bluuebunny/crossref_metadata_2025 huggingface dataset:
Plant Nutrient Concentrations in Runoff from Fertilized Cultivated Erosion Plots and Prairie in Eastern South Dakota
Authors: White E. M. , Williamson E. J.
Published: July 2010

Runoff waters from fertilized erosion plots and from native prairie in South Dakota were compared to determine the effect agriculture has had on water quality. Calcium, Mg, K, Na, total P, PO4‐P, NO3‐N , and NH4‐N contents were found to be similar in runoff from the erosion plots and from the prairie. The elemental contents in runoff from erosion plots planted to oats (Avena sativa L.), corn (Zea mays L.), and alfalfa (Medicago sativa L.) or fallowed were not distinctly different and varied from year to year. Variations in the ions in water collected from different basins in the prairie may be caused by differences (i) in the prairie vegetation and mulch in the drainage basins, (ii) in the time the runoff has to dissolve ions because of different overland flow distances, and (iii) in the dilution of the runoff by precipitation that falls directly into the basin. Losses of plant nutrients in soil eroded from cultivated land may be similar to average losses that would occur naturally if the area were in pristine prairie that was periodically subjected to fire.
Minimizing Nitrate Seepage from the Hula Valley into Lake Kinneret (Sea of Galilee): I. Enhancement of Nitrate Reduction by Sprinkling and Flooding
Authors: Raveh A. , Avnimelech Y.
Published: July 2010

Decomposition of organic matter in the drained soils of the Hula Valley leads to the accumulation of nitrates. These are leached during the rainy season to the Jordan River and endanger Lake Kinneret. Field studies have shown that nitrates can be reduced through the use of the irrigation systems exisitng in the area. A treatment of either sprinkling or flooding by raising the water table reduced the nitrate concentration to about half of its original amount. Both treatments induced anaerobic conditions in the soil and reduced the nitrate contents, probably by denitrification. The efficiency of the reduction depends on the existence of labile organic substrates in the soil.
Agricultural Chemicals in Surface Runoff, Ground Water, and Soil: I. Endrin
Authors: Willis G. H. , Hamilton R. A.
Published: July 2010

Endrin (1,2,3,4,10,10‐hexachloro‐6,7‐epoxy‐1,4, 4a,5,6,7,8,8aoctahydro‐1,4‐endo, endo‐5,8‐dimethanonapthalene) was surface applied at a rate of 0.337 kg/ha to sugarcane (Saccharum officinarum L.) plots instrumented to sample surface runoff and ground water. Runoff, ground water, and soil sampleswere collected over a 2‐year period and analyzed for endrin. Only small amounts of endrin were lost annually in runoff (less than 0.2% of that applied), and little endrin accumulated in soil. Trace amounts of endrin appeared to move through soil in the plots but not through soil columns. A delay of 72 hours between application and rainfall decreased the amount of endrin in runoff, ground water, and soil.
The Influence of Manure Slurry Irrigation on the Survival of Fecal Organisms in Scranton Fine Sand
Authors: Dazzo Frank , Smith Paul , Hubbell David
Published: July 2010

Samples of Scranton fine sand obtained from established fields of millet (Pennisetum typhoides) receiving 0, 1.27, 2.54, and 5.08 cm of cow manure slurry irrigation per week were inoculated with either a culture of Salmonella enteritidis serotype Enteritidis or fresh slurry containing fecal coliforms. The numbers of viable enteric organisms per gram of soil (dry weight) were determined at various times after inoculation. An inverse relationship was observed between death rates of the fecal organisms and the previous rate of slurry irrigation. Salmonella and fecal coliforms had a higher death rate in soil samples which had previously received 0 or 1.27 cm of slurry irrigation per week than in soil samples which had previously received higher irrigation rates.
Movement of Toxaphene and Fluometuron Through Dunbar Soil to Underlying Ground Water
Authors: LaFleur K. S. , Wojeck G. A. , McCaskill W. R.
Published: July 2010

One hundred kilograms per hectare of toxaphene (octachlorocamphene) and 40 kg/ha of fluometuron (3‐[m‐trifluoromethylphenyl‐1,1‐dimethylurea) were applied to Dunbar topsoil in a field plot in the South Carolina Coastal Plain. Loss of both pesticides from the topsoil and accumulation in underlying ground water were monitored for 1 year.

Toxaphene loss from topsoil seemed to occur in two stages. The second (major) stage was crudely linear on a log residue vs. log time plot. Half‐residence time in the topsoil was about 100 days.

Fluometuron loss from topsoil occurred in one continuous episode that was crudely linear on a log residue vs. linear time plot. Half‐residence time in the topsoil was about 120 days.

Toxaphene and fluometuron were found in underlying ground water within 2 months after they were applied to the topsoil. Both pesticides persisted in ground water during the entire year. Overall, concentrations gradually decreased with time.
Nitrogen Transformations During Subsurface Disposal of Septic Tank Effluent in Sands: II. Ground Water Quality
Authors: Walker W. G. , Bouma J. , Keeney D. R. , Olcott P. G.
Published: July 2010

