bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nitrogen Balance in a Pond System Receiving Tertiary Effluent
Authors: Lund L. J. 
Published: July 2010

AbstractA constructed wetland system near Riverside, CA, received tertiary treated effluent from the local wastewater treatment plant. This nitrate‐dominated effluent flowed through four ponds with a combined area of 10 ha, which were connected in series. Flow measuring devices were installed on the inlet and outlet to the pond system and suction lysimeters were installed beneath the ponds. Flow data, samples of surface water, and lysimeter extracts were collected for over 18 mo. Water and N balances were developed for a 1‐yr period, during which flow to the ponds was continuous. Of the water entering the pond system, 37% left as outflow, 3% evaporated, and 60% infiltrated. The average total inorganic nitrogen (TIN) concentration in the outflow was reduced by 32% compared with the inflow concentration (11.1 mg L−1 vs. 16.3 mg L−1). The average TIN concentration was 3.6 mg L−1 in extracts from beneath the ponds. Using a mass balance approach, 62% of the inflow TIN was not accounted for by TIN leaving the pond system in surface and subsurface flow. This TIN was lost from the system, most likely by denitrification. When expressed on an area basis, the TIN loss was approximately 1500 mg m−2 d−1, a value typical for many effluent dominated wetlands. Based on the results of this study, the city of Riverside decided to expand and enhance the wetlands for use in meeting their N discharge requirements, rather than investing in major capital improvements in additional in‐plant treatment facilities.
Mode of Transport of Surface‐Applied Phosphorus‐33 through a Clay and Sandy Soil
Authors: Djodjic Faruk , Bergström Lars , Ulén Barbro , Shirmohammadi Adel 
Published: July 2010

AbstractPhosphorus (P) is the limiting nutrient for primary production in most freshwater ecosystems. The magnitude of P leaching from agricultural soils is therefore critical. Preferential flow has been proposed as a major cause for high P losses in structured clay soils. Undisturbed soil of two texturally different soils, that is, a day soil in which preferential flow was expected to be the main mode of water transport and a sandy soil where piston flow is the dominant process, were used in this study. Use of labeled P made it possible to determine the origin of leached P. An equivalent of 100 kg P ha−1, labeled with 33P, was added to the soil surface of each lysimeter. Water equivalents to 100 mm were added on five occasions with 7 d between each watering event. Ponded flow conditions were established during periods when water was added, to trigger preferential Bow behavior. Phosphorus leaching loads from day columns were much higher than P loads from sand columns. The average P leaching load for the five day columns was 4.0 kg ha−1, compared to only 56 g ha−1 for the three sand columns. The main part of leached P was in dissolved (PO4‐P) form. The recently added P prevailed in leachate from the clay soil indicating rapid transport of added P from the soil surface through the profile via macropores.
Leaching of Total Nitrogen from Nitrogen‐15‐Labeled Poultry Manure and Inorganic Nitrogen Fertilizer
Authors: Bergström Lars F. , Kirchmann Holger 
Published: July 2010

AbstractField lysimeters containing an undisturbed sandy soil were used to evaluate leaching of manure‐derived N over 3 yr. Manure labeled with 15N (poultry excreta), which was either fresh or had been decomposed under aerobic or anaerobic conditions, was applied in May during the first year at a rate corresponding to 100 kg total N ha−1. For comparison, labeled 15NH415NO3 (100 kg N ha−1) was applied simultaneously to additional lysimeters while others were left unfertilized. During the second and third year, all lysimeters, except the unfertilized ones, received unlabeled NH4NO3 at a rate of 100 kg N ha−1. Each year, barley (Hordeum vulgare L.) was seeded prior to fertilization. Based on the difference method, leaching of total N during the first year was not significantly different (P > 0.05) between lysimeters treated with NH4NO3, fresh manure, and anaerobic manure, but lower from those with aerobic manure. Regarding leaching of residual manure‐ and fertilizer‐derived N estimated with the 15N method, there was a significant difference (P < 0.05) between the NH4NO3 fertilized and manured lysimeters. As much as 19, 28, and 26% leached in the treatments with fresh, anaerobically, and aerobically decomposed manure, respectively, whereas only about 3% leached in the NH4NO3 fertilized lysimeters in the two subsequent years. The crop uptake of labeled N were smaller in the manured lysimetcrs than in the NH4NO3 fertilized lysimeters. These results suggest that there is a greater potential for N leaching in the longterm from animal manures than from inorganic N fertilizers.
Phosphorus Retention Capacity of the Spodic Horizon under Varying Environmental Conditions
Authors: Nair V. D. , Villapando R. R. , Graetz D. A. 
Published: July 2010

