bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of Trace Metals on Some Soil Nitrogen Transformations
Authors: Chang F.‐H. , Broadbent F. E.
Published: July 2010

An investigation to evaluate the influence of trace metals on N immobilization, N mineralization, and nitrification was conducted. Samples of Yolo silt loam amended with 100 ppm NH4‐N, 1% sewage sludge, and 1% ground alfalfa (Medicago sativa L.) were treated with solutions to provide 100, 200, and 400 ppm of Cd(II), Cr(III), Cu(II), Mn(II), Pb(II) and Zn(II), and incubated for 2, 4, 8, and 12‐week periods. Metals were determined by extracting with water, KNO3, DTPA (diethylenetriaminepentaacetic acid), and HNO, at the end of each incubation period.

All metals reverted quickly to more insoluble forms. Quantities of metals extractable with water + KNO3 + DTPA decreased with time, while corresponding increases in HNO3‐soluble forms occurred. Nitrogen immobilization was measured during the 2‐ to 4‐week period, and N mineralization and nitrification during the 4‐ to 12‐week period. At low levels of metal addition Mn and Pb stimulated N immobilization, but at 400 ppm all metals were inhibitory to all N transformations. Among the six metals studied the sequence in order of decreasing inhibition was Cr > Cd > Cu > Zn > Mn > Pb. it was concluded that N transformation rates may be affected by trace metals in soils receiving heavy sludge applications.
Water Quality in a Stream Receiving Dairy Feedlot Effluent
Authors: Hollon B. F. , Owen J. R. , Sewell J. I.
Published: July 2010

Water quality in a stream that received effluent directly from a 200‐cow dairy feedlot operation was monitored during a 22‐month study to determine if the stream pollution level exceeded current Environmental Protection Agency (EPA) permissible levels for raw public water supplies, and to evaluate changes in water quality at selected distances downstream from the point source of discharge. Grab samples were collected at 2‐week intervals from stations located 400 m and 3 km upstream, and 100, 500, and 1200 m downstream from the point source of discharge. Samples were analyzed for biochemical oxygen demand (BOD), chlorides, dissolved oxygen, fecal coliform, fecal streptococci, nitrate nitrogen, nitrite nitrogen, orthophosphate, total solids, and pH. Mean concentration of fecal coliform exceeded the EPA permissible level of 2,000 col/100 ml at 100 and 500 m below the point source of discharge, but not at 1,200 m. All other parameter means measured were below the permissible levels. Mean concentrations increased significantly (P < 0.01 or P < 0.05) for all parameters, except BOD and pH, when downstream stations were compared with upstream stations. However, mean concentrations significantly declined (P <0.01) for fecal coliform, fecal streptococci, BOD and orthophosphate at 1,200 m below the point source of discharge, while other parameters either declined or remained unchanged. Water quality 1,200 m below the point source of discharge apparently was not different from that 400 m above. Discharge of effluent into the stream did not appear to have a great effect on water quality, and the value of controlling the discharge would be questionable in terms of improving water quality in the receiving stream.
Alfalfa Hay Grown with Municipal Waste Water and Pump Water
Authors: Day A. D. , Swingle R. S. , Tucker T. C. , Cluff C. B.
Published: July 2010

The influence of municipal waste water on the growth and yield of alfalfa (Medicago sativa L.) was studied in field experiments near Buckeye, Ariz., in 1974 and 1975. The crop was planted in October of each year at a seeding rate of 22.4 kg/ha (20 lb/acre). Approximately 150 cm (60 in) of irrigation water were applied in flood irrigations each year. The response of alfalfa to two irrigation treatments: (i) pump water from local wells (control) and (ii) municipal waste water from Phoenix and pump water in a 50:50 mixture was compared by sampling the first harvest in selected fields. The hay was harvested when 10% of the alfalfa stems had one or more flowers.

Alfalfa irrigated with the waste‐water and pump‐water mixture produced taller plants and higher yields of hay than did alfalfa grown with pump water alone. Total protein in the hay and in vitro dry matter disappearance (IVDMD) of the hay was the same for alfalfa grown with both sources of irrigation water. When municipal waste water was mixed with pump water high in total soluble salts, the salt content of the mixture was reduced and the quality of the irrigation water was improved. The higher hay yields obtained when alfalfa was irrigated with the waste‐water and pump‐water mixture than when grown with pump water alone probably resulted from lower concentrations of soluble salts in the water mixture than in the pump water.
Effects of Use Pattern, Cover, Soil Drainage Class, and Overwinter Changes on Rain Infiltration on Campsites
Authors: Vimmerstedt John P. , Scoles Frederick G. , Brown James H. , Schmittgen Mark C.
Published: July 2010

The objectives of this study were to examine how rainfall infiltration on developed Ohio campsites varied with soil drainage class, cover, use pattern, and overwinter changes. Infiltration and sediment yield were measured during 60‐min applications of 11 cm of simulated rain on campsite use zones, using a spray infiltrometer. Initial percent infiltration was 82 and 89 in fall and spring with sod cover, and 68 and 79 in fall and spring with hardwood cover. Initial infiltration also varied with use zone and season: heavy use—52% fall (F), 65% spring (Sp); moderate use—79% F, 87% Sp; and light use—95% F, 99% Sp. Fall infiltration during the last 10 min of simulated storms on poorly drained soils was 4% with sod cover vs. 12% with hardwood cover. But on well‐drained soils cover effect was reversed (62 vs. 42% on excessively drained and 56 vs. 35% on well‐drained soils for sod and hardwood covers, respectively). Final infiltration rate and total infiltration changed little from one use zone to another on poorly drained campsites, but on well‐ or excessively drained soils there was a marked and progressive reduction in infiltration from light‐ to moderate‐ and heavy‐use zones. Sediment concentration in runoff and soil bulk density increased with use intensity.
Responses of Radish to All Combinations of Three Concentrations of Nitrogen Dioxide, Sulfur Dioxide, and Ozone
Authors: Reinert R. A. , Shriner D. S. , Rawlings J. O.
Published: July 2010

