bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tropospheric Carbon Dioxide or Ozone Enrichments and Moisture Effects on Soil Organic Carbon Quality
Authors: Islam K. R. , Mulchi C. L. , Ali A. A. 
Published: July 2010

AbstractCarbon, as an active component of organic matter, has considerable effects on soil quality and productivity. The objective of this study was to examine the effect of climate change variables on soil organic C (CT) quality in an agroecosystem. Wheat (Triticum aestivum L.) and soybean [Glycine max (L.) Merr] plants were grown in 3 m in diam. open‐top field chambers and exposed to charcoal‐filtered (CF) air at 350 µL CO2 L−1; CF air + 150 µL CO2 L−1; nonfiltered (NF) air + 35 nL O3 L−1; and NF air + 35 nL O3 L−1 + 150 µL CO2 L−1 at two soil moisture levels from 1994 to 1996. The 150 µL CO2 L−1 addition was 18 h d−1 and the 35 nL O3 L−1 was 7 h d−1 from April until late October. In response to treatments, the Cr contents did not change significantly; however, participate, oxidizable, dissolved, humic (CHA) and fulvic (CFA) acid, and carbohydrate C pools increased in soils under CO2 enrichment and well‐watered conditions but decreased under O3 stress compared with soils under CF ambient air quality. Tropospheric CO2 enrichment and well‐watered condition increased, and O3 stress decreased the log optical density slope for both CHA and CFA fractions more than CF ambient air and restricted moisture treatment. Also, the E465/E665 ratios of both CHA and CFA fractions were higher for the CO2 enrichment and smaller for the O3 stress compared with CF ambient air quality. Results suggest that tropospheric CO2 enrichment and well‐watered conditions may favor an accumulation of low molecular weight and more aliphatic quality of C and O3 stress favor high molecular weight and more aromatic quality of C.
Soil Hydraulic Conductivity Changes Caused by Irrigation with Reclaimed Waste Water
Authors: Levy G. J. , Rosenthal A. , Tarchitzky J. , Shainberg I. , Chen Y. 
Published: July 2010

AbstractUse of reclaimed waste water (RWW) in arid and semiarid regions may alleviate problems of fresh water shortage; however, it also involves some potential risks among which are degradation of soil hydraulic properties. The objectives of the current study were to study the effects of organic matter (OM) loads found in RWW obtained from a secondary treatment plant in Tel Aviv, Israel, and different size fractions of the suspended solids in the RWW on the hydraulic conductivity (HC) of three Israeli soils. The hydraulic conductivity of a clayey grumusol (Typic Chromoxerert), a typic loamy loess (Calcic Haploxeralf), and a sandy loam hamra (Typic Rhodexeralf) was determined in the laboratory using soil columns, by leaching with RWW containing zero, low, or high OM load, followed by leaching with distilled water (DW). The effects of suspended solids' size fraction on the HC was determined by filtering RWW. Leaching with high OM load RWW caused the relative HC of the grumusol, loess and hamra to drop to final values of 13.9, 24.2, and 58.8%, respectively. Filtering out suspended solids >1.2 µ in this water improved the HC of the hamra, but did not significantly affect the final relative HC of the grumusol and loess. Leaching with low OM load RWW did not significantly decrease the HC beyond the decrease attributed to the effects of the concentration and composition of the electrolytes present in the zero OM load RWW. Subsequent leaching with DW caused an additional decrease in HC, whose magnitude for a given soil did not depend on the quality of the RWW previously used. The presence of OM in the irrigation water did not seem to have significant residual effects on soil HC. Evidently, in high OM load RWW the OM fraction determines the soils' HC, whereas in low OM load RWW, it is the electrolyte concentration and composition in the water, that seem to pose the hazard to soil hydraulic properties, especially during subsequent leaching with DW.
Purification of Fuel and Nitrate Contaminated Ground Water Using a Free Water Surface Constructed Wetland Plant
Authors: Machate Thomas , Heuermann Elisabeth , Schramm Karl‐Werner , Kettrup Antonius 
Published: July 2010

