bluuebunny/crossref_metadata_2025_split huggingface dataset:
Compost Age and Sample Storage Effects on Maturity Indicators of Biosolids Compost
Authors: Butler T.A. , Sikora L.J. , Steinhilber P.M. , Douglass L.W. 
Published: June 2010

ABSTRACTCompost product safety and quality assurance are required to meet the needs of the horticultural, agricultural, and silvicultural user markets. At present, there exist no industry‐wide sampling and testing protocols for compost products, thus limiting the production sector. The objective of this research was to test three methods for determining compost maturity. The study followed the composting process of a locally successful commercial composting operation that had been producing lime‐stabilized biosolids compost in the Washington, DC metro region for 12 yr. Change over time in the dependent variables—Dewar flask self‐heating capacity, oxygen uptake rate, and cation exchange capacity (CEC)—during a 57‐d composting of lime‐stabilized biosolids was studied. Because cold storage at 4°C is recommended when compost samples cannot be tested for maturity immediately, cold storage of up to 11 wk was included as a variable. Mathematical models were developed that predict change in the Dewar flask self‐heating capacity, oxygen uptake rate, and CEC with composting time and storage at 4°C. The Dewar flask self‐heating test was the most useful indicator of compost maturity. This test showed change throughout the 57‐d biosolids composting period while oxygen respirometry did not change after 29 d. The CEC was found to increase with age and storage. Storage effects varied for the different tests. Except for Days 1 and 57, composts continued to stabilize during storage. Testing stored composts may produce erroneous results that suggest the compost is mature.
Evaluation of the Application of Pig Slurry to an Experimental Crop Using Agronomic and Ecotoxicological Approaches
Authors: Diez J. A. , de la Torre A. I. , Cartagena M. C. , Carballo M. , Vallejo A. , Muñoz M. J. 
Published: June 2010

ABSTRACTThe agronomic and ecotoxicological effects of the application of pig (Sus scrofa) slurry during a maize (Zea maysL.) crop cycle under conditions of forced irrigation were evaluated. The 0.2‐ha experimental area, oftypical xerofluventsoil and of known vulnerability to nitrate (NO−3) contamination, was divided into 12 plots and provided with water measurement instruments (TDR‐probes, vertical tensiometers, and ceramic candles). Samples of soil, water, soil organisms, and the crop were subjected to analytical, agronomic, and biological test procedures. The following fertilizer treatments were applied to triplicate plots: urea (U;170 kg N ha−1), and an optimized (P1; 162 kg N ha−1) and triple (P3; 486 kg N ha−1) dose of pig slurry. Unfertilized plots (P0) served as controls. Calculation was made of seasonal drainage and leached NO−3and sodium losses during the experimental period. Conductivity, heavy metal concentration, hardness, pH, and redox potential were determined in soil solutions. The ecotoxicological evaluation of the soil solution and matrix was based on ecotoxicity bioassays and the quantification of organic and inorganic compounds [phenols, indols, polychlorinated biphenyls (PCBs)]. The results suggest that the P3 treatment is highly contaminating due to the leaching of nitrates and increased soil salinity. Despite the fact that aFolsomia candidareproduction test indicated chronic ecotoxicological effects on the soil in plots treated with P1 and P3, the absence of organic compounds suggests that these effects may be attributable to contaminants not considered in this study.
Spatial and Time Distribution of Dairy Cattle Excreta in an Intensive Pasture System
Authors: White S. L. , Sheffield R. E. , Washburn S. P. , King L. D. , Green J. T. 
Published: June 2010

