has become ex- 
 hausted. Hence commercial fertilizers have come to 
 be composed of various amounts and forms of nitro- 
 gen, phosphoric acid and potash. Commercial fer- 
 tilizers are simply concentrated forms of plant food. 
 A good top soil contains every element essential to 
 plant growth and is a fertilizer, but it is not suffi- 
 ciently concentrated to pay for handling and trans- 
 portation. 
 
 24. Each of the three plant foods, nitrogen, phos- 
 phoric acid and potash, have their respective market 
 values for each 1 per cent., or unit, of 20 pounds to 
 the ton. If a ton of fertilizer contains 3 per cent, of 
 an element that means 60 pounds. The purchaser
 
 18 FERTILIZERS 
 
 will have to know in addition to the amount, the 
 market value and the source of the nitrogen, phos- 
 phoric acid and potash, before he can determine the 
 value of a ton of certain analysis. The source is 
 very important, because the most available forms 
 have the highest market value. Without this know- 
 ledge, a certain brand may sell for $40 a ton and 
 another worth only one-half its value ($20 per ton) 
 may sell more readily for $38. 
 
 25. Each of the three essential plant foods has 
 its special part to do in the building of the plant. 
 One cannot do the work of the other. As an illus- 
 tration: Nitrogen in the absence of potash may 
 produce a luxuriant and rapid growth but it will 
 be weak, and broken down by the first wind ; add 
 potash and that same succulent, weak growth will 
 be matured and have strength enough to carry its 
 load of fruit. Potash alone will not produce the 
 growth, but will mature it. Both nitrogen and 
 potash have many other functions to perform. (69), 
 (71). 
 
 Phosphoric acid, or phosphorus, must be present 
 in order that the plant may assimilate its nitrogen. 
 The process (osmosis) by which nutrients pass 
 through the plant from cell to cell is facilitated by 
 the presence of phosphoric acid. Phosphorus is nec- 
 essary for the seed's embryo development and for the 
 formation of chlorophyl (the green coloring matter 
 of plants). (70). 
 
 Thus, while the essential plant foods each have 
 many independent functions to perform, they are 
 mutually dependent upon each other, and mutually 
 helpful in the building of the plant tissue.
 
 FERTILIZERS 19 
 
 The condition in the soil may be such that the 
 purchase of only one fertilizing element is necessary, 
 and since the source of nitrogen and phosphoric acid 
 and their functions are so many and varied, the 
 question, "What fertilizer to use," and "How to 
 purchase it most economically, "is of vital interest to 
 the farmer and one difficult to solve. 
 
 SOURCE OF FERTILIZERS. 
 
 THE SOURCE OF NITROGEN. 
 
 26. Nitrogen may be obtained from these sources : 
 Air, ammonia, nitrates, and animal matter. In certain 
 forms of animal matter, such as hoofs, horns, coarse 
 bone, leather and wool waste, the nitrogen becomes 
 available too slowly to be of much value. But as 
 green manure, ammonia, nitrates, blood, fine bone, 
 tankage, or blood and bone, fish and finely ground 
 and screened guano, the nitrogen is in good form 
 and soon becomes available. 
 
 27. As these forms require different lengths of 
 time to become available, judgment must be used in 
 their application. Nitrate of soda and sulphate of 
 ammonia dissolve almost immediately in water, so 
 the full amount of a year's supply should not be 
 applied at once, as some will be sure to be lost in 
 waste water. Blood and bone, as a source of nitro- 
 gen and phosphoric acid, would be a better combi- 
 nation than nitrate and bone. Blood and fish re- 
 quire more time to become available than nitrates, 
 and bone, a longer time than blood. (43)
 
 20 
 
 FERTILIZERS 
 
 The most valuable sources of organic nitrogen, 
 from the standpoints of uniformity in composition, 
 richness in the constituent, and availability, are dried 
 blood, dried meat, and concentrated tankage, fish 
 and animal, which are produced in large quantities 
 in slaughter houses and fish canneries. 
 
 28. The most concentrated form of nitrogen is 
 ammonium sulphate, containing about 19% or 24% 
 of ammonia. Nitrate of soda contains as high as 
 16% nitrogen, blood 14%, hoof and horn meal, 14%, 
 slaughter house tankage from 5% to 10%, raw bone 
 H^%, bat guano 3% to 20%, sea fowl guano 12%. 
 There are numerous other sources of nitrogen, but the 
 above are those most generally used. The contents 
 as given are in terms of nitrogen and approximately 
 the maximum. 
 
 FIGURB 3 THE NITROGEN CYCLE
 
 FERTILIZERS 21 
 
 NITRIFICATION. 
 
 29. This is the process by which the nitrogen of 
 organic matter is changed into nitrates. The 
 ammonia and nitrogen of all fertilizers comes from 
 organic matter, and all organic materials contain 
 more or less of those substances in some form. 
 Nitrate of soda in the nitrified product of some 
 organic material, whether of seaweed or animals, is 
 not definitely known. Ammonium sulphate also 
 has an organic origin, being a by-product of carbon- 
 izing works. 
 
 Humus (which is decayed animal or vegetable 
 matter) is the main source of the plant's nitrogen. 
 When organic matter is applied to the soil it must 
 first decay and then nitrify before its nitrogen be- 
 comes available to the plant. These two processes 
 are necessary. The decay is produced by one set of 
 bacteria and their product is humus. Then the sub- 
 stance is attacked by another set of bacteria which 
 form nitrates. This latter process is nitrification. 
 The nitrates thus formed are water-soluble and can 
 be absorbed by root hairs into plant tissue. (See 
 Figure 3.) 
 
 NITROGEN FROM AIR. 
 
 30. Certain plants of the leguminosae group have 
 power to accumulate nitrogen from the air in the 
 process of growth. Such plants are the lupins and 
 vetches, which with peas, clover, alfalfa and others, 
 when grown as catch or cover crops and ploughed 
 under, add to the store of nitrogen in soils. But in 
 this case, as with other organic substances, the two 
 processes of decay of tissue and nitrification, are nec- 
 essary before the nitrogen thus gathered becomes
 
 22 FERTILIZERS 
 
 available. As nitrogen is the most expensive of all 
 fertilizing elements, the importance and economy of 
 a green cover crop ploughed under is considerable. 
 
 NITROGEN FROM BLOOD AND TANKAGE, GUANO, ETC. 
 
 31. The nitrogen from organic sources such as 
 blood, tankage, guano, is prompt and decided in its 
 action under ordinary growing conditions if the 
 materials are finely ground. If drilled or ploughed 
 under with the soil reasonably moist and warm, the 
 effect, of added growth or better color may be seen 
 in 30 days. The finer particles decay and become 
 available first, the coarser particles taking more 
 time. The plant thus has a steady, long feeding 
 period. Where fruit trees are grown during a long 
 growing period as in arid countries, the organic 
 forms of nitrogenous fertilizer are most satisfactory. 
 
 NITROGEN FROM NITRATE OF SODA. 
 
 32. This is an immediately available form of nit- 
 rogen. It dissolves easily in water and can thus be 
 carried down to the subsoil and leached away ac- 
 cording to the course the water takes. It is there- 
 fore, not so steady or long timed a feed for plants if 
 it is all applied at one time. It is better, therefore, 
 to make at least two applications during the grow- 
 ing period. One objection to its continued use, as 
 shown by Dr. King, is that in time the accumulation 
 of the soda will combine with the soil carbonates 
 and form carbonate of soda (black alklai) which in 
 certain quantities is deleterious to all forms of vege- 
 tation. Such a harmful accumulation may require 
 years but it will finally become positive. Neither 
 rains or irrigation will leach the soda away, if, as it 
 is claimed, all the rains of England have not leached 
 it away from the soils of Rothampstead Station.
 
 FERTILIZERS 23 
 
 SOURCES OF PHOSPHORIC ACID. 
 
 33. Phosphoric acid, or phosphorus, in fertil- 
 izers, is always found in combination with other 
 elements. Usually it is obtained from bone or phos- 
 phate rocks. As rock it cannot become readily 
 available without treatment with sulphuric acid. 
 As bone, unacidulated, it must be very finely ground 
 to be available, and when thus ground is undoubt- 
 edly the best form for citrus culture, as it is all 
 equally available and its ability to rot or ferment 
 has not been destroyed by the acid. (40) 
 
 ACIDULATED PHOSPHATES. 
 
 34. These are made by treating bone or phos- 
 phate rock with sulphuric acid. Their value may 
 vary according to the amount of acid used by the 
 manufacturer, and the phosphorus content of the 
 mother rock. If 800 pounds of acid were used with 
 1200 pounds of bone or rock, it would be a 40>o 
 acidulation, as 800 is 40% of 2000. 
 
 In acidulated goods whether rock or bone, there 
 are always three forms of phosphoric acid a soluble 
 form, a "reverted" form, and an insoluble form. The 
 last is of least "commercial" value, but may have 
 very great agricultural value under proper soil con- 
 ditions. The "reverted" is of doubtful value, as it 
 has to first undergo a chemical change before becom- 
 ing available. An insoluble portion is necessary in 
 order to obtain the soluble, but does not add value 
 to the fertilizer. State laws allow the reverted to 
 be estimated as available with the water soluble, so 
 that the soluble and reverted forms constitute the 
 commercial or "available" phosphoric value of a fer-
 
 24 
 
 FERTILIZERS 
 
 tilizer but not necessarily the agricultural value. 
 (67). 
 
 Most authorities claim as great a value for the 
 insoluble form, in finely ground materials, provided 
 there is a normal or plentiful supply of humus in the 
 soil. (40). 
 
 REVERSION. 
 
