bluuebunny/crossref_metadata_2025 huggingface dataset:
Soil Temperature and Sewage Sludge Effects on Corn Yield and Macronutrient Content
Authors: Sheaffer C. C. , Decker A. M. , Chaney R. L. , Douglass L. W.
Published: July 2010

Availability of plant nutrients and subsequent plant growth are influenced by sewage sludge loading rates and soil temperature, but published information on the interaction of these two factors is limited. Corn (Zea mays L.) was grown in a sandy Typic Hapludult soil amended with 0, 56, or 112 metric tons/ha of anaerobically digested sewage sludge in field experiments during 1975 and 1976. Soil temperature regimes of 16, 27, 35°C or ambient (x̄ = 22°C) were applied to plots each year from planting to harvest. The objective of this research was to evaluate the effect of soil temperature on sewage sludge nutrient release for corn growth.

Increases in soil temperature increased germination and maturation rates of corn. A 16°C soil temperature significantly decreased stover and grain yields both years. In 1975, temperatures above ambient did not result in higher grain or stover yields, but in 1976 grain and stover yields increased as soil temperature rose to 35°C.

Sewage sludge application had no significant effect on 1975 stover yield, but at a 16°C soil temperature grain yields were significantly higher for the 112‐metric tons/ha sludge plots. In 1976, when pH and soil fertility of check plots had declined, check plots had significantly lower grain yields than sludge‐amended plots at all soil temperatures. Stover yields from 112‐metric tons/ha sludge plots were significantly higher than for check plots at all soil temperatures except 16°C.

Nitrogen, P, and K levels in corn ear leaves were higher at 35 than 16°C in both years, but Ca was lower. Higher ear leaf levels of N, P, Ca, and Mg occurred with 112 metric tons/ha sludge than the check in both 1975 and 1976.
Effect of Crushed Limestone Barriers on Chromium Attenuation in Soils
Authors: Artiole Juan , Fuller Wallace H.
Published: July 2010

The influence of agricultural limestone as a low‐cost landfill liner to retard the migration rate of Cr in municipal solid waste leachate through soils was studied. A limestone layer, 2 cm thick over a 10‐cm depth of soil in a column, delayed the breakthrough concentration (C/Co = 1.0) of the Cr in the effluent manyfold over that without limestone. Crushed limestone was more effective in retaining the cation Cr(III) than the anion Cr(VI). Retention of Cr(III) in soils due to the presence of a limestone liner is much greater than that for other metals tested (Be, Cd, Fe, Ni, and Zn). There appears to be a combined influence on the retention of Cr between the limestone liner and soil not apparent when municipal leachate was passed through the limestone barrier and soil independently. Usefulness of limestone (ranging up to 16% at breakthrough concentration) depends primarily on the pH and volume of the solution passed through the limestone.
Organic Matter Decomposition in a Soil Heavily Amended with Poultry Manure
Authors: Weil R. R. , Kroontje W.
Published: July 2010

A Davidson clay loam (Rhodic Paleudult) was planted to maize annually and amended with poultry manure at the rates of 0, 27, 54, 85, and 110 metric ton ha−1 year−1 for 5 years. In the fifth year soil organic matter content, microbial respiration, and leaf decomposition were studied to determine how these applications of poultry manure had affected the organic matter‐assimilating capacity of the soil.

In early May soil organic matter in the top 8 cm of the unmanured controls and the most heavily manured plots were 2.8 and 7.25, respectively. By November the latter value had dropped to 5.4% while the former remained unchanged. At the 28‐ to 36‐cm depth, well below the depth of tillage, organic matter averaged over all treatments increased from 0.70% in April to 1.16% in September, possibly due to leaching and earthworm activity.

Microbial respiration, as indicated by CO2 evolved from soil samples taken in November and incubated at 28°C, increased from 0.02 mg C g−1 in the unmanured soil to 0.101 mg C g−1 day−1 at the 85 metric tons ha−1 year−1 rate. However, at the highest rate of manure soil respiration dropped to 0.069 mg C g−1 day−1.

Disappearance of maize leaf pieces from litter bags with mesh openings of 0.02, 0.1, 1.0, and 7.0 mm was initially retarded in the manured plots. However, the total amount of leaf disappearance was generally greater in the 1.0‐ and 7.0‐mm mesh bags than in the 0.02‐ and 0.1‐mm mesh bags, indicating a significant contribution by the meso‐ and macrofauna in the soil. The manure treatments increased the numbers of mites (Acari) and springtails (Collembola) by two orders of magnitude, but greatly reduced the diversity of the soil arthropod community.

The overall ability of the soil to accept and dispose of the poultry manure did not appear to be seriously impaired even at high rates of manure application for it was estimated that only 7% of the 393 metric tons of organic matter added per ha remained in the plowlayer after the 5‐year period.
A Mass Balance Study of Application of Municipal Waste Water to Forests in Michigan
Authors: Burton Thomas M. , Hook James E.
Published: July 2010

