bluuebunny/crossref_metadata_2025_split huggingface dataset:
Longleaf Pine Photosynthetic Response to Soil Resource Availability and Elevated Atmospheric Carbon Dioxide
Authors: Runion G. B. , Mitchell R. J. , Green T. H. , Prior S. A. , Rogers H. H. , Gjerstad D. H. 
Published: July 2010

AbstractGas exchange responses during a drought cycle were studied in longleaf pine (Pinus palustris Mill.) seedlings after prolonged exposure to varying levels of atmospheric CO2 (≈365 or ≈730 µmol CO2 mol−1), soil N (40 or 400 kg N ha−1 yr−1), and water (“adequate” and “stressed”). Elevated atmospheric CO2 concentration increased photosynthesis, tended to decrease stomatal conductance, and increased water‐use efficiency (WUE). Although soil resource availability influenced gas exchange measurements, it generally did not affect the magnitude or direction of the response to CO2 concentration. However, significant interactions among treatment variables were observed for plant xylem pressure potential. In seedlings grown with high N, a positive growth response to elevated atmospheric CO2 increased whole‐plant water use resulting in more severe plant water stress, despite increased leaf‐level WUE; however, under low N conditions the lack of a growth response to elevated CO2 reduced whole‐plant water use, decreased water stress severity, and increased WUE. Photosynthetic response to CO2 was greatest in the high N treatment at the beginning of the drought cycle, but diminished as water stress increased; however, plants grown with low N showed greater photosynthetic responses to CO2 later in the drought cycle. Therefore, plant gas exchange rates interact with growth response in determining the severity of water stress under drought and, thus, the ability of elevated atmospheric CO2 to ameliorate the effects of drought and allow plants to maintain increased rates of photosynthesis may be influenced by the availability of other resources, such as N and water.
A Multi‐Year Study of Four Herbicides in Air and Precipitation from a Small Prairie Watershed
Authors: Rawn Dorothea F. K. , Halldorson Thor H. J. , Lawson B. D. , Muir Derek C. G. 
Published: July 2010

AbstractTemporal trends of three phenoxyacid herbicides: 2,4‐D, dichlorprop and MCPA and the phenolic herbicide: bromoxynil, were determined in ambient air and precipitation over a 4‐yr period within a well‐defined watershed in southern Manitoba. Air concentrations ranged from below detection limits to 3.5, 1.0, 13, and 2.0 ng/m3, for 2,4‐D; dichlorprop; MCPA; and bromoxynil, respectively. The herbicides under investigation were four of the highest use herbicides in the South Tobacco Creek Watershed and were present in both air and precipitation samples at maximum concentrations during periods of local use. Concentration patterns for each herbicide in precipitation were similar each year of the study. Of the four herbicides, precipitation fluxes were greatest for MCPA in the watershed and the surrounding region. Although bromoxynil and dichlorprop were less widely used than 2,4‐D, bromoxynil precipitation fluxes exceeded those of 2,4‐D in 1993 and 1994, and dichlorprop precipitation fluxes were greater than 2,4‐D in 1994. Elevated levels of these herbicides in creek water samples were observed during periods of high concentration in both atmospheric compartments, despite the lack of surface runoff events within the watershed over that period.
Agricultural Pesticides in the Patuxent River, a Tributary of the Chesapeake Bay
Authors: Harman‐Fetcho J. A. , McConnell L. L. , Baker J. E. 
Published: July 2010

AbstractThe Chesapeake Bay estuarine drainage area receives the highest pesticide application of any coastal area in the USA, however, large gaps exist in information on pesticide residues entering Chesapeake Bay tributaries. Twelve pesticides, one pesticide degradation product, and one formulation by‐product were measured in the surface waters of the Patuxent River during spring/summer 1995. Pesticide concentrations were compared with river flow and estimated use patterns in the watershed. Atrazine, 6‐amino‐2‐chloro‐4‐isopropylamino‐s‐triazine (CIAT), simazine, metolachlor, and chlorpyrifos were consistently detected with maximum concentrations of 3000, 800, 2700, 70, and 190 ng/L, respectively. Concentrations were highest in the upper watershed, an area where 70% of pesticide usage occurs, and decreased with distance down the river. While tidal dilution is an important removal mechanism, degradation appears to be the main factor leading to decreases in atrazine concentrations. Atrazine levels observed at the mouth of the river correlated more strongly with high river flow events compared with the other analytes. This may be due to a local source of atrazine in the lower Patuxent River. Despite similar use rates in the watershed, metolachlor concentrations were 25 to 40 times lower than atrazine. Overall, triazine herbicides appeared to move quickly into the river and persisted longer in surface waters compared with the acetanilide herbicides. Since land use and agricultural crop patterns in the Patuxent watershed are similar to other western shore Chesapeake Bay tributaries, results of this study may be used as a starting point to predict pesticide fate and transport in this region.
Copper‐Binding Ability of Dissolved Organic Matter Derived from Anaerobically Digested Biosolids
Authors: Han Nizhou , Thompson Michael L. 
Published: July 2010