Vegetation stress by air pollutants is frequently a result of a multiple pollutant exposure. Long‐range transport of major air pollutants may affect rural agricultural and forested regions of the eastern United States. Also, changes in the relative importance of the major phytotoxic pollutants, NO2, SO2, and O3, can be anticipated as a result of changing energy patterns. In experiments designed to evaluate the effects of the coincident occurrence of NO2, SO2, and O3, as well as the importance of the ratios of the pollutants to one another, we have demonstrated that the pollutants interacted to influence the response of radish (Raphanus sativus L.) foliage and root.

The influence of increasing O3 concentrations at increasing concentrations of NO2 and SO2 generally resulted in smaller root (hypocotyl) fresh and dry weight, and in most cases the relationship was linear. Fresh‐weight reductions in radish roots due to increasing O3 concentrations from 0.1 to 0.2 ppm and from 0.1 to 0.4 ppm at 0.1 ppm NO2 and SO2 were 24 and 51%, respectively. At 0.4 ppm NO2 and SO2, the root‐weight losses due to increasing O3 concentration from 0.1 to 0.2 and from 0.1 to 0.4 ppm were 20 and 38%, respectively. When SO2 reached 0.8 and 1.6 ppm, there was little change in root weight as NO2 and O3 concentrations were increased from 0.2 to 0.4 ppm. Nitrogen dioxide played a significant role in the response of radish to SO2 and O3, considering the high concentration of NO2 (> 2.0 ppm) needed to cause a response in radish from a single exposure to NO2 alone. These results suggested that valid assessment of the impact of siting additional sources of SO2 and NO2 in regions currently experiencing elevated O3 levels will require recognition of this interaction potential.
Plant Disease in an Old Field Ecosystem Irrigated with Municipal Waste Water
Authors: Epstein Lynn , Ditz Kimberly , Safir G. R.
Published: July 2010

During 1978 and 1979, plant disease on foliage was assessed in an old field dominated by goldenrod (Solidago canadensis and S. graminifolia) and quackgrass (Agropyron repens) and irrigated with waste water. Plant pathogens abundant in waste‐water‐irrigated areas included, Coleosporium asterum, Erysiphe cichoracearum, Phyllachora graminis, and Helminthosporium sp.; such fungi reportedly alternate their life cycles or reproduce on economically important plant species. The increased foliar disease in the irrigated areas was probably due to increased moisture. Frequencies of plant pathogens in the waste water were apparently low since wounded seedlings of numerous crop varieties immersed in waste water remained healthy. Alternaria alternata and Stemphylium sarcinaeforme survived equally well after 24 days in filter‐sterilized waste water or tapwater; however, Erwinia herbicola and E. atroseptica survived longer than 24 hours in buffered waste water but not in buffered tapwater.
Decomposition of Chelates Leached from Waste Disposal Sites
Authors: Avnimelech Yoram , Raveh Ariela
Published: July 2010

Heavy metals chelated by organic ligands and sites may endanger adjacent water bodies. Potential chelation capacity of solutions was determined through the effect of the chelating agents on the solubility of CaCO3. The method is simple and yields consistent results.

Leachates from sanitary landfill models were incubated aerobically and anaerobically with clay loam, calcareous clay loam, and CaCO3 for periods of up to 120 days. No significant adsorption of the chelates was detected. Decomposition of chelates in the anaerobic systems was very slow and insignificant. Decomposition in aerobic systems was relatively fast, leading to a residual chelation capacity of only 0.1–1% of the initial value after a 74‐day incubation. It is essential, accordingly, to avoid direct drainage of anaerobic leachates from a waste disposal site into a water body.
Storm Sediment Concentrations as Affected by Land Use, Hydrology, and Weather
Authors: Verhoff F. H. , Yaksich S. M.
Published: July 2010

A 26‐year record of daily suspended load carried by the Maumee River at Waterville, Ohio, was examined to determine any trends as a function of time for the period of record. This work was undertaken because earlier work with a 5‐year record of P transport could not determine trends in P loading caused by the abatement of P pollution at an upstream point source. As a result, a question was asked of the length of record required to determine trends. A flow‐weighted mean concentration averaged over an event month or year was used to eliminate flow differences. No significant trends in sediment transport were detected despite urbanization in the basin and changes in farm management practices over the period. Hydrology and weather appear to be the major factors affecting the storm average suspended sediment concentration in the Maumee River. The important variables are maximum discharge during the storm, duration of the storm, water temperature, and high wind average for the days since the previous storm. Such traditional variables as raindrop impact and rainfall energy, which influence sheet erosion, do not explain the variation in the suspended sediment concentration at Waterville on the Maumee River.
Effect of Atrazine on Soil Transformations of Nitrogen and Uptake by Corn
Authors: Cervelli Stefano , Ciardi Carlo , Perna Amalia
Published: July 2010

The influence of different rates of atrazine (2‐chloro‐4‐[ethylamino]‐6‐[isopropylamino]‐s‐triazine) (0,2, and 6 kg ha−1) on nitrogen balance and soil urease following 15N‐urea fertilization (200 kg ha−1) was investigated in corn (Zea mays L.) plots by emission spectrometry. Urease activity was affected by both urea and atrazine applications. Concentrations of NH4+‐N and NO3−‐N in soil were greater at the highest herbicide rate. Organic N buildup was slower in plots that received atrazine at the highest rate, but at the end of the cropping season the total amount of organic N was similar for all treatments.