AbstractContaminated ground water from a former coke plant site was purified in a free water surface (FWS) constructed wetland plant during a 3‐mo short‐term experiment. The pilot plant (total surface area 27 m2) was filled with a 1 m thick lava‐gravel substrate planted with cattail (Typha spp.) and bulrush (Scirpus lacustris). Major contaminants were low to moderate concentrations of polycyclic aromatic hydrocarbons (PAH 50–9000 µg L−1 according to USEPA, 1‐methylnaphthalene 2–1900 µg L−1, 2‐methylnaphthalene 3–4300 µg L−1), BTEX (10–450 µg L−1), nitrate (60 mg L−1 as N), and nitrite (7 mg L−1 as N). The wetland was dosed at hydraulic loading rates of qA = 4.8 and 9.6 cm d−1 with a hydraulic residence time (HRT) of 13.7 and 6.8 d. The surface removal rates of PAH were between 98.8 and 1914 mg m−2 d−1. Efficiency was always >99%. Extraction of lava gravel showed that approx. 0.4% of the applied PAH were retained on the substratum. The ratio of ∑2,3‐ring PAH and ∑4,5,6‐ring PAH showed a shift from 1:0.11 in water (influent) to 1:2.5 in lava (Tank 1). The removal of BTEX was >99%, but might be in part due to volatilization. The efficiency in the removal of nitrate was 91% (2.47–3.34 g m−2 d−1) and of nitrite was 97% (0.034–0.036 g m−2 d−1). Purification performance was not influenced by hydraulic loading rates or after die‐back of the macrophytes.
Effects of Silvicultural Activities on Wetland Biogeochemistry
Authors: Lockaby B. G. , Trettin C. C. , Schoenholtz S. H. 
Published: July 2010

AbstractThe unique biogeochemistry of wetlands either causes or influences many landscape functions that are valued by society. Because of their critical ecological role and the importance of wetlands to commodity and noncommodity values, we have reviewed the current state of knowledge regarding influences of silviculture on nutrient circulation, transformation, and retention in forested wetlands. Our approach was to contrast riverine and depressional systems. Globally, there are few generalizations that can be made regarding the effects of silvicultural disturbance. This conclusion is primarily a result of too few studies on the mechanisms and processes controlling ecosystem responses. Most work to date has focused solely on characterizing responses of state variables, and therefore a basis for integration is often lacking. While studies do show that water quality functions are not degraded as a result of harvesting, many other aspects of ecosystem functionality are not clarified. As examples, there are significant gaps in our understanding of biogeochemical controls on net primary productivity, organic matter turnover, and hydrologic interactions. Considerable research is warranted to provide information for effective resource management and conservation.
Lead Migration in Some Acid Forest Soils under Beech in Greece
Authors: Michopoulos P. 
Published: July 2010

AbstractThe ratio of Pb concentrations in A and H horizons (relative migration ratio or RMR) of acid forest soils under beech in Greece was determined and assumed as an index of potential Pb migration. The pH of the A horizon was the only factor studied that significantly and negatively correlated with RMR. Decreasing solubility of organic matter in the A horizon is a possible cause for this correlation. The E4/E6 ratio (absorbance at 465 nm/absorbance at 665 nm) in water extracts from H horizon did not affect RMR, suggesting that soluble organic matter of low molecular weight derived from humic layers could not significantly cause Pb leaching from the A horizon.
Chemistry of Arsenic in Soils: I. Sorption of Arsenate and Arsenite by Four Australian Soils
Authors: Smith E. , Naidu R. , Alston A. M. 
Published: July 2010

AbstractTen soils varying widely in chemistry and mineralogy were used to examine the physical and chemical properties that influence As sorption processes in soils. The sorption of As was measured using a batch technique with Asv and AsIII concentrations added in background solutions of NaNO3 (0.003–0.3 mol L−1) and a range of pH values (2.0–8.5). The soils generally sorbed more Asv than AsIII at equivalent As concentrations. In general, highly oxidic soils sorbed three times more Asv than soils containing small amounts of oxidic minerals. The effect of pH on As sorption varied considerably among the soils. In soils with low concentrations of oxidic minerals, increasing pH had little affect on the amount of Asv sorbed while in highly oxidic soils, sorption of Asv decreased with increasing pH. This decrease was attributed to two interacting factors, the increasing negative surface potential on the plane of sorption and increasing amount of negatively charged Asv species present in soil solution. In contrast to Asv, sorption of AsIII increased with increasing pH. The effect of ionic strength on As sorption varied between the As species. In general, there was a pH (∼3) below which Asv sorption decreased with increasing ionic strength and above which the reverse occurred. For AsIII species, increasing ionic strength had little effect on the amount of As sorbed.
Flue Gas Desulfurization By‐Product Weathering by Acidic Mine Drainage
Authors: Laperche Valérie , Traina Samuel J. 
Published: July 2010