 35. It must be remembered that in using acidu- 
 lated goods (bone or rocks) if an abundance of lime 
 be present in the soil, the soluble form of phosphoric 
 acid unites chemically with the lime and is made 
 again insoluble as if it had never been treated. Iron 
 and alumina, and other bases, produce the same 
 effect on acidulated phosphates. The reversion, how- 
 ever, depends on the amount of acid used by the 
 manufacturer and the quantity of lime, iron, etc., in 
 the soil. (77). 
 
 "FIXING" POWER OF SOILS. 
 
 36. The following table will show the "fixing" 
 power of a lime soil : 
 
 PHOSPHORIC ACID "FIXED" BY SOIL. 
 
 Kind of Soil. 
 
 Grains. 
 
 Grains of Soluble 
 Phosphoric Acid 
 Uted. 
 
 Phosphoric Acid 
 retained by the 
 Soil. 
 
 Deep Red\ 
 Loam j 
 
 Grains. 
 
 5250 
 
 After 
 
 24 hours 
 8 days 
 
 26 days 
 
 24 hours 
 8 days 
 
 26 days 
 
 Even a rich peat soil, high in either lime or iron, 
 will "fix" or hold phosphoric acid in an insoluble 
 condition, as shown in 49. 
 
 Lime soil 10500 
 
 40.67 
 
 81.17 
 
 24.29 
 31.49 
 38.23 
 72.81 
 80.31 
 81.17
 
 FERTILIZERS 25 
 
 STEAMED BONE. 
 
 37. Steaming bones removes the fat and gela- 
 tines, thus facilitating decay and availability, as 
 such bone can be ground finer than raw bone, and 
 thus becomes more subject to the attack of soil 
 moisture and various dissolving agents. 
 
 Raw bone contains from 3% to 4^/2% nitrogen and 
 about 22% or 23% phosphoric acid. Steaming re- 
 duces the nitrogen and correspondingly increases 
 the phosphoric acid, so that steamed bone may run 
 as low as 1% nitrogen and as high as 25% or 30% 
 phosphoric acid. The best effect from the phos- 
 phoric acid of steamed bone is had when the bone is 
 used in connection with some ammoniate such as 
 blood, tankage or manure. Nitrogen increases the 
 efficiency of phosphoric acid, and for this reason 
 phosphoric acid from animal or vegetable sources is 
 regarded as the best, the most effective and the most 
 readily available form. If mineral phosphates are 
 used, there must be humus in the soil. (40.) 
 
 THOMAS PHOSPHATE SLAG ( POWDER). 
 
 38. Thomas slag, a product from iron furnaces, 
 is a good source of phosphoric acid, though not so 
 generally used as bone or rock. This material has 
 to be finely ground to be of value, as it is not acidu- 
 lated. It will analyze as high as 20% phosphoric 
 acid, usually 17%. Thomas slag also contains much 
 lime, which fact should be considered when it is 
 used in the presence of ammonium sulphate, or 
 barn manures, as the lime will drive off the am- 
 monia. An average analysis might show 17.28% 
 phosphoric acid, 46. 20% lime and iron oxide 18. 37%.
 
 26 FERTILIZERS 
 
 It may be used to best advantage on trees which 
 have made strong, nitrogenous growth at the ex- 
 pense of fruit production, and also on peaty soils, 
 poor in lime. Water will not dissolve slag, there- 
 fore it should be put in as deeply as possible. 
 
 PHOSPHATE GUANOS. 
 
 39. The guanos of bats and sea fowl are also 
 valuable sources of phosphoric acid. These materi- 
 als, however, vary in analysis very much. Each 
 consignment should be analyzed and its price based 
 on its contents. The first shipments from a guano 
 deposit are usually the richest and most valuable, 
 and may deteriorate as the deposit is drawn upon. 
 
 CHEAPEST FORM OF PHOSPHORIC ACID. 
 
 40. The Pennsylvania State Department of Agri- 
 culture, in Bulletin No. 94, gives the results of 12 
 years' experiments with phosphates, both acidu- 
 lated and unacidulated, and seems to show conclus- 
 ively that the best form in which to purchase phos- 
 phoric acid is the untreated bone or rock. This is 
 only on condition that there is plenty of organic 
 matter, or humus-forming material, in the soil. 
 
 Under such conditions (with humus in the soil) finely 
 ground rock (unacidulated) gave better results than 
 acidulated rock or bone. This was from the stand- 
 point of both original cost of material and the 
 results obtained, and was true of all crops tried, 
 except wheat. Unacidulated fertilizers always con- 
 tain more phosphoric acid than the same fertilizers 
 acidulated, as the weight of the acid used displaces 
 some of the material, and if organic matter is used 
 with the former, the conditions thus created in the 
 soil give it additional life which takes the place of
 
 FERTILIZERS 27 
 
 acidulation, and results in greater fertility. A num- 
 ber of lay experiments and actual practice in, Calk. 
 fornia agree with the results of the Pennsylvania 
 State Experiment Station. Where there was little on 
 no humus-forming material in the soil, 
 
 forms gave the best results. Dr. Hopkins of the 
 Illinois State Experiment Station and many others 
 strongly advocate the use of finely ground, unacidu- 
 lated phosphates with plenty of humus material, 
 rather than the acidulated forms. (7),(8),(11). 
 
 SOURCES OF POTASH. 
 
 41. Potash is found as a chloride, or muriate, as 
 a sulphate, and in a crude form called kainit. The 
 latter contains 12 J /i% actual potash. The muriate 
 and sulphate analyze about 50% actual potash. 
 The Strassfurt mines in Germany supply the most of 
 this product. 
 
 The potash of manufactured fertilizers is never 
 all animal matter. All commercial forms dissolve 
 readily, so there is no danger of buying potash in 
 unavailable form. It takes about two pounds of sul- 
 phate, or muriate of potash to make one pound 
 actual potash, or 10% sulphate to make 5% "actual." 
 
 Wood ashes arid stable manure are also sources of 
 potash, obtainable, however, in very limited quan- 
 tities. Wood ashes, unleached, will contain from 
 4%% to 7% potash: mixed stable manure contains 
 about 0.4% potash. 
 
 The sulphate of potash is the best form in which 
 to purchase. It has no ill effects on many plants,
 
 28 FERTILIZERS 
 
 while the muriate or chloride form does. The sul- 
 phate can also be used as a "fixer" of ammonia in 
 stables and manure pits, while the muriate might 
 cause the escape of ammonia. 
 
 AVAILABILITY. 
 
 42. Buyers of fertilizers should always know the 
 source and form of the different plant foods. This 
 knowledge and the results obtained will determine 
 their availability. Nitrogen from nitrate of soda is 
 the most available form of any. Nitrogen from 
 blood is more available than that from tankage. 
 
 Phosphoric acid from acid phosphates (rock or 
 bone) is more soluble than the non-acid phosphates. 
 
 Steamed bone finely ground is more soluble than 
 raw bone, as the latter is seldom finely ground. 
 
 43. All nitrogenous substances become available 
 easily. The most highly nitrogenous are the most 
 readily available. For this reason it is difficult to 
 say whether steamed bone or raw bone as a source 
 of phosphoric acid is most readily available. The 
 former is always more finely ground and the latter 
 always higher in nitrogen, but as raw bone is usually 
 quite coarsely ground, it is less readily acted upon 
 by the various divSsolving agents of the soil, notwith- 
 standing its higher nitrogen content. The phos- 
 phoric acid from tankage is more available than 
 that from raw bone. Both the nitrogen and phos- 
 phoric acid, as found in animal tankage and guanos, 
 finely ground are very available forms. 
 
 44. Soil moisture, root acids and fermentation, 
 are the dissolving agents in all soils. The high tem- 
 peratures of summer increase their action. Humus 
 is essential to fermentation and to the carbonic acid 
 in soil water which is a very active solvent,
 
 FERTILIZERS 29 
 
 Roots cannot take up plant food unless it is pro- 
 vided in solution, and different forms of fertilizers 
 respond differently to these dissolving agents. Fine 
 grinding is very important. As a rule organic forms 
 are most available. There are some exceptions, such 
 as sulphate of ammonia, nitrate of soda, and the 
 acid phosphates. The latter act best in soils that do 
 not contain enough lime, or iron, or other bases to 
 cause rapid reversion to insolubility. (33) (34). 
 
 If the farmer knows the source and form of the 
 nitrogen and phosphoric acid, he has a guide to their 
 availability. 
 
 All forms of potash as usually purchased in fertil- 
 izers are readily dissolved and there is no danger of 
 buying this ingredient in an insoluble form. 
 
 45. Some substances, as lime carbonate and 
 gypsum, make all fertilizers more available but they 
 do not add plant food to the soil, and their use alone 
 will in time exhaust a soil. Better results will be 
 obtained by using commercial fertilizers with some 
 humus material than by using either one alone, 
 because the conditions of availability will be in- 
 creased. 
 
 46. Probable order of availability, nitrogenous 
 substances : 
 
 Nitrate of soda 
 
 Dried blood 
 
 Tankage (high in nitrogen) 
 
 (medium in nitrogen) 
 " (low in nitrogen ) 
 Guanos, same as tankage, unless greatly 
 
 nitrified. 
 
 Bone meal (finely ground) 
 " " (coarse)
 
 30 FERTILIZERS 
 
 47. Probable order of availability. Phosphates : 
 
 Double super phosphate ) if watered 
 Acidulated phosphates ) at once 
 Phosphorus from tankage, high in nitrogen. 
 
 " " guanos (as in tankage.) 
 
 Thomas slag 
 Steamed bone meal 
 Raw 
 
 4-8. Probable order of availability. Potassium, 
 (potash) substances : 
 
 ( Sulphate 
 All commercial forms 1 Muriate 
 
 ( Kainit 
 Wood ashes 
 
 Silicates (natural soil forms) 
 
 49. The amount of potash and phosphoric acid 
 carried by drainage and "run off" waters of good, 
 bad and indifferent soils, bear directly on this ques- 
 tion of availability. 
 