ABSTRACTThis study determined distribution of feces and urine from 36 lactating dairy cattle (Bos taurus) managed in a rotationally grazed 0.74‐ha endophyte‐free tall fescue (Festuca arundinacea Schreb.)–white clover (Trifolium repens L.) pasture. Cows were observed for 24 h five times from July 1997 to April 1998, and for 13.5 h in September 1997. During each 24‐h observation period, the first grazing period (12 h) used 54% of the paddock and the second grazing period (8 h) used the entire paddock. Times and locations of all defecations and urinations from a subgroup of eight cows, observed while in the pasture, feed area, milking parlor, or in transit were recorded during the observation periods listed above and another time in May 1997. On pasture, all defecations and urinations were surveyed and mapped for all 36 cows. Feces and urine from six observation periods covered an estimated 10% of the paddock area in one year. Within 30 m of the water tank, concentrations of feces and urine from three warm‐season observations were significantly greater than concentrations during three cool‐season observations. Percentages of defecations and urinations on the pasture, feeding, and milking areas were highly correlated (r > 0.90) with time spent in those areas. Pasture‐based systems could reduce manure handling and storage requirements proportional to the time cattle are on pastures. Manure on the pasture was evenly distributed, except around the water tank during warm‐weather grazings. Results indicate that pasture‐based dairy systems may require smaller, less‐expensive manure management systems compared with confinement dairy farms.
Predicting Physical and Chemical Water Properties from Relationships with Watershed Soil Characteristics
Authors: Shirazi Mostafa A. , Boersma Larry , Johnson Colleen Burch , Haggerty Patricia K. 
Published: June 2010

ABSTRACTThe Surface Waters component of the Environmental Monitoring and Assessment Program (EMAPSW) was developed by the USEPA to evaluate the extent and condition of lakes and streams over national and regional scales. Realistically, chemical or physical water properties (WPs) such as acidity or turbidity can be field‐sampled for only a small portion of all lakes and streams. However, soil characteristics (SCs) affect WPs and broad‐scale soil survey data have become available in the State Soil Geographic Data Base (STATSGO). We developed models relating observed WPs to SCs to extrapolate the sampled WPs to a region, potentially reducing extensive monitoring needs. Our study region consisted of 13 northeastern and Mid‐Atlantic states and contained 882 STATSGO soil map units. We used map units as the spatial component of WP analysis. The WPs were sampled in 721 randomly selected EMAPSW study sites. The watersheds of these sites represent 7.1% of the region's total area and spatially intersect 400 of its soil map units. Each intersected map unit was assigned the weighted average WPs from the corresponding watersheds. Conditional expectation models were used to extrapolate sampled WPs to 882 map units. The relative standard errors ranged from low for pH (0.8%), intermediate for total P (12.1%), and very high for chloride (54.8%). The high extrapolation errors indicate outlier conditions from natural, non‐soil, or anthropogenic sources.
Photodegradation of Selected Herbicides in Various Natural Waters and Soils under Environmental Conditions
Authors: Konstantinou Ioannis K. , Zarkadis Antonios K. , Albanis Triantafyllos A. 
Published: June 2010

ABSTRACTThe photochemical degradation of herbicides belonging to different chemical groups has been investigated in different types of natural waters (ground, river, lake, marine) and distilled water as well as in soils with different texture and composition. Studied herbicides and chemical groups included atrazine, propazine, and prometryne (s‐triazines); propachlor and propanil (acetanilides); and molinate (thiocarbamate). The degradation kinetics were monitored under natural conditions of sunlight and temperature. Photodegradation experiments were performed in May through July 1998 at low concentrations in water samples (2–10 mg/L) and soil samples (5–20 mg/kg), which are close to usual field dosage. The photodegradation rates of all studied herbicides in different natural waters followed a pseudo–first order kinetics. The half‐lives of the selected herbicides varied from 26 to 73 calendar days in waters and from 12 to 40 d in soil surfaces, showing that the degradation process depends on the constitution of the irradiated media. The presence of humic substances in the lake, river, and marine water samples reduces degradation rates in comparison with the distilled and ground water. On the contrary, the degradation in soil is accelerated as the percentage of organic matter increases. Generally, the photodegradation process in soil is faster than in water. The major photodegradation products identified by using gas chromatography–mass spectrometry (GC–MS) techniques were the hydroxy and dealkylated derivatives for s‐triazines, the dechlorinated and hydroxy derivative for the anilides, and the keto‐derivative for the thiocarbamate, indicating a similar mode of degradation for each chemical category.
Biosolids Application in the Chihuahuan Desert: Effects on Runoff Water Quality
Authors: Rostagno César M. , Sosebee Ronald E. 
Published: June 2010