AbstractWe examined the suitability using a flue gas desulfurization grout (FGDG) for the attenuation and abatement of acidic mine drainage (AMD). The FGDG used was a mixture of fly ash (FA) and filter cake (FC) with a FA/FC ratio of 1:1 to improve handling. Five percent of lime (CaO) was added to improve strength development and allow the use of this FGDG as a hydrologic seal for underground mines. Acidic mine drainage solutions collect from wells located within mine voids were reacted with samples of FGDG for up to 168 d, to evaluate the potential for grout dissolution subsequent to subterranean implacement. Shortly upon reaction with AMD, FGDG released a number of ions into solution (As, B, Ca, K, Na, Se, SO4), concomitant with a rapid increase in solution pH (8.5), causing decreases in the solubility of most cations (AI, Fe, Mn, Zn). Significant increases in dissolved As and B concentrations were noted. Both elements were present in solution at levels below respective regulatory limits for drinking water. Of the original quantities of As and B present in FGDG, 1.3 and 45.6%, respectively, were released to solution over a 168‐d reaction period. Concomitant with changes in solution composition, reaction of FGDG with AMD resulted in a loss of ettringite and hannebachgite and a growth of gypsum. Additional changes in mineralogy were observed as FGDG equilibrated with AMD solutions. From these reactions, the long‐term stability of FGDG in underground acidic mine environments is questionable and warrants study in situ.
Mobility of Cadmium‐109 and Zinc‐65 in Soil Influenced by Equilibration Time, Temperature, and Organic Matter
Authors: Almås Å. , Singh B. R. , Salbu B. 
Published: July 2010

AbstractPartitioning of 109Cd and 65Zn fractions in an alum shale soil as affected by time, temperature, and organic matter was investigated. The soil was extracted sequentially by H20 (F1), 1 M NH4OAc at pH 7 (F2), 1 M NH4OAc at pH 5 (F3), 0.04 M NH2OH HCl (F4), 30% H2O2 (F5), and finally by 7 M HNO3 (F6). Sequential extraction of metals was performed on soil samples collected at time intervals ranging from 0.5 to 8760 h (1 yr) after spiking the soil with 109Cd and 65Zn. The soil was placed incipiently in temperature controlled climate chambers at 9, 15, and 21°C. Before spiking, the soil was treated with 0 or 4% organic matter. Adsorption of 109Cd and 65Zn was rapid, but a subsequent slow diffusion of the metals toward chemisorbed fractions was also evident since the 109Cd and 65Zn concentrations decreased in the three mobile fractions (F1–F3) and increased in the inert fractions (F4, F5, F6 and F7) with time. Temperature elevation resulted in decreased concentrations of 109Cd and 65Zn in the F2 and F3 fractions, whereas the concentrations of these metals increased in the inert fractions. In the organic matter‐treated soil, 109Cd and 65Zn were increased significantly in the mobile fractions, with a corresponding reduction of 109Cd and 65Zn in the inert fractions. The effect of organic matter was more pronounced at 9°C than at 21°C. The results thus indicate that increasing time and temperature reduce the organic matter‐induced mobilization of 109Cd and 65Zn in soil.
Occurrence and Transport of Acetochlor in Streams of the Mississippi River Basin
Authors: Clark G. M. , Goolsby D. A. 
Published: July 2010

AbstractThe herbicide acetochlor [2‐chloro‐N‐(ethoxymethyl)‐N‐(2‐ethyl‐6‐methylphenyl) acetamide] was first used on corn (Zea mays L.) in the USA during the growing season of 1994. By 1996, it was the third most heavily used corn herbicide in the midwestern USA. During the growing season of 1997, 78% of 375 samples collected at 32 stream sites in the Mississippi River Basin contained detectable concentrations of acetochlor. However, concentrations in only 2% of the samples exceeded 2/µg/L, the maximum annual average concentration allowable in public water supplies derived primarily from surface water. The largest acetochlor concentrations were detected in streams draining basins in parts of Illinois, Indiana, and Iowa. The median concentration of acetochlor in streams was about 10% that of atrazine (6‐chloro‐N‐ethyl‐N‐isopropyl‐1,3,5‐triazine‐2,4‐diamine), about 25% that of metolachlor [2‐chloro‐N‐(2‐ethyl‐6‐methylphenyl)‐N‐(2‐methoxy‐1‐methylethyl) acetamide], about 50% that of cyanazine [2‐[[4‐chloro‐6‐(ethylamino)‐l,3,5‐triazin‐2‐yl]amino]‐2‐methylpropionitrile], and about threefold that of alachlor [2‐chloro‐2′,6′‐diethyl‐N‐(methoxymethyl) acetanilide]. Load estimates indicate that, during the growing season of 1997, agricultural subbasins draining areas of Illinois, Indiana, and Iowa contributed about 37 000 kg, or 74%, of the 50 000 kg of acetochlor measured in streams of the Mississippi River Basin.
Sorption‐Desorption and Solution Concentration of Phosphorus in a Fertilized Sandy Soil
Authors: He Z. L. , Alva A. K. , Li Y. C. , Calvert D. V. , Banks D. J. 
Published: July 2010

