Division of Agricu Sciences UNIVERSITY OF CALIFORNIA NITRATES IN THE UPPER SANTA ANA RIVER BASIN ,i*« CALIFORNIA AGRICULTURAL EXPERIMENT STATION BULLETIN 861 CAEBAD 861 1-60 (19731 Digitized by the Internet Archive in 2012 with funding from University of California, Davis Libraries http://archive.org/details/nitratesinuppers0861bran The extensive groundwater supplies in the Santa Ana Basin constitute a valuable resource which must be protected from excessive degradation if long-term bene- ficial use is to be realized. Nitrate in some of the Basin's well waters is already in excess of drinking-water standards of the U. S. Public Health Service. At the request of the Santa Ana Water- shed Planning Agency (SAWPA), the Kearney Foundation of the University of California made a 3-month study of the nitrate problem in the Basin. The study was restricted for the most part to the Upper Basin (above Prado Dam), where preliminary work indicated that nitrate degradation of waters was most serious. A multidisciplinary approach was used for analyzing problem areas of high ni- trate concentrations in the groundwaters, determining the probable cause of each problem area (agricultural fertilizers, manure disposal, waste-water disposal, etc.), and developing recommendations for prevention of future problems of a similar nature in the watershed. Univer- sity staff (from the Experiment Station and Agricultural Extension) involved in this study represented the fields of surface and groundwater hydrology, soil and water chemistry, soil microbiology, sanitary and agricultural engineering, water science, and plant science. Specific objectives included: a review of available data in order to identify and quantify existing high nitrate concentra- tions in groundwater; a review of the his- tory of land and water use, waste disposal, and other practices in each problem area to form judgments on causes of high ni- trate concentrations; development of guidelines for rates of fertilization, water application, and animal waste disposal which will appreciably reduce the poten- tial for nitrogen pollution of surface and groundwaters of the Basin consistent with reasonable levels of agricultural produc- tion; identification of areas of potential pollution related to nitrogen but not of primary concern in this study; and last but not least, identification of problems needing further study. May, 1973 THE AUTHORS: D. C. Adriano is Assistant Professor, Department of Crop and Soil Sciences, Michigan State University; R. S. Ayers is Extension Soil and Water Specialist, Davis; F. T. Bingham is Professor of Soil Science and Chemist, Riverside; R. L. Branson is Exten- sion Soil and Water Specialist, Riverside; A. C. Chang is Assistant Professor and Agricultural Engineer, Riverside; T. W. Embleton is Lecturer and Horticulturist, Riverside; W. C. Fairbank is Extension Agricultural Engineer, Riverside; G. L. Guymon is Associate Professor, Water Resources and Civil Engineering, University of Alaska; G. L. Huntington is Lecturer, Soils and Plant Nutrition, and Specialist in the Experiment Station, Davis; C. F. Krauter is Staff Research Associate, Agricultural Ex- tension, Davis; O. A. Lorenz is Professor of Vegetable Crops, Davis; A. W. Marsh is Extension Irrigationist and Soils Specialist, Riverside; J. P. Martin is Professor of Soil Science and Chemistry, Riverside; D. R. Nielsen is Professor of Water Science and Water Scientist, Davis; P. F. Pratt is Chairman and Professor of Soil Science and Chemistry, Riverside; V. H. Scott is Professor of Water Science and Civil Engineering, and Hydrologist in the Experiment Station, Davis; F. H. Takatori is Specialist, Plant Sciences, Riverside; K. K. Tanji is Lecturer and Associate Specialist, Water Science and Engineering, Davis. [i] NITRATES IN THE UPPER SANTA ANA RIVER BASIN IN RELATION TO GROUNDWATER POLLUTION 1 INTRODUCTION Nitrogen is an essential element for all biological life processes even though it is not one of the earth's more abundant ele- ments. When nitrogen or its compounds are in limiting amounts, food and fiber production is reduced, animal and human health is impaired by protein deficiency, and decay of waste materials may be slowed. Conversely, excessive amounts of nitrogen and its compounds may be harm- ful to infants and livestock, may contrib- ute to the eutrophication of surface water bodies, and may delay the ripening of certain fruits, vegetables, and other crops. Under an undisturbed virgin environment the cycle of synthesis, consumption, ex- cretion, and decay of nitrogenous matter takes place diffusively but at roughly the point of origin, so that excesses and de- ficiencies of nitrogen are more or less bal- anced. Man disturbs this delicate balance by choosing to live in cities, and by con- centrating livestock and dairy operations and producing and processing food and other products in localized areas. A con- centrating effect results, with sewage, ma- nure, other nitrogenous wastes, and fer- tilizers disposed or applied as point sources in such quantities as to overload nature's capacity to degrade and consume nitrate as fast as it is formed. The result is nitrate accumulation. Global nitrogen geochemistry and distribution Calvin (1956) estimates the earth to be 5 to 10 billion years old. About 4 billion years ago our atmosphere rose from gases emanated from the earth's interior. During this period of intense geologic activity gaseous nitrogen in the form of ammonia (NH 3 ), along with other gases, was emit- ted from fundamental rocks (Hutchinson, 1944). Then, 2 to 3 billion years ago, or- ganic molecules were formed by nonbio- logical activities (Calvin, 1956) from, for example, electrical discharges and solar radiation. Amino acids and other complex nitrogen compounds were thus synthe- sized. These inorganic and organic nitro- gen molecules accumulated randomly in the shallow seas, from which living organ- isms were systematically evolved some 1 to 2 billion years ago. This was the begin- ning of our biosphere. Green plants emit- ted oxygen through photosynthesis, and, as the atmosphere became oxygen-en- riched, the reduced forms of nitrogen were oxidized to molecular nitrogen (N 2 ). The evolution of living organisms then gave rise to biochemical nitrogen trans- formations (Bartholomew and Clark, 1965). Plants, for instance, consumed sim- ple inorganic nitrogen compounds and synthesized complex organic nitrogen compounds (proteins). Animals, in turn, consumed plant proteins to form animal proteins. At death, plant and animal pro- teins are decomposed to the more simple inorganic nitrogen forms by bacterial and fungal activities. Thus began the nitrogen cycle, and eventually our atmosphere at- tained the present level of 78.09 per cent nitrogen by volume, or 75.51 per cent nitrogen by weight (Hutchinson, 1954). Table 1 gives an estimated geochemical distribution of nitrogen. These estimates indicate that the bulk of the nitrogen is tied up in the lithosphere (98.03 per cent) Submitted for publication December 30, 1971. [3] Table 1 GEOCHEMICAL DISTRIBUTION OF NITROGEN (AFTER BARTHOLOMEW AND CLARK 1965) Distribution area Total amount of nitrogen in each area* Per cent of total nitrogen each area contains Atmosphere. . Lithosphere. . Biosphere. . . . geograms tons 38.6480 0.425 X 10 16 1,934.0000 2.127 X 10 17 0.0164 1.804 X 10 11 1.96 98.03 0.01 * Total amount of nitrogen in all areas equals 1,972.6644 geograms, or 2. 