A mass balance study of the effects of secondary municipal waste water on phosphorus and nitrogen cycling was conducted in 1976 and 1977 on three 1.2‐ha plots in a late successional, sugar maple (Acer saccharum Marsh.)‐beech (Fagus grandifolia Ehrh.) forest in southern Michigan. The treatments included an unirrigated control plot and 5‐ and 10‐cm/week waste water application plots. The 10‐cm/week site was deliberately overloaded hydraulically. Chloride concentrations at the 150‐cm depth on the waste water application plots did not approach input concentrations until the end of the 1976 irrigation season. Thus, 1977 data are emphasized in mass balance calculations. About 96% of the added inorganic nitrogen from 5 cm/week of waste water application leached past the root zone. Application of 10 cm/week waste water increased inorganic nitrogen “retention” on a mass balance basis to 69% of input apparently as a result of denitrification under anaerobic conditions in the water‐logged soils. However, the 10‐cm/week application resulted in nitrate concentrations approaching those of waste water input concentrations during peak runoff periods. The 10‐cm/week application also resulted in death of trees in the lower areas of the forest where water tended to pool. Phosphorus retention by the system was 96.5% at an application rate of 5 cm/week but decreased to 66% when the irrigation rate was increased to 10 cm/week as a result of runoff losses. Changes in soils included increased available phosphorus and exchangeable magnesium and potassium in the top 15 cm of soil and increased sodium and chloride concentrations throughout the 150‐cm depth sampled.
Runoff Losses of Surface‐Applied Herbicides as Affected by Wheel Tracks and Incorporation
Authors: Baker J. L. , Laflen J. M.
Published: July 2010

The effects of incorporation and wheel‐track compaction on runoff losses of herbicides were determined by measuring losses of propachlor (2‐chloro‐N‐isopropylacetanilide), atrazine [2‐chloro‐4‐(ethylamino)‐6‐(isopropylamino)‐s‐triazine], and alachlor [2‐chloro‐2′,6′‐diethyl‐N‐(methoxymethyl) acetanilide] in water and sediment from small plots during 122 mm of simulated rainfall. Losses of propachlor, atrazine, and alachlor that were surface‐applied to plots without wheel tracks were 3.0, 4.7, and 8.0%, respectively. Corresponding losses from plots where the herbicides were incorporated by disking were only 0.8, 1.6, and 1.7%. Hydrologic differences (more and sooner runoff) caused by wheel tracks on plots where herbicides were surface‐applied increased the corresponding losses to 12.7, 18.3, and 22.1%. Although herbicide concentrations were greater in sediment than in water for all treatments, from 82 to 89% of the losses were in solution.
Soil Lead Accumulation Alongside a Newly Constructed Roadway
Authors: Milberg Ronald P. , Lagerwerff John V. , Brower Donald L. , Biersdorf George T.
Published: July 2010

Accumulation of lead (Pb) in soil along a new north‐south section of Interstate 95 at Beltsville, Md., was monitored annually between 1971 and 1977. The increase in Pb content of the top 10 cm of soil was closely correlated with cumulative leaded fuel‐burning traffic. Of the Pb accumulated between 8 and 50 m from the highway, between 95 and 98% was found within the 8‐ to 25‐m region. Within this zone, the accumulation rate was estimated to be 0.85 ± 0.16 µg Pb/g soil per 106 leaded fuel‐burning vehicles at the 90% confidence level. Accumulation rates at 8 m from the highway were 1.04 ± 0.26 µg Pb/g soil per 106 vehicles on the west or upwind side and 2.06 ± 0.73 at 8 m on the east or downwind side. Although the fraction of traffic burning leaded fuel decreased from an estimated 94% in 1971 to 73% in 1977, the decline was offset by the increased average daily traffic on the highway and no significant decrease in the rate of Pb accumulation was found through 1977.
Effects of Slash Burial on Stream Water Quality
Authors: Larson A. G. , Wooldridge D. D.
Published: July 2010

A 3‐year study investigated impacts of buried logging residue on stream water composition. Burying of logging slash has been proposed as an alternative to burning. Residue was buried in trenches adjacent to two small ephemeral streams; one trench was filled with approximately 180 m3 of logging slash, the other with 94 m3 of mill residue. Streamflow was diverted to flow through the burial pits.

Stream water samples collected from above (pretreatment) and below (post‐treatment) the burial sites were analyzed for dissolved oxygen, pH, electrical conductance, alkalinity, temperature, K, Na, Ca, Mg, Fe, NO3‐N, NH4‐N, SO4‐S, PO4‐P, total N, and total P. Changes in chemical composition occurring between pre‐ and post‐treatment sampling sites were tested for significance using a paired sample t test.

With the exception of dissolved oxygen, surface water degradation resulting from burial was of no practical importance. Many ions decreased in concentration as waters passed through buried residue. Statistical comparisons of pre‐ and post‐treatment water composition indicate significant increases were limited to H; pH decreased from 6.56 to 6.42 as a result of the buried slash. Oxygen depletion may be the most serious burial effect, with mean concentrations in the buried slash stream decreasing from 10 to approximately 8 mg/liter, a drop in oxygen saturation from 93 to 71%.
Efficiencies of Extractants Used in Analyses of Heavy Metals in Sludges
Authors: Neuhauser E. F. , Hartenstein R.
Published: July 2010

A comparison of extractability was made for three solvents commonly used in estimating availability of heavy metals in soils to living plants. Small, intermediate, and large amounts of heavy metals were removed, respectively, from an anaerobic digest of a sewage sludge with 2.5% acetic acid, 0.1N HCl, and 1.0N HCl respectively. With 10, 20, 30, and 40 ml 1N HCl per g sludge, approximately the same amount of each heavy metal was extracted during 1 hour of shaking, while for 0.1N HCl and 2.5% acetic acid increasing amounts were extracted at 10, 20, and 30 ml/g, with somewhat higher or lower amounts being obtained at a ratio of 40 ml extractant per g sludge. With 0.1N HCl, an extraction period of 0.5 hour appeared to be sub‐optimal, while periods longer than 1 hour did not yield significantly greater extractability except for Cd, extracted for 3 hours. Extraction of Ni for 5 hours and Pb for 5 or 7 hours resulted in significantly less metal than was obtained at 1 hour. Since it is highly likely that availability of heavy metals to plants will depend on numerous and unpredictable variables, it is proposed that until such factors are resolved, a standard extraction procedure be used by all workers on sludges and soils. This would provide a basis for comparisons of published data.
Simulated Forest Response to Chronic Air Pollution Stress
Authors: West D. C. , McLaughlin S. B. , Shugart H. H.
Published: July 2010

