bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modeling of Oxygen Transport and Pyrite Oxidation in Acid Sulphate Soils
Authors: Bronswijk J. J. B. , Nugroho K. , Aribawa I. B. , Groenenberg J. E. , Ritsema C. J. 
Published: July 2010

AbstractDrainage and aeration of previously submerged acid sulphate soils could lead to oxidation and acidification of the soil and to related problems such as high Fe and Al concentrations in the soil solution. Agricultural production on these acidified soils is low. Furthermore, leaching of acid and toxic compounds from the soil to surface waters may cause environmental damage, such as degradation of ecologically valuable wetlands. A computer simulation model was developed to compute the rate and magnitude of pyrite oxidation in pyritic deposits such as acid sulphate soils, and the resulting acidity, soluble Fe and sulphates produced. The model includes vertical gaseous O2 diffusion from the atmosphere into the soil macropores, lateral diffusion of dissolved O2 into the soil matrix, and O2 consumption inside the soil matrix by pyrite oxidation and organic matter decomposition. Oxygen consumption by pyrite oxidation was modeled by combining the equal diameter reduction model with an O2 concentration dependent rate constant for pyrite oxidation. The model was validated by comparing computations and measurements in an acid sulphate soil subjected to drainage for a period of 440 d. Computed and measured pyrite content profiles, gaseous O2 concentrations in the macropores and sulphate concentrations in the soil solution corresponded well. The present model, combined with a chemical equilibrium model and a solute transport model, can be applied to predict the (long‐term) effects of water management strategy on the quality of soils, drainage waters and surface waters in areas with pyritic deposits.
Anatomical, Chemical, and Ecological Factors Affecting Tree Species Choice in Dendrochemistry Studies
Authors: Cutter Bruce E. , Guyette Richard P. 
Published: July 2010

AbstractRecently, element concentrations in tree rings have been used to monitor metal contamination, fertilization, and the effects of acid precipitation on soils. This has stimulated interest in which tree species may be suitable for use in studies of long‐term trends in environmental chemistry. Potential radial translocation of elements across ring boundaries can be a confounding factor in assessing environmental change. Thus, the selection of species which minimizes radial translocation of elements can be critical to the success of dendrochemical research. Criteria for the selection of species with characteristics favorable for dendrochemical analysis are categorized into (i) habitat‐based factors, (ii) xylem‐based factors, and (Hi) element‐based factors. Species with a wide geographic range and ecological amplitude provide an advantage in calibration and better controls on the effects of soil chemistry on element concentrations. The most important xylem‐based criteria are heartwood moisture content, permeability, and the nature of the sapwood‐heartwood transition. The element of experimental interest is important in determining which tree species will be suitable because all elements are not equally mobile or detectable in the xylem. Ideally, the tree species selected for dendrochemical study will be long‐lived, grow on a wide range of sites over a large geographic distribution, have a distinct heartwood with a low number of rings in the sapwood, a low heartwood moisture content, and have low radial permeability. Recommended temperate zone North American species include white oak (Quercus alba L.), post oak (Q. stellata Wangenh.), eastern redcedar (Juniperus virginiana L.), old‐growth Douglas‐fir [Pseudotsuga menziesii (Mirb.) Franco] and big sagebrush (Artemisia tridentata Nutt.). In addition, species such as bristlecone pine (Pinus aristata Engelm. syn. longaeva), old‐growth redwood [Sequoia sempervirens (D. Don) Endl.], and giant sequoia [S. gigantea (Lindl.) Deene] may be suitable for local purposes.
Influence of Cattle‐Manure Slurry Application on the Solubility of Cadmium, Copper, and Zinc in a Manured Acidic, Loamy‐Sand Soil
Authors: del Castilho P. , Chardon W. J. , Salomons W. 
Published: July 2010