170 X 10 17 tons. One geogram = 10 20 grams. and in the atmosphere (1.96 per cent). The lithosphere (soil, substrata, rocks) contains 50 times as much nitrogen as the atmosphere on a geochemical scale. Al- though amounts of nitrogen present in the biosphere are comparatively quite insig- nificant, it is this insignificant fraction that supports life on earth. Nitrogen pools in the Upper Santa Ana River Basin Another perspective on nitrogen distribu- tion is provided by the appraisal of the entire Upper Santa Ana River Basin shown in table 2, with the sources and sinks of nitrogen grouped arbitrarily into several nitrogen pools. (These pools may serve as either sources or sinks, but more often as both.) The mass given for nitro- gen in these pools is an estimate based on the 1960 level of development and for the 356,000 acres of land overlying the water-bearing zone in the Upper Basin; it does not encompass the watershed or the nonwater-bearing zones. In making these estimates it was assumed that the soil zone represents the surface 6 feet be- neath the land surface, and that the re- spective mean thicknesses of the unsatu- rated and saturated zones are 150 and 750 feet. If we examine only the top 900 feet of the earth's crust and 356,000 acres of land surface in the Upper Basin, the relative distribution of nitrogen is quite different from that on a geochemical scale. Table 2 shows that the total mass of nitrogen in the Basin is nearly 1.3 billion tons, dis- tributed as 96.66 per cent in the atmos- phere, 3.08 per cent in the substrata, 0.2 per cent in the soil, and the remainder in other nitrogen pools. Table 2 footnotes give the rationale for estimation of these masses of nitrogen. The atmospheric nitrogen pool is a major nitrogen reservoir containing about 78 per cent nitrogen by volume of air, or about 35,000 tons nitrogen per acre of land surface (Bartholomew and Clark, 1965). Nitrogen in the atmosphere exists primarily as molecular nitrogen (N 2 ), which is an inert gas. Nitrogen losses from the atmosphere are more or less balanced by gains in gaseous nitrogen Table 2 MASS OF NITROGEN IN THE UPPER SANTA ANA RIVER BASIN (BASED ON 1960 LEVEL OF DEVELOPMENT; 356,000 ACRES OVERLYING GROUNDWATER RESERVOIR; 960-FOOT-THICK WATER-BEARING SEDIMENTS) Location of nitrogen pools in basin Tons of nitrogen in each pool Per cent of total nitrogen in each pool Atmosphere* Land surface! Soilt Substrata§ Surface water|| .... Groundwater^ 1.246 X 10 9 2.87 X 10* 2.85 X 10 6 3 97 X 10 7 5.94 X 103 5.79 X 10^ 96.66 0.002 0.22 3.08 0.0005 0.004 Total nitrogen in 1.289 X 10 9 * 78.09% nitrogen by volume; 35,000 tons nitrogen per acre; 3.56 x 10 5 acres. t Vegetation: 6.50 tons dry matter per acre per year; 1.5% nitrogen; 1.62 x 10 B acres arable land, 1 .5-year growth (23.814 x 10 3 tons). Man: 70 g protein per capita; 16% nitrogen; 630,000 popu- lation (3.528 X 10 3 tons). Poultry: 6.4 X 10 6 chickens; 3 lb per chicken; 3% nitrogen (0.288 X 10 3 tons). Cattle: 70,122 head; 1,000 lb per head; 3% nitrogen (1.053 X lOHons). t 0.07% nitrogen, bulk density of 1.4 g per cc; 6 ft deep; 3.56 x 10 5 acres. § 46 g nitrogen per ton, bulk density of 1.8 g per cc; 900 ft deep; 3.56 x 10& acres. || Pumped: 540,170 acre-feet water; 30 ppm NO3 (4.995 x 10 3 tons). Streamflow, imported: 147,630 acre-feet water; 1 ppm nitrogen (0.201 x 10 3 tons). Agricultural return flow: 174,460 acre-feet water; 3 ppm nitrogen (0.712 X 10 3 tons). Urban irrig. return flow: 15,230 acre-feet water; 0.4 lb nitrogen per acre-inch (0.037 X 10 3 tons). 1 Saturated zone: 15.716 X 10 6 acre-feet water; 10 ppm NO3 (4.916 x lOUons). Unsaturated zone: 0.715 x 10 6 acre-feet water; 40 ppm NO3 (8.752 X 10 3 tons). [4] from soil and land surface. However, in areas of high population density and in- dustrial activities gains generally exceed losses so that the atmosphere becomes pol- luted with oxides of nitrogen and other emissions (smog components). Air currents presumably export to other basins much of the nitrogen emitted, but some is re- turned to the land surface. According to Odum (1959), dry-matter productivity of various ecosystems ranges from less than 0.5 grams dry matter per meter per day (in deserts) to 1 gram (in grasslands and some agriculture) to as high as 10 grams (in intensively cultivated lands). It was assumed that the Upper Basin produced 4 grams per square meter per day (6.50 tons of dry matter per acre- year) for 162,000 acres of arable land, and that the dry matter contained 1.5 per cent nitrogen. It was further assumed that the vegetative cover averaged 1.5 years of growth. The protein content of children, women, and men varies between 40 and 100 grams (USDA Food Yearbook, 1959). By assuming 70 grams protein per capita, 16 per cent nitrogen in protein, and a population of 630,000 (WRE, 1969), one can estimate for the Upper Basin the mass of nitrogen in humans (second footnote in table 2). Nitrogen estimates for the poul- try and cattle were derived from popula- tion figures, average weight of animals, and 3 per cent nitrogen by weight (Chang and Fairbank, 1971). Needless to say, there are other sources of nitrogen on the land surface, but estimates are difficult to obtain. Some of the nitrogen-containing matter is imported to or exported from (or both) to other basins. On the land and in the soil zone, most nitrogen is tied up in the organic form (plant and animal proteins or their tran- sitory decay products) with smaller frac- tions in inorganic forms. Except in the atmospheric nitrogen pool, organic and in- organic forms of nitrogen tend to degrade to nitrate under natural biological proc- esses. The nitrate is then recycled as it is consumed by plants and microbes. If the consumption rate is less than the rate of emission, nitrates will accumulate. Ni- trates are stable but they are completely water-soluble and thus move with water, so that