A mathematical model (FORET) previously developed to examine the successional dynamics of eastern deciduous forests was applied to the study of long‐term interactions of air pollution stress and forest community dynamics. Differential levels of growth reduction (0, 10, and 20%) were applied to trees in three pollution sensitivity classes to simulate changes in biomass of both individual species and the entire forest stand. The response of individual species in a forest stand may differ markedly from results predicted on the basis of responses determined in the absence of plant competition. Some species may show growth enhancement in spite of pollutant stress, since they may gain a competitive advantage as a result of greater impacts on other species with which they interact in the successional process. Other species may experience much greater than anticipated beneficial or injurious impacts due to reduced competitive potential. The results presented are intended to stress important considerations to be addressed in predicting the response of a forest to stresses such as air pollution. Responses described are not intended to be final quantitative answers.
Geologic Nitrogen: A Potential Geochemical Hazard in the San Joaquin Valley, California
Authors: Strathouse Scott M. , Sposito Garrison , Sullivan P. J. , Lund L. J.
Published: July 2010

Nitrogen geochemistry was studied in two selected drainage basins of the Diablo Range, which is adjacent to the San Joaquin Valley in California. Cantua Creek Basin drains into alluvial soils which contain up to 2,000 mg/liter indigenous nitrate N in the soil solution. It represents a fairly complete stratigraphic section of Upper Cretaceous to Tertiary geologic sediments, dominated by fine‐grained mudrocks and shales. The Ortigalita Creek Basin drains into alluvial soils with low levels of indigenous nitrate. It contains an incomplete stratigraphic section dominated by Upper Cretaceous coarse‐clastic rocks with subordinate amounts of mudrocks, capped by Tertiary gravels and marls.

Total N concentrations in the Cantua Creek Basin geologic sediments ranged from a few µg/g to nearly 4,800 µg/g. Organic N was the major species in the Cretaceous sediments, reaching a maximum concentration approaching 1,200 µg/g. Nitrate N concentrations were always < 100 µg/g in the Cretaceous sediments, but approached 4,800 µg/g in a rock sample from a recent Tertiary unit. The total N and nitrate N concentrations increased from older to younger geologic sediments, while ammonium N concentrations varied from a few µg/g to 360 µg/g.

Organic N concentrations in the Ortigalita Creek Basin geologic sediments attained a maximum value of 500 µg/g and nitrate N concentrations there reached a maximum of 600 µg/g. However, the highest total N concentration of 2,000 µg/g occurred as 75% fixed and soluble‐exchangeable ammonium.

The contrast in concentrations and chemical species of nitrogen between the two basins was explained partially by sediment type. Organic matter is associated with fine‐grained sediments and, consequently, Cantua Creek sediments contain a higher portion of organic matter and a more available geologic source of nitrogen. On the other hand, the presence of high ammonium concentrations and a corresponding high‐charge smectite in the Ortigalita Creek Basin suggested that one of the principal sources of nitrogen in rocks from that basin was fixed ammonium bound to layer silicates.
Fertilizer Nutrient Losses from Rangeland Watersheds in Central Oklahoma
Authors: Olness Alan , Rhoades E. D. , Smith S. J. , Menzel R. G.
Published: July 2010

Four native grassland watersheds were monitored for nitrogen and phosphorus nutrient losses in surface runoff. The watersheds, paired in surface hydrology and grazing management, were 8 to 11 ha in area with 3% slopes. One watershed of each pair was fertilized with 85 kg N/ha (as NH4+‐N) and 75 kg P/ha surface broadcast. Ten 3.66 by 5.49 m (20 m2) areas within each watershed were covered with plastic sheets during fertilization to provide unfertilized check plots. Fertilizer losses in surface runoff over the first year were 5% or less of the amounts applied. Soluble NH4+‐N concentrations in surface runoff increased significantly only during the first month after fertilizer application. Soluble P concentrations increased sharply after fertilization and remained relatively high even after 12 mo. Forage yields were increased 50 to 100% on fertilized areas. Increases in nutrient uptake of fertilized vegetation the first year equaled 17 to 25.5 kg/ha and 7.5 to 11 kg/ha of the added N and P, respectively.
Adsorption‐Desorption of Diuron by Freshwater Sediments
Authors: Peck D. E. , Corwin D. L. , Farmer W. J.
Published: July 2010