ABSTRACTSurface‐applied biosolids, the option most often used on rangelands, can increase the concentration of macronutrients and trace elements in the runoff water and can potentially produce eutrophication or contamination of surface waters. In this study, the effects of postapplication age of biosolids (18, 12, 6, and 0.5 mo) and rate of application (0, 7, 18, 34, and 90 Mg ha−1) on the quality of runoff water from shrubland and grassland soils were assessed. Between July and October 1996 simulated rainfall was applied to 0.50‐m2plots for 30 min at a rate of 160 mm h−1. All of the runoff water was collected. The concentration of NH+4–N, NO−3–N, PO3−4–P, total dissolved phosphorus (TDP), Cu, and Mn in the runoff water increased with rate of biosolids application and decreased with time of postapplication on the two soils. The highest PO3−4–P and NH+4–N concentrations, 4.96 and 97 mg L−1, respectively, were recorded in the grassland soil treated with 90 Mg ha−1of biosolids 0.5 mo postapplication. For the same soil, rate, and postapplication age of biosolids, Cu exceeded the upper limit (0.50 mg L−1) in drinking water for livestock. Ammonium N and PO3−4–P should be the main compounds considered when surface‐applying biosolids. Ammonium N at concentrations found in all biosolids‐treated plots may affect the quality of livestock drinking water by causing taste and smell problems. Orthophosphate can contribute to eutrophication if the runoff from biosolids‐treated areas enter surface waters.
Field‐Scale Preferential Transport of Water and Chloride Tracer by Depression‐Focused Recharge
Authors: Derby Nathan E. , Knighton Raymond E. 
Published: June 2010

ABSTRACTA tracer study was initiated in November 1993 to investigate depression‐focused recharge and to monitor solute movement through the vadose zone into the shallow ground water in southeastern North Dakota. Granular potassium chloride (KCl) was surface‐applied to two areas overlying subsurface drains and to one area instrumented with soil solution samplers, ground water monitoring wells, time domain reflectometry (TDR) probes, and temperature probes. One of the subsurface drain tracer plots was located on level ground while the other two sites were in small topographic depressions. Formation of ground water mounds beneath the depressions indicated that these areas are recharge sites. The applied Cl− tracer was found to move rapidly to the shallow ground water under the depressional areas after infiltration of spring snowmelt in 1994. Excessive rainfall events were also responsible for focused recharge and the rapid transport of the applied Cl− tracer. Water flow through partially frozen soil at the bottom of the depressions during thaw enhanced preferential movement of the tracer.
Nutrient Movement and Removal in a Switchgrass Biomass–Filter Strip System Treated with Dairy Manure
Authors: Sanderson Matt A. , Jones Ronald M. , McFarland Marshall J. , Stroup Jason , Reed Roderick L. , Muir James P. 
Published: June 2010

ABSTRACTManure use on cropland has raised concern about nutrient contamination of surface and ground waters. Warm‐season perennial grasses may be useful in filter strips to trap manure nutrients and as biomass feedstock for nutrient removal. We explored the use of ‘Alamo’ switchgrass (Panicum virgatum L.) in a biomass production–filter strip system treated with dairy manure. We measured changes in extractable P in the soil, NO3–N in soil water, and changes in total reactive P and chemical oxygen demand (COD) of runoff water before and after a switchgrass filter strip. Five rates of dairy manure (target rates of 0, 50, 100, 150, and 200 kg N ha−1 from solid manure in 1995; 0, 75, 150, 300, and 600 kg N ha−1 from lagoon effluent in 1996 and 1997) were surface‐applied to field plots of switchgrass (5.2 by 16.4 m) with a 5.2‐ by 16.4‐m switchgrass filter strip below the manured area. Yield of switchgrass from the manured area increased linearly with increasing manure rate in each year. Soil water samples collected at 46 or 91 cm below the soil surface on 30 dates indicated <3 mg L−1 of NO3–N in all plots. Concentrations of total reactive P in surface runoff water were reduced an average of 47% for the 150 kg N rate and 76% for the 600 kg N rate in 1996 and 1997 after passing through the strip. Manure could effectively substitute for inorganic fertilizer in switchgrass biomass production with dual use of the switchgrass as a vegetative filter strip.
Rapid Methods to Determine Potentially Mineralizable Nitrogen in Broiler Litter
Authors: Qafoku O. S. , Cabrera M. L. , Windham W. R. , Hill N. S. 
Published: June 2010