 Table : "Matters dissolved by water from 100,- 
 000 parts of various soils." (From Johnson's 'How 
 Crops Feed.') 
 
 Soils 
 
 Lime 
 
 Mag. 
 
 Pot. 
 
 Phos. A. 
 
 Silica 
 
 Iron 
 
 Organic 
 
 Total. 
 
 Rich 
 
 18 
 
 2 
 
 13 
 
 2 
 
 11 
 
 5 
 
 53 
 
 134 
 
 Good 
 
 34 
 
 7 
 
 8 
 
 
 
 22 
 
 
 
 36 
 
 136 
 
 Garden 
 
 23 
 
 1.5 
 
 7 
 
 1.5 
 
 38 
 
 2 
 
 30 
 
 110 
 
 Peat 
 
 164 
 
 11 
 
 47 
 
 trace 
 
 trace 
 
 77 
 
 449 
 
 1095 
 
 Poor 
 
 10 
 
 trace 
 
 1 
 
 
 
 
 
 3 
 
 18 
 
 46 
 
 Fair 
 
 6 
 
 1 
 
 4 
 
 
 
 2 
 
 2 
 
 23 
 
 43 
 
 Sandy 
 
 1 
 
 2.5 
 
 2 
 
 trace 
 
 trace 
 
 
 
 33 
 
 39.5 
 
 The matters least soluble are those found in the 
 ash of plants. Where organic and volatile matter 
 is carried in more appreciable amounts there is
 
 FERTILIZERS 31 
 
 greater solubility. There is no element less soluble 
 than Phos. A. while potash is present in the drain- 
 age water in quantity greater than a trace. Even 
 silica is more soluble than phosphoric acid. 
 CONCLUSIONS. 
 
 50. The amount of soluble matter is greater in 
 wet, peaty soils. Poor soils yield to water the least 
 amount. Very rich soils, and well manured soils 
 yield more to water than poor soils. From the 
 table it is seen that where water extracted most 
 organic matter, it extracted large quantities of other 
 elements. Cultivation and irrigation use up organic 
 matter rapidly. So the supply of humus materials 
 must be constantly renewed. Humus and organic 
 matter are the key to availability but are also prob- 
 ably the means of exhausting other plant foods 
 through the production of larger growth and crops. 
 (86). 
 
 INSOLUBILITY DESIRABLE. 
 
 51. It is well known that the nitrates may easily 
 be lost by leaching, because they are soluble. This is 
 not the case with the phosphates, or phosphorus 
 compounds, as these are always insoluble even in the 
 most fertile soils. Numerous analyses of the "run 
 off" waters show this. The nitrates being always 
 available to the plant, stimulate its feeding powers 
 and force it to act on such insoluble compounds as 
 the phosphates, which, in turn, by yielding slowly, 
 regulate growth and maintain for a longer time the 
 soil's productive power. 
 
 It can readily be seen that the loss would be 
 many times greater if the phosphates and other com- 
 pounds were soluble as well as the nitrates.
 
 32 FERTILIZERS 
 
 The phosphoric acid of fertile soils is practically 
 always insoluble. This is true of new lands, the rich- 
 est and most productive known. It is nature's 
 method. All fertile soils contain such bases as lime, 
 iron and others that hold phosphorus in insoluble 
 compounds from whence it is released only by the 
 processes of plant growth and the chemical activities 
 of fertile soils, due to a sufficient supply of humus. 
 (35) (36). 
 
 THE PURCHASE OF FERTILIZERS. 
 
 52. Fertilizers should be purchased by the unit of 
 plant food contained, with due consideration of its 
 source, and not simply by the ton or brand, as is 
 usually the case. Each twenty pounds of a ton is 
 called one unit or \% ; 5% is five units or one hun- 
 dred pounds. The value of a fertilizer depends en- 
 tirely upon the amount and source of plant food con- 
 tained. High grade analyses are worth more than 
 low grade. Freight, sacking, storing and handling 
 are fixed expenses on low or high grades. Therefore, 
 high grades are cheapest. 
 
 All the simple forms of fertilizer material, such as 
 bone meal, tankage, blood, sulphate of potash, ni- 
 trate of soda, etc., carry definite amounts or per- 
 centages of their respective plant foods. (28). 
 
 53. If, for instance, blood is pure and cleanly 
 handled, its nitrogen content is from 13% to 14%, 
 or 260 Ibs. to 280 Ibs. per ton. Pure bone meal (raw 
 and steamed) varies in nitrogen from \% to 5% and 
 in phosphoric acid from 20 % to 30%. If the nitro-
 
 FERTILIZERS 3* 
 
 gen is as low as 1% the phosphoric acid will be 
 about 30%. If the nitrogen is as high as 5% the 
 phosphoric acid will be about 20%: and so with all 
 the simple materials. Their limits are known. 
 
 It is quite possible with these limits known, to tell 
 from the guarantee given by a dealer, whether the 
 highest grade materials have been used in a given 
 mixture. Suppose a dealer guarantees, as found on 
 the bag, or tag : 
 
 Nitrogen, 5% (from high grade blood) 
 Phosphoric acid, 10% (from steamed bone meal) 
 Potash (K 2 O), 2% (from the sulphate) 
 High grade blood contains at least 13% nitrogen 
 pure, or 260 Ibs. to the ton. To obtain the 5% or 
 100 Ibs. guaranteed will require $ of a ton of blood 
 or 769 Ibs. 
 
 The phosphoric acid guaranteed is 10.% As 
 steamed bone meal may contain 30%, to obtain 
 10% will require ^ of a ton or 666.66 Ibs. 
 
 Sulphate of potash usually runs 50% actual (K2O) 
 potash, so that the guarantee of 2% or 40 Ibs. could 
 be obtained from 80 Ibs. of sulphate. Altogether the 
 above guarantee of: 5% nitrogen, 
 
 10% phosphoric acid, 
 
 2% potash 
 can be obtained from : 
 
 Blood, 769. Ibs. 
 
 Steamed bone, 666.66 
 
 Sulphate of potash, 80. ,, 
 
 or, total material 1515. 66 Ibs. 
 
 Make weight to one ton 484.34? ,, 
 
 2000.00lbs.
 
 34 FERTILIZERS 
 
 The foregoing illustration shows that from a given 
 guarantee it is possible to prove whether a full ton 
 of high grade materials was used or not. It would 
 be interesting also to figure how much higher the 
 analysis would be if the amounts of blood, bone and 
 sulphate of potash were increased proportionately, 
 so that there was no room for "make weight." 
 
 It is only fair to the dealer to say that the 484.34 
 Ibs. "make weight" is not necessarily worthless filler. 
 Low grade material may have been used. They are 
 offered in the same market with the best. Blood can 
 be so carelessly handled as to be full of floor refuse 
 and foreign matter. The source of tankage influ- 
 ences its grade. Both low and high grades are legit- 
 imately bought and sold in the same market and the 
 low grade often takes the place of "filler." To make 
 the foregoing guarantee without filler, we could 
 substitute 1150 Ibs. of Thomas slag for 666.66 Ibs. 
 of steamed bone meal so the weights would be : 
 Blood, 769 Ibs. @ 13%= 99.9 Ibs. or 5. % 
 
 Thomas slag, 1150 " @18%=207. " or 10.25% 
 
 8 " @50 % = 40 ' " or 2 - % 
 
 Total 1999 Ibs., or no room for filler. 
 
 54. If ammonia is given instead of nitrogen, you 
 can find its equivalent in nitrogen by multiplying 
 by .825%; for instance, 5.5% ammonia equals 4.54% 
 nitrogen. 
 
 Do not confuse sulphate of potash with the actual 
 (or K2O) potash. The sulphate usually runs about 
 50% actual. So, it takes 2 pounds of sulphate to 
 make one pound actual, or 2% sulphate to make 1% 
 actual.
 
 FERTILIZERS 35 
 
 The muriate contains about 48% actual potash 
 and kainit about 12%. 
 
 Bone phosphate must not be confused with phos- 
 phoric acid. The latter is derived from bone phos- 
 phate and is 45.8% of the bone phosphate; for 
 instance, 40% bone phosphate=18.32% phosphoric 
 acid. 
 
 55. Allowance must be made for phosphoric acid 
 if it is derived from raw bone. It is then worth 
 about 2c. per pound, while if taken from steamed 
 bone would be worth fully 5c. per pound. In acidu- 
 lated goods the phosphoric acid is in three different 
 forms, with market values from 2c. up to 5%c. per 
 pound : the water-soluble being worth 5Msc. per 
 pound, the insoluble, 2c. per pound.* 
 
 The source is just as important a consideration 
 as the quantity when considering the value. Both 
 the quantity of plant food (that is of nitrogen, 
 phosphoric acid and potash) and its source, which 
 determines its form, are really the only factors which 
 compose the value of a ton of fertilizers. (67) 
 
 *No attempt is made to give market values. These fig- 
 ures are simply for comparison of the different forms of 
 phosphoric acid and are those usually used by State Agri- 
 cultural Stations.
 
 36 FERTILIZERS 
 
 Here are two analyses of different total value 
 which will illustrate the foregoing : 
 
 ANALYSIS I. 
 
 Nitrogen in terms of ammonia, 5 % . 
 Equivalent in nitrogen (5X.825) 
 
 4.13% or 82.60 pounds at 20c $16.52 
 
 Phosphoric acid (from steamed bone) 
 
 12% or 240 pounds at 5V 2 c 13.20 
 
 Equivalent to bone phosphate 26% 
 Potash (actual, K 2 O) 
 
 3% or 60 pounds at 6c 3.60 
 
 Sulphate of potash, 5.9% 
 
 Total value of ton $33.32 
 
 Note. No account is taken of either the 26% of 
 bone phosphate or of the 5.9% sulphate of potash as 
 they are only repetitions of the 12% phosphoric acid 
 and the 3% actual potash respectively. 
 