Freshwater sediments were collected from eight different locations in California to study the influence of sediment properties on the adsorption and desorption of the model herbicide, diuron (3‐(3,4‐dichlorophenyl)‐1,1‐dimethylurea). The sediments were characterized as to physical and chemical properties using the same methods used for soils. The sediments had a range of organic carbon of 0.91 to 19% and were high in silt and clay. The adsorption of diuron was described by the Freundlich equation. Adsorption at 25°C expressed as the Freundlich coefficient, k, was positively correlated to the amount of organic carbon present. There was no correlation with total CEC. The desorption of diuron was evaluated by taking the difference between the slopes of the adsorption and desorption isotherms. As the difference between these slopes increased, less diuron was desorbed. These differences were positively correlated to k and organic carbon. Adsorption at temperatures of 5, 25, and 40°C on three sediments indicated that the adsorption of diuron decreased as the temperature increased.
The Role of Forest Vegetation in the Biogeochemical Cycle of Heavy Metals
Authors: Heinrichs H. , Mayer R.
Published: July 2010

Concentration of the heavy metals Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd, and Pb was measured in different compartments of vegetation and soil in a beech (Fagus silvatica) and a spruce (Picea abies) forest and the inventory of these elements was calculated. During a period of 3 years the heavy metal concentration in precipitation and soil water fluxes below tree root zone was determined and total element fluxes were calculated.

Annual input from the atmosphere is small (≤30%) for the metals Cr, Mn, and Ni when compared to the amounts stored in the annual increment of biomass. The percentage is higher for Fe (40 to 60%). Uptake of these metals must be supplied partly by weathering of soil minerals. Accumulation of Cu in biomass is completely accounted for by atmospheric input. Total uptake of Co, Zn, Cd, and Pb into the cycling fraction (leaves, needles) and the noncycling fraction (wood) can be accounted for or is exceeded by atmospheric input. Air pollution from industry, home firing, and motor vehicles is the probable source.

Biomass contained up to 27% of total Cd in the ecosystem, but only about 8% of Cu, 2 to 5% of Ni, Zn, and Mn, about 1% of Pb and Cr, and <0.3% of Fe and Co. Accumulation of Pb, Fe, and Co is very strong in the organic surface layer which contains up to 180 times the amount of metal reaching soil as annual litterfall, but only 3 times the amount of Mn, indicating a fast release of the metal by decomposition of organic matter.
Estimation of the Salt Burden of Irrigation Drainage Waters
Authors: Jury W. A. , Pratt P. F.
Published: July 2010

The problem of predicting salt concentrations and mass emissions below irrigated fields is studied with three models, ranging from an inert proportional model frequently used by water quality regulatory agencies, to steady state and transient models which include chemical reactions as well as salt transport. Calculations of salt movement are made for four waters and three leaching fractions, for depths up to 450 cm below the surface.

Results suggest that the proportional model will overestimate salt burden for waters which tend to precipitate Ca2+‐salts and will underestimate the salt burden of waters which tend to dissolve native CaCO3 in the soil. The extent of the error is a function of the leaching fraction (LF) and the irrigation water composition. The steady state model, which does not consider ion exchange, predicts a greater tendency toward mineral dissolution than occurs when Ca2+ ions are brought into solution through ion exchange, but calculates a more accurate salt balance than the proportional model. For instance, with a saline irrigation water at a LF = 0.1, the steady state and transient model mass emission predictions were 22 and 36% less, respectively, than the estimates of the proportional model. At the other extreme, with a high‐quality irrigation water at a LF = 0.4, the mass emission predictions of these two models were 198 and 201% higher, respectively, than the predictions of the proportional model.

The transient stage of salt movement was found to persist until Mg2+ had reached steady state, which required about 12 years/m at a moderate leaching fraction of 0.25. It was concluded that the steady‐state and proportional models are not appropriate for estimating the salt burden of irrigated fields on underlying ground water.
Coastal Bermudagrass Yield and Soil Properties as Affected by Surface‐Applied Dairy Manure and its Residue
Authors: Lund Zane F. , Doss Basil D.
Published: July 2010

Land spreading of animal manure is a common practice for waste disposal and plant nutrient utilization, but it may cause problems by polluting runoff and ground water. Field experiments were conducted on two soils: Dothan loamy sand (Plinthic Paleudults) and Lucedale fine sandy loam (Rhodic Paleudults). Dairy manure was surface‐applied for 3 years as a solid at rates of 45 and 90 metric tons ha−1 year−1 and as a liquid at rates of 45, 90, and 135 metric tons ha−1 year−1, dry wt basis. Check plots received N, P, and K at the rates of 470, 225, and 470 kg ha−1 year−1 from mineral fertilizer. The effects of manure on soil properties and on period of time coastal bermudagrass [Cynodon dactylon (L.) Pers.] responds to residue were determined. Residue from the manure 3 years after the final manure application with no additional fertilizer was still producing considerably higher yields of coastal bermudagrass on both soils than on the check plots at the beginning of the residual phase of study. Yields were higher the third year on the Dothan than on the Lucedale soil, but organic N was higher in the forage from the Lucedale soil. Nitrogen was one of the most limiting factors of production on both soils by the end of three cropping seasons.

Additions of manure increased K, Mg, and pH in the subsoil, and the increase was still evident after three cropping seasons. There was also some downward movement of P, but less than there was of the other elements. There was more movement of all ions in the sandier Dothan soil than in the Lucedale soil.