one finds nitrate as the principal nitrogen compound in surface and groundwater nitrogen pools. The largest nitrogen pools next to those in the atmosphere are found in the soil and substrata zones. Nitrogen in the soil zone ranges from about 0.02 to 0.5 per cent of total nitrogen by weight, or about 800 to 20,000 pounds per acre-foot of sur- face soil (Lyon et at., 1952). For the Upper Basin it was assumed that soil nitrogen is 0.07 per cent, bulk density is 1.4 grams per cubic centimeter, soil depth is 6 feet, and the surface area is 356,000 acres. Much of this nitrogen is in the or- ganic form, and is not readily available as fertilizer nutrient to plants, or readily leached out by percolating water. Sedi- ments in the substratum zone are derived chiefly from igneous rocks, which contain about 46 grams nitrogen per ton (Feth, 1966). By assuming a bulk density of about 1.8 grams per cubic centimeter, a depth of 900 feet and a surface area of 356,000 acres, the mass of nitrogen in the substrata nitrogen pool was estimated. Nitrogen in substratum materials is not readily leached or released, because it is tightly fixed in the mineral or rock as am- monium ion (NH+). Thus, even though nitrogen pools in the soil and substrata contain the larger fractions of nitrogen present in the biosphere, they do not fig- ure significantly in over-all transfer of nitrogen in the environment. Precipitation, natural streamflow, and applied waters that infiltrate the land sur- face and pass through the soil zone carry the mobile forms of nitrogen (nitrate [NO J ]; nitrite [NOT ]; and to some extent ammonia [NHf ]) and are leached into the substrata. In the unsaturated zone (zone of aeration), water generally per- colates deeply to the water table and re- charges groundwater reservoirs. Depend- ing on profile stratification in the basin, some percolating water may become perched and move horizontally as subsur- face flow. For the Upper Santa Ana Basin, nitrates in subsurface and groundwater eventually reappear with rising waters at Prado Dam and a few other points in the Santa Ana River. Travel time is, how- ever, exceedingly long because ground- water flow rates range from less than 5 feet per year to about 20 feet per year [5] (Todd, 1959). Because a major source of water supply in this basin is groundwater, nitrates in the groundwater nitrogen pool are to some extent recycled back to the land surface. Background nitrate concentrations in surface and groundwaters are reported to be about 20 ppm nitrate or less (Feth, 1966). The estimated mass of nitrogen in surface and groundwaters was developed from hydrologic data reported by Water Resources Engineers, Inc. (WRE) (1970) and California Department of Water Re- sources (DWR) Bulletins 71, 71-64, and 104-3 (1960, 1966, 1970); estimates on nitrogen concentration are given in the footnotes of table 2. It was estimated that streamflow and imported water contained about 1 ppm nitrogen (DWR Bui. 65-61, 1964), agricultural return flow about 3 ppm nitrogen (Sylvester, 1961), and urban irrigation return flow about 0.4 pounds nitrogen per acre-inch (Kaiser Engineers, 1969). For saturated and unsaturated zones (comprising the groundwater nitro- gen pool), it was estimated that the re- spective nitrate concentrations were 10 and 40 ppm. Even though the largest ni- trogen sources are geochemical in origin (atmosphere, soil, and substrata), they are immobile, inactive, or in various stages of decay, so that it is the man-induced ac- tivities which generallv contribute to the presence of nitrates in excess of back- ground levels. Man's activities are mani- fested by his intense and diverse use of land, by waste treatment and disposal practices, and by management of water. Water is the principal carrier of nitrates to the groundwater. Nitrogen standards for water Although nitrogen pollution of waters may result from organic and inorganic forms, and from dissolved and particulate forms, it is the nitrate form which has been commonly monitored and accepted as a pollution parameter. The rationale has been that nitrate is one of the end products of biological oxidation and is the traditional public-health measure of pol- lution. The hazard of high nitrate to in- fants and livestock is illustrated by a dis- ease known as methemoglobinemia or nitrate cyanosis which is caused by nitrite formed from reduction of nitrate in the intestinal tract. Nitrite enters the blood stream and combines with hemoglobin to form methemoglobin, thus reducing the blood's capacity to transport oxygen. This reduction to nitrite occurs in infants be- cause their gastric juices are more nearly neutral than those of adults which have an acidic balance (Fair et al., 1968). Methemoglobinemia may also result from congenital heart diseases and inhalation or ingestion of certain kinds of chemicals in drugs (Walton, 1951). Similar nitrate-nitrite poisoning effects have been noted in ruminants (such as cattle) at concentration levels in waters exceeding 2,000 ppm nitrate, but nitrate poisoning results more commonly from the consumption of large amounts of feeds or plants containing high levels of nitrate (Tucker, et al., 1961). Tucker lists over 50 plants that have been involved in nitrate poisoning, or which have been reported as capable of accumulating appreciable amounts of nitrate. These plants, ranging from weeds to shrubs, vegetables, and other crop plants, are considered poten- tially toxic if thev contain more nitrogen than about 2,000 ppm (green weight) in the form of nitrate. The U. S. Public Health Service in its 1962 Drinking-Water Standards recom- mends a limit of 45 ppm nitrate or 10 ppm nitrogen (McKee and Wolf, 1963). At this concentration, the public is to be warned of the potential dangers of using the water for infant feeding. Prior to 1962, nitrate standards were not used for drinking waters. Since well waters with nitrates exceeding this standard are wide- spread in California without being known to produce methemoglobinemia (DWR Bui. 143-6, 1968), California has a rec- ommended limit of 45 ppm and a man- datory limit of 90 ppm nitrate. McKee and Wolf (1963) reported that many well waters containing over 500 ppm of nitrate have never been linked with reported cases, but most cases of this disease (oc- curring elsewhere in the U. S. and Eu- rope) have been associated with waters containing more than 50 ppm nitrate. Moreover, most reported cases involve use of water from dug wells or shallow wells [6] near barnyard waste-disposal sites. Ex- cess nitrates have been known to cause diarrhea when one liter of water contain- ing 500 ppm nitrate was consumed. Ap- parently there is