AbstractThe concentrations of Cd, Cu, and Zn were evaluated bimonthly in the soil solution of five acidic loamy‐sand soil plots during an 18‐mo period, before and after application of 25 Mg ha−1 cattle‐manure slurry on top of the plots. pH, Cd, Zn, Cu, and Fe concentrations, electrical conductivity (EC), and dissolved organic carbon (DOC) were monitored in the soil‐solution samples extracted from soil down to 80‐cm depth. Dissolved metal concentrations ranged from 9 × 10−7 to 9 × 10−5 mmol m−3 for Cd, from 0.14 to 33 mmol m−3 for Zn, from 0.005 to 5 mmol m−3 for Cu, and from 0.54 to 4.6 × 10−3 mmol m−3 for Fe. Maximum soil solution concentrations of Cd (9 × 10−5 mmol m−3) and Zn (33 mmol m−3) were found between 0‐ and 40‐cm depth 6 wk after cattle‐manure slurry application; Cu and Fe concentrations were not elevated. Except for the peak concentrations of Cd and Zn following the cattle‐manure slurry application, no statistically significant temporal trends in heavy metal concentrations were observed. Multiple linear regression analysis showed a positive correlation between the metal concentrations with DOC and a negative correlation with pH. High EC levels in topsoil layers, resulting from manuring were also found to increase metal concentrations. In the topsoil the Cd and Zn concentrations were affected by soil solution pH, and in the subsoil by DOC variations. The Cu concentration was affected by DOC variations in all soil layers. Supercentrifugation of selected subsoil samples from one sampling date removed 80% of the Cd, Zn, and Cu from the solution along with DOC and Fe. Cation‐exchange column experiments as well as anodic stripping voltammetry measurements (speciation) of selected soil solution samples, showed that 30 to 70% of the dissolved Cu and all Cd was bound in relatively fast dissociating metal complexes. The observed variations in soil solution heavy metal concentration and speciation show that a distribution coefficient that describes the partition of metals over soil solution and solid phase is not a constant but depends on the physicochemical situation.
Influence of Freeze‐Thaw and Flooding on the Loss of Soluble Organic Carbon and Carbon Dioxide from Soil
Authors: Wang F. L. , Bettany J. R. 
Published: July 2010

AbstractFreeze‐thaw and flooding significantly affected the loss of water soluble organic carbon (SOC) and carbon dioxide carbon (C‐CO2) from a well‐drained Black Chernozemic soil (Udic Boroll) in a leaching‐incubation study. At the end of 12 wk, the total loss of SOC was 90, 107, 399, and 224 mg kg−1 for soils with normal (incubated at field capacity moisture), freeze‐thaw, flooding and flooding‐freeze‐thaw treatments, respectively. The E4/E6 values of the leachates obtained from the four treatments ranged from 10 to 32, suggesting that SOC in the leachates was mainly low molecular weight in nature. The rate of the SOC leaching changed over time and the amount of SOC leached from the flooded treatments reached a maximum in the middle of the incubation period. In contrast, the rate of SOC leaching for unflooded treatments appeared little changed with no distinctive rate maximum. The cumulative loss of C‐CO2 and total C (sum of SOC and C‐CO2) from the treatments decreased in the order of flooding > normal > flooding‐freeze‐thaw > freeze‐thaw. The rates of C‐CO2 evolution decreased with time for the freeze‐thaw treated soils whereas the rate of C‐CO2 evolved from the normal treatment initially decreased and then increased after 8 wk of incubation, suggesting transient kinetics for the system. For the flooding treatment, the rate of C‐CO2 evolution showed a similar pattern to that of SOC leaching. There was a high linear correlation between the cumulative C‐CO2 evolved and SOC leached from the soil.
Storage and Migration of Fallout Strontium‐90 and Cesium‐137 for Over 40 Years in the Surface Soil of Nagasaki
Authors: Mahara Yasunori 
Published: July 2010