Ground water observation wells were installed in the immediate vicinity of four septic tank effluent soil disposal systems. Potentiometric maps were constructed from measurements of the groundwater level at each site to establish the direction of movement. Ground‐water samples were pumped from each well to establish patterns of N enrichment in the ground water around the seepage beds and to evaluate the performance of these disposal systems in sands in terms of N removal. Soil disposal systems of septic tank effluent in sands were found to add significant quantities of nitrate (NO3‐N) , formed by nitrification of NH4‐N , the dominant N form in the effluent, to underlying ground water. The data obtained suggest that in sands, the only active mechanism of lowering the NO3‐N content is by dilution with uncontaminated ground water. Relatively large areas of 0.2 ha (0.5 acre) down gradient were needed the studied systems before concentrations in the top layer of the ground water were lower than 10 mg/liter. The average N‐input per person was 8 kg (10 Ib) per year. Essentially complete nitrification in the soil results in addition of approximately 33 kg NO3‐N (73 lb) to the ground water per year for an average family of four.
Mortality Factors Affecting Cotton Insects: I. Resistance of Smooth and Nectariless Characters in Acala Cottons to Heliothis zea, Pectinophora gossypiella, and Trichoplusia ni
Authors: Davis D. D. , Ellington J. J. , Brown J. C.
Published: July 2010

Host plant resistance to insects has become a major breeding objective in cotton (Gossypium hirsutum L.), since significant increases in resistance may result simultaneously in yield increases and reduced usage of insecticides. Nectariless ‘Acala’ cotton strains with reduced pubescence are being developed in an attempt to gain significant host plant resistance against harmful Lepidoptera. Extensive studies were undertaken to evaluate the first‐order effects that the nectariless and reduced pubescence plant modifications would have upon oviposition behavior of three key insects. Cage trials with pink bollworms (Pectinophora gossypiella) have been difficult to manage and results are inconclusive. It was found that cabbage loopers (Trichoplusia ni) showed a slight increase in oviposition on nectariless cottons with reduced pubescence. The increase was so small as to be of doubtful economic importance. Paired isolation cage studies conducted over a 4‐year period showed that similar numbers of Heliothis zea moths laid only 45% as many eggs on nectariless Acala strains as on their normally hairy, nectaried companion lines. There was a disturbing reversal in form in certain tests, due to variables not yet clearly understood. However, there was a clear trend indicating that the suppression of oviposition is greatest when environmental conditions are most favorable for a bollworm epidemic. This large reduction of egg numbers at peak oviposition is the strongest confirmation of the value of developing nectariless cottons to minimize Heliothis damage.
Suppression of Oxidant Injury by Benomyl: Effects on Yields of Bean Cultivars in the Field
Authors: Manning W. J. , Feder W. A. , Vardaro P. M.
Published: July 2010

Bean (Phaseolus vulgaris L.) cultivars ‘Tempo’ and ‘Pinto III’, which are sensitive to oxidant injury, and cultivar ‘Tenderwhite’, which is resistant to oxidant injury, were grown in field plots. Some plants were sprayed once a week with the fungicide benomyl at 2.4 g/liter to suppress oxidant injury and allow for yield comparisons. Benomyl suppressed 75–80% of the oxidant injury on Pinto and Tempo, but did not suppress slight injury on Tenderwhite. Nonsprayed plants of Pinto and Tempo, with extensive oxidant injury, matured faster and set fruit earlier than did sprayed plants with slight visible injury. Initial fruit set was somewhat greater on nonsprayed plants of resistant Tenderwhite. Significant differences between sprayed and nonsprayed plants for total yields and fresh and dry weights of plant remains at harvest were observed only with Tempo, which was the most sensitive to oxidant injury.
Malathion Degradation by an Arthrobacter Species
Authors: Walker W. W. , Stojanovic B. J.
Published: July 2010

The dissipation of malathion from agricultural soils has been shown to involve both chemical and biological mechanisms, with biodegradation being of substantial magnitude. This investigation was conducted to (i) isolate from soil by enrichment techniques bacterium or several bacteria capable of readily metabolizing malathion, and (ii) isolate and identify the malathion metabolites resulting from this microbial degradation. Of 18 soil bacteria examined, 5 were capable of utilizing the malathion molecule with degradation of added insecticide ranging from 47 to 95%. The most efficient malathion utilizer, an Arthrobacter species, degraded malathion to malathion half‐ester, malathion dicarboxylic acid, potassium dimethyl phosphorothioate, potassium dimethyl phosphorodithioate, and one other unidentified metabolite. O‐desmethyl malathion, potassium salt, was also produced, but the mechanism involved was nonbiological in nature. Malathion dissipation was monitored by electron‐capture gas‐liquid chromatography, and metabolites were identified by thin‐layer chromatography and infrared spectroscopy.
Effect of Cattle Feedlot Volatiles, Aliphatic Amines, on Chlorella ellipsoidea Growth
Authors: Mosier A. R.
Published: July 2010

An appreciable portion of the tons of basic N‐compounds, volatilized from cattle feedyards each year, are aliphatic amines. The effect of these nonammoniacal organic bases upon organisms in surface waters located near cattle feedlots is unknown. This study was designed to determine the effect of the aliphatic amines identified as feedlot volatiles, upon a common fresh water alga, Chlorella ellipsoidea, in laboratory pure culture studies. Individual aliphatic amines caused a 50% reduction in population growth of C. ellipsoidea at concentrations ranging from 1.2 to 143 ppm amine‐N. Primary amines were more inhibitory than iso‐, sec‐, and dialkylamines. The algae did not utilize amine‐N for growth with or withour an added N source.
Relative Sensitivity of Soybean Genotypes to Ozone and Sulfur Dioxide
Authors: Miller V. L. , Howell R. K. , Caldwell B. E.
Published: July 2010