Nitrogen losses, as determined by an N balance sheet, were 51, 32, and 22% of added N in the plots treated with 0, 2, and 6 kg ha−1 of atrazine, respectively.

The main role of organic N in the N cycle of the soil‐plant environment in the presence of atrazine is suggested.
Toxicity of Anakeesta Formation Leachates to Shovel‐Nosed Salamander, Great Smoky Mountains National Park
Authors: Mathews Raymond C. , Morgan Eric L.
Published: July 2010

Following reconstruction of U.S. Highway 441 in 1963 near New‐found Gap, Great Smoky Mountains National Park, aquatic life was almost completely eliminated in stream areas immediately downstream from the construction site. In Beech Flats Prong, for example, aquatic life was virtually absent for approximately 8 km downstream from highway roadcut and fill areas. Salamander (Leurognathus marmoratus) mortality in this stream area was attributed to acidic heavy metal leachate formed through redox processes associated with pyritic content of the Anakeesta roadfill bedrock. To evaluate the lethality of simulated leachate, salamanders were subjected to 96‐hour time‐until‐death acute toxicological assays under laboratory conditions. In this study, leachate components derived from Anakeesta rock thought to be contributing jointly to intoxication processes were elevated acidity and heavy metal concentrations.
Movement of Diffuse Source Pollutants in Small Agricultural Watersheds of the Great Lakes Basin
Authors: Hubbard R. K. , Erickson A. E. , Ellis B. G. , Wolcott A. R.
Published: July 2010

A study was conducted to determine losses and distributions of nitrogen (N) and phosphorus (P) in runoff waters and sediments from heavily fertilized agricultural watesheds during both the growing and nongrowing seasons. The study was done on two small watersheds having well‐drained, fine, sandy loam soils. Runoff was measured continuously and sampled proportionately during 50–60 events over a 2‐year period.

Ninety nine percent of the sediment loss over the period occurred during 11 months; 64–86% occurred during a single storm in April when no crop canopy was present. This event was associated with rainfall probabilities rising rapidly toward a primary annual peak for East Lansing, Mich. A second storm of equal magnitude in August was associated with a secondary annual peak in normal rainfall for this location. Both storms exceeded the 20‐year expectancy in erosion potential (erosion index = 68). Seventy to 95% of the N in runoff, and 90–98% of the P, were carried in sediments, except during winter months when up to 80% of the N and 33% of the P were in solution. Sediments were enriched, relative to soils, in total N, but not in extractable P.
Nutrient Mobilization Following Winter Fires in an Irregularly Flooded Marsh
Authors: Faulkner Samuel P. , de la Cruz Armando A.
Published: July 2010

The effects of prescribed winter burning on nutrient pools in an irregularly flooded marsh in St. Louis Bay, Miss., were investigated. Nutrient levels were determined in field‐collected pre‐fire vegetation, post‐fire regrowth, pre‐fire and post‐fire sediments, combustion residues, and reference materials from unburned adjacent sites. Post‐fire soil chemistry was characterized by transitory elevation of sediment‐water pH, P extractable in 0.10N HCl + 0.03N NH4F, and exchange + solution phase K, Ca, and Mg in surface sediments. Although input of ash‐borne nutrients into the marsh appeared minimal for most elements, estimated losses of N and K from combustible plant matter exceeded 90 and 50%, respectively, for both vegetation communities examined, one dominated by needle rush (Juncus roemerianus Scheele), and the other by giant cordgrass (Spartina cynosuroides (L.) Roth). Losses of these elements in standing elemental pools amounted to 70% for N and nearly 40% for K within both communities. Increases in both absolute elemental concentrations and elemental standing stocks in early spring regrowth, particularly with respect to N, appeared associated with marsh burning. Stimuli including slight increases in some elements in the sediments, sediment warming, and increased insolation, may have contributed to the higher nutrient levels found in plants from burned areas, although a slight lag in physiological ages of plants within burned and reference sites may account for observed differences.
Interception and Retention of Technetium by Vegetation and Soil
Authors: Hoffman F. Owen , Garten Charles T. , Huckabee John W. , Lucas Deborah M.
Published: July 2010

Field experiments were performed to quantify the initial interception and retention of technetium (Tc) by herbaceous vegetation as a consequence of direct deposition and uptake from soil. A simulated rain containing a solution of 95mTcO4− was applied to plots of bare soil and plots with standing vegetation. Vegetation emerging in the bare‐soil plots obtained Tc predominantly from root uptake. Vegetation standing during the initial application obtained Tc from both direct foliar interception and root uptake. For the plots with standing vegetation, the estimated initial interception fraction (r) ranged from 0.079 to 0.17. The mass interception factor (r/Yv) ranged from 0.65 to 1.1 m2/kg. The retention of Tc by vegetation receiving direct foliar contamination varied with environmental half‐times (Tw) ranging from 15.9 to 18.7 days. Adjusting for the effects of growth dilution increased the values of Tw (range 21.6–28.7 days). For vegetation emerging from the plots of initial bare soil, retention was equivalent to a Tw of 43 days. These data indicated that uptake of Tc from soil diminished with time and that Tc was removed from plant tissue. In soil, a downward movement was evident, because Tc in the top 2 cm decreased with time and concentrations at lower soil depths (6–8 and 14–15 cm) increased with time. The application of these data to predict steady‐state concentrations of Tc in vegetation resulting from continuous deposition does not differ substantially from predictions based on the use of generic‐default parameter values recommended in Regulatory Guide 1.109 of the U.S. Nuclear Regulatory Commission (1977).
Application of an Approximate Analytic Method of Computing Solute Profiles with Dispersion in Soils
Authors: Rose C. W. , Chichester F. W. , Williams J. R. , Ritchie J. T.
Published: July 2010