 ANALYSIS II. 
 
 Nitrogen in terms of ammonia, 5^2%. 
 Equivalent to nitrogen (5%X.825) 
 
 4.54% or 90.80 pounds at 20c '. $18.16 
 
 Phosphoric acid (from raw bone) 
 
 13% or 260 pounds at 2c 5.20 
 
 Equal to bone phosphate, 31% . 
 Potash, (actual, K 2 O) 
 
 4% or 80 pounds at 6c 4.80 
 
 Sulphate of potash, 7.95%. 
 
 Total value of ton $28.16 
 
 Although Analysis II is higher in its percentage 
 of plant food, the form of the phosphoric acid is 
 against it and cheapens it so much that the total 
 value of the ton is considerably less. 
 
 Either of these analyses might be offered to the
 
 FERTILIZERS 37 
 
 grower for, say, $35 per ton and No. 1 would be the 
 best buy for the grower, and No. 2 the best sale for 
 the agent or manufacturer. 
 
 It is quite possible for the nitrogen to be in cheap 
 form also and worth considerably less than 20c. per 
 pound. The nitrogen from raw bone is worth less 
 than that from blood, or guano, or tankage. 
 
 So the value of a ton of fertilizer is based upon 
 the source or form of the nitrogen, phosphoric acid 
 and potash, and the quantity of each. 
 
 COST OF NITROGEN. 
 
 56. Nitrate of soda, 96% pure, 16% nitrogen at 
 $50 per ton. This yields 307 pounds of nitrogen, 
 which at $50 per ton, equals 16. 3c per pound or 
 $3.24 per unit of 20 pounds. 
 
 Dried, ground blood, analyzing 14% nitrogen, or 
 280 pounds at $60 per ton, equals 21c. per pound, 
 or $4.20 per unit. Market values change constantly. 
 At times, nitrate may be worth $60 and blood 
 worth $55 per ton. 
 
 COST OF PHOSPHORIC ACID. 
 
 57. Steamed, ground bone (not acidulated) at 
 $35 per ton, containing 25% phosphoric acid (500 
 pounds (equals 7c. per pound, less the value of 1% 
 nitrogen (20 pounds) contained in steamed bone at 
 20c. per pound would make the net cost of phos- 
 phoric acid about $1.24 per 20 pounds, or 6%c. per 
 pound. Thomas Phosphate Powder, 17% phos- 
 phoric acid, at $22.50 per ton, would cost $1.30 per 
 unit, or 6M$c. per pound. 
 
 COST OF POTASH. 
 
 58. The sulphate yielding 49% actual potash can 
 be bought for $60 per ton, making the actual potash 
 cost 6c. per pound or $1.20 per unit, (20 pounds).
 
 38 FERTILIZERS 
 
 COST OF COMBINATIONS 
 
 59. Based on the foregoing, a tankage containing 
 5.5% nitrogen and 13% phosphoric acid would have 
 value as follows : 
 
 5.5% (units) nitrogen @ $4.20 per unit $23.10 
 
 13% phosphoric acid @ $1.24 16.12 
 
 $39.22 
 
 The nitrogen and phosphoric acid are in much the 
 same form as found respectively in blood and 
 steamed bone. 
 
 A guano containing 5% nitrogen, 10% phosphoric 
 acid and 2% potash, would have a value as follows : 
 
 5% (units) nitrogen, @ $4.20 (21c. per Ib. )$ 21.00 
 10% " phosphoric acid @ $1.24 12.40 
 
 2% " potash $1.20 2.40 
 
 $35.80 
 
 MOST ECONOMICAL FORM OF FERTILIZERS. 
 
 60. If the price of nitrogen is the same in nitrates, 
 and bone and blood, the cheapest is that which 
 becomes available just as fast as the crop requires it, 
 neither faster nor slower. Is nitrate too quickly 
 soluble for the crop to use all of it before a part of it 
 is carried away by wasted water ? Is ground bone 
 too slowly available or blood and bone just right? 
 are questions to be answered by crop and con- 
 ditions. 
 
 If a form of plant food becomes available too 
 rapidly, the moisture holding it in solution rises and 
 evaporates, leaving this soluble, valuable food on 
 the top of the ground, whence it is partly lost by 
 escaping surface waters and part carried back into 
 the soil by penetrating moisture. That is why slow- 
 running water gives the most profitable irrigation.
 
 FERTILIZERS 39 
 
 A "waste water" right on one ranch from another 
 may become also a fertilizer right. 
 
 If, however, some form of plant food, not so 
 quickly soluble in running water as nitrate of soda, 
 and yet readily soluble by soil moisture and root 
 action, is used, there is much less actual loss during 
 a season, and its effect is more sure and lasting. Yet 
 there are times when a quick-acting fertilizer is 
 needed. This would then be the most economical 
 form. It depends upon the needs at the time, and 
 the farmer should know enough about the nature of 
 the different forms of plant food to exercise judg- 
 ment in the selection. (46-48) (68-71). 
 
 GENERAL PURCHASING PRINCIPLES. 
 
 61. The market value of every brand depends 
 upon the amount, or percentage of plant food con- 
 tained, and its form. The nitrogen, phosphoric acid 
 and potash each have their own market value per 
 pound, and these must be known to the grower, in 
 order to purchase economically. 
 
 Be sure the food elements are of proper source and 
 form to be available as fast as wanted by the trees. 
 This availability depends upon soil conditions. 
 
 Purchase high grade materials. 
 
 EXAMPLE OF FERTILIZER WORTH $6.50 PER TON. 
 
 Fresh water mud, 2000 pounds, contains : 
 
 30 pounds nitrogen (1V 2 %) at 20c $6.00 
 
 4>y 2 " phosphoric acid (.23%)at 5M>c... .23 
 
 4% " potash (.23%) at 6c 27 
 
 $6.50 
 
 EXAMPLE OF FERTILIZER WORTH $41.10 PER TON. 
 
 Eighteen hundred pounds of blood and bone, 
 containing 7% nitrogen and 10 % phosphoric acid,
 
 Nitrogen 5%Kl f 
 lro 
 
 40 FERTILIZERS 
 
 added to 200 pounds of sulphate of potash, will make 
 
 one ton, analyzing as follows : 
 
 Nitrogen,6.3 % or 126 Ibs. @ 20c $25.00 
 
 Phosphoric acid, 9% or 180 Ibs. @ 5V 2 c.... 9.90 
 
 Potash (K 2 O) 5% or 100 Ibs. @ 6c 6.00 
 
 $41.10 
 
 62. ILLUSTRATION NO. I A HIGH GRADE 
 
 FERTILIZER CONTAINING NO FILLER. 
 ANALYSIS. OBTAINED FROM LBS. 
 
 1400 Ibs. raw bone, 
 
 3.5% nitrogen 49.00 
 
 (110 Ibs ) f llwl " 400 Ibs. nitrate soda 
 ( 96 % pure 16 % 
 
 nitrogen) 61.00 
 
 110.00 
 
 Phosphoric acid \f rnrn fl400 Ibs raw bone @ 
 
 16%. / (23%phosphoricacid.. 320.00 
 
 Potash 5 % \f 1 200 Ibs. sulphate @ 
 
 (100 Ibs.) actual) 11 m }50% actual potash.... 100.00 
 
 COST OF ABOVE MATERIALS. 
 
 1400 Ibs. bone @ $35.00 per ton $24.50 
 
 400 " nitrate... 50.00 " " 10.00 
 
 200 " sulphate 60.00 " " 6.00 
 
 2000 Ibs. Total $40.50 
 
 ILLUSTRATION NO. II A LOWER GRADE FERTILIZER 
 
 CONTAINING 230 LBS. FILLER. 
 ANALYSIS. OBTAINED FROM LBS. 
 
 1300 Ibs. raw bone, 3.5% 
 nitrogen 45.00 
 
 Nitrogen 5% \ f 
 (100 Ibs.) J lr0n 
 
 390 Ibs. blood, 14% nitro- 
 gen 54.60 
 
 99.60
 
 FERTILIZERS 41 
 
 Phosphoric acid\ f /1300 Ibs. bone, 23% 
 15%, 300 Ibs. J lr ^phosphoric acid 299.00 
 
 : 80 Ibs. sulphate 40.00 
 
 COST OF ABOVE MATERIALS. 
 
 1300 Ibs. bone @ $35.00 per ton.. $22.00 
 
 390 " blood @ 50.00 " " 11.70 
 
 80 " sulphate of potash @ 60.00 " " 2.40 
 
 1770 
 230 filler 
 
 2000 Ibs. Total $36.85 
 
 Illustration No. I shows that if the analysis is 
 high, only high grade materials can be used. Illus- 
 tration No. II shows that if the analysis is low, 
 either low grade materials or fillers were used. In No. 
 II, high grade materials up to 1770 Ibs. were used, 
 and their value, pound for pound, is the same as in 
 No. I. A filler used with high grade materials is 
 equivalent to the use of low grade goods and the 
 resulting analysis in No. II shows it. Less blood 
 and bone could have been used in No. II, and more 
 filler, but the resulting analysis would have been 
 still lower. 
 
 63. If, however, the fertilizer is acidulated, the per- 
 centage of plant food may be low, as the weight of 
 acid used displaces some of the material, yet the 
 fertilizer should be considered high grade on account 
 of the more soluble condition of its phosphoric acid. 
 Here, the better form of plant food compensates for 
 the smaller quantity. If the acid phosphate should 
 revert to insolubility on account of the lime or other 
 bases in the soil, its purchase would be equivalent to 
 low grade materials, as the advantage of greater
 
 42 FERTILIZERS 
 
 solubility is largely lost and the total amount of 
 phosphoric acid purchased is small, yet its better 
 distribution in the soil by water, may compensate 
 for reversion. (8). 
 