AbstractThe spodic (Bh) horizon of Spodosols with Al, Fe, and C accumulations usually has a high P sorption capacity. However, the Bh horizon of prevalent Spodosols in the Lake Okeechobee basin of Florida is subject to a fluctuating watertable that could change the dynamics of P in these soils under alternating aerobic and anaerobic conditions. Further, the Bh horizon of this basin is often impacted by P moving vertically following heavy surface application of dairy manure. Our objectives were to relate the P retention capacity of the Bh horizons of the Lake Okeechobee basin to other soil parameters, and to evaluate P retention of manure‐impacted Bh horizons under aerobic and anaerobic conditions. High watertable decreased the P retention capacity for the majority of the soils in this study. High manure‐impacted areas have Bh horizons with high P concentrations as a result of P movement from the surface A horizon through the eluted E horizon. The P appeared to be temporarily retained and could be released upon prolonged contact with water. This P is likely to move horizontally above the Bh horizon to drainage ditches and eventually into the lake, causing eutrophication. The equilibrium P concentrations and water soluble P concentrations of Bh horizon soils that did not receive high rates of manure application (native soils and pasture soils) are low and it is unlikely that P would move laterally out of such systems, above the Bh horizon.
Soil Carbon Inventories under a Bioenergy Crop (Switchgrass): Measurement Limitations
Authors: Garten C. T. , Wullschleger S. D. 
Published: July 2010

AbstractApproximately 5 yr after planting, coarse root (>2 mm) carbon (C) and soil organic C (SOC) inventories (0–40 cm deep) were compared under different types of plant cover at four switchgrass (Panicum virgatum L.) production field trials in the southeastern USA. There was significantly (p ≤ 0.05) more coarse root C under switchgrass (Alamo variety) and forest cover than under tall fescue (Festuca arundinacea Schreb.), corn (Zea mays L.), or native pastures of mixed grasses. Inventories of SOC under switchgrass were not significantly greater than SOC inventories under other plant covers. At some locations the statistical power associated with ANOVA of SOC inventories was low, which raised questions about whether differences in SOC could be detected statistically. A minimum detectable difference (MDD) for SOC inventories was calculated. The MDD is the smallest detectable difference between treatment means once the variation, significance level, statistical power, and sample size are specified. The analysis indicated that a difference of ≈50 mg SOC/cm2 or 5 Mg SOC/ha, which is ≈10 to 15% of existing SOC, could be detected with reasonable sample sizes (n = 16) and good statistical power (1 − β = 0.90). The smallest difference in SOC inventories that can be detected, and only with exceedingly large sample sizes (n > 100), is ≈2 to 3% (≈10 mg SOC/cm2 or 1 Mg SOC/ha). These measurement limitations have implications for monitoring and verification of proposals to ameliorate increasing global atmospheric CO2 concentrations by sequestering C in soils.
Sewerage Overflows Put Production and Fertility of Dairy Cows at Risk
Authors: Meijer Gerwin A. L. , de Bree J. , Wagenaar J. A. , Spoelstra S. F. 
Published: July 2010

AbstractMore than 50% of the dairy farmers in the Netherlands use surface water as the main source of drinking water for their cows during the grazing season. The quality of this water may be affected by discharges from sewerage overflows, but possible effects on health of dairy cows have not been quantified. Our objective, therefore, was to assess the risk of impaired production and fertility in dairy cows that drink surface water in direct contact with a sewerage overflow. Standardized milk production of cows from 60 farms using surface water in direct contact with a sewerage overflow was 0.9 L d−1 less (P = 0.09) than that of cows from 397 farms using surface water not in contact with an overflow. Also, age at first calving was 20 d higher (P < 0.01) in heifers exposed to drinking water in contact with sewerage overflows. These results strengthen earlier suggestions that sewerage overflows may reduce production and fertility of dairy cows.
Herbicide Transport on Wind‐Eroded Sediment
Authors: Larney Francis J. , Cessna Allan J. , Bullock Murray S. 
Published: July 2010