AbstractThere has been increasing concern about drinking water contamination and accelerated eutrophication of surface water bodies. A field experiment was conducted to assess leaching potential of PO4‐P in a Riviera fine sand (loamy, siliceous, hyperthermic Arenic Glossaqualf) under grapefruit (Citrus paradisi Macfad.) production that received 0 to 30 kg P ha−1 yr−1. The PO4‐P concentration was measured in soil solution sampled using suction lysimeters installed above (120 cm) and below (180 cm) the hardpan (argillic horizon). Phosphorus sorption‐desorption in soil samples from different depths of the soil profile was determined to understand the transport and leaching of P in the sandy soil. Phosphorus sorption capacity of the argillic horizon was much greater than the soil above and below it. The PO4‐P concentrations in soil solution varied from 0.031 to 0.976 and from 0.002 to 0.083 mg P L−1 at the 120‐ and 180‐cm depths, respectively. Solution PO4‐P concentrations generally increased with P application rates. The concentrations of P in solution at the 120‐cm depth were much greater than those at the 180‐cm depths, due to the greater P retention capacity of and restricted flow of P through the hardpan. This study demonstrates that leaching of P into groundwater was reduced by the presence of a hardpan in the Riviera fine sand. However, the water drained from the soil above the hardpan contains phosphorus and could be a potential P source to surface waters.
Soil Nitrate‐Nitrogen under Tomato following Tillage, Cover Cropping, and Nitrogen Fertilization
Authors: Sainju Upendra M. , Singh Bharat P. , Rahman Syed , Reddy V. R. 
Published: July 2010

AbstractManagement practices can influence NO3‐N content and movement in the soil. We examined the influence of 3 yr of tillage [no‐till (NT), chisel (CH), and moldboard (MB)], cover crop [hairy vetch (Vicia villosa Roth) (HV), and no hairy vetch (NHV)], and N fertilization (0, 90, and 180 kg N ha−1) on residual NO3‐N content and movement on a Norfolk sandy loam (fine‐loamy, siliceous, thermic, Typic Kandiudults) under tomato (Lycopersicon esculentum Mill) in central Georgia. Because of low N recovery by tomato, NO3‐N content in the soil increased with depth, regardless of treatments, and ranged from 127 to 316 kg ha−1 at 0‐ to 120‐cm depth in the fall (September 1997). The content increased with increasing rate of N addition from cover crop residue and N fertilizer. From fall to spring (March 1998), 22 to 58% (37 to 129 kg NO3‐N ha−1) of this content was lost, mostly due to leaching. Greater loss occurred in NT than in CH or MB, with HV than with NHV, and with 180 or 90 than with 0 kg N ha−1. Similarly, greater loss at 0‐ to 60‐cm than at 60‐ to 120‐cm depth and significant correlation between soil NO3‐N and clay concentration with depth indicates that NO3‐N moved from the surface layer to the underlying clay layer, where it moved slowly. Nitrate‐N content and movement in the soil from cover crop residue and N fertilizer were similar. Minimum tillage reduced NO3‐N movement compared with NT, yet avoided the negative effects on soil and water quality associated with MB. Although HV increased tomato N uptake and recovery, it was not effective in reducing NO3‐N content and movement compared with N fertilizer.
Calibration of Paired Basins prior to Streambank Fencing of Pasture Land
Authors: Galeone Daniel G. 
Published: July 2010