considerable uncertainty over the scientific validity of these nitro- gen standards. The National Technical Advisory Committee for public water sup- plies recently recommended for surface waters permissible levels for ammonia of 0.5 ppm nitrogen and, for nitrate plus nitrite, 10 ppm nitrogen (Federal Water Pollution Control Administration [FWPCA] 1968). No standards for well waters were reported by the Committee. Nitrates in water may be undesirable or harmful for certain industries such as brewing, or for other fermentation proc- esses or food processing. Recommended limits are generally set at 15 to 30 ppm nitrate (McKee and Wolf, 1963). Nitrates in irrigation waters may be considered beneficial because of their fertilizer value: for example, a 4-inch application of water containing 50 ppm nitrate is equivalent to a rate of 10 pounds of nitrogen per acre. For certain crops, however (e.g., sugar beets, grapes), a continuous supply of nitrogen is undesirable because it ad- versely affects crop maturation. The abil- ity of water bodies to produce aquatic plants and animals is affected by nutrient supply. Insufficient sources of nitrogen often limit the growth of algae and other planktons which are a food source for plant-eating aquatic organisms (zooplank- tons), which in turn are themselves con- sumed by higher forms of predators. This is repeated on up the food chain to fish. If other environmental factors are favor- able, the more abundant the nutrient sup- ply (N, P, C, etc.) the more dense the aquatic vegetation. It is only when aquatic plants become too dense and/or interfere with the beneficial uses of water that eutrophication is considered detri- mental (FWPCA, 1968). The critical level, above which nitrogen contributes to det- rimental algal bloom and to rank growth of aquatic weeds, is difficult to assess be- cause many factors are involved. It has been suggested, for example, that a criti- cal level for Wisconsin lakes is about 0.3 ppm inorganic nitrogen (State Water Quality Control Board [SWQCB] Pub. No. 34, 1967), but this level should not be extrapolated to all California bodies of water because each stream, lake, or es- tuary has individual characteristics. For example, algal blooms have not resulted from 1 ppm nitrogen in the Sacramento River or from 3 ppm nitrogen in the east- ern Sacramento-San Joaquin Delta (Kai- ser Engineers, 1969). However, factors other than nitrogen are presumed to be limiting to growth of algae; these may in- clude clarity or turbidity of the water body (lack of sunlight energy source), ab- sence of certain essential trace elements, presence of one or more toxic elements, or low or insufficient levels of other nor- mal essential nutrients such as phosphorus or carbon. Algae require both sunlight and plant nutrients. THE NITROGEN PROBLEM IN BASIN-WIDE SYSTEMS Figure 1 presents an over-all appraisal of nitrogen pools and fluxes for the Upper Santa Ana River Basin. Along the left margin of this flow sheet are the surface and subsurface subsystems or zones. For each of these subsystems there are one or more pools (table 2) represented in figure 1 by rectangular boxes. The arrows going from one pool to another pool represent the various transport pathways. The num- bers in and around these arrows are the fluxes (transfer rates) of nitrogen in thou- sands of tons nitrogen per year. These fluxes were estimated by evaluating (among many others) the various mechan- isms or processes in the nitrogen cycle, the nitrogen contents of natural and man- made substances, the land use, and the hydrologic data. Sources making up these fluxes are shown in table 3, and the fate of the nitrogen loadings in table 4. The atmosphere in this basin loses about 4,628 tons of nitrogen per year. Of this 2,136 tons return to the land in rain, [7] 4.6 C Losses 0.2 Water 5.0 ATM N POOL 1.25 x 10 9 tons 4.6 < L Gains ^ Interbasin Transfers ^ ^Vecip. 2.1 JmE > Waste, N Fert 17.4 4.5 2.8 >0.30 >2.30 >7.0 >1.2 >0.6 B Fet Mnt >260 >250 >1000 Znt >300 Cu >22 Mo§... >100 CI Na Li >0.7 >0.25 >35 As F§ >5 >100 * With the exception of nitrogen values this guide can be applied for grapefruit, lemon and probably other com- mercial citrus varieties. t Potassium ranges are for effects on numbers of fruit per tree. j Leaves sprayed with Fe or Mn or Zn materials may analyze high in these respective elements, but the following growth may have values in the deficient range. 6 § From fruiting terminals, (Chapman, H. D. 1960). || Based on concentration of elements in five- to seven-month-old, spring-cycle leaves from nonfruiting terminals. Leaves selected for analysis should be free of obvious tipburn, insect or disease injury, mechanical damage, etc., and from trees that are not visibly affected by disease or other injury. 1 These elements are not known to be essential for growth of citrus. [27] Fig. 18. Nitrogen fertilizer use on non-citrus fruit and nut crops in the Upper Santa Ana Basin as a function of time. I960 YEARS Fig. 20. Nitrogen fertilizer use on turf grass in the Upper Santa Ana Basin as a function of time. Acreage of field crops in the Upper Santa Ana Basin declined from 48,639 acres in 1950 to 36,300 in 1970. Produc- tion is widely distributed, with the high- est concentration (in the Chino district) having about 40 per cent of the total. Commercial nitrogen fertilization rates range from pounds per year for dry beans, to 100 pounds for several other crops. Silage crops receive, in addition, high rates of manure applied as a disposal practice. Total commercial nitrogen ap- plied to field crops in this Upper Basin Fig. 19. Nitrogen fertilizer use on field crops in the Upper Santa Ana Basin as a function of time. [28 was 1,168 tons in 1950 and 1,038 tons in 1970 (fig. 19). No turfgrass acreage figures were avail- able. However, a detailed survey of all types of turfgrass in Los Angeles County in 1954 provided data for estimating acreage in the Upper Basin. When the Los Angeles County survey ratio of 76.3 persons per acre of turf is used, acreage in the Upper Basin is estimated to be 2,082 in 1930 and has increased progressively since, to 10,605 acres in 1970. Rates of nitrogen fertilization of turf- grass vary considerably depending upon whether professional management is in- volved or not. Types of turf managed professionally (including golf courses, athletic fields, parks, commercial, etc.) receive an average of about 4 pounds nitrogen per 1,000 square feet per year — about 175 pounds nitrogen per acre per year. Homeowner-managed turfgrass, in contrast, receives an average of approxi- mately 1 pound nitrogen per 1,000 square feet per year — about 40 pounds nitrogen per