Projection of the loss of organic N in the surface soil indicated that residue would be negligible 45 to 55 months after applications ceased.
Effect of Antibiotics in Beef Cattle Feces on Nitrogen and Carbon Mineralization in Soil and on Plant Growth and Composition
Authors: Patten D. K. , Wolf D. C. , Kunkle W. E. , Douglass L. W.
Published: July 2010

The potential human health hazard associated with the use of antibiotics in animal feeds is currently being reevaluated by the Food and Drug Administration. This study was conducted to investigate the impact of the addition of antibiotic‐containing feces on soil biological activity. A total of nine beef cattle were placed on either a control feed, or a feed supplemented with chlortetracycline (CTC) or oxytetracycline (OTC) for a period of 10 days. Feces from these cattle were collected and analyzed for chemical, physical, and microbiological properties. Samples of the feces were added to an Evesboro sandy loam at rates equivalent to 0, 9.4, and 18.8 dry metric tons/ha (0, 20, and 40 wet tons [U.S.]/acre). Carbon and nitrogen mineralization were studied in the soil‐feces system. Analyses of the feces indicated antibiotic‐related changes in several properties. Total nitrogen in the feces of cattle receiving OTC was, at 1.50%, significantly lower than the 1.74% level found in the feces of CTC fed cattle. Feces from cattle receiving OTC contained a higher concentration of potassium, more fungi, and fewer volatile solids than did wastes from control animals. Antibiotics in the feed had no effect on number of total bacteria, total and fecal coliforms, or fecal streptococci; concentration of NH4‐N, NO3‐N, P, Ca, Mg, Na, Zn, Mn, Fe, or Cu; pH; percent moisture; or chemical oxygen demand in the feces. The antibiotics CTC and OTC were found at levels of 5.3 and 11.3 µg/g, respectively, in the feces of cattle receiving the antibiotics. When added to the soil, feces from antibiotic‐fed cattle evolved approximately 20% more carbon than did control feces during a 70‐day period. Nitrogen immobilization occurred for 28 days following feces addition to the soil. No significant differences due to the use of feces from antibiotic‐fed cattle were observed in the rate of nitrogen mineralization in the soil during a 60‐day incubation. Greenhouse experiments using feces from antibiotic‐fed cattle as a soil amendment demonstrated no changes related to the antibiotics in the growth, yield, or elemental composition of 30‐day‐old corn seedlings (Zea mays L.).
Environmental Contamination Through Residual Trace Metal Dispersal from a Derelict Lead‐Zinc Mine
Authors: Johnson M. S. , Eaton J. W.
Published: July 2010

Studies of historical and current environmental problems in the vicinity of a derelict Pb‐Zn mine at Parc, near Llanwrst in North Wales, have shown that heavy metal dispersal occurs through contaminated mine drainage waters and episodal erosion of an unstable tailings dam.

Since the discontinuation of mining operations an estimated 13,000 metric tons of metalliferous spoil, equivalent to 43 metric tons Pb, 104 metric tons Zn, and 1 metric ton Cd, have been eroded from the main tailings dam. Dispersal by a tributary of the River Conwy and redeposition during flooding events has caused extensive contamination of lowland agricultural pastures. Streamwater pollution by tailings and dissolved metal salts in mine effluent continues to have a pronounced adverse effect on the flora and fauna of the tributary.

Under normal discharge conditions mean net transfer of metals into the main Conwy River approximates to 0.27 kg Pb, 15 kg Zn, and 0.1 kg Cd over 24 hours. However, because of the increased particulate load during surface drainage and flooding episodes, net dispersal increases unequally for the different metals, to a rate above that anticipated from discharge‐concentration relationships.

With a remaining deposit of 250,000 metric tons of mine tailings, tip stabilization measures have been initiated as a safeguard against further degradation of natural resources in the locality.
Effects of Water Quality on Forage Production
Authors: Zartman R. E , Miller T. D. , Goodin J. R. , Gichuru M.
Published: July 2010

Field studies were conducted during a 4‐year period to determine the influence of water quality on forage production. Three levels of blow down water (used to cool the electrical generating facility) (EC = 12 mmhos/cm, SAR = 11) and city water (EC = 1.5 mmhos/cm, SAR = 4.3) were used to irrigate alfalfa (Medicago sativa L.) and fourwinged saltbush [Atriplex canescens (Pursh.) Nutt.]. Forage stands were initiated in 1975 on a Friona fine sandy loam which is a fine‐loamy, mixed, thermic, Petrocalcic Paleustoll. Alfalfa yields responded positively to irrigation. The highest yield occurred in the high‐irrigation city water treatment followed by the high‐irrigation blow down water treatment. The medium‐irrigation levels produced intermediate yields, with the dryland production decreasing during the span of the experiment. Atriplex yields were not significantly affected by irrigation. There was no difference in forage production with respect to irrigation with either city or blow down water.

The results of this experiment indicate that both alfalfa and Atriplex can utilize blow down water as an irrigation water source. From a forage management perspective, however, there is a difference between the crops. Alfalfa responds to water additions with increased forage production, whereas Atriplex does not under these conditions.
Dye‐Sensitized Photooxidation of Bromacil in Water
Authors: Acher A. J. , Saltzman Sarina
Published: July 2010

Irradiation of an aerated bromacil (3‐sec‐butyl‐5‐bromo‐6‐methyluracil) aqueous solution (250 ppm), by exposure to direct solar radiation in the presence of different dye‐sensitizers and an appropriate pH, led to complete and fast photodecomposition of the title compound. The photoreaction mixture spotted on TLC showed one major intermediate, 3‐sec‐butyl‐2‐acetyl‐2‐hydroxy‐hydantoin. GLC showed another, minor, intermediate, the 5,5′‐dimer photo‐product of 3‐sec‐butyl‐6‐methyluracil. The most effective dye sensitizers checked were riboflavin (10 ppm) and methylene blue (2 to 5 ppm). Less effective were rose bengal (5 ppm), humic acids (20 ppm), and chlorophyll (20 ppm). The rate of reaction was pH dependent, being faster at alkaline pH and almost negligible in acidic solutions. Under optimal experimental conditions the photooxidation was completed after about 1 hour, and further irradiation resulted in the decomposition of the intermediate products and the formation of unidentified polar products.
Mineralization of Soil‐Incorporated Tomato Solid Waste
Authors: Timm H. , Flocker W. J. , Akesson N. B. , O'Brien M.
Published: July 2010