AbstractThe vertical migration of 90Sr and 117Cs produced by the explosion of the atomic bomb in 1945 was investigated in an unsaturated soil layer in the Nishiyama area of Nagasaki. The in situ migration rates of 90Sr and 137Cs were estimated to be 4.2 mm yr−1 and 1.0 mm yr−1, respectively, when the rate of movement of soil water was 2500 mm yr−1. The in situ Kd values of 90Sr and 137Cs were calculated to be 0.3 m3 kg−1 and 1.2 m3 kg−1, respectively. These are probably the only results that exist for the interaction between soil and 137Cs and 90Sr over 40 yr. These results suggest that since fallout 137Cs and 90Sr have remained in the surface soil for a long period of time, we should pay significant attention to radiological effects of nuclear accidents such as the Chernobyl disaster.
Accumulation of Cesium‐137 and Strontium‐90 in Ponderosa Pine and Monterey Pine Seedlings
Authors: Entry James A. , Rygiewicz Paul T. , Emmingham William H. 
Published: July 2010

AbstractBecause ponderosa pine [Pinus ponderosa (Dougl. ex Laws)] and Monterey pine (P. radiata D Don) have exceptionally fast growth rates and their abscised needles are not readily dispersed by wind, these species may be valuable for removing radioisotopes from contaminated soils. Ponderosa and Monterey pine seedlings were tested for their ability to accumulate 137Cs and 90Sr—characteristic radioisotopes of nuclear fallout—from contaminated soil. Seedlings were grown for 3 mo in 165 cm3 sphagnum peat moss/perlite (1:1 V/V) in a growth chamber. In Exp. 1, seedling accumulation of 137Cs and 90Sr after 1 mo of exposure was measured. In Exp. 2, seedling accumulation of the radioisotopes during different‐length exposures was measured. Seedling accumulation of 137Cs and 90Sr at different concentrations of the radioisotopes in the growth medium was measured in Exp. 3. Ponderosa pine accumulated 6.3% of the 137Cs and 1.5% of the 90Sr present in the growth medium after 1 mo; Monterey pine accumulated 8.3% of the 137Cs and 4.5% of the 90Sr. Accumulation of 137Cs and 90Sr by both coniferous species was curvilinearly related to duration of exposure. Accumulation of 137Cs and 90Sr by both species increased with increasing concentration in the growth medium and correlated curvilinearly with radioisotope concentration in the growth medium. Large areas throughout the world are contaminated with 137Cs and 90Sr as a result of nuclear weapons testing or atomic reactor accidents. The ability of trees to sequester and store 137Cs and 90Sr introduces the possibility of using reforestation to remediate contaminated soils.
Biogeochemical Responses of a Forested Watershed to Both Clearcut Harvesting and Papermill Sludge Application
Authors: Kraske C. R. , Fernandez I. J. 
Published: July 2010

AbstractThe biogeochemical responses of a forested watershed to both clearcut harvesting and papermill sludge application were evaluated. A mixed northern hardwood and conifer stand in Letter E Township, ME, was clearcut during the winter of 1985–1986. Harvest residues were windrowed, and red pine (Pinus resinosa Aiton) seedlings were planted. In 1987, herbicide was applied to reduce vegetative competition. In the fall of 1989, a combined primary and secondary papermill sludge was operationally applied with a rate of 40 Mg ha−1 (dry sludge). Actual loading rates varied considerably. Study plots were established in sludge‐harvest, control‐harvest, and uncut forest zones. Soils within the treatment zones consisted of Typic Haplorthods developed from loamy basal tills. Selected soil and soil solution properties were measured in 1989 and 1990. In 1989, harvest area forest floor pH was 0.6 to 0.8 units higher, and organic matter content was up to 40% lower, when compared with that of the uncut forest area. This reflected the accelerated decomposition of the forest floor as a result of the harvest activities. Sludge application further increased forest floor pH by approximately one unit, exchangeable Ca2+ and Mg2+ by ≈100 and 60%, respectively, cation‐exchange capacity by 60%, and base saturation by 34% compared with that of the control‐harvest area. Exchangeable Mg2+ and Na+, and water‐soluble SO2−4 were the mineral soil properties most affected by sludge application. Harvesting increased concentrations of major nutrients in soil solution. In 1989, solution Ca2+ was two to three times greater, and Mg2+ was three to six times greater in the harvest area than in the uncut forest area. Flushes of Ca2+, Mg2+, Na+, and SO2−4 into soil solution occurred immediately following sludge application. Only N+ and SO2−4 remained elevated in 1990, being five and three times greater, respectively, in the sludge amended harvest area than in the uncut forest area. Compared with the harvest operations, one‐time papermill sludge application appeared to have only small effects on the biogeochemical processes of the treated Letter E site.
Irrigation and Polymer Effects on Herbicide Transport through the Unsaturated Zone of a Sparta Sand
Authors: Wietersen R. C. , Daniel T. C. , Fermanich K. J. , Lowery B. , McSweeney K. 
Published: July 2010