Twenty‐one soybean genotypes [Glycine max (L.) Merr.] were evaluated for resistance to ozone and 19 genotypes for sulfur dioxide in the greenhouse and growth chamber. ‘PI 157474’ was most resistant to ozone, but ranked 14 in resistance to sulfur dioxide. ‘York’ was most resistant to sulfur dioxide and ranked fourth when subjected to ozone. ‘Peking’ was least resistant to both phytotoxicants. Experimental conditions necessary to investigate inheritance of resistance to ozone were determined by fumigating soybean plants equally spaced in a growth chamber. Relative sensitivity of each of the parents at several stages of foliar development must be established before classifying the progeny.
Surface Runoff Losses of Soluble Nitrogen and Phosphorus Under Two Systems of Soil Management
Authors: Klausner S. D. , Zwerman P. J. , Ellis D. F.
Published: July 2010

Evaluation of surface runoff losses of soluble nitrogen (NO3‐N, NH4‐N) and phosphorus (inorganic P) was initiated due to recent concerns about the discharge of plant nutrients from the agricultural sector. The annual loss of these two elements from field plots, as derived from natural rainfall, was determined. The influence of a crop rotation, soil management practice and fertilizer rates of the previous 15 years was studied. Corn (Zea mays L.), beans (Phaseolus vulgaris L.), and wheat (Triticum aestivum L.) were combined factorially with two rates of fertilization (high and moderate) and two soil management practices (good vs. poor). Well‐managed soils produced the least surface runoff losses of N and P. Ammoniacial N losses were not significantly associated with crop, fertility level, or management practice. Values ranged from 0.14 to 1.30 kg/ha per year. Surface losses of nitrate N and inorganic P were directly influenced by crop, fertility level, and soil management. These losses ranged from 0.39–29.23 and 0.04–0.49 kg/ha per year, respectively. Heavy fall fertilization of N on wheat prior to intense rains on poorly managed soils produced the largest loss of nitrate N. Except for heavy fall fertilization of N on poorly managed soils, the total yearly accumulative N discharge in surface runoff did not exceed the amount delivered in rainfall as measured during a 10‐month period. Phosphorus losses exceeded that amount contained in rainfall.
Land Disposal of Waste Gases: II. Gas Flow from Buried Pipes
Authors: Warrick A. W. , Miyamoto S.
Published: July 2010

Steady‐state compressible gas flow in homogeneous soils from buried porous pipes is analyzed for the purpose of developing land disposal systems for waste gases. Two different cases are considered (i) the ground surface is partially covered by an impermeable barrier, and (ii) the surface is corrugated with alternating ridges and valleys with the pipe buried under the ridges. The partial surface barrier provides a more uniform gas flow in soils than without it, but leads to an increase in the power required to inject gas at a given rate, especially when the pipe spacings are wide. Compared to an open level surface, the corrugated geometry results in a better gas distribution with little increase in power required and is probably the better system for injecting waste gas in nonstratified soils.
Occurrence of 2,4,5‐T and Picloram in Surface Runoff Water in the Blacklands of Texas
Authors: Bovey R. W. , Burnett Earl , Richardson Clarence , Merkle M. G. , Baur J. R. , Knisel W. G.
Published: July 2010

This investigation was conducted to determine the concentration of 2,4,5‐T [(2,4,5‐trichlorophenoxy)acetic acid)] and picloram (4‐amino‐3,5,6‐trichloropicolinic acid) in surface runoff water that may move from herbicide sprayed pastures and rangeland to untreated areas as a result of each major rainfall following treatment.

A 1:1 mixture of the triethylamine salts of 2,4,5‐T + picloram was sprayed 5 times at 1.12 kg/ha every 6 months on a native‐grass pasture watershed. Soil, grasses and runoff water were analyzed periodically following herbicide treatment. Herbicide content in the Houston Black clay from May 1970 to May 1972 remained low (0 to 238 ppb). Herbicide content on grass was high (50 to 70 ppm) immediately after treatment, but degraded rapidly thereafter. Plant “washoff” was the main source of herbicide detected in runoff water. Concentration of herbicide was moderately high (400 to 800 ppb) if heavy rainfall occurred immediately after treatment, but low (<5 ppb) if major storms occurred 1 month or longer after treatment. No damage occurred to cotton (Gossypium hirsutum L.) or sorghum (Sorghum bicolor (L.) Moench) from either spray drift or subsequent runoff water in fields adjacent and below several herbicide‐treated watersheds.
Nitrate Concentrations in Deep Soil Cores as Related to Soil Profile Characteristics
Authors: Lund L. J. , Adriano D. C. , Pratt P. F.
Published: July 2010

Fifteen sites within a 30‐ha study area were studied to determine the effect of soil profile characteristics on nitrate concentrations (NO3−‐N) below the root zone. The N input, crop removal of N, and water management were similar for all sites during the previous 6 years.

The soils of the study area were primarily Alfisols and Entisols of fine‐loamy, coarse‐loamy, sandy and sandy over loamy families. Nitrate concentrations varied between sites and with depth. The average nitrate concentrations below the root zone ranged from 4.9 to 15.3 µg/g when expressed on an oven‐dry soil basis.

Profile characteristics were significantly correlated with the average nitrate concentrations below the root zone. A regression equation relating average nitrate concentration in the 1.8–8 m depth to control section characteristics explained 86% of the variability of the NO3−‐N concentration and was highly significant. Hence, to minimize ground‐water pollution, soil profile characteristics should be considered in selecting land for high N input whether by fertilization or waste disposal.
Losses of Inorganic Nitrogen from Aquatic Systems
Authors: Bouldin David R. , Johnson Robert L. , Burda Charles , Kao Chun‐Wei
Published: July 2010

Additions of NH4NO3 were made to 6 ponds near Ithaca, New York, and the loss of NH4+ and NO3− from solution was followed over a 2‐month period with the objective of investigating the mechanisms and magnitude of losses of inorganic nitrogen. In the ponds which were used, biological immobilization of nitrogen was small in relation to the total amount added.