acre per year. Using data from the Los Angeles survey, the percentages of turfgrass under professional and home- owner management are estimated at re- spectively 14 per cent and 86 per cent. Estimated total nitrogen applied to all turfgrass types amounted to 130 tons in 1950 and increased to 322 tons in 1970 (fig. 20). ] Vegetable crop acreage and nitrogen fertilization. In 1969, the Upper Santa Ana River Basin had about 5,000 acres of vegetables; in that year there were 2,000 acres of vegetables in San Bernardino County, mostly in the Chino Sub-Basin, and 3,000 acres in Riverside County, mostly in the Riverside-Arlington-Corona area. This is a considerable decrease from the 7,596 acres in vegetables in San Ber- nardino County alone in 1930, and doubt- less it reflects the shift from irrigated agri- culture to specialized dairy operations in the Chino Sub-Basin. Riverside County saw an increase from 1,971 acres in 1930 to 3,078 acres in 1969. Table 10 gives these data in more detail. The rate of nitrogen fertilization of vegetables increased markedly between 1930 and 1969 (table 11). Average annual nitrogen rates are estimated to have been 30 to 45 pounds per acre in 1930, about 90 to 100 pounds in 1950, and about 180 pounds per acre by 1969. Crop yields have increased substantially as rates of fertilization have increased, so it has been extremely profitable to apply these addi- tional quantities of fertilizer. While yields have gone up, however, the percentage of applied nitrogen recovered in the crop has gone down. With the low rates of 30 to 45 pounds nitrogen applied in 1930, as much as 65 to 75 per cent of the nitrogen applied was accounted for in the crop produced. By 1950, about 50 per cent of the applied nitrogen was in the crop, and by 1969 only about 40 per cent was re- covered. The 60 per cent unaccounted for was presumably tied up in the soil-nitro- gen pool, lost to the atmosphere as gas- eous nitrogen from denitrification, or leached below the point where crops could recover it. Concentration of nitrates in drainage water reaching the water table can be re- duced by: (1) reducing total rates of nitro- gen applied to these vegetables crops — though at a resultant cost in lower crop yields (assuming optimum yield for rate of nitrogen formerly applied); (2) increas- ing water applied above consumptive use of the crop (more inefficient use of water); or (3) utilizing the best agricultural tech- nology available for producing the best crop possible while recognizing that cer- tain compromises may be necessary to re- duce leaching losses at times when ni- trates are most readily available for leach- ing. Although plant analysis is useful in assessing the nitrogen status of vegetable crops, there are limits to its usefulness. Interpretation of leaf analysis values is based upon data developed from samp- ling of a specific part of the plant at a definite time or stage of development. By the time the proper stage of development has been reached for satisfactory evalu- ation of the nitrogen status, it is usually too late to apply additional fertilizer. The Table 10 ACREAGE, ESTIMATED NITROGEN APPLICATION, AND ESTIMATED NITROGEN REMOVAL OF VEGETABLES IN RIVERSIDE AND SAN BERNARDINO COUNTIES, 1930-1969 Number of acres Total N applied Pounds N per acre Total N removed in crops N excess (application less crop removal) Year Riverside County San Bernar- dino County Riverside County San Bernar- dino County Riverside County San Bernar- dino County Riverside County San Bernar- dino County Riverside County San Bernar- dino County 1930 1940 1950 1960 1996 1971 1109 1603 2248 3078 7596 5604 6797 6587 2647 thousands 59 72 144 315 539 of pounds 342 462 709 977 482 30 65 90 140 180 45 82 105 148 182 48 30 66 124 209 thousands 228 216 379 441 198 of pounds 11 42 78 191 330 114 246 330 536 284 [29] Table 11 ESTIMATED NITROGEN APPLICATION AND REMOVAL BY VEGETABLE CROPS, UPPER SANTA ANA BASIN* Year Riverside County San Bernardino County Total Pounds of N per acre available for leachingf 1930 11 42 78 191 330 thousands of pounds 114 246 330 536 284 125 288 408 727 614 12.5 1940 1950 1960 42.5 48.5 81.5 1969 107.1 * Nitrogen applied less crop removal. Assumes that all N removed in the crop came from fertilizer N applied, t Calculated from total acres of vegetables for San Bernardino County and Riverside County and total pounds of N applied less removal by crop. information obtained is of value, however, in determining fertilizer applications on subsequent crops grown under similar conditions. The text-tables immediately following provide guidelines for nitrogen fertilization and plant analysis of selected vegetable crops. Soil analysis prior to planting is most useful for helping growers decide on probable need for fertilization with phosphorus, potassium, and zinc. To a much less extent it may be useful in helping to decide whether nitrogen will be needed at planting, or if enough is present that the usual planting application may be reduced or eliminated. Typical Rates of Nitrogen Fertilization (Vegetables) Pounds of Crop N per acre Carrots 120 Celery 250-300 Melons 120 Potatoes 220 Strawberries 200 Tomatoes (canning) 100 Tomatoes (fresh-market) 200 Miscellaneous vegetables 120-150 These rates can be expected to produce near-optimum yields with a minimum ex- cess of applied nitrogen. The recommen- dations are based on data from field ex- periments. Waste disposal: trends in population and waste production by humans, cattle, and poultry. Disposal of nitrogenous or- ganic wastes is a major problem in the Upper Santa Ana Basin. These nitrogen- ous organic wastes include sewage from people, manures from dairy and beef cattle and poultry, industrial wastes, crop residues, and other unclassified solid wastes. Prior to World War II the Basin was mostly rural, with many small farms and a few isolated cities. Dramatic changes be- gan in 1950, with a great influx of people to these cities, and with movement of dairies to the Chino Basin. This trend in movement of both people and the live- stock industry continues today at an ac- celerated rate (figs. 21, 22, 23, 24). As a result, waste-load and nitrogen input into the Upper Santa Ana River Basin have in- creased tremendously (figs. 25, 26, 27). People and animals together contribute roughly 40 million pounds of nitrogen to the Upper Basin. Based on an estimate of 12 pounds nitrogen per capita per year, one dairy cow is equal to 12 people in nitrogenous waste-load produced, and 1,000 laying hens are equal to 90 people. About 77 per cent of the population of the Upper Basin is now (1971) served by mu- nicipal or district sewers, and these sys- tems handle