AbstractState‐sponsored monitoring programs show that the Sparta sand (sandy, mixed, mesic Entic Hapludoll) of the Lower Wisconsin River Valley (LWRV) is susceptible to herbicide movement through the vadose zone, especially atrazine [2‐chloro‐(4‐ethylamino)‐6‐(isopropylamino)‐s‐triazine]. Experiments were initiated to examine the effect of irrigation scheduling and pesticide formulation on transport through the vadose zone. Intact Sparta sand (SP) columns were extracted from the LWRV and instrumented to simulate temperature, irrigation and drainage conditions encountered in the field. Labeled 14C‐atrazine, alachlor [2‐chloro‐N‐(2,6‐diethylphenyl)‐N‐(methoxymethyl) acetamide], and metolachlor [2‐chloro‐N‐(2‐ethyl‐6‐methylphenyl)‐N‐(2‐methoxy‐1‐methylethyl) acetamide] were monitored in the leachate. Treatments included irrigation schedules to match no‐irrigation or rainfed (RF), evapotranspiration (ET) and ET plus an additional 25% (ET +). Formulation treatments consisted of standard pesticide tank‐mix mixtures with and without the addition of a polymer (2% by volume). Increased water input significantly increased metolachlor transport through the SP profile. Due to variability in the leachate data, no significant differences in the total amount of atrazine leached through the columns were shown to exist between the ET and ET + treatments; however, after initial irrigation, atrazine concentration in leachate from ET + treatment was 10 to 15 times greater than leachate of the ET treatment. When compared to the standard herbicide formulation, the use of the polymer significantly reduced and delayed the peak concentrations of metolachlor in the leachate. A significant difference also was observed in the amount of metolachlor retained in the surface soil (0–10 cm) of those columns receiving the polymer treatment compared to those receiving the standard application of the herbicide.
Selenite and Selenate Quantification by Hydride Generation‐Atomic Absorption Spectrometry, Ion Chromatography, and Colorimetry
Authors: Blaylock Michael J. , James Bruce R. 
Published: July 2010

AbstractThe need for a routine, inexpensive method with nanomolar detection limits for soluble SeO2−3 and SeO2−4 is increasing as Se research on soil‐plant‐water systems intensifies and speciation of Se valence states is required. This study was undertaken to compare hydride generation‐atomic absorption spectrometry (HGAAS), colorimetry using 2,3‐diaminonaphthalene (DAN), and ion chromatography (IC) as suitable methods for analysis of SeO2−3 and SeO2−4 in soil extracts and water samples. Selenium standards in solutions of either 1.0 mM KH2PO4, CaSO4, and KNO3, or in distilled water were analyzed to determine detection limits (DL), limits of quantitation (LOQ), and practicality for routine use of the above methods. A 0.1 mM K2HPO4/KH2PO4 soil extract spiked with 2.0 or 20 µM SeO2−3 and SeO2−4 was also used to compare the precision of the three methods. The HGAAS method was the most sensitive (0.212 absorbance units/µM) and had the lowest DL for SeO23 (0.03 µmol Se/L) of the three methods employed. Detection limits for the DAN and IC methods were significantly higher (18 and 0.24 µmol Se/L, respectively). Poor reproducibility between methods was obtained for SeO2−4 content of the soil extract containing 20 µM SeO2−4, with concentrations ranging from 9.1 ± 1.2 µmol/L determined by HGAAS to 24.6 ± 0.05 µmol/L by IC. The variability and poor recovery of SeO2−4 was due to variabilty in efficiency of the HCl reduction required to reduce SeO2−4 to SeO2−3 before analysis in the HGAAS and DAN procedures. Selenium determinations in samples where low detection limits (<0.1 µM) are required are most effectively accomplished with HGAAS. Colorimetry requires greater effort and time from the analyst to obtain the low detection limits of HGAAS, but is useful in that only a visible light spectrometer is required. Ion chromatography is capable of automated determinations of Se2−3 and SeO2−4 directly in combination with other ions of interest and may be appropriate for soil solution Se analysis where Se speciation is required.
Water Resource Implications of Midwest Agroecosystems
Authors: Oberle Steven L. , Burkart Michael R. 
Published: July 2010