Solid waste from the processing of tomatoes (Lycopersicum esculentum Mill.) consisting primarily of fruit peels and seeds was incorporated into Yolo sandy loam soil, wetted, and incubated at 10, 20, or 30°C for 32 weeks. At 2‐week intervals the soil was analyzed for NO3‐N, PO4‐P, SO4‐S, Cl, total N, organic C, and exchangeable Ca, Mg, K, and Na. Soil pH and electrical conductivity were measured at the beginning of the study and after 32 weeks.

With each increment of dried tomato waste applied at rates of 2.5, 5.0, and 10.0% of air‐dry soil, the total organic C and N content of the soil increased. The amount of NO3‐N released from 2.5% rate of waste at 20°C soil temperature was similar to that released from 60 ppm N applied as (NH4)2SO4. Nitrogen released from waste applied at rates of 5.0 and 10.0% air‐dry soil exceeded the level of N usually applied for crop production at about 76 kg N/ha.

Significant interactions occurred on NO3‐N release among waste application rates, soil temperatures, and times. At 10°C, there was an increase in NO3‐N released with each increase in waste application. At 20°C, a NO3‐N increase occurred at 2.5 and 5.0% waste application rates, but the increase was less at 10.0 than at 5.0%. At 30°C, a marked reduction of NO3‐N release occurred between 16 and 32 weeks of incubation at all rates of waste application, but was more acute at 10.0% than at lower rates. A similar response, but of lesser magnitude, occurred with release of PO4‐P. Variability in release of NO3‐N and PO4‐P was attributable to the composition of tomato waste and to microbiological activity.

Release of SO4‐S was a function of waste loading rate and time. Essentially, all Cl was released within the first week of incubation. An appreciable increase of K, slight increase of Ca, minimal increase of Na, and no change of Mg was found in the soil after 32 weeks of incubation. Although tomato waste is acidic, soil pH decreased only at the highest loading rate after 32 weeks of incubation.
Use of Interfaced Gas Chromatography‐Mass Spectrometry for Detection of Concurrent Mineralization and Denitrification in Soil
Authors: Focht D. D. , Valoras N. , Letey J.
Published: July 2010

A method using an interfaced gas chromatograph‐mass spectrometer (GC‐MS) is described for measuring the amount of N2O and N2 derived during denitrification from tagged 15NO3− and from 14NO3−, the latter of which is produced during mineralization of soil organic matter. More mineralization and less denitrification was noted with the respective order related to air‐filled pore content: 10%, 5%, 0 (saturated). Denitrification measured directly from the cumulative emissions of N2O and N2 was considerably underestimated by comparison to measuring denitrification by loss of 15NO3−.
Gas Diffusion as a Factor in Laboratory Incubation Studies on Denitrification
Authors: Letey J. , Jury W. A. , Hadas Aviva , Valoras N.
Published: July 2010

Lack of nitrogen balance has been frequently observed in laboratory incubation studies on denitrification. Equations were developed for nitrogeneous gas diffusion from incubated soil cores. Calculations using the developed equations indicate that only a fraction of the produced nitrogeneous gases in the soil core diffuses into the incubation container and is measured. The fraction diffusing from the soil core increases as the soil air‐filled porosity increases and the adsorption coefficient between the gas and soil decreases. Under saturated soil conditions, only about 30% of the produced N2O is calculated to be evolved even if adsorption is zero for soil cores 2.5 cm deep. Furthermore, several days are required for produced N2O to evolve from the core after production ceases under saturated conditions. Similar results are calcualted for N2. Thus, nitrogen deficits can be explained by diffusion analysis which eliminates the need for a postulated unknown intermediate compound. In a comparison between calculated and measured N2O evolution, 34% evolution was calculated and 24% was observed for the experimental conditions. The assumptions used in developing the equations lead to a slight overprediction of evolved gases.
A Simple Chamber Technique for Field Measurement of Emissions of Nitrous Oxide from Soils
Authors: Matthias A. D. , Blackmer A. M. , Bremner J. M.
Published: July 2010

A simple technique for field measurement of the rate of emission of nitrous oxide (N2O) from soil is described. It involves placement of an insulated cylindrical metal chamber over the soil surface for 20 min and removal of air samples from the chamber at 5‐min intervals for N2O analysis by a sensitive gas chromatographic technique that permits use of the xenon in air as an internal standard. The rate of N2O emission is calculated from the rate of increase in the concentration of N 2O in the air within the chamber. This technique is sensitive and precise, and it has the important advantages that it does not significantly disturb the structure or environment of the soil under study and is not limited in use to sites where electricity or special equipment is available. The chamber described is inexpensive and easy to fabricate, transport, and use, and it is well suited for an extensive program of research on N2O emissions from soils.
Seepage Vs. Terrace Density in Reclaimed Mineland Soil
Authors: Prunty Lyle , Kirkham Don
Published: July 2010

The seepage pattern of infiltrated water through hillside mine overburden materials is of concern because of the possible pollution hazard presented by leachates.