 THE "SIMPLES" AND HOME MIXTURES. 
 
 64. The "simples" are the original materials or the 
 bases of which factory-mixed fertilizers are composed. 
 They are such materials, as nitrate of soda, pure 
 blood, sulphate of ammonia, potash, salts, bone, 
 phosphate rock, super phosphates, etc. Tankage 
 and the guanos are "simples," as they are the bases 
 of manufactured brands. There are low and high 
 grades of the "simples" as well as of brands, and 
 guarantees should always be obtained by the buyer. 
 
 Sometimes these materials can be purchased 
 cheaper separately than when mixed. Such is the 
 case if the buyer is near a seaport or near the source 
 of the material. The advantages are, the buyer 
 knows what he is getting ; he buys only the ingre- 
 dients he needs and he buys direct. Such advantages 
 however, do not always hold if the quantity wanted 
 is less than a carload. 
 
 If, however, a complete fertilizer is needed, it is 
 better to buy of a reliable manufacturer, as the goods 
 are then mixed and blended more evenly and cheaply. 
 If several ingredients are needed and these can be 
 purchased to advantage separately, it would be 
 better to apply them separately than to attempt 
 home mixing, for a shovel and a barn floor will not 
 mix materials evenly and uniformly without extreme 
 care. 
 
 As a rule home mixing pays when compared with 
 the purchase of low grade brands. If the manufac-
 
 FERTILIZERS 43 
 
 turer offers HIGH GRADE fertilizers it is time and 
 money saved to use them. 
 
 WHY THE ANALYSIS DOES NOT ADD TO ONE HUNDRED 
 PER CENT. 
 
 65. The Vermont Agricultural Experiment Sta- 
 tion Bulletin No. 47 says: "The question is often 
 asked why the plant food contained in a fertilizer 
 does not add up to 100. For instance, the average 
 Vermont goods this year contain in a hundred, 2.22 
 pounds nitrogen, 10.93 pounds total phosphoric 
 acid and 3.46 pounds of potash, a total of 16.61 
 pounds. Of what did the other 83.39 pounds con- 
 sist, and is it needed for plant food ? It will be re- 
 membered that nitrogen is a gas, and phosphoric 
 acid and potash respectively strong acid and alkali, 
 and they can only be useful in combined forms. If 
 medium grade materials were used in the manufac- 
 ture of the average fertilizer, as stated above, it 
 might be made up as follows : 
 
 440 pounds of organic matter (blood, tankage, etc. ) 
 850 pounds of ground S.C. rock and sulphuric acid. 
 110 pounds of muriate of potash. 
 
 1400 Ibs. 
 
 This would leave 600 pounds, or 30 per cent of 
 the gross weight in every ton for moisture, dirt and 
 useless material on which freight, mixing and bag- 
 ging expenses, storage, etc., must be paid by the 
 consumer. 
 
 A complete analysis of the above 1400 pounds 
 would probably resemble the following :
 
 44 FERTILIZERS 
 
 Water 16.0 (combined with organic 
 
 matter and sulphuric acid) 
 
 Nitrogen 2.0 
 
 Phosphoric acid 10.6 
 
 Potash 2.9 
 
 Volatile and organic 33.0 (Combined with nitrogen) 
 
 Gypsum 16.0 (Formed by action of 
 
 sulphuric acid on rock.) 
 
 Lime 7.1 (Left combined with phos- 
 phoric acid) 
 
 Sand 4.0 (Impurity prosp. rock.) 
 
 Chlorine and Salts.. 3.0 (Combined with potash.) 
 
 Miscellaneous 5.2 
 
 100.0 
 
 Of the ten substances which compose the above 
 100 per cent, only three are of interest to the farmer. 
 The value of the whole ton is based on the value of 
 the nitrogen, phosphoric acid, and potash, only. 
 
 In raw bone, for example, it is impossible to give 
 a farmer the 3% nitrogen and the 24-% phosphoric 
 acid contained without giving him the 73% of lime, 
 gelatines and fats, etc., found in bone, for these sub- 
 stances are in combination and the process of separ- 
 ation would be too costly. 
 
 HOW TO UNDERSTAND A FERTILIZER ANALYSIS 
 
 66. Manufacturers often state the analysis of their 
 fertilizers in a confusing way. They use two terms 
 to express the same thing. Nitrogen and ammonia 
 both mean one thing, and the analysis should read, 
 for example, "nitrogen 4.95% equal to ammonia 
 6%," showing that there is not both the 4.95%, and 
 the 6%, but only one or the other. That the one 
 repeats the other. Multiply the percentage of am- 
 monia by .825 and the result will be the equivalent
 
 FERTILIZERS 45 
 
 in nitrogen, as for example, 6% ammonia, X.825= 
 4.95% nitrogen, It takes 4.95% nitrogen to equal 
 6% ammonia. In figuring the value of a ton in 
 dollars and cents, if the nitrogen from blood or 
 nitrate of soda has a market value of 16 cents per 
 pound, its equivalent in ammonia is worth only 
 13M> cents per pound. Only one should be included 
 in the estimate. 
 
 And so with the terms bone phosphate and phos- 
 phoric acid. The phosphoric acid comes from the 
 bone phosphate. For example, it takes 30% of bone 
 phosphate (sometimes called 'bone phosphate of 
 lime') to make 13.74% of phosphoric acid. When 
 both terms are employed by the manufacturer 
 the words "equal to" should be used thus: "Bone 
 phosphate of lime, 30%, equal to phosphoric acid, 
 13.74%," which means that the manufacturer used 
 600 pounds of bone phosphate or bone 30% of the 
 ton to obtain 13.74% of phosphoric acid. 
 
 Multiply the percentage of bone phosphate by 
 .458 and the result will be the equivalent in phos- 
 phoric acid thus: 30% bone phosphate of lime 
 X. 458=13. 74% phosphoric acid. 
 
 In estimating the value, for comparison, of a ton 
 in dollars and cents, phosphoric acid from fine bone 
 is worth about 5 1 / cents per pound, while its equiva- 
 lent in terms of bone phosphate is worth only 2^ 
 cents per pound. Only one should be included in the 
 estimate. 
 
 Where the "soluble," the "reverted," and the 
 "insoluble," and the "total" phosphoric acid are all 
 given, it is understood that the "total" is made up 
 of the first three mentioned .
 
 46 FERTILIZERS 
 
 The sulphate and muriate of potash will analyze 
 in round numbers about 50% actual potash (some- 
 times expressed as K2O). In other words it takes 
 two pounds of sulphate or muriate of potash to 
 make one pound of actual potash (K2O). When an 
 analysis states : "Sulphate of potash 8%, actual 
 potash 4%," it means simply that there is only 4% 
 of actual potash in the ton, or 80 pounds, and that 
 the manufacturers used 8% or 160 pounds of sul- 
 phate of potash to get it. The actual potash is 
 worth about six cents per pound, while the sulphate 
 is worth only three cents per pound. 
 
 When both terms are used in stating the analysis, 
 only one of them should be included in the estimate 
 of the value of a ton. 
 
 COMMERCIAL VS. AGRICULTURAL VALUE. 
 
 67. Farmers frequently confound the agricultural 
 and commercial value of a fertilizer. If one is high 
 it does not necessarily imply that the other must be. 
 
 The commercial value of any commodity is its 
 market price, its purchase price, and depends entirely 
 upon "supply and demand." 
 
 The agricultural value of a fertilizer is its ability 
 to improve the fertility of the soil and the condition 
 of the crop in question. 
 
 As an illustration, suppose a steady, long-lived 
 food were wanted for some perennials as an orchard, 
 blood would answer the purpose while nitrate of 
 soda would be soon exhausted or lost by leaching. 
 Now, if the price of both nitrate and blood is about 
 the same, the agricultural value of blood is far 
 greater. If a quickly acting manure was wanted, 
 the nitrate of soda would have the higher agricul- 
 tural value.
 
 FERTILIZERS 47 
 
 Again, if phosphoric acid was not needed for a 
 particular soil and crop, it would then have no agri- 
 cultural value in that case, but would still have a 
 market, or commercial value. 
 
 In the selection of a fertilizer, the agricultural 
 value should be considered first and the commercial 
 value second. Good results are of first importance 
 and depends on the agricultural value. 
 
 THE USE OF FERTILIZERS. 
 
 68. In order to use fertilizers intelligently, it is 
 necessary to know the specific action of the three 
 plant foods; nitrogen, phosphoric acid, and potash, 
 their sources, and when and how to apply them. 
 The few experiments which have been made with 
 various fertilizers on citrus trees confirm the same 
 general principles that hold with reference to other 
 crops. They will be briefly stated. 
 
 EFFECT OF NITROGEN. 
 
 69. The presence of available nitrogen is shown 
 by a dark, healthy, green color of leaves and stems. 
 Growth is vigorous. The feeding power of the plant 
 is increased. If an excess of nitrogen is available at 
 the time of flowering, and the supply of phosphoric 
 acid insufficient, the bud and bloom and fruit will be 
 imperfect and the total amount of fruit lessened. 
 The fruit will then be rough and thick-skinned. 
 Constant use of stable manure, without the addition 
 of phosphoric acid, will produce thick-rind fruit. 
 The size of fruit may be increased by nitrogen. A
 
 48 FERTILIZERS 
 
 lack of nitrogen is shown by yellow trees and 
 small growth, or lack of vigor. Nitrogen will not 
 give its best effect unless phosphoric acid and potash 
 are present. 
 
 EFFECT OF PHOSPHORIC ACID. 
 