Losses of NH4+ ranged from 2 to 38% per day in different ponds. An NH3 volatilization model based on concentration of ammonium N and water pH was consistent with the experimental data, and the results were in agreement with the hypothesis that the major avenue of NH4+ loss was by NH3 volatilization across the air‐water interface.

Nitrate losses ranged from 7 to 15% per day in the different ponds. The results were consistent with the hypothesis that nitrate loss was primarily by denitrification in the bottom sediments.

Models for loss of both ions were derived which have general application to other bodies of water. Although the experimental data were obtained in ponds which are not necessarily typical of other bodies of water, the models are based on general chemical and physical parameters which are not peculiar to the ponds studied (that is, depth of water, water pH, and a reduced zone of sediments underlying a thin oxidized layer of sediment). The results suggest that NH3 volatilization and denitrification are mechanisms which may account for appreciable losses of N from many bodies of water.
Volatility of Atrazine from Plant, Soil, and Glass Surfaces
Authors: Burt Gordon W.
Published: July 2010

Volatility of atrazine (2‐chloro‐4‐(ethylamino)‐6‐isopropylamino‐s‐triazine) from glass, plant, and soil surfaces was determined by passing air above the experimental material through Florisil3 columns. Atrazine volatility was determined by counting the 14C‐atrazine present in the column eluate and that remaining on the treated surfaces.

Volatility from 125‐ml glass erlenmeyer flasks was influenced most by the amount of atrazine present. At 40C with an air velocity of 2 liters/min 70% of the applied atrazine was recovered from the florisil columns in 2 days when 1 µg of atrazine was applied; whereas, 10% was recovered when 1,000 µg was applied. Temperature, air velocity, and atrazine purity also affected atrazine volatility. Volatility was 25% greater at 40 than at 20C at an air velocity of 2 liters/min. An increase in air velocity increased atrazine volatility more at 20C than at 40C. Approximately 10% more atrazine was lost from a commercially formulated material than from a technically pure material. Dried plant material lost 18–27% of the applied atrazine in 2 days at 40C. Atrazine (37mM) was also applied in 2 µliter droplets to intact Cirsium arvense (Canada thistle) leaves. Two days after treatment 50% of the activity was located in the Florisil column. Volatility of atrazine from the soil was less than 10% in 2 days at 40C. It was concluded that atrazine volatility is a major factor for atrazine dissipation when applied to foliage but not when applied to the soil.
Volatility of DDT Residues in Soil as Affected by Flooding and Organic Matter Applications
Authors: Spencer W. F. , Cliath M. M. , Farmer W. J. , Shepherd R. A.
Published: July 2010

In a field experiment, flooding with and without organic matter additions was evaluated as a means of preferentially degrading residual DDT and thereby changing the ratio of the various isomers and metabolites volatilizing from the soil surface. Flooding for a 7‐week period, either with or without manure or alfalfa (Medicago sativa L.) meal applications, effectively degraded DDT isomers, primarily to the respective DDD isomers, but had little effect on DDE isomers. Both flooding and organic matter decreased the volatility even when soil concentrations were not affected, apparently because of increased adsorption of the compounds by added organic matter or by organic matter in the soil altered by flooding. The data indicate that minor changes in vapor concentration ratios were accomplished by flooding and organic matter additions, but regardless of treatment, the major constituent evaporating from the surface was p,p′‐DDE. To accomplish significant changes in volatilization patterns, it will be necessary to use such management practices before a major part of the DDT has been degraded to DDE. However, flooding and organic matter treatments will ultimately decrease the total quantity of DDE volatilizing from residual DDT in soils over long‐time periods because of their effectiveness in degrading DDT to DDD instead of DDE.
The Phosphorus Status of Eutrophic Lake Sediments as Related to Changes in Limnological Conditions—Total, Inorganic, and Organic Phosphorus
Authors: Wildung R. E. , Schmidt R. L. , Gahler A. R.
Published: July 2010

To aid in the assessment of the role of sediments as a source of P to lake waters and to provide insight into the factors which may influence sediment P release, changes with time in the P status of noncalcareous sediments of a eutrophic lake were related to changes in sediment C and N, surface water composition, pH, temperature, and phytoplankton growth.

The nature and extent of changes in sediment P status and the relationship of these changes to limnological conditions differed with location in the lake. Changes in sediment composition were greatest in a bay which received agricultural runoff in the early spring. This additional supply of nutrients apparently provided the initial impetus for increased surface water biological activity in the spring relative to other locations as reflected in increased surface water organic C and N, turbidity, and phytoplankton growth. At this location, total sediment P, C, and N decreased during the late spring and early summer. These changes corresponded to the period of exponential growth of the lake phytoplankton population. During the late summer and early fall when plankton growth entered the stationary and declination phases, sediment organic C, total N and P increased, evidently as a result of the deposition of detritus containing these elements.