AbstractAlthough wind erosion is a pervasive soil degradation problem on the semiarid Canadian prairies, few studies have been conducted on wind‐eroded sediment as an environmental pathway for herbicide transport. An experiment was conducted on a clay loam soil at Lethbridge, AB, in 1993 to 1994, to examine wind‐eroded sediment as a transport mechanism for two soil‐incorporated [trifluralin (2,6‐dinitro‐N,N‐dipropyl‐4‐trifluoromethylaniline) and triallate (S‐2,3,3‐trichloroallyl diisopropylthiocarbamate)] and four surface‐applied herbicides [diclofop {(±)‐2‐[4‐(2,4‐dichlorophenoxy)phenoxy]propanoic acid), bromoxynil (3,5‐dibromo‐4‐hydroxybenzonitrile), mecoprop {(±)‐2‐(4‐chloro‐2‐methylphenoxy)propanoic acid}, and 2,4‐D (2,4‐dichlorophenoxyacetic acid)]. The concentrations of diclofop and bromoxynil in sediments decreased with increasing capture height, with the 100‐cm height having significantly lower concentrations (diclofop, 627 µg kg−1; bromoxynil, 70 µg kg−1) than the 10‐cm height (diclofop, 1132 µg kg−1; bromoxynil, 231 µg kg−1). This implies that these herbicides were primarily associated with larger soil particles captured closer to the soil surface. For the soil‐incorporated herbicides, concentrations were significantly higher in the surface soil (0–2.5 cm) than in the wind‐eroded sediment, whereas concentrations of surface‐applied herbicides were generally higher in wind‐eroded sediment than in surface soil. Overall wind erosion losses (expressed as a percent of amount applied) of the two soil‐incorporated herbicides (1.5%) were about three times lower than those of the four surface‐applied herbicides (average loss, 4.5%). The results demonstrate the potential hazard of environmental transport of herbicides on wind‐eroded sediment and its associated implications for off‐site air and water quality.
Organic Waste Amendments Effect on Zinc Fractions of Two Soils
Authors: Shuman Larry M. 
Published: July 2010

AbstractOrganic soil amendments can ameliorate metal toxicity to plants by redistributing metals to less available fractions. The objective of this study was to determine the effects of organic amendments on Zn distribution among soil fractions. Two soils (fine‐textured and coarse‐textured) were amended with five organic waste materials (some of which contained Zn) or commercial humic acid with and without 400 mg kg−1 Zn, incubated, and fractionated using a sequential extraction technique. Where no Zn was added most of the metals were in the residual fraction. Commercial compost, poultry litter, and industrial sewage sludge increased Zn in the exchangeable (EXC), organic (OM), and manganese oxide (MnOx) fractions due to Zn in the materials. Spent mushroom compost (SMC) redistributed Zn from the EXC fraction to the MnOx fraction for the coarse‐textured soil. Where Zn was added, most of the metal was in the EXC and OM fractions. The SMC and humic acid lowered Zn in the EXC fraction and increased Zn in the other fractions. Effects of the organic materials on Zn in soil fractions were more evident for the sandy soil dominated by quartz in the clay than for the finer‐textured soil dominated by kaolinite in the clay‐size fraction. It was concluded that organic materials high in Zn can increase Zn in the EXC, OM, and MnOx fractions where the soil is not contaminated and others such as SMC and HA can lower the potential availability of Zn in contaminated soils by redistributing it from the EXC to less soluble fractions.
Water Treatment Residual to Reduce Nutrients in Surface Runoff from Agricultural Land
Authors: Gallimore L. E. , Basta N. T. , Storm D. E. , Payton M. E. , Huhnke R. H. , Smolen M. D. 
Published: July 2010

AbstractApplication of animal manures in excessive amounts can result in surface runoff of nutrients and degradation of surface water. Best management practices that use chemical or by‐products to sorb nutrients can reduce nutrient loss from agricultural land. The objective of this work was to determine the ability of water treatment residual (WTR) to reduce N and P runoff from land treated with poultry litter. Different WTR (ABJ or WISTER) were used in two experiments different locations. Three WTR treatments were applied to plots that received poultry litter at 6.72 Mg ha−1 broadcast on bermudagrass [Cynodon dactylon (L.) Pers.] pasture. Treatments were broadcast (11.2 or 44.8 Mg ha−1), and a buffer strip (44.8 Mg ha−1) to the bottom 2.44 m of the plot. Experimental plots received simulated rainfall for 75 min at 6.35 cm h−1 within 24 h of litter and WTR application. Nitrogen, NH4, P, Al, and dissolved solids in surface runoff were determined. Mean dissolved P of 15.0 mg L−1 was reduced to 8.60 mg L−1 by the high broadcast and to 8.12 mg L−1 by the buffer strip ABJ treatments. Reductions in runoff P were attributed to amorphous Al in the WTR. Soluble NH4‐N was reduced from 33.7 to 11.3 mg L−1 (high broadcast) and to 17.9 mg L−1 (buffer strip) by ABJ. WISTER did not, however, reduce soluble NH4‐N or total N. Reduction in NH4‐N was related to cation‐exchange capacity of the WTR. Land application of WTR did not increase dissolved solids or Al in surface runoff.
Preferential Flow and Water Quality in Two New Zealand Soils Previously Irrigated with Wastewater
Authors: Magesan G. N. , Dalgety J. , Lee R. , Luo J. , van Oostrom A. J. 
Published: July 2010