about 210 acre-feet of waste water per day in at least 10 different treatment plants. In an activated-sludge secondary-sew- age-treatment plant, solids are separated from water. The effluent is then usually allowed to percolate into the soil for dis- posal, and solids are dried and disposed of on or in the topsoil. During treatment, [30] PLANT ANALYSIS GUIDE FOR VEGETABLE CROPS Crop Time of sampling Plant part Deficiency levels NO^-N (ppm, dry- weight basis) Cabbage At heading Leaf midrib of 5,000 Carrots Midgrowth wrapper leaf Petiole of young mature leaf 5,000 Cauliflower At buttoning Midrib of young mature leaf 5,000 Celery At midgrowth when 12-15 in. tall Petiole of youngest fully elongated leaf 5,000 Lettuce At heading Leaf midrib of 4,000 Melons Early fruit set wrapper leaf Petiole of 6th leaf 5,000 Pepper Early fruit set from growing tip Petiole of young mature leaf 4,000 Potatoes Tuber set Petiole of 4th leaf 6,000 Snap beans Full bloom from growing tip Petiole of 4th leaf 4,000 Spinach Midgrowth from growing tip Petiole of young mature leaf 4,000 Sweet corn At tasseling Leaf midrib of 1st 500 Sweet potato At midgrowth leaf above primary ear Petiole of 6th leaf 1,500 Tomatoes Early bloom from growing tip Petiole of 4th leaf from growing tip 2,000 about 50 per cent of the nitrogen stays with the primary effluent. From 10 to 30 per cent of the nitrogen component in the primary effluent may be denitrified and lost as inert N 2 gas to the atmosphere in the secondary treatment process. The remaining nitrogen is in the sludge but tied up in organic form. Handling and disposal of this sludge is probably the most troublesome part of waste-water POPULATION OF PEOPLE, CATTLE, AND POULTRY IN THE UPPER SANTA ANA BASIN EXPRESSED AS NUMBER OF PEOPLE ON THE BASIS OF NITROGEN WASTE PRODUCTION Total people equivalent Year People Cattle Poultry for basin 1930 154,000 20,000 (est.) ___ 394,000 1940 200,000 22,000 (est.) — 464,100 1950 336,000 30,300 2,616,500 928,000 1960 658,000 71,200 6,399,300 2,148,500 1970 809,100 125,200 11,059,000 3,379,000 [31] Fig. 25. Nitrogen contributed to the Upper Santa Ana Basin from wastes of animals and humans. (Dotted line indicates estimate.) Fig. 21. Total population of people in the Upper Santa Ana Basin as a function of time. Fig. 22. Population of people in sub-basins of the Santa Ana Upper Basin as a function of time. Fig. 26. Nitrogen contributed to the Bunker Hill Sub-Basins from wastes of animals and humans. Fig. 23. Poultry population in the Upper Santa Ana Basin as a function of time. (Dotted line indicates estimate.) Fig. 27. Nitrogen contributed to the Chino- Riverside Sub-Basins from wastes of animals and humans. 1950 YEARS Fig. 24. Cattle population in the Upper Santa Ana Basin as a function of time. (Dotted line indicates estimate.) treatment, particularly as it relates to groundwater pollution. Most poultry manures and perhaps as much as 15 per cent of the beef and dairy manures are processed and/or exported from the Upper Basin. Disposal of re- maining animal and human wastes is limited to a relatively small acreage of land, and loading rates no doubt greatly exceed the natural capacity to assimilate without resulting in pollution. Handling of animal wastes is less advanced than [32] handling of domestic waste — most animal wastes remain in the corral until semi- annual cleanout and disposal. Once ma- nure is defecated, its composition changes rapidly. According to our estimates, ap- proximately 50 per cent of the nitrogen in the wastes disappear before cleanup of the corral, through a combination of leaching, runoff, volatilization of am- monia, and denitrification. In addition to manure solids, dairies also generate 50 to 100 gallons per cow of waste-water every day. In the Chino- Riverside area, this could amount to 9 million gallons per day (about 30 acre- feet per day). During the growing season, most of these waters are used on irrigated pastures. Waste disposal in the Bunker Hill Sub- Basin study area. Redland's sewage-treat- ment plant has been located along the north edge of the Bunker Hill Sub-Basin Area since 1963. It has a primary settling basin and an activated-sludge secondary treatment, and produces 7.4 acre-feet of effluent a day containing 30 to 40 ppm of ammonia (equivalent to 103 to 138 ppm nitrate) and 40 ppm COD (Chemical Oxy- gen Demand) discharged into the Santa Ana River bed. The sludge is dried on a sand drying-bed, and supernatant liquid from the sludge digester is stored in a 0.5-acre lagoon; discharge from the la- goon is by evaporation and percolation only. Prior to completion of this plant, an older plant treated essentially the same amount of waste water, but no record is available for study of its operation though it is known that its effluent percolated into the river bed. Waste disposal in Middle Chino Sub- Basin study area. The Ontario-Upland sewage-treatment plant is located at the north edge of the high-nitrate area of the Middle Chino Sub-Basin. The history of sewage disposal in this area dates back to 1915. In 1917, Upland joined Ontario and both cities utilized the golf course area as a sewage farm. In 1950, the system treated 1 1 acre-feet per day, with disposal mostly to the golf course. In 1959, dis- posal to the golf course was reduced to about 3 acre-feet per day. The present plant utilizes a pre-aerated primary set- tling tank; secondary treatment is split for parallel flow through two trickling fil- ters. The effluent, containing 15 to 25 ppm ammonia (equivalent to 52 to 86 ppm of nitrate) is discharged onto an ad- jacent golf course or to a flood plain along Cucamonga Creek. The supernatant liq- uid from the digester is stored in ponds until it can be recycled through secondary treatment. Ponding of sludge and sand- bed drying could cause leaching of ap- preciable nitrogen through the soil pro- file. However, no full assessment has been made of contributions from these two treatment plants. It is suggested that a water analysis for the detergent ABS (alkylbenzosulfanate) might confirm the presence of sewage effluent in the ground- water supply. Its absence, however, does not preclude sewage contamination, since ABS is not as mobile as chlorides or ni- trates and is degraded by soil microor- ganisms. Although actual nitrate contributions from the specific sewage-disposal plants at these two primary study sites have not been evaluated, evaluation of a similar situation (San Luis Obispo County) was made by Perry R. Stout et al. (1965). This report states that Arroyo Grande sewage effluent contains nitrogen equal to 172 ppm of nitrate. The effluent flowed from the treatment plant into a