AbstractThe fate of metals in soils where soluble organic compounds are present may be strongly influenced by the degree to which they are complexed by organic ligands. We undertook this study to determine the combined effect of molecular weight (MW) and hydrophobicity on the Cu‐binding ability of dissolved organic compounds in biosolids (i.e., sewage sludge). Dissolved organic matter (DOM) from anaerobically digested sewage biosolids was fractionated by using a combination of MW fractionation and XAD‐8 resin chromatography (to separate the dissolved organic compounds according to hydrophilic and hydrophobic characteristics). The Cu‐binding abilities of the DOM fractions were obtained by using a Cu2+‐ion‐selective electrode (Cu‐ISE) technique. The Cu‐binding ability of fractionated DOM decreased significantly with increasing molecular weight, indicating that low‐MW DOM had more metal‐binding sites than high‐MW DOM. Within each MW fraction, the hydrophilic and the hydrophobic components also exhibited differences in Cu‐binding ability. For the DOM with MW 500–3500 Da, the hydrophilic fraction showed a greater Cu‐binding capacity than did the hydrophobic fraction, whereas the hydrophobic acid components were most important in binding Cu for DOM with MW > 3500 Da. The maximum Cu‐binding capacities of different biosolids‐derived DOM fractions, estimated by employing a Langmuir model, ranged from 1.85 to 14.3 mmol Cu mol−1 dissolved organic C (DOC), which is the same order of magnitude as similar measurements of DOM from other sources.
Validation of EPIC for Two Watersheds in Southwest Iowa
Authors: Chung S. W. , Gassman P. W. , Kramer L. A. , Williams J. R. , Gu R. 
Published: July 2010

AbstractThe Erosion Productivity Impact Calculator (EPIC) model was validated using long‐term data collected for two southwest Iowa watersheds in the Deep Loess Soil Region, which have been cropped in continuous corn (Zea mays L.) under two different tillage systems (conventional tillage vs. ridge‐till). The annual hydrologic balance was calibrated for both watersheds during 1988 to 1994 by adjusting the runoff curve numbers and residue effects on soil evaporation. Model validation was performed for 1976 to 1987, using both summary statistics (means or medians) and parametric and nonparametric statistical tests. The errors between the 12‐yr predicted and observed means or medians were <10% for nearly all of the hydrologic and environmental indicators, with the major exception of a nearly 44% overprediction of the N surface runoff loss for Watershed 2. The predicted N leaching rates, N losses in surface runoff, and sediment loss for the two watersheds clearly showed that EPIC was able to simulate the long‐term impacts of tillage and residue cover on these processes. However, the results also revealed weaknesses in the model's ability to replicate year‐to‐year variability, with r2 values generally <50% and relatively weak goodness‐of‐fit statistics for some processes. This was due in part to simulating the watersheds in a homogeneous manner, which ignored complexities such as slope variation. Overall, the results show that EPIC was able to replicate the long‐term relative differences between the two tillage systems and that the model is a useful tool for simulating different tillage systems in the region.
Predicting Water and Chloride Transport in Drained Soils Derived from Glacial Till
Authors: Vinten A. J. A. 
Published: July 2010

AbstractField‐scale predictions of nitrate (NO3) leaching from farmland are needed to enable zones vulnerable to ground or surface water pollution with NO3 to be identified. Use of simple water, solute transport, and N dynamics models is one way of making these predictions. In this paper, linked water and solute transport models (WATBAL/TRANSOL) are calibrated for two important arable soil types in Scotland: a clay loam (aeric haplaquept) and a sandy loam (aquic eutrochrept). Error in prediction of water and solute transport is evaluated using data from two drained plot experiments. WATBAL predicted annual deep percolation of 25 and 44% of the measured drainage flux at the clay loam and sandy loam sites, respectively. The RMS errors in prediction of annual drainflow were 14 and 13% at the clay loam and sandy loam sites, respectively. Prediction of the onset of autumn drainflow over 3 to 5 yr was good for the clay loam soil, but not the sandy loam soil. Chloride leaching was underpredicted by about 22% at the sandy loam site and by 15% at the clay loam site in the first year after chloride tracer application. This indicates the likely extent of under prediction of solute leaching to drains when these models are linked to other models, such as simulations of N dynamics.
Environmental Consequences of Apple Waste Deposition on Soil
Authors: de Cockborne A. M. , Vallès V. , Bruckler L. , Sevenier G. , Cabibel B. , Bertuzzi P. , Bouisson V. 
Published: July 2010