 70. Phosphoric acid helps a plant to assimilate 
 other plant foods. It is also essential to the final 
 maturity of the plant or its seed production, and 
 hastens this maturity, if abundant and available at 
 blossoming time. Although the navel orange con- 
 tains no seed, phosphoric acid is as essential as 
 though it did. What usually thus goes into seed is 
 needed elsewhere in the development of the fruit. 
 
 If maturity is hastened by the presence of an 
 abundance of available phosphoric acid at the time 
 of blossom, the early ripening of the orange can be 
 likewise effected, though plant food effects are 
 directly dependent upon culture and water. 
 
 Phosphoric acid will not give its best effect unless 
 there is some nitrogen present. Plants well supplied 
 with phosphorus, vegetate faster and are earlier. 
 If an over abundance of nitrogen is making fruit 
 rough or "puffy," phosphoric acid will help to 
 correct this. Its tendency is to make thin-skinned, 
 smooth fruit. 
 
 EFFECT OF POTASH. 
 
 71. Potash is necessary to the full development of 
 the wood of the tree. If potash is wanting, the 
 wood not only will not mature, but is subject to 
 frost and disease ; neither can immature wood carry 
 much fruit. Potash aids in the formation and trans- 
 fer of starch, first to the leaves and from there to 
 the flesh of the fruit, which would be imperfect other-
 
 FERTILIZERS 4$ 
 
 wise. The best authorities agree that potash in- 
 creases the sweetness of fruit and their shipping 
 quality. (19). 
 
 Plants, undoubtedly, begin their growth in the 
 spring on the food that was stored in their tissues 
 the previous fall. Potash is largely the source of 
 this stored food, and is consequently necessary to 
 the full growth and health of the tree. 
 
 It is generally admitted, however, that applica- 
 tions of potash are unnecessary in most California 
 soils. Many cases are reported in which heavy 
 applications of wood ashes gave no appreciable 
 results. If the land in question has been continuously 
 cropped many years, as in a fifteen or twenty years' 
 old orchard, the potash question should be carefully 
 investigated. 
 
 72. Besides its effect on the plant as potash or 
 potassium, increasing the starches and sugars, the 
 use of potash salts has another indirect fertilizing 
 effect similar to that of lime and common salt, by 
 causing the soil to yield more quickly, its natural 
 and other plant foods. Potash salts while neutral, 
 may increase the alkalinity of the soil and thus 
 foster and encourage the work of nitrifying and 
 other bacteria which transform decayed organic 
 matter into useful forms. Carbon is one of the result- 
 ant products, so that the carbonic acid which soil 
 moisture carries, may be increased thus making it 
 a better solvent of many other plant foods. This 
 increased alkalinity of the soil may therefore increase 
 the formation of the nitrates and more vigorous 
 growth will result. Potassium as such, did not pro- 
 duce this result, which was due rather to the added
 
 50 FERTILIZERS 
 
 alkaline effect of the potash salt. Lime carbonate or 
 gypsum or common table salt might have produced 
 the same effect. 
 
 GENERAL PRINCIPLES. 
 
 73. In a general way, both phosphoric acid and 
 potash influence the quality and fineness of the fruit, 
 while nitrogen produces the vegetable tissue, such as 
 the skin and pulp of fruit, and leaves and bark of 
 trees. The juice and seed and smoothness and the 
 number of the fruits, and earliness, can be increased 
 by phosphoric acid and potash . The size and coarse- 
 ness and large growth and late maturity can be 
 secured by the excessive use of nitrogen. These effects 
 are noticeable only when there is an excess of one 
 element and a deficiency of the others. 
 
 AVOIDING PURCHASES OF UNNECESSARY FERTILIZERS. 
 
 74. Knowing the specific effect of the three essen- 
 tial plant foods, as just stated, and by observing the 
 condition of an orchard, a grower may frequently 
 avoid the purchase of unnecessary plant food. 
 
 Bottom lands are usually rich in nitrogen. Sandy 
 soils are apt to lack potash. Clay soils usually con- 
 tain much potash, etc. Coarse, thick-rind fruit, with 
 deep green color of leaves and a too vigorous growth 
 may indicate that nitrogen could profitably be 
 omitted one season, or used very lightly. An over 
 abundance of smooth fruit on yellow trees of slow 
 growth may indicate an excess of phosphoric acid 
 for the nitrogen present, or a lack of nitrogen. Iron 
 is as essential as nitrogen to green leaves and stems, 
 so yellow foliage may, in rare cases, be caused by the 
 absence of iron as well as nitrogen. The amount of 
 iron necessary for green foliage is so small, that lack
 
 FERTILIZERS 51 
 
 of nitrogen is usually the cause of yellow color in 
 citrus orchards. 
 
 A careful record of previous applications, namely : 
 The amount and analysis of the fertilizer, time of 
 application, and its effects on growth and crop will 
 be a guide to selection. 
 
 TIME TO APPLY FERTILIZERS. 
 
 75. In the book of nature we read that growth is 
 dormant for some months preceeding the blossom 
 and fruit setting period. This is naturally the time 
 of most moisture in soils, which with root acids and 
 fermentation, are rendering available the unavail- 
 able plant foods natural to the soil. So, when the 
 important time of blossom comes, the plants have 
 their greatest store of available plant food to draw 
 upon, so that fertilizers should be applied long 
 enough before the blossom time to become avail- 
 able. 
 
 76. Nitrate of soda requires the least time. Blood 
 requires more time than nitrate, and raw bone more 
 time than blood. Coarse bone, and hoof and horn 
 meal, are slowest in their action. Acidulated phos- 
 phate acts more quickly than any other form (that 
 is the soluble portion.) Steamed, fine ground bone, 
 used with some ammoniate, is next in order, while 
 fatty, raw bone takes still more time to decompose. 
 (46-48). 
 
 Many apply a part of the fertilizer in early sum- 
 mer. This is intended to feed the latter growth of 
 tree and crop. It is a practice that undoubtedly 
 gives better results arid is gaining in favor. 
 
 77. Acidulated forms should always be applied 
 just before an irrigation or rain, for then the water
 
 52 FERTILIZERS 
 
 will carry the soluble portion to the deepest roots, 
 wherever, in fact water can go. There, reversion to 
 insolubility may and probably does occur in a few 
 days, but the phosphoric acid is where the roots can 
 act on it directly. (8) (35). 
 
 Nitrate of soda should not be applied in late fall 
 or winter months while growth is dormant, as it 
 would probably be leached away before the tree could 
 take it up. Organic forms should be applied in Janu- 
 ary or February. 
 
 AMOUNT TO APPLY. 
 
 78. The quantity of fertilizer that should be used 
 varies with the conditions. It depends upon : 
 
 1. The percentage richness of the fertilizer. 
 
 2. Record of past experience. 
 
 3. Natural richness of soil. 
 
 4. Age and number of trees per acre. 
 
 5. Kind of tree or crop. 
 
 One popular way of estimating the amount to use 
 is to say one pound of high grade fertilizer to each 
 year of age of the tree. This, while very inaccurate, 
 gives good results, but the practice of citrus culture 
 has demonstrated the wisdom of using considerably 
 more than this amount, probably two pounds for 
 each year of age of citrus trees will be fully war- 
 ranted in most cases. 
 
 This is particularly true of trees over twelve and 
 fifteen years old. If the fertilizer is low grade, the 
 amount used should be increased. 
 
 If trees have been topped for budding or very 
 severely pruned, the amount may be reduced accord - 
 dingly.
 
 FERTILIZERS 53 
 
 METHODS OF APPLICATION. 
 
 79. The best method of application is undoubt- 
 edly by drill, on account of its labor saving and 
 uniformity. 
 
 Though not over five inches deep, the drill covers the 
 fertilizer, which can be placed deeper by subsequent 
 plowing. The use of drill obviates the unpleasantness 
 of applying in any winds which may prevail. No 
 hand process is so uniform or inexpensive, though 
 some other methods place the fertilizer deeper. It is 
 well worth the extra cost to hire a hand to follow 
 each plow furrow and place the fertilizer that depth. 
 
 STABLE MANURE. 
 
 80. An average analysis of one ton of horse 
 manure would be : 
 
 Nitrogen 0.50% or 10 Ibs. of a ton at 20c $2.00 
 
 Phosphoric acid 0.25% or 5 Ibs. of a ton at 6c. .30 
 
 Potash 0.40% or 9. 6 Ibs. of a ton at 6c 58 
 
 $2.88 
 
 The commercial value of the plant food is then 
 about $2.88 per ton. Barn yard manure when cared 
 for properly, is a most profitable form of fertilizer, 
 because of its humic and mulch value. It is a bi- 
 product of every ranch, costs nothing, and is worth 
 about $2.88 per ton for the actual plant food con- 
 tained. In dry countries it has a still greater value 
 in its moisture saving properties. As a source of 
 humus it is worth considerably more than its plant 
 food value. 
 
 81. The more decomposed the manure, the more 
 available is its plant food. If, however, decomposi- 
 tion is too rapid, the nitrogen escapes in the air as 
 ammonia, and humus-forming matter is destroyed.
 
 54 FERTILIZERS 
 
 High temperatures produce rapid decomposition, 
 especially in a loose heap, so that the rate of decay 
 maybe regulated by compacting the heap and sprink- 
 ling with water to exclude the air and reduce the 
 temperature. If compacted too tightly, decomposi- 
 tion may be too slow. Moderate fermentation is the 
 object desired. Loss of nitrogen, as ammonia, may 
 be detected by the strong odor arising, from the heap. 
 
 If it is desired to obtain the benefits of the plant 
 food in manure quickly, it should be stored under 
 cover to prevent loss by leaching, and the tempera- 
 ture kept down by frequent wetting, and air ex- 
 cluded by settling the heap : decomposition may 
 thus take place with a minimum loss of ammonia. 
 If from one to two pounds of either gypsum, or sul- 
 phate of potash be sprinkled on the heap each day 
 as it accumulates from one or two animals, the am- 
 monia is converted to the sulphate form and thus 
 prevented from escaping. The gypsum must be 
 moist for this use to be effective. 
 