series of perco- lation ponds, where it percolated through sandy soils to the underground. The per- colation ponds were rotated and allowed to dry between fillings. Each pond was flooded about once a week. Soil-solution values for nitrate concentrations under these ponds were obtained from soil samples taken from 12 different sites. Nitrate concentrations in the soil solution in the surface foot of soil ranged from 15 to 2300 ppm. The greatest concentration of nitrates in the soil solution immediately above the zone of saturation at the 4-foot depth was 459 ppm. Appreciable quan- tities of nitrate at rather high concentra- tion were reported to be contributing to contamination of the underground water supplies of this rather small basin. Sewage disposal probably contributes to the nitrate problem in each of these two study areas. Further study could evaluate its contribution to the problem. [33] Poultry ranch near Santa Ana River bottom. (Courtesy Max Clover, UCR.) HP Santa Ana River bottom near Rubidoux. (Courtesy Max Clover, UCR.) [34] ga^gr :\ k ;:^:M'' :: fulM? SmMsi: Dairy ranch near Chino. (Courtesy Max Clover, UCR.) r Riverside city sewage treatment plant. (Courtesy Max Clover, UCR.) [35] RELATION OF NITRATE MOVEMENT TO GROUNDWATER HYDROLOGY Potential for groundwater pollution by nitrogen additions. Nitrates are com- pletely water-soluble and thus they can move in solution. Subsurface movement of dissolved nitrates is therefore con- trolled primarily by the movement of water, which in turn is related to the water content and geologic properties of the sediments making up groundwater basins. The Santa Ana groundwater basin has two major subsurface zones to be con- sidered: the zone of aeration, and the zone of saturation. Each zone plays an impor- tant role in the transport of nitrates and in their storage. The zone of aeration. This upper zone (from soil surface to water table) is char- acterized by pore spaces only partly filled with water. Water movement there is pre- dominately as unsaturated flow, although local regions of saturated flow may some- times be present in the soil profile. Move- ment of water and dissolved nitrates in this unsaturated zone is controlled by gravity plus pressure differences caused by variable soil-water content and chem- ical forces. The direction of water move- ment is predominately vertical, although local structural variations and changes in water content with depth cause some de- flection from the vertical. Thus, a point application of water at the ground surface tends, in general, to diffuse or spread out over a narrow band down through the zone of aeration. This phenomenon be- comes more pronounced as depth to water table increases. In general, nitrate move- ment through the zone of aeration will be slower than bulk-fluid movements because of dispersive and diffusive mechanisms. The zone of saturation. In this zone, all voids are filled with water and the rate of water movement depends on the hydrau- lic and transmissive character of basin sediments, and on the hydraulic gradient. Direction of movement of water in this zone is a function of gradients, storage coefficients, and transmissive properties. Basin sediments vary in their properties, but the predominant direction of ground- water movement is parallel to that of the water table (i.e., horizontal). Only where there is an impermeable fault zone or sig- nificant up-thrust of bedrock is there any appreciable vertical velocity component of the flow. Variations produced by indi- vidual wells in the water surface profile have little over-all influence on general horizontal movement of water in the basin. Therefore, basin-wide vertical ve- locity components are relatively insignifi- cant, with horizontal movements of water dominating. Because nitrates move with the water, factors which affect water flow will also have about the same effect on the nitrates. Additionally, dispersive mechan- isms associated with the pronounced het- erogeneity of substratum materials will influence the transport and mixing of nitrates. Table 12 summarizes a few of the more important factors relating to flow. It is particularly noteworthy that horizontal movement in the nitrate study areas is exceedingly slow, ranging from 0.003 to 0.1 mile per year for the hydraulic gradi- ents reported in each area. Therefore, the movement of a specific particle of water 1 mile downslope requires 10 years in the Riverside-Arlington area and 300 years in the Middle Chino Sub-Basin. Figures 28 and 29 show idealized cross sections of the geology and changes in wa- ter level over the last 25 to 30 years for four hydrologic units of the basin. In most of the separate sub-basins of the Upper Santa Ana Basin, the groundwaters are usually unconfined and can be in hydrau- lic contact with the basin ground surface. Nitrate, therefore, can percolate readily (along with applied waters) through the zone of aeration to the water table. If lo- calized layers of clays and silts are pres- ent, however, they will retard the down- ward movement of waters and serve as partially-confining aquifers. Such an area exists above the Bunker Hill Dike near San Bernardino; it extends eastward to about the Bunker Hill Sub-Basin study area and is an example of a confined aquifer having little hydraulic contact with the basin surface. Artesian pressures [36] Table 12 GEOMETRIC, PHYSICAL, AND HYDRAULIC VARIABLES IN FOUR SUB-BASINS OF THE UPPER SANTA ANA BASIN Geometric variables physical parameters* Hydraulic variables* Sub- basin Approxi- mate area Thickness of zone of saturation Thickness of zone of aeration Water permea- bilityf Hydraulic gradients Horizontal water velocities near top of zone of saturation Middle Chino. . Pomona Redlands Arlington- Riverside. . . . acres 2200 Over 4000 5900 Over 33,000 / 400-800 550 300-600 400 400-900 500 100-200 100 I. 100-250 175 200-400 300 150-250 200 50-300 75 mi. per year 2-8 4 0.1-3 1 2-7 5 3-50 10 ft. per ft. 4.7 X lO- 3 - 2.1 X 10-' 3 X 10-* 2.1 X 10-2 _ 8.6 X 10-" 2 X 10"* 2.5 X 10-2 - 3.8 X 10~ 3 4 X 10~* 9.5 X 10"* - 3.0 X 10-' 4 X 10-* mi. per year 0.003 0.005 0.1 0.1 * Parameters and variables based on order of magnitude estimates and information for 1965 obtained from State of California, Department of Water Resources, Southern District. Under-scored values represent tyical magnitudes. California Department of Water Resources, Southern District. 