AbstractIn the Provence Alpes Côte d'Azur region (France), overproduction of apple (Malus domestica Borkh.) can result in a significant surplus (0–230 000 Mg per year between 1986 and 1995) which has to be used or destroyed. Among the possibilities for disposing of overproduction, land application is flexible and inexpensive. A field study was undertaken to identify the environmental risks and main biogeochemical processes involved when apple waste is applied to farm land. Three experimental plots receiving 0, 500, or 1000 Mg of apple ha−1 were studied. Soil solutions were collected at three depths (0–0.3, 0.3–0.6, and 0.6–0.9 m) at different times, pH and Eh were measured, major ions, metals, and total and carbonated alkalinity were analyzed. Rapid pH and Eh decrease (from 7.0‐5.5 for the pH and from +500 to −300 mV for the redox potential) were observed. The soil became reduced, thus causing the dissolution of Mn. Nitrogen immobilization and denitrification resulting from waste application explained NO−3 depletion in the soil. The formation of organic anions complexed the metals and major cations. Finally, the oxidation of the soil during drying created conditions which polluted less, emphasizing the importance of the choice of season for land application of organic waste.
Nitrogen Availability and Leaching from Soil Amended with Municipal Solid Waste Compost
Authors: Mamo M. , Rosen C. J. , Halbach T. R. 
Published: July 2010

AbstractBeneficial use of municipal solid waste compost depends on identifying a management strategy that supports crop production and protects water quality. Effects of compost and N fertilizer management strategies on corn (Zea mays L.) yield and NO−3‐N leaching were evaluated in a 3‐yr study on a Hubbard loamy sand soil (sandy, mixed, Udorthentic Haploboroll). Two composts were each applied at either 90 Mg ha−1 yr−1 from 1993 to 1995, or at 270 Mg ha−1 in one application in 1993. The compost and non‐amended plots were sidedressed annually with N fertilizer as urea at 0, 125, and 250 kg ha−1. Biochemical properties of the compost as well as compost management strongly affected crop response and fate of N. Compost increased grain yield with no significant yield response to N fertilizer with the single compost application in Year 1 and the annual compost application in Year 3. Plant N uptake increased with N fertilizer rate, except in the 270 Mg ha−1 compost treatments in Year 1. Over the 3‐yr period, NO−3‐N leaching with the 270 Mg ha−1 compost application was 1.8 times greater compared to that with the annual application. The estimated N mineralization ranged from 0 to 12% and 3 to 6% in the annual and single compost addition, respectively. Under the conditions of this study, annual compost application with reduced supplemental N fertilizer was the best management strategy to reach optimum crop yield while minimizing NO−1‐N leaching losses.
Effect of Air‐Drying on Sorption Kinetics of the Herbicide Chlortoluron in Soil
Authors: Altfelder Sven , Streck Thilo , Richter Jörg 
Published: July 2010

AbstractBatch techniques were utilized to investigate sorption kinetics of chlortoluron (3‐(3‐chlor‐p‐tolyl)‐1,1‐dimethylurea) in two field‐moist soils, a silt loam (Typic Hapludalf) and a loamy sand (Aquic Haplumbrept), containing 1.1 and 0.7% organic C. To investigate effects of soil pretreatment, a part of both soil samples was initially air‐dried. Initially sorption‐desorption isotherms were measured using field‐moist soils. Both isotherms exhibited pronounced hysteresis. The fit of a nonlinear kinetic two‐stage sorption model to the data suggests that hysteresis was caused by nonattainment of equilibrium within the 24‐h agitation periods. This hypothesis is supported by the fact that the estimated kinetic parameters were well suited to predict concentration vs. time experiments in both soils. The prediction of sorption‐desorption isotherms measured using air‐dried soils failed. Compared with the predicted data, adsorption in air‐dried soil was increased while desorption hysteresis was less pronounced. Further experiments indicated that changes of soil organic matter (SOM) caused by air‐drying were responsible for this effect. Measuring 24‐h partitioning coefficients using the air‐dried soils, rewetted to field‐moisture for varying periods of time, revealed that in the course of 80 h (silt loam) and 500 h (loamy sand) after rewetting, the sorption properties of the air‐dried soils were again equal to those of the respective field‐moist soils.
Baseline Concentrations of 15 Trace Elements in Florida Surface Soils
Authors: Chen Ming , Ma Lena Q. , Harris Willie G. 
Published: July 2010