Here detailed seepage patterns as found by Gram‐Schmidt analysis are presented for (i) a uniform‐slope topography, (ii) a four‐terrace topography, and (iii) a one‐terrace topography. The aspect ratio (depth/width of the mine pit) of 1:40 and average slope of 5% are the same for each topography and correspond approximately to the aspect ratio and slope of an actual research coal mine. The volume of overburden is also the same for each topography.

Saturation of the overburden is assumed. The results, therefore, depict the maximum possible seepage condition for each topography, not average or normally expected conditions. A plot of the total relative seepage rate as a function of the reciprocal of the terrace density (number of terraces) is presented. The total seepage rate for the four‐terrace topography is 10 times greater than for the uniform‐slope topography.
Nitrate Reduction in an Organic Soil‐Water System
Authors: Reddy K. R. , Sacco P. D. , Graetz D. A.
Published: July 2010

Flooded organic soil as a treatment system for nitrate‐nitrogen (NO3‐N) removal from agricultural drainage water was evaluated under controlled conditions. Nitrate‐N reduction rates in the flood water (agricultural drainage water) and in the underlying organic soil column were measured as a function of NO3‐N concentration (10, 25, and 50 µg NO3‐N/ml), energy source, and temperature (8, 18, and 28°C). Labeled NO3‐N was used to differentiate between denitrification and NO3‐N reduction to ammonium‐N (NH4‐N) or organic N.

Nitrate‐N reduction rates in the soil column incubated at 28°C with no excess flood water were best described by first‐order kinetics with an average rate constant (k) of 0.751 day−1. Flood water NO3‐N removal rates were also described by first‐order kinetics. Nitrate removal rates from low oxygen‐demand flood water (expressed as first‐order rate constants) with an underlying soil column were 0.038, 0.750 day−1 for an incubation temperature of 8, 18, and 28°C, respec‐ 28°C, respectively. In soil columns incubated with high oxygen‐demand flood water, most of the added NO3‐N disappeared before it reached the underlying soil column, with k values of 0.172, 0.292, and 0.790 day−1 for an incubation temperature of 8, 18, and 28°C, respectively. In all treatments, denitrification was the dominant process in the removal of flood water NO3‐N. At low temperature (8°C), a greater portion of 15NO3‐N was reduced to 15NH4‐N and organic N. Most of the immobilized 15NO3‐N appeared as soluble organic N. At 8°C, flood water NO3‐N diffused deeper into the soil column as compared to the flooded soil columns incubated at 28°C.

The results obtained in this study indicate that flooded organic soil can function as an effective sink for reducing NO3‐N levels of agricultural drainage waters.
A Study of a Method for Displacing Soil Solution by Centrifuging with an Immiscible Liquid
Authors: Whelan B. R. , Barrow N. J.
Published: July 2010

Soil solution can be effectively displaced by centrifuging at 170,000 m s−2 for 30 min with tetrachloroethylene. The solution collects at the top of the dense, organic liquid and can be separated from it by pouring through phase‐separating paper. Suspended material is removed by passing through a membrane filter after which the solution may be analyzed. Tetrachloroethylene was preferred because of its lower toxicity than carbon tetrachloride. The technique is well suited to the study of the movement of water‐soluble pollutants through soil and was used to study phosphate movement below the discharge from a septic tank.
Release Characteristics of Starch Xanthide Herbicide Formulations
Authors: Baur J. R.
Published: July 2010

A laboratory procedure was developed using a cucumber (Cucumis sativus ‘Straight Eight’) root‐length bioassay to measure the relative rate of release of herbicides entrapped in various starch xanthide (SX) matrices. SX herbicide formulations placed in vials containing deionized water were decanted periodically and evaluated by bioassay to examine herbicide released into the water. In leaching experiments, fractions of effluent were collected from glass columns containing SX herbicide formulations applied to a glass‐wool pad resting on a sand bed. Collected aqueous fractions were bioassayed. The herbicides examined were salt and ester formulations of picloram (4‐amino‐3,5,6‐trichloropicolinic acid), ester formulations of 2,4‐D [(2,4‐dichlorophenoxy)acetic acid], and salt formulations of dicamba (3,6‐dichloro‐o‐anisic acid). Comparison of salt and ester starch xanthide formulations of picloram indicated that the ester formulation had a release rate three to five times slower than that of the salt formulation. Differences were noted between starch xanthide formulations of salt herbicides designated as fast and slow releases.
Chemical Characterization of Fly Ash Aqueous Systems
Authors: Elseewi Ahmed A. , Page A. L. , Grimm Sabine R.
Published: July 2010

Aqueous chemistry of fly ash from a western coal‐fired power plant was characterized through measurements of solubility of Ca, Mg, Na, K, OH, CO3, HCO3, Cl, SO4, and B in filtrates from water and electrolyte suspensions of the fly ash obtained at various dilution ratios. Acid titrations of dilute suspensions of the fly ash were also characterized. The study also examined the quantitative relationship between electrical conductivity of the filtrates and their total ionic composition. Relative concentrations of Ca and OH ions in solution and the nature of the acid titration curves suggest that solutions of fly ash are nearly saturated in Ca(OH2). Elements of low to moderate solubility, such as Ca, Mg, SO4, and B, showed greater dissolution as the fly ash suspensions were diluted. Ammonium acetate (NH4OAc‐HOAc) solutions (pH ≅ 5) were found to extract essentially all Ca and S and > 50% of Mg in the fly ash. Substantial fractions of total B in the fly ash were extracted in water (27%) and in an initially acidified (pH = 3) 0.01N NaCl (41.4%). Positive and highly significant correlations were found between total ionic concentration and electrical conductivity of the solution. The slope of the straight‐line relationship was, however, considerably less than that commonly used in describing soil salinity. It is concluded that aqueous systems of fly ash do not represent a true equilibrium and that there is a need to standardize methods of salinity and base analyses in fly ash.
Use of Fermentation Residue from Citric Acid Production as a Soil Amendment
Authors: King Larry D.
Published: July 2010

Fermentation is used in the production of pharmaceutical chemicals, alcoholic beverages, food supplements, and organic acids. After removal of the desired product, the fermentation residue must be disposed of properly. Since these residues contain organic matter and plant nutrients, they may be useful as soil amendments.