 If, however, it is not desired to get the benefits of 
 plant food quickly, the manure had better be applied 
 fresh and incorporated with the soil at once. Decom- 
 position may be slower in such cases, but loss of 
 ammonia is surely prevented and a much better 
 mulch obtained. This is the most practical method. 
 
 GREEN MANURING. 
 
 82. The object of sowing the leguminous, or pod- 
 bearing plants is chiefly four-fold. 
 
 1. For humus, which is always necessary for any 
 form of crop because of its various functions in the 
 soil, such as : (a) nitrification ; (b) Rendering insol- 
 uble forms of plant food available by the process of
 
 FERTILIZERS 55 
 
 decay, (29) ; (c) Increasing the moisture holding 
 power and friability of the soil. (90.) 
 
 2. To obtain the nitrogen which they gather 
 during their growth. (30). 
 
 3. To set free unavailable plant foods by the 
 direct action of their roots. (Insoluble substances 
 are coroded, and dissolved and taken up into the 
 plant tissue and later become available as the plant 
 decays.) 
 
 4. To prevent soil washing and leaching by win- 
 ter rains. 
 
 83. The common vetch (Vicia Sativa) is at pres- 
 ent the most popular legume for the California orch- 
 ardist. Field peas, some clovers, and other varieties 
 of vetch are also used. Barley and other non legu- 
 minous plants have not the same nitrogen gather- 
 ing power but are beneficial as far as their roots set 
 free unavailable forms of potash and phosphoric 
 acid. 
 
 The volunteer non-leguminous plants and weeds 
 such as alfilerea mallow, foxtail and others, are per- 
 haps as beneficial as legumes plants for their humus 
 value and root petetration and while it is not cer- 
 tainty known just now how much nitrogen may be 
 added by various legumes it is probably safe to 
 assume that they add some and for this reason are 
 preferred to the non-leguminous plants. 
 
 COVER CROPS AND WATER. 
 
 84. It is well known that the winter cover crops 
 use up a good portion of the rain that falls so that 
 comparatively the clean culture orchards begin the 
 dry season with more moisture in the ground. While 
 this loss is usually more than compensated for by
 
 56 FERTILIZERS 
 
 the many advantages of the cover crop already 
 cited there may be special situations where the 
 water is all necessary to the orchard. If the water 
 right were limited by the capacity of the ditch or if 
 the season's rainfall were too short to risk the loss 
 of water necessary to a cover crop, straw or dam- 
 aged hay could be hauled and spread and plowed 
 under as a fair substitute. Any amount of humus 
 could be added in this way and all of the rainfall con- 
 served for the summer months. 
 
 SUMMER COYER CROPS. 
 
 85. It is difficult to maintain the supply of humus 
 material under conditions of constant irrigation and 
 cultivation. Cover crops have been raised in sum- 
 mer as well as in winter in a few instances. Horse 
 beans and cow peas have been used for the purpose. 
 They are planted in May or June and turned under 
 in August, and while the results are undoubtedly 
 beneficial the extra water necessary will prevent the 
 practice from becoming general. 
 
 The United States Government has found by ex- 
 periment in California orchards, several legumes that 
 promise a greater tonage of green matter, under 
 equal conditions, than the present Oregon or com- 
 mon vetch so generally used. These include two 
 species of Vicia; one pea, and one bean. So that 
 this phase of agriculture will no doubt be improved 
 and modified from time to time. 
 
 The green manure wanted by orange growers is 
 one that will grow quickly as California winters are 
 short and dry, and growers cannot afford to let the 
 ground rest undisturbed very long.
 
 FERTILIZERS 57 
 
 HUMUS FERTILIZERS-NECESSITY OF 
 ORGANIC MATTER. 
 
 86. Humus is decayed organic matter. It is neces- 
 sary for fertility, because all the nitrogen in soils 
 comes from either an animal or vegetable source. 
 (Very minute quantities are absorbed from the air 
 as ammonia and as nitrogen). The nitrates come 
 from humus. They are water soluble and can be 
 taken up by the roots. Thus the plant gets its 
 nitrogen. (15) (29) 
 
 All fertile soils are rich in organic matter. The ex- 
 ceeding richness of new lands is due to the humus 
 deposited by succeeding crops for generations. This 
 is true of both the high mesa and the valley land. 
 It is possible to use some chemical form of nitrogen 
 and raise a plant, but it is expensive, requires close 
 watching and is not practical. The nitrogen from 
 organic fertilizers is yielded to the plant gradually, 
 with greater certainty, and is more lasting. 
 
 87. Organic manures, whether of blood and bone, 
 or stable manure, or green cover crops, not only 
 furnish nitrogen to plant life, but their decay gen- 
 erates several well known acids, notably carbonic, 
 which combine with the soil moisture and dissolve 
 other forms of plant food. Without these acids, 
 phosphorus, potash and other necessary elements 
 would not be so available to the plant. Direct root 
 and water action would then have to do the work 
 alone, and the plant would not thrive so well. Hu- 
 mus influences the availability of the phosphoric 
 acid and potash and converts them into forms more 
 readily utilized by the plant. (49-50).
 
 58 FERTILIZERS 
 
 88. Organic fertilizers lighten soils. Their decay 
 leaves the soil open and porous. More oxygen is 
 thus admitted, which gives more life to the micro- 
 organisms, which, after all, are the cause of all fer- 
 tility. Better cultivation is possible in such soils. 
 Light, porous soils are more retentive of moisture. 
 Thus, organic matter literally builds up a soil. It 
 increases its depth. A "worn-out" soil is simply a 
 soil devoid of humus. It is lifeless. Liberal applica- 
 tions of organic matter restore it and change it from 
 a tax to an income. 
 
 89. Humus forming-materials are, therefore, 
 necessary to successful and practical farming. The 
 best results from inorganic fertilizers, such as rock 
 and acid phosphates, Thomas slag and sulphate of 
 potash, are obtained when they are used with ma- 
 nure, or blood, or blood and bone, or a green cover 
 crop turned under. 
 
 90. "Humus is not only the principal source of 
 nitrogen in soils, but it influences to a marked ex- 
 tent the available potash and phosphoric acid. 
 Humus forming materials, like green manures and 
 yard manure, have the power, when they decompose 
 in the soil, of combining with the potash and phos- 
 phoric acid of the soil and thus converting them into 
 forms which are readily utilized by the plants. "(82). 
 
 CULTIVATION AND FERTILIZERS. 
 
 91. Cultivation increases the availability of fer- 
 tilizers by aiding nitrification and by saving soil 
 moisture. All organic forms must first decay and 
 then be turned into nitrates (nitrification), and
 
 FERTILIZERS 59 
 
 other salts before water can carry their elements to 
 the roots of plants. (29). 
 
 The decomposed matter (humus) is attacked by 
 nitrifying bacteria and these require oxygen for 
 their work. Cultivation increases this supply of 
 oxygen so that nitrification proceeds faster, and 
 better growth results. The more frequent and deep 
 the cultivation, the better the nitrifying bacteria can 
 work. The size of fruit can be increased in this way, 
 or a short season made equal to a long one. 
 
 Cultivation therefore uses up humus very rapidly 
 so that the supply must be frequently renewed. The 
 extra growth and yield are probably proportional 
 to the supply of humus and frequency of cultivation. 
 
 92. This principle of aiding nitrification applies 
 to all forms of animal and vegetable fertilizers such 
 as yard manure, blood, raw bone, guano, tankage, 
 and peas and clover, planted for their fertilizing 
 value when ploughed under. 
 
 Frequent, deep cultivation increases the supply 
 of water in soils. Several well-known acids, result- 
 ing from decomposition, unite with soil moisture 
 and dissolve what ordinary water will not. Insol- 
 uble forms of fertilizers, such as phosphate of lime 
 and silicate of potash, are probably thus made 
 available to the plant. 
 
 93. Moist soils swell and are more permeable. 
 Roots can develop faster in them, and the fertilizers, 
 applied to the top, six inches, as they gradually dis- 
 solve, can be carried more easily and deeply, increas- 
 ing the feeding area of the roots and the develop- 
 ment of the plant. 
 
 Frequent and through cultivation, helps and 
 multiplies these beneficial effects of soil moisture.
 
 60 FERTILIZERS 
 
 IRRIGATION AND FERTILIZERS. 
 
 94. Plants can take up food, only when it is pro- 
 vided in solution. The food may be dissolved by 
 water, or by direct root action, or by the process of 
 fermentation, which is almost constant in all soils. 
 In either case water is essential, and the common 
 carrier, and the way in which it is used, seriously 
 effects the results of fertilization. Especially is this 
 true because the top foot of soil contains the most 
 valuable fertilizing ingredients. 
 
 There are three kinds of water in soils : free water 
 which moves by gravity ; hygroscopic water, detect- 
 able only by laboratory methods even in the dryest 
 earth, and capillary water, which moves by the 
 power of attraction between particles of matter. 
 This capillary water is what plants feed and depend 
 upon mainly. It travels up and down freely with 
 very little motion, sideways, carrying with it the 
 soluble fertilizers. 
 
 95. It is useless to apply fertilizers on dry ground 
 that is not dampened by irrigating water, as for 
 instance ; far under very old trees or on the midway 
 spaces in young orchards where furrows are not 
 made. 
 
 As moisture evaporates at the surface, it is con- 
 stantly supplied from below by the capillary move- 
 ment. The dissolved fertilizers contained, remain at 
 the surface from which the water evaporates ; hence 
 they accumulate so that top soils are always the 
 richest. The next rain or irrigation carries the plant 
 food down only to rise again as evaporation pro- 
 gresses at the surface. There is thus an oscillation 
 of water containing many kinds of plant food, up 
 and down many times a year.
 