Changes in inorganic P accounted for most of the changes in total sediment P. Combining data from all sampling locations in the lake, sediment inorganic P was not correlated with changes in surface water temperature or pH, but was inversely correlated with surface water organic C. The results thus indicate that sediment inorganic P was directly related to the biological productivity of the surface waters, and in at least one location, sediments served as a significant source of P to these waters supporting increased biological growth.
Corn Silage Yield and Soil Chemical Properties as Affected by Cattle Feedlot Manure
Authors: Mathers A. C. , Stewart B. A.
Published: July 2010

Cattle feedlot manure was applied at rates of 0‐, 22‐, 45‐, 112‐, and 224‐metric tons/ha for 3 successive years to irrigated corn (Zea mays L.). Additional plots received 448‐ and 896‐tons/ha for 2 years. Nitrate‐nitrogen in the top 180 cm of soil was maintained at about 100 kg/ha by 22 tons/ha manure applied annually. However, manure rates of 45 tons/ha caused a small increase in soil nitrate‐nitrogen and 112‐ and 224‐tons/ha rates increased the nitrate‐nitrogen remaining in the soil after three seasons to over 1,000 kg/ha. The highest concentration of the nitrate was between 30 and 60 cm, but nitrate accumulated to a depth of 360 cm. Organic matter, phosphorus, extractable potassium and sodium, and conductivity of a saturated paste extract increased in the top 30 cm of soil as the manure rate was increased. Applications of 224 tons/ha or more manure reduced corn silage (dry matter) yields. The optimum rate of manure application of corn silage production was 22 tons which supplied an average 300 kg/ha of nitrogen. Higher rates caused nitrate and salt accumulation in the soil and increased nitrate in the forage.
Relative Movement of Bromide and Nitrate Through Soils
Authors: Smith S. J. , Davis R. J.
Published: July 2010

Miscible displacement experiments were conducted with eight different surface soils (0–15 cm depth) and their associated subsoils (61–76 cm depth). Results indicate that the movement of bromide relative to that of nitrate (0.005N salts) is identical in subsoils but variable in surface soils. Differences in relative movement of the two anions may be attributed to microbial activity involving nitrate. With the exception of 5% anion sorption in a Greenville subsoil, anion exclusion values ranged from 5 to 39%, indicating the anions were moving 1.05 to 1.64 times as fast as they would if they had been uniformly associated with all the soil water. The results support the view that bromide has utility for following the potential path of nitrate movement through soils.
Plant Uptake of Cadmium as Influenced by Cation Exchange Capacity, Organic Matter, Zinc, and Soil Temperature
Authors: Haghiri F.
Published: July 2010

The effects of several soil factors on cadmium (Cd) accumulation by plants were determined. Cadmium concentration in oat shoots (Avena sativa L.) was decresaed by increasing the cation exchange capacity (CEC) of the soil. Except for its CEC effect, organic matter did not influence the concentration of Cd in oat shoots. The results indicate that the retaining power of organic matter for Cd is predominately through its CEC property rather than chelating ability. Cadmium concentration of soybean shoots (Glycine max L.) increased with increased soil temperature. In the presence of 10 ppm of soil‐applied Cd, the addition of Zn from the 5 to 50 ppm range, apart from raising the Zn concentration, significantly increased the Cd concentration of soybean shoots. The increased Cd concentration was primarily due to decreased plant growth. A depression in Cd concentration of soybean shoots, relative to control, began to occur at the 100 ppm Zn level.
The Unreliability of Tile Effluent for Monitoring Subsurface Nitrate‐Nitrogen Losses from Soils
Authors: Thomas Grant W. , Barfield Billy J.
Published: July 2010

Investigation of a completely tiled field showed that only a small proportion of the total flow reaching the drainage ditch came from tile effluent. In two measurements, 63 and 89% of the flow to the drainage ditch came from seepage other than through tiles. The nitrate‐nitrogen concentrations in the tile effluent were far higher than those calculated in the nontile flow by mass balance. We conclude that nitrate‐nitrogen concentrations in tile effluents may not be reliable indicators of nitrate‐nitrogen losses from agricultural land, when the tiles do not intercept all subsurface flow.
Nutrient Losses from Fertilized Grassed Watersheds in Western North Carolina
Authors: Kilmer V. J. , Gilliam J. W. , Lutz J. F. , Joyce R. T. , Eklund C. D.
Published: July 2010

The transport of plant nutrients in drainage waters from two steeply sloping, differentially fertilized, grassed watersheds located in western North Carolina was determined over a 4‐year period. Watershed No. 1 has a drainage area of 1.89 ha, No. 2, 1.48 ha. The dominant slopes on both watersheds are 35 to 40%. During this period, watershed No. 1 received a total of 112‐48‐24 kg N‐P‐K/ha; watershed No. 2 received 448‐192‐24 kg N‐P‐K/ha.

Average annual measured N losses were 3.28 and 12.08 kg/ha for watershed No. 1 and watershed No. 2, respectively; NO3‐N comprised 70% and 85% of the total N lost in discharge waters from the two watersheds. Total N lost over the 4‐year period from each watershed was 6 to 10% of the fertilizer N applied.

Annual P losses were negligible, amounting to 0.15 kg/ha from watershed No. 1 and 0.27 kg/ha from watershed No. 2.

Measured K losses averaged 3.99 and 5.83 kg/ha annually; S losses were 1.92 and 2.54 kg/ha from watershed No. 1 and watershed No. 2, respectively.

Additional nutrient losses likely occurred because of deep seepage and an estimate of these losses was made.

Losses of all nutrients were highest during the winter and spring months. Concentrations of nutrients in discharge waters from watershed No. 2 were consistently higher compared with watershed No. 1. However, NO3‐N concentrations exceeded 10 ppm on watershed No. 2 only once during the 4‐year period.