AbstractThe objective of this study was to establish baseline concentrations for 15 potentially toxic elements (Ag, As, Ba, Be, Cd, Cr, Cu, Hg, Mn, Mo, Ni, Pb, Sb, Se, and Zn) based on 448 representative Florida surface soils using microwave assisted HNO3‐HCl‐HF digestion. Baseline concentrations of those elements were (mg kg−1): Ag 0.07–2.50, As 0.02–7.01, Ba 1.67–112, Be 0.04–4.15, Cd 0–0.33, Cr 0.89–80.7, Cu 0.22–21.9, Hg 0.00075–0.0396, Mo 0.13–6.76, Ni 1.70–48.5, Pb 0.69–42.0, Sb 0.06–0.79, Se 0.01–1.11, and Zn 0.89–29.6, respectively. Upper baseline values for most elements corresponded with these reported in literature, except Ba, Hg, Mn, Sb, and Zn, which were 3 to 23 times lower. Soil properties, including pH, organic carbon (OC), particle size, cation‐exchange capacity (CEC), available water, extractable base, extractable acidity, total Ca, Mg, P, K, Fe, and Al concentrations, were related to metal concentrations using factorial analysis. Eight factors were identified (total Fe and Al, CEC, pH, clay, OC, total Ni and Mo, total Sb and Pb, and total Hg) and accounted for 87% of the total variance, suggesting that metal concentrations were primarily controlled by soil compositions. Multiple regression of elemental concentrations against total Fe, total Al, clay, OC, CEC, and pH was significant for all elements. Partial correlation coefficients indicated that total Fe and/or Al explained most of the variance for Mn, Ni, Ba, Be, Hg, As, Cd, Cr, Cu, Mo, Pb, and Zn concentrations. Most of the variance in Se was related to clay, whereas those of Ag and Sb related to clay and total Al.
Oxidation and Mobilization of Selenium by Nitrate in Irrigation Drainage
Authors: Wright Winfield G. 
Published: July 2010

AbstractSelenium (Se) can be oxidized by nitrate (NO−3) from irrigation on Cretaceous marine shale in western Colorado. Dissolved Se concentrations are positively correlated with dissolved NO−3 concentrations in surface water and ground water samples from irrigated areas. Redox conditions dominate in the mobilization of Se in marine shale hydrogeologic settings; dissolved Se concentrations increase with increasing platinum‐electrode potentials. Theoretical calculations for the oxidation of Se by NO−3 and oxygen show favorable Gibbs free energies for the oxidation of Se by NO−3, indicating NO−3 can act as an electron acceptor for the oxidation of Se. Laboratory batch experiments were performed by adding Mancos Shale samples to zero‐dissolved‐oxygen water containing 0, 5, 50, and 100 mg/L NO−3 as N (mg N/L). Samples were incubated in airtight bottles at 25°C for 188 d; samples collected from the batch experiment bottles show increased Se concentrations over time with increased NO−3 concentrations. Pseudo first‐order rate constants for NO−3 oxidation of Se ranged from 0.0007 to 0.0048/d for 0 to 100 mg N/L NO−3 concentrations, respectively. Management of N fertilizer applications in Cretaceous shale settings might help to control the oxidation and mobilization of Se and other trace constituents into the environment.
Redistribution of Trace Elements from Contaminated Sediments of Lake Coeur d'Alene during Oxygenation
Authors: La Force Matthew J. , Fendorf Scott , Li Guangchao , Rosenzweig R. Frank 
Published: July 2010