 FERTILIZERS 61 
 
 96. Certain forms of fertilizers, such as the ni- 
 trates (both soda and potash) ammonium sulphate, 
 the sulphate of potash, and the acid and super-phos- 
 phates are easily carried by water. If applied just 
 previous to an irrigation they go to the deepest 
 roots, or -wherever water can go. If there is any 
 waste water a part of them is lost. 
 
 If the grade from the flume is very steep for fifty 
 feet or more, the trees in that space will be the first 
 to turn yellow, although they are nearest the flume 
 and receive the most water. The nitrates have been 
 washed to lower levels. Manure or straw should be 
 used in such places so that the water will move 
 more slowly and the nitrates retained where they 
 belong. 
 
 On account of the solubility of many forms of 
 plant food, irrigation water should be handled very 
 carefully. Do not turn a heavy head of water into a 
 furrow until after the furrow is soaked a little and 
 the fine earth compacted. This will lessen washing. 
 The ideal movement of water is up and down, with 
 as little movement on the surface as possible. In 
 this way the rich top soil with its humus and fer- 
 tilizers will be retained where it belongs. 
 
 VALUE OF SOIL ANALYSIS. 
 
 97. Soil analyses are valuable for determining in 
 a general way the needs of a crop. The greater the 
 number of samples examined, the more accurate will 
 be the information obtained. Very little can be con- 
 cluded from one sample. Taken in connection with 
 the appearance of trees and vegetation raised on the 
 soil, many a useless expenditure for fertilizing ingre- 
 dients may thus be avoided.
 
 62 FERTILIZERS 
 
 If samples of soil be taken according to the direc- 
 tions of the State Experiment Station the results 
 may be relied upon as indicating that soil's capacity 
 for various crops. This information, with the 
 owner's knowledge of previous treatment, together 
 with the appearance of the vegetation and growth 
 gives a pretty thorough diagnosis. Each of these 
 sources of information acts as a check or supple- 
 ments the other two. 
 
 98. Soil analysis should be interpreted by an ex- 
 pert for where T \c of 1 % would be considered a suffic- 
 iency of some element, it would be regarded as a 
 deficiency of other elements. A soil containing % of 
 1% humus is lacking in that substance, while that 
 amount of potash or lime would be considered 
 ample for fertility. (100). 
 
 Again, soil analyses may reveal the presence of 
 some poison, such as carbonate of soda, or chlorine, 
 in the midst of otherwise fertile conditions, An ex- 
 cess of either acid or alkali can likewise be deter- 
 mined. Plant food may be present in abundance and 
 yet the results be unsatisfactory on account of poor 
 cultural conditions, or lack of humus. This, also, 
 soil analysis would reveal. 
 
 Whenever there is uncertainty about the needs of 
 crops or orchard, soil analysis should always be 
 taken. One element, only may be lacking and thus 
 discovered, and the purchase of the element unneces- 
 sary be avoided. The California State Experiment 
 Station has advised farmers that sufficient potash is 
 present in nearly all California soils. General experi- 
 ence has confirmed this statement, thus saving the 
 farmers many dollars annually.
 
 FERTILIZERS 63 
 
 99. The mechanical analysis of soils is always 
 important. Most California soils are sedimentary 
 and composed of irregular strata varying in thick- 
 ness from a few inches to many feet. They may be 
 impenetratable and poorly drained, or too open and 
 coarse to hold the requisite moisture. The subsoil 
 conditions should be known. (20-21-22). 
 
 100. The following table is compiled mainly from 
 the records of the California State Experiment Sta- 
 tion and from Dr. Hilgard's book, "Soil," which 
 state quite positively that when the chemical deter- 
 mination of certain elements in soils run below a 
 certain amount that soil is quite sure to be unpro- 
 ductive. These figures are the result of a large num- 
 ber of analyses representing years of work. 
 
 ADEQUATE PLANT FOOD. 
 
 RICH ADEQUATE INADEQUATE 
 PER CENT. PER CENT. PER CENT. 
 
 Humus in soil 2.00 1.00 0.85 
 
 Nitrogen in humus 9.00 4.00 2.00 
 
 Lime 1.50 1.00 0.40 
 
 Phosphoric acid 0.20 0.10 0.05 
 
 Potash (K 2 O) 1.00 0.45 0.25 
 
 These figures will vary for different crops. Ade- 
 quacy for one kind of crop might be inadequate for 
 another. But they are averages for a large number 
 of determinations and very suggestive. It has been 
 well established also that when the per cent, of lime 
 is high, much smaller amounts of the other plant 
 foods will suffice.
 
 64 FERTILIZERS 
 
 FERTILIZING VALUE OF STRAW, STABLE MANURE, 
 ORANGE CULLS, AND CERTAIN LEGUMES, f 
 
 101. N. P.A. POT.* 
 
 JPea vine hay 3.00 $12.00 
 
 IVetchhay 2.55 10.20 
 
 Burr clover hay 2.68 10.72 
 
 Alfalfa hay 2.19 1.51 1.68 11.37 
 
 Wheat straw 0.59 0.12 0.51 3.12 
 
 Stable manure 0.50 0.25 0.50 2.87 
 
 Orange culls 0.18 0.12 0.21 1.10 
 
 *(Nitrogen @ $4.00 per unit. Phos. acid @ $1.00 
 per unit and potash @ $1.25 per unit.) 
 
 fThe value of the above materials for humus is 
 probably equal to, or greater than their fertility 
 value as judged by the results obtained from their 
 use. 
 
 tit is assumed in the table that the pea, vetch and 
 burr clover were raised as a cover catch crop in the 
 orchard, and that this nitrogen is all gain, which 
 fact is not yet established beyond doubt. Their 
 phosphoric acid and potash are not reported, as 
 what they take of these from the soil is returned 
 with them.
 
 INDEX. 
 
 Acidulated Phosphates 23 
 
 Adequate plant food 63 
 
 Agricultural value 46 
 
 Alfalfa, fertilizing value 64 
 
 Analysis adding to 100 per cent 43 
 
 Analysis of fertilizer. How to understand 44 
 
 Analysis of soil 61 
 
 Applying fertilizers, Time for 51 
 
 Applying fertilizers, Amount 52 
 
 Applying fertilizers, Method 53 
 
 Applying fertilizers deeply 9 
 
 Availability 28 
 
 Availability, Order of 29 
 
 Basic slag 25 
 
 Bone 25 
 
 Burr clover, fertilizing value 64 
 
 Canadian peas, fertilizing value 64 
 
 Commercial value 46 
 
 Clover crops and water 55 
 
 Culls, fertilizing value 64 
 
 Cultivation, relation to fertilizers 58 
 
 Drainage of soils 16 
 
 Economical form of fertilizers 38 
 
 Effects of plant foods 50 
 
 Essential plant food 17 
 
 Example of fertilizer worth $6.50 per ton 39 
 
 Example of fertilizer worth $41.10 per ton 39 
 
 Fertilizers, purchase 32 
 
 Fertilizers, source 19 
 
 Fertilizers, use 47 
 
 General principles, effect of fertilizers 50 
 
 Green manure 54 
 
 High grade fertilizer, example 40
 
 INDEX. 
 
 Home mixtures 42 
 
 Humus (organic matter) 57 
 
 Insolubility, desirable 31 
 
 Irrigation, relation to fertilizers 60 
 
 Lower grade fertilizers, example 40 
 
 Manure, green 54 
 
 Manure, stable 53 
 
 Manure, fertilizing value B4 
 
 Most economical form 88 
 
 Nitrification 21 
 
 Nitrogen, cost of 37 
 
 Nitrogen, effect of 47 
 
 Nitrogen, from air 21 
 
 Nitrogen, sources of 19 
 
 Nitrogen from organic sources 22 
 
 Nitrogen cycle 20 
 
 Nitrate of soda and carbonates 22 
 
 Orange culls 64 
 
 Organic matter (humus) 57 
 
 Peas, green manure 54 
 
 Phosphate guanos 26 
 
 Phosphoric acid, cheapest form 26 
 
 Phosphoric acid, cost of 37 
 
 Phosphoric acid, effect of 48 
 
 Phosphoric acid, sources of 23 
 
 Plants, general 5 
 
 Plant food, amount necessary 63 
 
 Plant food 11 
 
 Plant food "essential" 17 
 
 Plant food, air derived II 
 
 Plant food, soil derived 11 
 
 Plant food, definition 17 
 
 Potash, effect of 48
 
 INDEX. 
 
 Potash, cost of 37 
 
 Potash, sources of 27 
 
 Purchasing, general principles 39 
 
 Purchase of fertilizer 32 
 
 Roots 8 
 
 Reversion of phosphates 24 
 
 "Simples" 42 
 
 Soil analysis, value of 61 
 
 Soils, composition of 11 
 
 Soils, fix phosphorus 24 
 
 Soils, drainage of 16 
 
 Soils, physical condition 15 
 
 Source of fertilizers 19 
 
 Solubility in different soils 30 
 
 Stable manured 53 
 
 Steamed bone 25 
 
 Straw, fertilizing value 64 
 
 Summer cover crop 56 
 
 Thomas phosphate slag 25 
 
 Unnecessary fertilizers, avoiding purchase 50 
 
 Use of fertilizers 47 
 
 Vetch, common, fertilizing value 64 
 
 Vetch, green manure 54
 
 UNIVERSITY OF CALIFORNIA LIBRARY 
 
 Los Angeles 
 This book is DUE on the last date stamped below. 
 
 MM 17 
 
 OK 1 4 1954 
 
 Form L9-25m-9,'47(A5618)444
 
 s 
 
 633 
 
 S61i3f 
 
 1911