The authors conclude from this study that steeply sloping pastures, judiciously fertilized, are not an important source of nutrients occurring in surface and ground waters.
Columns Representing Mound‐Type Disposal Systems for Septic Tank Effluent: I. Soil‐water and Gas Relations
Authors: Magdoff F. R. , Bouma J. , Keeney D. R.
Published: July 2010

Columns were designed to represent the vertical dimensions of a mound‐type disposal system for receiving septic tank effluent on problem soils. The columns were filled with gravel (representing creviced bedrock), silt loam (representing the original topsoil), a sand or sandy loam till (fill material), gravel (the seepage bed), and another layer of silt loam (the mound cover). The columns were dosed with septic tank effluent at the rate of 2 cm every 6 hours. Until crusting caused permanent ponding at the fill‐gravel interface, the fill was aerobic and the silt loam at the bottom of the column was anaerobic. Redox potentials were higher in the fill (350 to 600 mV) than in the silt loam (200 to 410 mV). Moisture tension fluctuations after a 2 cm addition were greatest near the fill‐gravel interface and decreased with depth in the column. After continuous ponding, tension fluctuations almost ceased, the subcrustal soil became anaerobic, and the redox potentials decreased to around −250 mV. In a separate experiment, simulating field conditions, aerobic conditions were maintained in the subcrustal fill, by perforating column walls. The moisture tension regime and the rate of crust formation were similar to nonperforated columns.
Nitrogen Movement Resulting from Surface Application of Liquid Sewage Sludge
Authors: King Larry D. , Morris H. D.
Published: July 2010

One of the factors limiting the rate at which sewage sludge can be applied to soil is the speed at which inorganic N is formed and the fate of that inorganic N. A greenhouse lysimeter study was initiated in order to quantify some of the sinks into which N from sludge applications might move. For 12 weeks soil columns were treated at 3‐week intervals with a surface application of 2.5 cm of liquid sewage sludge. During each 3‐day interval 2.5 cm of water was applied to: (i) soil receiving no sludge (Soil‐2.5), (ii) soil receiving sludge (Sludge‐2.5), and (iii) soil planted to Coastal bermudagrass (Cynodon dactylon L. Pers.) receiving sludge (Grass‐2.5). Five centimeters of water was added to soil + grass + sludge (Sludge‐5) during each 3‐day interval. Another treatment was used to encourage a nitrification‐denitrification cycle. This treatment (Grass‐F) was identical to Grass‐2.5 except that during each third week sufficient water was added to bring the 3‐week total to the same as that in Grass‐5. Provisions were made to collect the leachate for NO3‐N analysis and to measure NH3 volatilization from the sludge.

The average loss of N as NH3 was 36% of the applied NH4‐N in the Soil‐2.5 treatment and 24% in the three grass treatments. This represented 4.9 and 3.3%, respectively, of the total N applied. The Grass‐5 treatment resulted in the maximum NO3‐N leaching loss (5.4% of the applied N). The Grass‐F treatment did not result in reduced NO3‐N leaching. Grass removed 10.3% of the applied N. From 52 to 64% of the applied N remained in the sludge crust on the soil surface.
Lead, Cadmium, and Calcium Selectivity Coefficients on a Montmorillonite, Illite, and Kaolinite
Authors: Bittell J. E. , Miller Raymond J.
Published: July 2010

Selectivity coefficients for Pb2+, Cd2+, and Ca2+ exchange adsorption with montmorillonite, illite, and kaolinite clays were determined over a wide range of clay surface concentration and found constant. The average selectivity coefficients describing the ion distributions for montmorillonite, illite, and kaolinite, respectively, were 0.60, 0.44, 0.34 for Pb‐Ca exchange, 1.04, 1.01, 0.89 for Cd‐Ca exchange and 0.58, 0.56, 0.31 for Pb‐Cd exchange. Whereas Cd2+ may compete more or less on an even basis with Ca2+ for clay adsorption sites, the adsorption of Pb2+ would be favored by a factor of 2 or 3 over Ca2+.
The Effect of Large Applications of Manure on Movement of Nitrate and Carbon in an Irrigated Desert Soil
Authors: Meek B. D. , MacKenzie A. J. , Donovan T. J. , Spencer W. F.
Published: July 2010

Feedlot manure was applied in the field at rates of 0, 45, 90, 180, and 360 metric tons/ha to a Holtville clay under irrigated conditions. Holtville clay is a soil with restricted internal drainage. Ceramic cups were installed at various depths in the soil profile to monitor the movement of manganese, nitrate, and soluble organic carbon.

The manure greatly increased the amount of soluble organic carbon in the soil solution. An increase in the manure application rate to 180 or 360 metric tons/ha increased the nitrate in the soil solution at 20 and 40 cm, but there were only small differences at 80 and 140 cm. The lack of movement of nitrate to the 80‐cm depth for the high rates of manure application appeared to be due to denitrification, because high nitrate levels were present in the surface soil and sufficient water was applied to leach to this depth. Nitrate leaching was less when manure was applied annually than when it was applied only the first year. Less movement of nitrate to the 80‐cm depth in treatments receiving manure annually seems to be the result of denitrification caused by the higher level of soluble organic carbon. The application of manure did not result in reducing conditions at 20 cm under regular irrigation as measured by redox potential, but the double irrigation schedule caused soil reducing conditions at 20 cm. At 80 cm, manganese in the soil solution was inversely correlated to nitrate level.
Changes in the Rhizosphere Effect of Millet Associated with Sprinkler Irrigation with Animal Wastes
Authors: Dazzo Frank B. , Smith Paul H. , Hubbell David H.
Published: July 2010