The calculation of mean solute penetration (or solute peak position), e.g., using the method of Rose et al. (1982), provides a Lagrangian (or moving) coordinate system about which solute dispersion takes place. An approximate analytic equation, useful in calculating the convection and dispersion of applied N fertilizer was then developed as follows: the solution of the convection/dispersion equation for a step change in concentration under constant flux boundary conditions was assumed to apply approximately under non‐steady conditions, using an equivalent constant flux; then an equation describing convection/dispersion of an initially rectangular concentration pulse (which approximates the initial concentration profile following fertilizer application) was constructed by superposition.

This model gave a useful interpretation of the field monolith lysimeter data of Chichester and Smith (1978), who used 15N‐labelled N fertilizer to study the N balance. Such discrepancies as remained require separate investigation, but are likely to be due to assumptions on the theory not being met in the permanently fissured bedrock lower in the profile.
Bacteriological Quality of Surface and Subsurface Runoff from Manured Sandy Clay Loam Soil
Authors: Culley J. L. B. , Phillips P. A.
Published: July 2010

The bacterial quality of surface waters determines their acceptability for both drinking and recreational uses. Since livestock activities have been implicated as sources of fecal contamination, information on the bacterial quality of runoff from manured cropland is required. Bacteriological parameters (total coliform [TC], fecal coliform [FC], and fecal streptococcus [FS]) were monitored in spring surface and subsurface discharge from continuously corn‐cropped sandy clay loam that was amended with either liquid dairy manure, chemical N‐P‐K fertilizer at about recommended rates, or no fertilizer. Liquid manure was applied for 6 years at three rates, which averaged 105, 263, and 420 m3 ha−1 year−1, plowed under after harvest, in spring prior to seeding, or split between spring and fall. Liquid manure was also applied directly to snow or frozen ground.

With the exception of winter‐applied treatments, neither rate nor time of manure application significantly affected organism contents in spring surface or subsurface discharge. Winter manure applications resulted in significantly higher FC and FS counts in surface runoff and FS counts in subsurface discharge when compared with other application times. Fecal coliform and FS counts did not increase with increased winter application rates. Fecal streptococcus populations of winter‐applied manure changed little during the first 100 days after application, while both TC and FC counts declined in the manure to low levels 24–40 days after spreading.
Effects of Ammonium Sulfate and Urea on the Growth of Chlorophycean Algae From Rice Fields
Authors: Barrett Michael R. , Koch Arthur R.
Published: July 2010

Algal growth in rice (Oryza sativa L.) fields is often abundant, but the quantitative effect of fertilization on algae is not well‐understood. The growth of four unialgal isolates from fertilized rice floodwater, including Bracteacoccus minor, Scenedesmus sp., and two species of Chlamydomonas, was studied in soil water extract enriched with an inorganic algal medium and with N as either urea (CO(NH2)2) or ammonium sulfate ((NH4)2SO4). Except for one species of Chlamydomonas, isolates had higher cell counts in urea‐enriched cultures. There was no significant difference between the growth of cultures with 25 or 50 mg/liter N as urea added or between those with 25 or 50 mg/liter N as (NH4)2SO4. The maximum biomass of all N‐enriched cultures was significantly greater than that of cultures with no N added to the medium. Differences in final biomass among isolates were significant but were not proportional to that observed at earlier stages in the growth curve.
Chalk Point: A Case Study of the Impact of Brackish Water Cooling Towers on an Agricultural Environment
Authors: Mulchi Charles L. , Armbruster James A. , Wolf D. C.
Published: July 2010

The construction of two brackish water, natural‐draft cooling towers (Units 3 and 4) by the Potomac Electric Power Co. at their Chalk Point Generating Station, located in a major agricultural region in southern Maryland, aroused concern that saline aerosol emissions from the facility might significantly impact the crops and soils near the facility. Permanent research and monitoring sites were established at distances of 1.6, 4.8, and 9.6 km north, east, south, and west from the cooling towers. Over the period May 1973–May 1980, baseline and postoperational information was obtained on monthly Na and Cl deposition rates; foliar chemistry and yields of corn (Zea mays L.) and soybeans (Glycine max L. (Merr.)); soil pH and extractable P, K, Ca, Mg; Na; and electrical conductivity values on 0‐ to 15‐cm depth soil samples. Unit 3 began operations in July 1975.

The quantities of saline aerosol emissions from Unit 3 were insufficient to cause detectable changes in the Na and Cl deposition rates above baseline values at or beyond the 1.6‐km sites, the closest agricultural areas to the power plant. Also, no significant changes were observed in Na and Cl levels in vegetative samples collected from corn and soybeans grown in the research sites after Unit 3 began operations. Significant reductions in corn yields that were more associated with rainfall patterns than to salt emissions were observed during post‐Unit 3 operations. Significant changes that, in most cases, could be closely associated with the general increases observed in soil acidity, were observed in each of the soil chemistry parameters with time.