Presscake residue from citric acid production was applied to Coastal bermudagrass (Cynodon dactylon L. Pers) which was overseeded with rye (Secale cereale L.) each fall. Presscake supplied appreciable quantities of N, P, Ca, and S. Although all plots received identical rates of supplemental inorganic P and K, single spring applications of presscake at rates up to 76 metric tons/ha (1,500 kg N/ha) were not as effective in increasing bermudagrass yields as were five periodic applications of 112 kg N/ha as NH4NO3. Higher rye yields were obtained with application of 38 metric tons/ha of presscake (375 kg N/ha) than with 180 kg/ha of inorganic N. Residual effect of presscake the year after application produced bermudagrass yields that were about 75% of first year yields.

Over a 2‐year period, repeated applications of presscake supplying 224 kg N/ha per application produced identical total yields of bermudagrass and rye as did the same number of applications of 112 kg N/ha from NH4NO3. Presscake rates supplying 224 and 448 kg N/ha per application resulted in an accumulation of excess nitrate in the soil profile. Over the 3‐year study period, presscake N was approximately 50% as efficient as NH4NO3 in increasing forage yields. Supplementing presscake with inorganic P did not increase forage yield.
Nitrogen Availability from Sewage Sludge
Authors: Magdoff F. R. , Amadon J. F.
Published: July 2010

Aerobically treated secondary liquid sewage sludge was applied to both corn (Zea mays L.) and hay growing on Hadley sandy loam and Nellis loam soils. The nine treatments consisted of a check, four ammonium nitrate levels (50, 100, 150, and 200 kg N ha−1 yr−1), and four sludge levels (chosen to supply amounts of available N similar to the ammonium nitrate rates).

About 54% of the organic‐N added to the sludge‐amended corn soils was mineralized under laboratory conditions. The amount of N mineralized was well correlated with a chemical test of N availability.

While the corn and hay on the sludge‐amended Hadley soil out‐yielded the N treatments, nitrate recovery to 1.2 m in the corn plots indicated that the available N supplied by the sludge treatments was no greater than that supplied by ammonium nitrate. Other factors, such as increased K supply to both corn and hay and residual N effect on the second‐year hay, probably caused the increased response of crops to sludge over N. There was little or no response of corn yields to sludge or N on the Nellis loam, while the hay responded more to N than sludge. Estimates of mineralization of organic‐N from sludge applied to corn and hay averaged 55% for the first year of applications.

Recovery of N in the corn at harvest plus soil NO3‐N to a depth of 1.2 m was positively correlated with the estimated mineralization of organic‐N (from the N availability test) plus the inorganic‐N added. The autoclaving test of N availability appears useful in predicting mineralization of organic‐N from sludge under field conditions.
Land Application of Chemically Treated Sewage Sludge: III. Effects on Soil and Plant Heavy Metal Content
Authors: Soon Y. K. , Bates T. E. , Moyer J. R.
Published: July 2010

Anaerobically digested sewage sludges resulting from treatment of sewage with Ca(OH)2, Al2(SO4)3, or FeCl3 for phosphorus precipitation were applied to corn (Zea mays L.) and bromegruss (Bromus inermis Leyess) grown on a soil having an initial pH of 7.3. Rates of sludge supplied 200, 400, 800, and 1,600 kg N/ha each year for 5 years. Treatments with NH4NO3 supplying 0, 100, 200, and 400 kg N/ha were included for comparison. Plant tissue was analyzed for Cu, Zn, Mn, Cd, Ni, Cr, and Pb. No toxicity or deficiency symptoms were noted. Soil Zn, Cd, and Ni extracted by NTA (nitrilotriacetic acid) were increased by continued sludge application. The NTA‐extractable Zn and Cd were positively correlated with the Zn and Cd concentrations in corn stover. Soil pH was reduced by the Fe‐sludge application, slightly affected by the Al‐sludge, and increased by the Ca‐sludge. Increases in Cu concentrations in bromegrass and corn stover were associated with increases in the N content rather than the source of N, and plant Cu concentrations remained relatively constant across years. Sewage sludge application increased Zn, Cd, and Ni concentrations in bromegrass and corn stover, and Zn and Ni concentrations in corn grain, particularly at the higher metal loadings from sludge application. Zinc and Cd concentrations, especially in corn stover, increased with continued sludge application during the 5‐year period. The inclusion of soil pH as a factor, in addition to cumulative amounts of Zn or Cd added as a constituent of sludge, improved the regression equations predicting Zn or Cd uptake. Manganese concentrutions in bromegrass were reduced by the sludges used in this study, but did not change from one year to the next. Chromium and Pb concentrations in corn and bromegrass were not significantly increased by the application of 680 kg Cr/ha and 310 kg Pb/ha from sludge.