The microbial population changes in Scranton fine sand and adjacent millet rhizospheres resulting from sprinkler irrigation with cow manure slurry were investigated. Increasing the rate of irrigation with manure slurry resulted in a decline in the R/S ratio of ureolytic, proteolytic, amylolytic, and lipolytic microorganisms. A nutritional grouping study of the predominant bacteria indicated a significant increase in incidence of bacteria requiring amino acids and a decrease in incidence of bacteria requiring soil extract within non‐rhizosphere soil receiving manure applications. These findings, in addition to observed declines in the R/S ratio of microorganisms within soil receiving waste, are taken as evidence that the microbial environment created by irrigating Scranton fine sand with animal waste slurry may become similar to the microbial environment created by the roots of millet.
Column Studies of Soil Clogging in a Slowly Permeable Soil as a Function of Effluent Quality
Authors: Daniel T. C. , Bouma J.
Published: July 2010

Clogging as a function of effluent quality was investigated in cores of the very slowly permeable Almena silt loam soil which offers problems for conventional on‐site liquid waste disposal. Undisturbed 60 cm long cores were subjected for approximately 120 days to constant ponding with simulated septic tank effluent, extended aeration effluent and distilled water. Column influents and effluents were monitored with respect to chemical oxygen demand (COD), biochemical oxygen demand (BOD), and solid residue fractions. Column influents differed markedly in COD and BOD content but column effluents had consistently low contents indicating the high renovative capacity of the soil. In situ tensiometric, redox, and flow rate measurements indicated development of the most severe barriers to flow in columns ponded with low BOD aerated effluent, followed closely by those ponded with high BOD septic tank effluent. No barriers developed in columns ponded with water. Total concentrations of solid residue fractions in the two effluents and the cumulative load of solids applied to the columns did not differ significantly, but particle sizes in the aerated effluent were smaller. Increased pore clogging in aerated influent treatments points to the significant role of effluent solids in the clogging process in slowly permeable clayey soils. Additional studies are in progress to better define critical waste characteristics as related to soil clogging.
Microbial Activity in Soils Treated with Acephate and Monitor
Authors: Focht D. D. , Joseph H.
Published: July 2010

A Hanford loamy sand, a Domino silt loam, and an Altamont clay loam were treated separately with three repeated applications (20 ppm) of the organophosphate insecticides, acephate (O,S‐dimethyl acetylphosphoramidothioate) and Monitor (O,S‐dimethyl phosphoramidothioate) over a 50‐day time span. Population levels of actinomycetes, bacteria, and fungi were not substantially affected by the addition of either pesticide. Neither could a marked effect be shown upon ammonification, nitrification, sulfur oxidation, or respiration rates. Replica plating failed to isolate bacteria from soils that were adversely affected by either pesticide. It is concluded that neither acephate nor Monitor had any adverse effect upon soil microorganisms.
Plant Nutrient Losses from Tile‐Outlet Terraces
Authors: Hanway John J. , Laflen John M.
Published: July 2010

Plant nutrient losses in runoff water from four tile‐outlet terrace systems in Iowa and in tile drainage from two of the systems were measured annually from April to November over a 3‐year period. Total P losses in surface runoff varied from 0.44 to 1.06 kg/ha and, at any one location, were highly correlated with sediment losses. Average annual concentrations of total P in surface runoff ranged from 1.01 to 3.60 ppm and in tile drainage from two sites were 0.028 and 0.061 ppm. Soluble P concentrations in surface runoff were related to available P in the surface soils, and concentrations in tile drainage were related to available P in the subsoils. Annual average inorganic P concentrations in surface runoff varied from 0.013 to 0.204 ppm and in tile drainage were 0.004 and 0.018 ppm. Concentrations of inorganic N varied widely among locations, but were relatively constant at a location. Average annual inorganic N concentrations in surface runoff were 4 ppm or less at three of the four sites and 11 ppm at one site. Concentrations of inorganic N and sulfate S were similar and were lower in surface runoff than in tile drainage. There was no relation between the amounts of fertilizer applied and plant nutrient losses or concentrations in runoff or drainage water.
Application of Municipal Refuse and Liquid Sewage Sludge to Agricultural Land: I. Field Study
Authors: King Larry D. , Rudgers L. A. , Webber L. R.
Published: July 2010

The feasibility of using land for both waste disposal and crop production was studied by applying pulverized municipal refuse and liquid sewage sludge or liquid manure to land which was later planted to rye (Secale cereale L.) and subsequently to corn (Zea Mays L.). Refuse was applied at 188 metric tons/ha singly (R) or in combination with either 2.3 cm of liquid sewage sludge (RS) or 1.4 cm of liquid poultry manure (RM). Other treatments were a double waste rate—376 tons/ha of refuse + 4.6 cm of sludge (2[RS]), sludge alone (S), and a control (C) receiving no additions.

Yield of rye forage was not affected by treatment. Highest corn grain yields were obtained with the R treatment while yields with the S and 2(RS) treatments were significantly lower than yields with R. No treatments resulted in corn yields significantly different from the control treatment. Levels of Zn, Cu, Cd, and Pb in the rye and corn tissue were usually increased by waste additions but were below levels toxic to the crops or to animals that might consume the crops. Soil nitrate was increased by the various waste treatments. A considerable fraction of the nitrate lost from the soil profile during the winter could not be attributed to crop uptake.
Precipitation Nitrogen Contribution Relative to Surface Runoff Discharges
Authors: Schuman G. E. , Burwell R. E.
Published: July 2010