AbstractPreferential flow of bromide tracer through two New Zealand soils, Horotiu (Typic Hapludand) and Te Kowhai (Typic Ochraqualf) soils, was examined. These two soils differed in physical, chemical, and drainage characteristics. These soils had been irrigated with meat‐processing wastewater for 38 mo that ceased 3 mo before this study. Impact of heavy rainfall on residual water quality from such wastewater applied soils was examined by measuring the concentrations of anions (nitrate and phosphate), and cations (Na, K, Ca, Mg, and ammonium) in leachates collected. Heavy rainfall did not appear to have any impact on leachate quality, as indicated by low nitrate‐N and phosphate concentrations compared with those measured during wastewater irrigation. While no preferential flow occurred in the Horotiu soil when it was wetted to field capacity, preferential flow occurred to depth in the Te Kowhal soil under similar conditions. Other water quality problems (e.g., pathogens), which were not investigated in this study may arise in Te Kowhai soils under heavy rainfall.
Lolium perenne Grasslands May Function as a Sink for Atmospheric Carbon Dioxide
Authors: van Ginkel J. H. , Whitmore A. P. , Gorissen A. 
Published: July 2010

AbstractModel calculations and scenario studies suggest the existence of a considerable positive feedback between temperature and CO2 levels in the atmosphere. Rising temperatures are supposed to increase decomposition of soil organic C leading to increased production of CO2 and this extra CO2 induces a positive feedback by raising the temperature still further. Evidence was found that negative feedback mechanisms also exist: more primary production is allocated to roots as atmospheric CO2 rises and these roots decompose more slowly than roots grown at ambient CO2 levels. Experimental data partly obtained with 14C‐techniques were applied in a grassland C model. The model results show that at an atmospheric CO2 concentration of 700 µL L−1 increased belowground C storage will be more than sufficient to balance the increased decomposition of soil organic C in a ryegrass (Lolium perenne L.) grassland soil. Once a doubling of the present atmospheric CO2 concentration has been reached, C equivalent to 55% of the annual CO2 increase above 1 ha ryegrass can be withdrawn from the atmosphere. This indicates that grassland soils represent a significant sink for rising atmospheric CO2.
Mineralogy of Agricultural Source Soil and Respirable Dust in California
Authors: Clausnitzer H. , Singer M. J. 
Published: July 2010

AbstractInhalation of respirable dust (RD), defined as particles ≤4 µm in aerodynamic diameter, is a health concern. Soil disturbance by farming produces a range of airborne soil minerals of various sizes, but little is known about RD mineralogy compared with source soil or about mineralogy of RD as a function of particle size. General assumptions are that dust mineralogy reflects the source soil and that there is no sorting of RD mineralogy by particle size. We tested these assumptions by determining the size and mineralogy of RD particles from specific farming activities and comparing them to the source soil mineralogy. Samples were taken from plots growing furrow‐irrigated crops near Davis, CA. Source‐soil was analyzed by x‐ray diffraction (XRD). Respirable dust was analyzed by scanning electron microscopy and transmission electron microscopy (TEM) with selected area electron diffraction. Mineralogy and size data of mineral groups from the two techniques were different. The TEM method was more reliable because it included crystallographic data as well as elemental composition and particle morphology. The same major mineral groups (quartz, mica, feldspar, and clays) were found in the RD and the source soil, but minor constituents of the RD such as serpentine minerals and zeolites were not detected in the source soil because they were not sufficiently abundant to be detected by standard XRD techniques. No significant sorting of source soil mineralogy occurred over the short distance between soil and RD sampler.
Plant Nutrient Availability from Mixtures of Fly Ashes and Biosolids
Authors: Schumann Arnold W. , Sumner Malcolm E. 
Published: July 2010