In conclusion, saline aerosol emissions from Chalk Point Unit 3 natural draft cooling tower did not have a detectable impact on the agricultural crops and soils adjacent to the emission source.
Environmental Effects of a Medium‐Fertility 12‐Month Pasture Program: I. Hydrology and Soil Loss
Authors: Owens L. B. , Van Keuren R. W. , Edwards W. M.
Published: July 2010

Four small, sloping upland watersheds in Ohio (0.5–1.1 ha) were studied for 5 years to investigate hydrologic and soil erosion changes resulting from a beef cattle pasturing program. The cattle grazed all four pastures rotationally during the summer (May–October) and were wintered on hay (November–April) on the same pasture each year. The long‐term record for these pastures, which had been in meadow and light pasturing during the previous years, showed average annual surface runoff to be approximately 15 mm. During the 5 years of the grazing project, the three summer‐grazing‐only pastures showed a slight increase in surface runoff and a trace of soil loss. However, the winter‐feeding/summer‐grazing area showed a large increase in surface runoff (131 mm/year) and soil loss (1,355 kg/ha per year). Eighty‐one percent of the soil loss occurred during the dormant season. Large runoff events, although a small percentage of the total number of events, produced most of the runoff volume and most of the soil loss. Water balance studies indicated that subsurface flow was relatively unchanged by the grazing program. The increase in surface runoff was offset by a decrease in the evapotranspiration.
Chemical Properties and Mineralogical Characteristics of Selected Dredged Material
Authors: Combs S. M. , Dowdy R. H. , Gupta S. C. , Larson W. E. , Gast R. G.
Published: July 2010

Transporting dredged spoils inland for use in reconditioning adjacent lands marginally suited for agricultural production may be an attractive alternative to other disposal practices. The objective of this study was to evaluate dredged materials (DM) by determining the elemental content and mineralogical characteristics of 10 freshwater and estuarine DM from eastern and central U.S. waterways.

Dredged materials ranged from very acidic (pH ≤ 4.7) to alkaline (pH ≥ 7.4) in reaction. Acidity was attributed to S2− and/or Fe2+ oxidation resulting when initially reduced sediments were exposed to aerobic conditions. Dredged materials had cation exchange capacity values that ranged from 1.0 to 33.5 meq/100 g. Organic matter contents (5.9–22.5%) accounted for approximately 60% of the variation in the exchange capacity of fine‐textured DM. Total N was mainly in organic forms and C/N ratios ranged from 13:1 to 22:1.

Dredged materials exhibited variable accumulations of nutrients and metals reflecting varying degrees of waterway contamination. The levels of Al, Ca, K, Mg, P, and S were generally higher in DM than in reference Minnesota soils. Cadmium, Cr, Ni, Pb, and Zn concentrations in DM were 2 to 6 times, and Cu 20 times, those observed in the reference soils. Manganese concentrations were substantially less in DM than in the soils.

Mineralogy varied with geographical location, contributing watershed, and environmental conditions. All DM contained kaolinite and illite. Amounts of montmorillonite varied because of some conversion to pedogenic chlorite during rapid leaching conditions of sediment drainage. Crystalline Fe2O3 was associated with DM clay fractions, indicating precipitation of colloidal‐sized hydrous oxide particles and/or surface coatings on clay complexes.
Monitoring of a Municipal Sludge Entrenchment Site
Authors: Sikora L. J. , Burge W. D. , Jones J. E.
Published: July 2010

Raw, highly limed, filter‐cake sludge (22% solid) was entrenched 18 ha of well‐drained, silt loam soil of the Manor (Typic Dystrochrept) and Glenelg (Typic Hapludalf) soil series in 1975 at a rate 2,200 wet metric tons/ha. As part of the overall evaluation of the environmental effects of sludge entrenchment, the USDA‐ARS, in cooperation with the Maryland Environmental Service, began to monitor the site in 1977 to determine the mineralization and movement of N, movement of heavy metals, and die‐off rate and movement of salmonellae, ascaris ova, and fecal indicators in the entrenched sludge and soil profile. Total N, NH4‐N, and Cl levels decreased in the entrenched sludge with time, and leached through the soil profile past the lowest sampling point, which was 100 cm below the trench bottom. Nitrate‐N was formed and migrated to the deepest sampling point, and direct evidence that denitrification occurred was lacking. Heavy metal losses from the entrenched sludge were negligible probably because the pH of the sludge after 45 months was above 7.0. A predictive equation based on decreases in sludge total N was developed for use as a tool for determining the age when the entrenched sludge was stablized. Fecal coliform concentrations were very low. Ascaris ova were not detected in the sludge prior to entrenchment or in samples taken during the monitoring period which, in part, may have been due to analytical limitations. Pathogen hazard associated with the entrenched, limed sludge appeared to be minimal. The major environmental effect of sludge entrenchment is possible contamination of ground water by N leached from the sludge.
An Analysis of Short‐ and Long‐Term Impacts of Several Soil‐Loss Control Measures
Authors: English Burton C. , Heady Earl O.
Published: July 2010

Two large‐scale interregional and national linear‐programming models are used to examine the impacts on agricultural production, resource use, and soil loss of several soil‐loss control measures. The short‐run model (1985) incorporates no productivity loss due to soil erosion, while the long‐run model (2000) does. Five short‐run and six long‐run alternatives are analyzed. These alternatives include reducing soil losses by fixed percentage values or to a fixed multiple of the soil‐loss tolerance levels (2T in the short‐run and T in the long‐run model).

The base solutions with no targeted soil‐loss reductions project gross soil losses of 2.8 and 1.1 billion t for 1985 and 2000, respectively. By limiting soil losses to 2T and T, the soil losses are reduced to 1.4 and 0.6 million t, respectively.