Ammonia and nitrate concentrations in precipitation and surface runoff from two adjacent watersheds, fertilized at 168 and 448 kg N/ha, respectively, were studied to determine the relative contribution of precipitation N in relation to surface runoff N discharge. The data show that 69% of the N discharged by surface runoff from the sampled events could be accounted for by precipitation‐originated N on the watershed fertilized at 168 kg N/ha, whereas 53% of the N discharged from the watershed fertilized at 448 kg N/ha could be attributed to N originating in the precipitation. However, the data indicate that, on an annual basis, the surface runoff N discharge accounts for only 20% of that in the total incoming precipitation. This difference can be accounted for by precipitation intensity or duration that did not cause runoff, absorption of NH4‐N by the soil material, or leaching of NO3‐N into the soil profile.
Some Effects of Beef‐Feedlot Effluent Applied to Forage Sorghum Grown on a Colo Silty Clay Loam Soil
Authors: Sukovaty J. E. , Elliott L. F. , Swanson N. P.
Published: July 2010

Beef‐feedlot effluent and water additions to a forage sorghum [Sorghum bicolor (L.) Moench] were compared for two consecutive growing seasons. Applications of each at 2.5 and 5.0 cm/week were made in 1971 and 1972 for 11 and 10 weeks, respectively.

The 2.5‐cm/week effluent application produced the highest forage yield in both years of the study, with the yield being significantly higher in 1972. In 1972, the lower 30 cm of the forage stalks (butts), receiving 5 cm of effluent/week, showed significantly greater NO3‐N than the other treatments. The application of beef‐feedlot effluent did not affect the concentrations of Ca, Mg, Na, and K in the forage during the 2‐year study.

After 2 years of effluent application at 5.0 cm/week, available P in the top 10 cm of soil increased from 52 to 118 ppm; soil pH increased from 6.2 to 6.6. Electrical conductivity changes were not significant. Soil solution samples collected from plots receiving the effluent treatments showed only small increases in Ca, Na, and K, 60 cm below the soil surface. Soil solution NO3‐N was higher beneath the plots receiving 2.5 cm effluent/week than beneath the 5.0‐cm effluent/week treatment.
Foliar‐Applied Nitrogen for Citrus Fertilization
Authors: Embleton T. W. , Jones W. W.
Published: July 2010

Fifty‐six “experiment‐years” of citrus data are presented which show that kilogram for kilogram, foliar‐applied N was as effective as soil‐applied N for fruit production. However, while one annual soil application sufficed to supply adequate N, three to six or more foliar sprays per year were required. “N‐production efficiency” (kg fruit produced per kg applied N) varied from 97 to 484. At or near the maximum nutritionally‐attainable yield, “fruit‐N‐removal efficiency” (kg N removed in fruit per kg applied N × 100) varied from 11 to 75%. The kg of N per 1,000 kg of fresh California citrus fruit varied from 1.15 to 1.73 and increased with increasing N rates.
Computer Modeling of Nitrogen Transformations in Soils
Authors: Mehran Mohsen , Tanji Kenneth K.
Published: July 2010

A nitrogen‐transformation model was formulated for simultaneous computation of various N transformations: nitrification, denitrification, mineralization, immobilization, ion exchange, and plant uptake. These processes were assumed to obey first‐order kinetics. Differential equations that describe the above processes are solved simultaneously by using the 4th‐order Runge‐Kutta method and the Adams‐Bashforth‐Moulton predictor‐corrector equations. The computer model was tested against data reported from several incubation studies. This model could be linked to a transport model to predict the temporal and spatial distribution of various N species in soil profiles.
Nitrate and Chloride Leaching in a Swelling Clay Soil
Authors: Kissel D. E. , Ritchie J. T. , Burnett Earl
Published: July 2010

Leaching losses of applied NO3−‐N and Cl− from a swelling clay soil were measured using an undisturbed field drainage lysimeter. Nitrate‐N and Cl−, applied at 110 and 279 kg/ha, respectively, were detected in drainage water collected at a depth of 125 cm after the first large rainstorm. Applied fertilizer was leached when percolating rainwater carried the applied materials through large connected pores, bypassing other soil water inside soil structural units. Even though applied fertilizer began to be lost with the first rainstorm, concentrations of NO3−‐N and Cl− were not high until large amounts of water had drained below the root zone. For example, Cl− concentrations during the first 25 mm of drainage increased by about 7 ppm. The greatest increase in Cl− concentration did not occur until 60 mm of drainage accumulated after fertilizer application.

Much more native soil nitrate was leached than soil nitrate concentrations in unfertilized plots would have indicated. The data indicate that leaching losses of nitrate from mineralization may be greater than those of applied nitrate when accumulated drainage is <50 mm following fertilizer application.
Nitrate Removal from Floodwater Overlying Flooded Soils and Sediments
Authors: Engler R. M. , Patrick W. H.
Published: July 2010

The floodwater NO3− removal rate of intermittently‐flooded fresh water swamp soils and continuously‐flooded saline marsh soils of southern Louisiana was quantitatively characterized in a laboratory study. Of the two areas studied, the marsh area was the more effective sink for NO3− contaminated waters with an average initial removal rate of 9.15 ppm N/day. After correcting for the rate of NO3− diffusion, the microbial NO3− removal rate was calculated to be 7.64 ppm N/day. The swamp soil had a removal rate of 4.38 ppm N/day. The microbial NO3− removal rate for this area, after correcting for diffusion, was 2.50 ppm N/day. Studies on samples of floodwater separated from the soil showed the active site of microbial NO3− reduction to be the soil‐water interface or within the soil, but not in the floodwater. Additions of organic matter to a mineral soil flooded for rice (Oryza sativa L.) culture decreased the thickness of the aerobic‐anaerobic zone at the soil‐water interface and increased the rate of NO3− reduction.