ABSTRACTAlthough broiler (chicken,Gallus gallus domesticus) litter has long been used as a fertilizer, estimating the rate required to supply a desired amount of plant‐available N is still hampered by the lack of rapid methods to estimate potentially mineralizable nitrogen (PMN). Previous research has suggested that near infrared reflectance spectroscopy (NIRS) and certain poultry litter characteristics, such as water‐soluble organic nitrogen (WSON), may be useful for estimating PMN. The objectives of this study were to evaluate NIRS and WSON as tools to estimate PMN in broiler litter. Sixty sieved (2 mm) and freeze‐dried broiler litter samples were mixed with Cowarts sandy loam soil (fine‐loamy, kaolinitic, thermic Typic Kanhapludult) and incubated at 25°C for 112 d. Cumulative net N mineralized with time was fitted to a single‐pool exponential model to determine PMN for each broiler litter sample. The PMN values obtained were regressed against NIRS (780 to 2500 nm) and WSON measurements. We found strong relationships between measured‐ and NIRS‐predicted PMN, and between measured PMN and WSON. These results demonstrate the feasibility of using either of these two methods to estimate PMN in broiler litter. Future work should further test both methods for their ability to estimate mineralizable N in whole, moist broiler litter under field conditions.
Transport of Escherichia coli in Sand Columns with Constant and Changing Water Contents
Authors: Powelson David K. , Mills Aaron L. 
Published: June 2010

ABSTRACTUnderstanding how changes in volumetric water content (θ) affect bacterial adsorption could help reduce transport of pathogenic and indicator bacteria that may be present in infiltrating wastewater. Three flow regimes that simulated infiltration from a household septic system were evaluated: saturated, unsaturated with a constant volumetric water content θ (constant unsaturated flow), and unsaturated with cyclic changes in θ (variable unsaturated flow). Escherichia coli was suspended in artificial sewage (AS) and applied as step inputs to sand columns, with regular interruptions in input for variable unsaturated flow. A transport model was fit to the saturated and constant unsaturated flow breakthrough curves to determine retardation (R), the first‐order filtration coefficient (μ), and the maximum outflow relative concentration (Cmax). The total cells transported as a fraction of input (τ) in all three flow regimes was calculated. Constant unsaturated flow resulted in a significantly lower Cmax (0.633) in comparison with saturated flow (0.803, P ≤ 0.05), although unsaturated μ (0.0693 h−1) was not significantly different from saturated μ (0.0259 h−1). Constant unsaturated flow also resulted in a significantly smaller τ (0.617) than saturated (0.806) or variable unsaturated flow (0.734). In variable unsaturated flow, cell concentrations were out of phase with θ—as the column drained, cell concentrations in the outflow increased; and when a pulse of suspension was applied, cell concentrations decreased. Constant unsaturated flow is probably the best for removal of pathogenic bacteria because this regime resulted in lower maximum concentrations of E. coli and greater cell removal, in comparison with saturated and variable unsaturated flow.
Alfalfa Rapidly Remediates Excess Inorganic Nitrogen at a Fertilizer Spill Site
Authors: Russelle Michael P. , Lamb JoAnn F.S. , Montgomery Bruce R. , Elsenheimer Donald W. , Miller Bradley S. , Vance Carroll P. 
Published: June 2010

ABSTRACTBy 1996, standard remediation techniques had significantly reduced the concentration of nitrate nitrogen (NO−3–N) in local ground water at the site of a 1989 anhydrous ammonia spill, but NO−3–N concentrations in portions of the site still exceeded the public drinking water standard. Our objective was to determine whether local soil and ground water quality could be improved with alfalfa (Medicago sativaL.). A 3‐yr study was conducted in replicated plots (24 by 30 m) located hydrologically upgradient of the ground water under the spill site. Three alfalfa entries [‘Agate’, Ineffective Agate (a non‐N2–fixing elite germplasm similar to Agate), and MWNC‐4 (an experimental germplasm)] were seeded in the spring of 1996. Corn (Zea maysL.) or wheat (Triticum aestivumL.) was seeded adjacent to the alfalfa each year. Crops were irrigated with N‐containing ground water to meet water demand. During the 3‐yr period, about 540 kg of inorganic N was removed from the aquifer through irrigation of 4.9 million L water. Cumulative N removal from the site over 3 yr was 972 kg N ha−1in Ineffective Agate alfalfa hay, compared with 287 kg N ha−1for the annual cereal grain. Soil solution NO−3concentrations were reduced to low and stable levels by alfalfa, but were more variable under the annual crops. Ground water quality improved, as evidenced by irrigation water N concentration. We do not know how much N was removed by the N2–fixing alfalfas, but it appears that either fixing or non‐N2–fixing alfalfa will effectively remove inorganic N from N‐affected sites.
Phosphate Release from Seasonally Flooded Soils
Authors: Young Eric O. , Ross Donald S. 
Published: June 2010