Many more hectares are placed in conservation practices and reduced‐tillage methods in the long‐run when compared with the short‐run model. Soil‐conserving practices such as contours, strip cropping, and terracing are not used in the short run, indicating that conservation practices will not be utilized under a short planning horizon and an objective of profit maximization. The private economic benefits for conserving soil in the short run are less than the costs in doing so. When yield impacts from soil erosion are considered as in the long‐term solution, it is profitable to use these conservation practices.
Residues of 4‐(2,4‐Dichlorophenoxy)butyric Acid in Winter Wheat
Authors: Leather G. R. , Forrence L. E.
Published: July 2010

Residue data were collected during a 1‐year field investigation to support a label amendment for the use of 2,4‐DB (4‐[2,4‐dichlorophenoxy]butyric acid) in small grains. The 2,4‐DB was applied to ‘blue boy’ winter wheat (Triticum aestivum L.) at the “recommended” and “twice the recommended” rates as the dimethylamine salt (1.68 and 3.36 kg ai [active ingredient]/ha) and the isooctyl ester (1.12 and 2.24 kg ai/ha). Low levels of 2,4‐DB residues (4.9–7.4 ppmw) were found in wheat straw harvested 70 d after spraying with the isooctyl ester formulation, but no 2,4‐DB residues were found in wheat straw treated with the dimethylamine form. The grain did not contain detectable levels of 2,4‐DB or 2,4‐D [(2,4‐dichlorophenoxy] acetic acid) residues from any 2,4‐DB treatment. No difference in yield between the control and 2,4‐DB‐treated plots was obtained. Rainfall that occurred 4 h after application may have resulted in some loss of the herbicide and the data presented should be considered preliminary.
Radionuclide Concentrations in Vegetation at a Solid Radioactive Waste‐Disposal Area in Southeastern Idaho
Authors: Arthur W. J.
Published: July 2010

Concentrations of 238Pu, 239,240Pu, and 241Am in crested wheatgrass (Agropyron cristatum (L.) Gaertn) and Russian thistle (Salsola kali L.) samples collected at a solid radioactive waste‐disposal area in southeastern Idaho were significantly (P ± 0.05) greater than concentrations in control vegetation. No significant differences were found for 90Sr or 137Cs concentrations between the waste‐disposal and control‐area vegetation. Russian thistle had more radionuclide contamination than crested wheatgrass, presumably because of its greater rooting depth and spreading growth. The total radionuclide inventory of 90Sr, 137Cs, 238Pu, 239,240Pu, and 241Am in vegetation at the 36‐ha waste‐disposal area (77 µCi) was not significantly (P > 0.05) greater than the 17 µCi in control‐area vegetation. Ninety percent of the radioactivity in waste‐disposal area vegetation and 99% in control‐area vegetation were attributed to 90Sr and 137Cs. The Pu inventory in Subsurface Disposal Area (SDA) vegetation was only 0.02% of the quantity of Pu estimated to occur in SDA surface soils in 1974. Accumulation of radionuclides by vegetation is not considered a major mode of radionuclide transport through the environment surrounding this radioactive‐waste‐disposal area.
A Comparison of Cadmium and Zinc Accumulation by Four Cultivars of Barley Grown in Sludge‐Amended Soils
Authors: Chang A. C. , Page A. L. , Foster K. W. , Jones T. E.
Published: July 2010

A greenhouse experiment was conducted to compare the plant‐tissue accumulation of Cd and Zn by four cultivars of barley (Hordeum vulgare L.) grown on three soils amended with 20 and 100 t/ha dried Imhoff tank sludges. Results indicated that metal uptakes by four cultivars of barley (Barsoy, Briggs, Florida 103, and Larker) were not significantly different when they were grown on both sludge‐treated and non‐sludge‐treated (control) soils. The Cd and Zn concentrations of the plant tissue from sludge‐treated soils, however, were significantly influenced by the sludge application and the soil type. For four cultivars of barley grown on the Ramona sandy loam soil, the Cd content of grain averaged < 0.04 (< 0.04–0.03) µg/g at the control and increased to 0.38 (0.19–0.53) µg/g at the 100‐t/ha sludge treatment. Under the sameconditions, the average Zn concentrations of barley grain were 41, 67, and 92 µg/g for the control, 20‐t/ha, and 100‐t/ha treatments, respectively. Both soil texture and pH influenced Cd and Zn contents of barley. Crops grown on the Domino loam soil (fine, mixed, thermic Xerollic Calciorthid) accumulated the least amounts of Cd and Zn. At heavy sludge applications, higher levels of plant‐tissue Cd and Zn were often found in barley grown on soils of coarser texture (Ramona sandy loam [fine, mixed, thermic Typic Haploxeralf] and Greenfield sandy loam [coarse, mixed, thermic Typic Haploxeralf]) and lower pH (Ramona sandy loam, pH = 6.0).
Concentrations of Six Trace Metals in Some Major Minnesota Soil Series
Authors: Pierce F. J. , Dowdy R. H. , Grigal D. F.
Published: July 2010