AbstractSediments of Coeur d'Alene Lake in northern Idaho are contaminated with heavy metals as a result of mining in the Coeur d'Alene River basin. Dredging and disposal operations have been suggested as a possible means of environmental remediation; thus, detailed knowledge is required as to how sediment oxygenation can result in the redistribution of trace elements. To simulate changing physicochemical soil conditions, stirred batch experiments were conducted using fresh sediment core material retrieved from the lake. Fifty grams of sediment were added to 750 mL of double deionized water and mixed while being oxygenated for 260 h. The following parameters were monitored as a function of time: pH and Eh, contaminant trace‐element release into the aqueous phase, and metal abundance within operationally defined fractions of the solid phase: magnesium chloride (exchangeable), sodium hypochlorite (organic), sodium acetate‐acetic acid (carbonate), ammonium oxalate in the dark (non‐crystalline), hydroxylamine hydrochloride (crystalline), and potassium perchlorate‐hydrochloric‐nitric acid (sulfidic) extractable sediment fractions. In all trials, levels of aqueous‐phase Zn remained high throughout the simulations (6.60 mg L−1) and were highly correlated (sigma value = 0.95) with Mn. Oxygenation and disturbance resulted in a shift in trace element partitioning from the sodium hypochlorite (organic) and potassium perchlorate‐hydrochloric‐nitric acid extractable (sulfidic) fractions into the ammonium oxalate in the dark (noncrystalline) extractable fraction. Overall, these results indicate that oxygenation and agitation of anaerobic sediment results in Zn release into solution with concomitant redistribution of trace elements in the solid‐phase.
Seasonal Surface Runoff Losses of Nutrients and Metals from Soils Fertilized with Broiler Litter and Commercial Fertilizer
Authors: Wood B. H. , Wood C. W. , Yoo K. H. , Yoon K. S. , Delaney D. P. 
Published: July 2010

AbstractWhile elevated concentrations of N and P have been observed in surface runoff from broiler litter‐amended fields, impacts of other nutrients in broiler litter such as Ca, K, Mg, Mn, Cu, and Zn have not been identified. A study was conducted on a 4% slope during 1991 to 1993 at Belle Mina, AL, on a Decatur silty clay (clayey, kaolinitic, thermic Rhodic Paleudult) to determine effects of broiler litter (BL) on seasonal transport losses of nutrients and heavy metals in surface water. A corn (Zea mays L.)‐winter rye (Secale cereale L.) cropping system was fertilized with either: (i) 9 Mg BL ha−1 (BL9), (ii) 18 Mg BL ha−1 (BL18), or (iii) commercial fertilizer at the recommended rate (CF). Runoff water samples were collected after each runoff producing rainfall event. Litter treatments decreased sediment flow‐weighted concentrations during the second corn growing season owing to residual broiler litter. Flow‐weighted concentrations of NO3‐N and NH4‐N were highest under BL18 during the second corn season. Total P and dissolved P flow‐weighted concentrations and seasonal transport losses were highest under BL18 during the second corn season. Sediment nutrient flow‐weighted concentrations of K, Mg, and Mn were highest under CF during the second corn season. Dissolved nutrient flow‐weighted concentrations of Ca, K, and Mg were highest under BL18 during the second corn season. Nutrient flow‐weighted concentrations, except Ca, from all treatments provide adequate levels to support algae growth.
Phosphorus Loss in Drainflow from Intensively Managed Grassland Soils
Authors: Hooda P. S. , Moynagh M. , Svoboda I. F. , Edwards A. C. , Anderson H. A. , Sym G. 
Published: July 2010

AbstractThe loss of P in subsurface drainage from lysimeters (0.5 ha), managed as either monoculture grass or grass‐clover for the last 9 yr have been quantified. Both systems received two to three cattle slurry applications annually and were cut two to three times before being grazed by dairy cattle. Mineral fertilizer‐P was applied only to the grass‐clover (about 25 kg P ha−1 yr−1). After 9 yr, NaHCO3‐soluble P in the topsoil (0–10 cm) averaged 38 and 47 mg P kg−1 for the grass and grass‐clover respectively, giving an average increase of 1.0 mg OIsen‐P kg−1 yr−1 in the grass‐clover. Drainage‐weighted molybdate‐reactive phosphorus (MRP) and total phosphorus (TP) concentrations ranged from 0.16 to 0.38 mg P L−1 and 0.45 to 0.79 mg P L−1, respectively during the 2‐yr study period. The MRP and TP losses in subsurface‐flow from the grass‐clover (1.68–2.03 and 3.47–5.03 kg P ha−1 yr−1, respectively) were significantly larger than those from the grass (1.27–1.34 and 2.97–3.58 kg P ha−1 yr−1, respectively). Averaged across years and pastures, MRP accounted for 42% of the TP loss, while a non‐MRP form accounted for 41% of the TP loss through field drains. Particulate‐associated P represented about 17% of the TP loss. The P losses in subsurface runoff measured in the present study were much larger than previous estimates. The results also showed that, despite the subsoil having much larger P‐sorption capacity than the topsoil, significant amounts of P losses could occur through preferential hydrological pathways.