AbstractNutrient imbalances, both deficiencies and excesses, are one reason for the poor acceptance of waste materials as fertilizer substitutes. Two greenhouse experiments were established using 24 different fly ashes with sewage sludge and poultry manure to estimate nutrient availability and imbalances to maize (Zea mays L.). The maximum maize growth attained with fly ash amendment of 80 Mg ha−1 was significantly less (50%) than a fertilized control treatment. The additional growth improvements obtained from mixtures with sewage sludge or poultry manure ranged from 30 to 49% and 30 to 71%, respectively. Organic materials applied alone achieved only 54 and 62% of the maximum potential, while growth on poultry manure mixtures was up to 94% of the best performing fertilized treatment. Results of foliage and soil analyses suggest that P and K were the main nutrient deficiencies, while B phytotoxicity and an imbalance in the K/Ca/Mg ratio also were likely causes of plant growth reduction. Fly ashes did not contribute significant P or K to correct soil and plant deficiencies, but more often exacerbated the imbalances by precipitation or adsorption of soil P. Sewage sludge mixed at 26% and poultry manure at 13% (DM) with fly ash had negligible effect on availability of phytotoxic fly ash B, but were good sources of P (both) and (poultry manure). Good agreement between plant nutrition in pot experiments and previous laboratory extraction studies implies that chemical analysis, efficient formulation and optimized application rates may overcome nutrient limitations for use of wastes as fertilizer substitutes.
Biodegradation and Mineralization of Atrazine in Shallow Subsurface Sediments from Illinois
Authors: Ames Rachel A. , Hoyle Blythe L. 
Published: July 2010

AbstractAgricultural chemical dealerships represent potential point sources of contamination by the corn (Zea mays L.) herbicide atrazine (2‐chloro‐4‐ethylamino‐6‐isopropylamino‐1,3,5‐triazine), which is frequently detected in ground water in the Midwestern USA. The objective of this study was to investigate the potential for atrazine to biodegrade under imposed N‐limited conditions in subsurface sediments collected from a contaminated former dealership in Illinois. Ten cores, 4.9 to 6.1 m deep, were obtained from four locations within the 3‐ha dealership. Forty‐four selected samples were screened in duplicate for the ability to biodegrade 21 mg L−1 atrazine in the presence of 1 g L−1 each of the C sources citrate and succinate. Although the shallow stratigraphy was fairly uniform across the site, the biodegradation of atrazine occurred predominantly in samples obtained from the southeastern corner of the site. In most of these samples atrazine was biodegraded to concentrations below detectable levels within 40 to 80 d with no detectable metabolites. In one sample from this location, indigenous bacteria mineralized 80% of applied [U‐ring‐14C]atrazine in 100 d. Sediment N and atrazine residue concentrations were not good primary predictors of the samples' ability to biodegrade atrazine. These results indicate that without knowledge of the distribution of atrazine‐degrading microorganisms, comparisons of bulk sediment parameters are useless for predicting biodegradation potential.
Isoxaben Dissipation in Field Soil as Affected by Application Timing
Authors: Chandran Rakesh S. , Derr Jeffrey F. 
Published: July 2010

AbstractTiming of preemergence (PRE) herbicide application is critical for effective weed management in turfgrass and ornamentals. Information on soil dissipation, as affected by application timing and rate, is needed when using preemergence herbicides for weed control. Field studies were established at Blacksburg, VA, to determine the effect of spring, fall, and a double (spring followed by fall) application on the dissipation of isoxaben applied at 0.56, 0.84, and 1.12 kg a.i. ha−1. The half‐life of isoxaben was estimated to be 2.7 mo following spring application, 5.7 mo following fall application, and 6.1 mo following spring plus fall application. Application rate did not affect the degradation pattern of isoxaben following spring or fall application. Residues of isoxaben at 3 and 6 months after treatment (MAT) following fall application at 1.12 kg ha−1 were higher than that following spring application. A positive correlation (γ = 0.62) was determined between daily isoxaben breakdown rate and mean ambient daily temperatures following the two application timings. Degradation following fall application may be slower than that following spring application due to lower microbial activity during winter months. Negligible levels of the herbicide remained in the top 3.8 cm of soil 9 mo following spring or fall application. Double application of isoxaben resulted in higher mean levels of isoxaben residues than single spring or fall application at 0, 1, 6, and 9 MAT.