Concentrations of Cd, Cr, Cu, Ni, Pb, and Zn were determined in 16 soil series in Minnesota to establish baseline levels of these trace metals. These soils are representative of those formed on seven major parent materials in the state and comprise a broad range of soil properties. Extracts with 0.1M K4P2O7·3H2O, 1.0NW HNO3, and a concentrated HCl‐HNO3‐HF acid mixture were used to characterize the soils for organically bound, “biodiagenetically” available, and total metal content, respectively. Total metal contents were in the lower portion of ranges reported in the literature and represented levels naturally present in uncontaminated soils. Total Cd, Cr, Cu, Ni, Pb, and Zn averaged (± SD) 0.31 (±0.21), 43 (±28), 26 (±9), 21 (±14), <25, and 54 (±18) µg/g, respectively. The average extraction efficiency of HNO3 for total metals was highest for Cd (52 ± 19%) and the lowest for Cr (14 ± 7%). The predominate trend in both available and total metal content showed highest concentrations of Cd, Pb, and Zn in the surface soil and highest concentrations of Cr, Cu, and Ni in subsoil and parent materials. Cadmium was often higher in soils containing free carbonates. Concentrations of organically bound metals in soil were very low, and, with the exception of Cu, were usually negligible below the surface layer. Differences in metal content among soils were believed due to differences in the parent materials. Variations within soil series were low, with genetic horizons showing narrow ranges in HNO3‐extractable metals.
Selected Trace Elements in Plants Grown on Retorted Oil Shales
Authors: Kilkelly M. K. , Lindsay W. L.
Published: July 2010

Western wheatgrass (Agropyron smithii Rydb. ‘Arriba’) and fourwing saltbush (Atriplex canescens (Pursh) Nutt.) were sampled from oil shale revegetation plots in northwestern Colorado. Plants were growing on two types of retorted shales: TOSCO II, produced by the Tosco Corporation; and USBM, produced by the U.S. Bureau of Mines. Various treatments included leaching and different depths of soil covering over the retorted shales. Plant samples were analyzed for B, Mo, As, Se, and F on a dry‐weight basis. Plant samples with elevated Mo concentrations were also analyzed for Cu.

Boron in western wheatgrass from the TOSCO retorted shale ranged from 85 to 202 ppm, compared with ranges of 4 to 15 ppm B in plants from the soil control. Analysis of variance indicated significant differences in B content due to site, aspect, type of retorted shale, and amount of soil cover over retorted shale. The concentration of B in western wheatgrass growing on retorted shales, especially TOSCO retorted shale, could affect plant growth. Fourwing saltbush samples, growing on USBM retorted shales, contained levels of Mo averaging 28 ppm, and low‐to‐moderate Cu content (4.8–6.8 ppm). This combination could make this species unacceptable as forage for ruminants. The concentrations of As (0.03–0.44 ppm), Se (0.02–0.94 ppm); and F (0.5–10.0 ppm) in the plant species investigated in this study were below limits usually set for either plant or animal toxicities and appear to be of little environmental significance.
Using EPA's Computerized Data Base (STORET) to Analyze for Agricultural Water Pollution
Authors: Reardon John C. , Hanson Lowell D. , Randolph John
Published: July 2010

The U.S. Environmental Protection Agency's computer data base (STORET) was employed to retrieve stream water quality data for a 9‐year period on an agricultural watershed in Maryland, 40 km northwest of Washington, D.C. Most of the farms in the area are large dairy operations that have waste management and storage facilities. During the study period, farmers increased their use of no‐till and minimum‐tillage corn (Zea mays L.) practices by as much as 90%, and several operators also installed animal waste‐control facilities.

Total PO4, fecal coliform, and NO3 + NO2‐N data from four sampling stations in the watershed were retrieved from STORET and statistically analyzed using linear regression to relate concentration and time. The regressions indicated that concentrations of total PO4 and fecal coliform decreased with time. Total PO4 data from all four sampling stations showed a significant inverse relationship between time and concentration (5% probability or less). Of the four fecal coliform regressions, the furthest‐upstream sampling station was significant while the next one downstream approached significance (6% level). No statistical significance was evident in the NO3 + NO2‐N regression equations at any of the four stations during the 9‐year period.

Results indicated that the time and costs for this type of analysis were reduced substantially by using the computer‐stored data base rather than direct sampling and laboratory analysis. A study similar to this one, but with in‐house data collection and analysis, would cost approximately 10 times more than the study reported herein.
Growth and Nutrition of White Pine and White Spruce Seedlings in Solutions of Various Nickel and Copper Concentrations
Authors: Lozano F. C. , Morrison I. K.
Published: July 2010

As part of an investigation of the ways in which supply is related to growth and foliage concentration, and as part of a larger problem of tree establishment on certain polluted soils, seedlings of white pine (Pinus strobus L.) and white spruce (Picea glauca (Moench) Voss) were grown from seed over a 20‐week period in nutrient solutions of various Ni and/or Cu concentrations in growth chambers. In one series, Ni was supplied during the latter part of the test period at 0, 0.01, 0.1, 1, and 10 ppm; in a second, Cu was supplied at 0, 0.01, 1, 10, and 100 ppm; and in a third, Ni and Cu were supplied together in factorial combination at 0, 1, and 10 ppm. At the end of each experiment the seedlings were harvested and growth and chemical composition were determined. In general, substantial reductions in growth occurred when concentrations of Ni and/or Cu in the nutrient solutions were ≥ 10 ppm. There was some suggestion that white spruce seedlings were more susceptible than white pine seedlings to elevated Ni levels, with the order being reversed for Cu. Foliage concentrations of Ni and/or Cu increased in relation to their concentrations in the external solutions. No definitive trends were evident in foliage concentrations of other dements except Fe and Zn, both of which decreased: Fe in relation to both Ni and Cu supply, Zn chiefly in relation to Ni supply.
Retention and Movement of Fluoride in Soils
Authors: Flühler H. , Polomski Janina , Blaser P.
Published: July 2010

Displacement and retention of fluoride in soils were studied in laboratory experiments. Fluoride adsorption and desorption isotherms were determined in the range of 0 to 5,000 µg mL−1 of dissolved F by shaking 1:10 soil/NaF solution suspensions. The observed relationship was nonlinear. Neither Langmuir nor Freundlich equations were unbiased predictors of the measured relationship.