1071 . Computer printouts for hydrologic model runs. Personal communication. t Water permeability values are averages in zone of saturation. have existed in the past in this area. Analysis of the data cited above, and of other hydrologic information, leads to several significant observations concern- ing movement of water and nitrates. In general, hydrologic responses are highly damped in space and time. Consequently, seasonal variations in withdrawal and re- charge are reflected in changes in water levels taking place over months and years. The presence and movement of nitrates must also be associated with this slow movement of water, the damping mecha- nism of the zone of aeration, and the na- ture of the hydrologic responses in each Sub-Basin. Because of the slow horizontal movement of water, high nitrates persist- ing in groundwaters of some areas must be related directly to a nitrogen source in the soils or ground surface overlying these. Similarly, the slow vertical move- ment of nitrates through the zone of aera- tion suggests that high nitrates presently found in some wells can be accounted for only by events initiated many years ago. Specifically, changes in the groundwater quality may reflect changes in surface ni- trogen levels that occurred over a span of tens or perhaps even hundreds of years. A limited number of water quality anal- yses of water pumped from wells perfor- ated at different depths within the zone of saturation indicate that higher nitrate concentrations occur in wells perforated near the top of the saturated zone, and that lower concentrations occur in wells perforated near the bottom of the zone of saturation. This is explained by the fact that vertical velocities are slight, so that vertical mixing of nitrate water resulting from accumulation of percolating nitrated waters in the upper saturated zone is slow. Where the zone of saturation is rel- atively thin (such as in the Riverside-Ar- lington area) mixing takes place more completely and nitrates appear to be mixed more uniformly with depth. Conse- quently, there is little evidence of nitrate variation with depth in that area. Two other hydrologic factors need to be considered in explaining how nitrates are transported and mixed in the zone of saturation. One is the long-term change in water-table levels within the Upper Basin. The other is the annual fluctuation in water-table level due to summer pump- ing and winter recharge. Figure 30 shows the nature of these water-table fluctua- [37] frmj sou. zone W=-\ clay SAHPyCLAT f^SlLT EO SW *° !*"&! QMHKL [^SANDV GRAVE U feOO — C 450 350 1200 HYDROGRAPH OF STATE WELL NO. 2S/7W-I5K1 LOCATED * MILES W. OF NURA LOMA BASE OF AQUIFER ELEVATION. O FT HYDROGRAPH OF STATE WELL NO. ls/3W-l7CI LOCATED 3 MILES N W OF REDLANDS ■BASE OF AQUIFER ELEVATION: 400 FT Fig. 28. Hydrographs and geology in the Middle Chino (upper) and Redlands (lower) areas. [38] »m sou. zone Wt SANDY CLAY fe-"3 SILT SAND tS] GRAVtL [13 SANDY GRAVEL aoo 850 800 C50 600 500 ♦50 C>o£>* 6 (P cf>go u; _i. i-7 -^, vuv^ca^ HYDROGRAPH OF STATE WELL NO IS/8W -28 El LOCATED I MILE E OF POMONA 1 I I I I I I I I I I 1 I I I 1 I I I I I 1 I I I I 1 50 YEAR BASE OF AQUIFER ELEVATION 200 FT STo j o„oo BASE OF AQUIFER ELEVATION 2O0 FT I I I I I I I I I I I I I I I I I I I I I I I I I I I M I 45 50 YEAR 55 GO Fig. 29. Hydrographs and geology in the Pomona (upper) and Corona (lower) areas. [39] tions (coupled with nitrogen and water inputs) for an idealized geologic section and well hydrograph. There are essentially three cases to be considered. The first assumes that a known concentration of nitrate (J N0 3) is moving through the zone of aeration to the water table. Then, the first situation is for periods when the water level is dropping faster than the percolating re- charge waters are moving through the zone of aeration; here, no new accretions of nitrates from the surface take place. During such periods nitrate concentra- tions decrease at the water-table surface as nitrates which have previously moved from the surface are slowly mixed with the deeper groundwater; this results in an increase in nitrate with depth and time. The second case is when the water table rises to intercept the downward- moving nitrates passing through the zone of aeration. In this case there would be a marked increase in nitrate concentration at the water table, assuming of course that nitrate concentrations moving through the zone of aeration are greater than those in the water table below. The third case would be to assume that all nitrate additions to the zone of satura- tion would diminish with time because of imposed management practices. In this situation, previously contributed high ni- trates from upper layers would continue to mix with waters of lower concentrations in the deeper layers; this would take tens or hundreds of years. The horizontal movement of nitrates would also take tens to hundreds of years, because the gradi- ents are very low. This predicted mixing behavior assumes that the surface config- uration of the water table within the Basin will remain essentially unchanged. Some vertical mixing of nitrates takes place locally in the zone of saturation as a result of fluctuations of water tables pro- duced by the pumping of individual wells. It is probable, however, that these effects are secondary to regional fluctuations in the water table. ZONE OF CONVERSION OF NITROGENOUS MATTER TO NITRATE Fig. 30. Schematic diagram showing subsurface nitrate transport in relation to hydrologic responses. >f *"*>5 percent slopes / ( MODERATE □ Neorly level 1 I Sloping LOW _J Neorly level, permeoble substratum I Bl Sloping, permeable substratum ^H Sloping, dense substratum or rock VERY LOW I I Sloping, permeable substratum I I Sloping, dense substratum or rock — 1 SOIL ASSOCIATIONS - bb Arlington- Buren association, 2-9 percent s Dl-D Altomont-D.oblo association, 9-30 percent Ge-SZ Altomont -Gov.oto - Soper association, 15-50 p - Pn Arbockle - Perkins association, 2-9 percent -sF Badlond - San Timoteo association, 15-50 pe Li Caiolco- Las Posas association, 5-15 perce •Th Cajalco -Temescol rocky association, 9-50 Chino association, 0-2 percent slopes - Fa Cienebo - Follbrook ossociotion, 2-75 pe - SE Crolton - Sheephead association, 15-50 p Cropley association, 0-2 percent slopes Po-Hq Delhi - Pachappo - Hit mar association, 0-15 Wk-CE Dommo-Willows- Chino association, 0-5 per Vl-D Fallbrook-Vislo association. 2-15 percent VI -F Follbrook -Vista association, rocky 15-50 pe -G« Foster -Grongeville association, 0- 2 percent -Em Frionl -Escondido ossociotion, rocky. 30-75 Em-Vc Frionl, rocky, - Escondido, rocky, - Vallecilos 2 - 50 percent slopes, eroded LB-Ero Fnant, rocky-Lodo, roc k» - EsconrJ , do . 2-50 SOIL ASSOCIATIONS - cont Andreas - San Benito association, 30-70 pe Benito - Soper ossociotion, 30-50 percent I ungo - Greenfield- Honford association, 0-9 roded TD- X