AbstractStreambank fencing is a best management practice that is targeted to reduce suspended sediment and nutrient inputs to streams by reducing direct inputs from animals, eliminating streambank trampling, and promoting streambank revegetalion. A paired basin study is being conducted in two small adjacent basins to determine the waler quality effects of streambank fencing. This article documents the 3‐yr calibration period between control and treatment basins prior to fence installation. Approximately 70% of land adjacent to streambanks in the study area is used as pasture. Nutrient quantities applied as manure, benthic‐macroinvertebrate communities, and the physical habitat of each stream were similar in both basins. Total N, P, and suspended sediment yields measured at the outlet of each basin averaged about 56, 2.8, and 2650 kg ha−1 on an annual basis. For both basins, about 90% of the total N yield was attributable to dissolved NO3‐N and about 90% of the total N yield occurred during nonstormflow; conversely, about 90% of the total P yield was attributable to stormflow and 60 to 65% of the total P yield was suspended. Regression equations developed between both basins for low flow and stormflow samples for nutrients, suspended sediment, and discharge indicated a significant relation for most constituents. Pretreatment relation between basins for low flow and stormflow samples would need to change by 6 and 14% for total N concentrations and 24 and 9% for total P concentrations in order for streambank fencing to significantly affect water quality in the treatment basin.
Trend Analysis of Nutrient Concentrations and Loads in Surface Water in an Intensively Fertilized Watershed
Authors: Bouraoui Fayçal , Turpin Nadine , Boerlen Pascal 
Published: July 2010

AbstractNutrient concentrations and loads from 1988 to 1997 at the surface‐water outlet of a heavily fertilized watershed in the Brittany region, west of France, were analyzed for trends. The 1240‐ha watershed is characterized by milk production and an increasing indoor pig and poultry production. A nonparametric statistical analysis performed on mean monthly and mean annual data detected no trend in nitrate and total P concentrations and loads from 1988 to 1997. When comparing data from the same month for each year of the study, a decreasing trend was detected in the November nitrate flow adjusted concentrations, and in the October maximum nitrate flow adjusted concentrations. An increasing trend was detected in the August total P flow adjusted concentrations. No trend was detected in the monthly and annual nitrate and total P loads. A multiple regression analysis showed that the annual nitrate concentration is positively correlated to the annual rainfall and to the percent area of corn (Zea mays L.). A nutrient global mass balance was constructed for 1988, 1991, and 1994 to explain the lack of an increasing trend in nutrient concentrations and loads despite an intensification of the pig production during these years. Results from this analysis showed that farmers have compensated for increased on‐farm production of nutrients from animal manure by purchasing less fertilizers; therefore, the total nutrient budget remained relatively stable.
Metamodeling Potential Nitrate Water Pollution in the Central United States
Authors: Wu JunJie , Babcock Bruce A. 
Published: July 2010

AbstractThis article presents a modeling system for identifying the spatial patterns of potential water pollution from N fertilizer use in the central USA. The model uses a geographic information system (GIS) and a statistical technique to integrate an environmental process simulation model with spatially referenced databases on crop management and resource characteristics. The potential for NO3‐N runoff and leaching was estimated for a total of 128 591 sites using information on soil, climate, crop, rotation, tillage, irrigation, and conservation practices at each site. For the entire study region, the average annual NO3‐N runoff and leaching, respectively, were estimated to be 5 and 3 kg ha−1, which accounted for about 7 and 4% of total N applied. The potential for NO3‐N runoff was relatively high in much of the Corn Belt, Kansas, and the Nebraska Platte River Basin, and the potential for NO3‐N leaching was relatively high in Ohio, Indiana, and southern Illinois and Missouri. Because much of the area with high leaching potential was tile drained, a large portion of the leached NO3‐N will be discharged to surface water, rather than continue downward to ground water. Finally, the model was applied to estimate the effects of a 25% reduction in N application rates and adoption of crop rotations on potential NO3‐N runoff and leaching.
Modeling Radionuclide Transport and Uptake in an Integrated Lysimeter Experiment: I. Model Development
Authors: Butler A. P. , Wheater H. S. 
Published: July 2010

AbstractA model of a set of integrated lysimeters used to study radionuclide transport and uptake in vegetated soils is described. The experimental facility is conceptualized as a network of linked compartments. Observed water fluxes provide the basis for simulating the movement and distribution of radionuclides throughout the entire experimental system. The model incorporates a simplified representation of upward migration of radionuclides into an unsaturated soil followed by leaching. The transfer of radionuclides from the soil to the crop is represented using a dynamic root uptake submodel. The application of the lysimeter system model to data for the radionuclide 22Na is presented in an accompanying paper.