ABSTRACTPhosphorus derived from agricultural practices has been targeted as a leading cause of water quality degradation in Lake Champlain. Mobilization of P from seasonally flooded agricultural soils is a concern. Using 14 soils from a research farm in New York's Champlain Valley, we characterized the available P status, extractable Fe and Al, P sorption capacities, and soluble phosphate release in flooded laboratory microcosms. Quantities of NH4–acetate available P ranged from 3 to 100 mg kg−1 and fluoride‐extractable P from 10 to 211 mg kg−1 Flooding soils induced significant release of phosphate to the porewater over a 60‐ to 90‐d period in 13 of the 14 soils studied. Porewater phosphate increases ranged from 2.2 to 27.0 times the initial phosphate concentrations. However, floodwater phosphate increases were much lower, with a maximum of 3.6 times the initial concentration. Average porewater phosphate concentrations over the flooding period ranged from 0.046 to 7.0 mg L−1 and average floodwater P from 0.032 to 3.70 mg L−1 Ammonium‐acetate P and the degree of phosphorus saturation (DPS) were highly correlated with the average porewater and floodwater phosphate concentration. Average ratio of porewater to floodwater phosphate concentrations ranged from 1.0 to 3.3. Five soils that were lower in fluoride‐extractable P had increasing porewater phosphate accompanied by increasing porewater Fe2+ and decreasing floodwater phosphate. Results suggest that P solubility and mobility were a function of both the available P status and redox cycling.
Overview of Hypoxia around the World
Authors: Diaz Robert J. 
Published: June 2010

ABSTRACTNo other environmental variable of such ecological importance to estuarine and coastal marine ecosystems around the world has changed so drastically, in such a short period of time, as dissolved oxygen. While hypoxic and anoxic environments have existed through geological time, their occurrence in shallow coastal and estuarine areas appears to be increasing, most likely accelerated by human activities. Several large systems, with historical data, that never reported hypoxia at the turn of the 19th century (e.g., Kattegat, the sea between Sweden and Denmark) now experience severe seasonal hypoxia. Synthesis of literature pertaining to benthic hypoxia and anoxia revealed that the oxygen budgets of many major coastal ecosystems have been adversely affected mainly through the process of eutrophication (the production of excess organic matter). It appears that many ecosystems that are now severely stressed by hypoxia may be near or at a threshold of change or collapse (loss of fisheries, loss of biodiversity, alteration of food webs).
Nitrogen Input to the Gulf of Mexico
Authors: Goolsby Donald A. , Battaglin William A. , Aulenbach Brent T. , Hooper Richard P. 
Published: June 2010

ABSTRACTHistorical streamflow and concentration data were used in regression models to estimate the annual flux of nitrogen (N) to the Gulf of Mexico and to determine where the nitrogen originates within the Mississippi Basin. Results show that for 1980–1996 the mean annual total N flux to the Gulf of Mexico was 1568000 t yr−1 The flux was about 61% nitrate N, 37% organic N, and 2% ammonium N. The flux of nitrate N to the Gulf has approximately tripled in the last 30 years with most of the increase occurring between 1970 and 1983. The mean annual N flux has changed little since the early 1980s, but large year‐to‐year variations in N flux occur because of variations in precipitation. During wet years the N flux can increase by 50% or more due to flushing of nitrate N that has accumulated in the soils and unsaturated zones in the basin. The principal source areas of N are basins in southern Minnesota, Iowa, Illinois, Indiana, and Ohio that drain agricultural land. Basins in this region yield 1500 to more than 3100 kg N km−2 yr−1 to streams, several times the N yield of basins outside this region.