The experimental errors propagated in the computational analysis and made such adsorption data quite error‐prone. For soils with a low F retention the confidence interval was wide, and vice‐versa. In an acid clay soil an apparent adsorption equilibrium was attained within 3 h, but several days were required for the equilibration of the calcareous soils with the NaF solution. Adsorption and desorption of the calcareous soils exhibited a hysteretic behavior, but in the case of the acid soil no hysteresis was observed.

The transport of F was studied by percolating soil columns at a constant flow rate. The F breakthrough depended primarily upon the F concentration in the infiltrating solution and soil type, whereas the ionic composition of the infiltrating solution had a less pronounced effect on the breakthrough behavior.

The F retention within the soil columns and the adsorption estimates obtained from the isotherms agreed well in the case of the acid soil, but the calcareous soils retained one‐third to one‐half as much F during the percolation experiment.
Agriculture and Water Quality in the Canadian Great Lakes Basin: II. Fluvial Sediments
Authors: Wall G. J. , Dickinson W. T. , van Vliet L. J. P.
Published: July 2010

Unit‐area yields of suspended sediments discharged from 11 small (<6,000 ha) agricultural watersheds in southern Ontario ranged from <100 to 1,000 kg ha−1 year−1 in a 2‐year study. Estimated bank erosion contributed between 0 and 30% of the suspended sediment, while estimated cropland sheet and rill erosion contributed 70–100%. Regression analyses relating 14 watershed characteristics to unit‐area yields showed that percent clay of the surface soil and percent row crop were the most significant (R2 = 0.64) factors in estimating suspended sediment yields.

Detailed studies in the agricultural watersheds were used to generate and test three independent methods for the prediction of suspended sediment yields from cropland. The agricultural contribution to suspended sediment were predicted for the Grand and Saugeen river basins and for the over 300 subbasins of the Canadian Great Lakes Basin. It was estimated that agricultural land‐use activities contribute over 650 × 103 t of suspended sediment to the Great Lakes annually.
An Evaluation of Three Pesticide Runoff Loading Models
Authors: Lorber Matthew N. , Mulkey Lee A.
Published: July 2010

Three nonpoint source runoff models were tested and compared for their abilities to predict the movement of the pesticides toxaphene and atrazine (2‐chloro‐4‐(ethylamino)‐6‐(isopropylamino)‐1,3,5‐triazine) from a 15.6‐ha watershed in the Mississippi Delta region and a smaller watershed in the Southern Piedmont. The three models are the Agricultural Runoff Management (ARM), Continuous Pesticide Simulation (CPS), and the Chemical, Runoff, and Erosion from Agricultural Management Systems (CREAMS). Published data on runoff, erosion, toxaphene, and atrazine runoff were used to test the models. Testing exercises indicated that all models accurately reproduced field data. For the total period of study, model predictions of total runoff differed from field observations by 15% or less. For the CPS and ARM models, predictions of total erosion differed from observations by 6%, whereas CREAMS underpredicted erosion by 25%. All models are within 10% of observations in overland toxaphene loss predictions. Five‐year simulations indicated that the models can differ in their predictions of peak events. Sensitivity analysis indicated that ARM can predict higher losses of soluble chemicals than CPS or CREAMS, due to an interflow component unique to the ARM model. Similarly, estimation of a sediment enrichment in the CREAMS model resulted in higher toxaphene loss predictions than the other two models.
Nitrogen and Phosphorus Movement in Compost‐Amended Soils
Authors: Inman J. C. , Mc Intosh M. S. , Foss J. E. , Wolf D. C.
Published: July 2010

The application of high rates of sewage sludge can pollute ground water if significant levels of nutrients move through the soil. A field study was conducted to investigate the effect of composted sewage sludge on NO3‐N, PO4‐P, and electrical conductivity (EC) levels in soil water collected at three depths. Composted municipal sewage sludge was disked into a Chester silt loam (Typic Hapludult) at rates of 0, 150 and 300 dry t/ha. White pine (Pinus strobus L.) seedlings and hybrid poplar (Populus generosa Henri) cuttings were grown on the plots, which had been seeded with ‘Kentucky 31’ tall fescue (Festuca arundinacea Schreb.). For 30 months, beginning the spring after compost application, NO3‐N, PO4‐P, and EC of the soil‐water solution were monitored in subsurface water samples taken from the Ap, B, and C horizons, which corresponded to depths of 15, 45, and 100 cm, respectively.

During the year following the compost application, concentrations of NO3‐N were highest, 70–80 µg NO3‐N/mL, in the C horizon in the 300‐t/ha treatment. However, the corresponding concentrations decreased to <10 µg NO3‐N/mL by 30 months after compost addition. Total Kjeldahl N (TKN) concentrations of the soils treated with 150 and 300 t/ha of compost were approximately two and three times higher than those in control soils, respectively. The TKN concentrations in compost‐treated soils showed <7% decrease over the 30 months. The PO4‐P concentrations of water samples in compost‐treated soils were generally below 0.08 µg PO4‐P/mL, and never exceeded those concentrations found in control soils. The EC of water samples increased with the compost additions. After 267 d, EC values averaged 1.0 mmhos/cm in the 300‐t/ha treatment, and 0.7 mmhos/cm in the 150‐t/ha treatment, as compared with 0.2 mmhos/cm in the control. The EC values of the sludge compost treatments declined to <0.4 mmhos/cm by the second spring after the compost application, and EC levels were below levels toxic to plants.