AbstractAgriculture contributes to nonpoint‐source pollution of the nation's water resources through leaching and runoff of crop nutrients, pesticides, and animal wastes, and through soil erosion from cropland. Development of effective solutions to water quality problems resulting from agricultural activities requires input of information synthesized from many disciplines, and coordination and integration of various scientific and technical programs. This article describes a program for synthesizing information resulting from USDA, USEPA, and USGS projects into evaluations of the regional impact of existing and innovative agroecosystems on surfacewater and groundwater quality. The program involves two facets with equal function and importance: assembling and analyzing information to characterize Midwest agroecosystems and to estimate water quality response; and developing effective systems for disseminating information and technology to end users. Four phases are presented as sequential, interdependent components of the program: (i) information acquisition and assessment; (ii) synthesis and systems development; (iii) education and technology transfer; and (iv) evaluation. Integration of information from water quality programs in the Midwest will provide a comprehensive and regional analysis, and can serve as the basis for disseminating information and technology necessary to implement agricultural management systems with maximum potential for protecting water resources. Regional analysis can also serve as input into the development of agricultural policy that is compatible with the nation's environmental and fiscal goals.
Modeling Alternatives to Reduce Dairy Farm and Watershed Nonpoint Source Pollution
Authors: Sugiharto Toto , McIntosh T. H. , Uhrig R. C. , Lardinois J. J. 
Published: July 2010

AbstractManagement practices are available that may reduce sediment or phosphorus (P) loading to streams draining agricultural land. An evaluation of the long term effects of implementing one or more of these practices is needed. We used the Erosion Productivity Impact Calculator (EPIC) and Agricultural Non‐Point Source (AGNPS) models to evaluate 20 management practices for sediment and P yields from 4 ha fields in a 1272 ha watershed of dairy farms. Five crop sequences [continuous corn (Zea mays L.) CC(OA)AAA, CC(OA)AAAA, CCC(OA)AAA, and CCCAAA; 0, oat (Avena sativa L.); A, alfalfa (medicago sativa L.)] combined with either fall moldboard plowing (mFMP), chisel plow (mFCP), no‐till (mNT), or no‐till substituting anhydrous ammonia for manure (aNT), were imposed on a toposequence of three Alfisols. The normal sequence, 2 yr of corn, oat/alfalfa seeding, 3 yr of alfalfa with fall application of solid manure followed by moldboard plowing, CC(OA)AAA‐mFMP, served as reference. Scenarios were subjected to 42 yr of simulated local climate. Scenarios with 43% or less row crop and mNT on a 4% sloping soil reduced sediment yield from 24 to 47%, at edge of field, but increased total P yield from 158 to 338%, mostly as soluble P. The EPIC output parameters (soil loss ratio [C] for June, erodibility [K], Manning's n, and SCS curve number [CN]) served as inputs to the (AGNPS) model, a cell based single rainfall event model that simulates runoff, sediment, and P yields from a watershed. Crop sequences not exceeding 43% corn and mFCP or aNT reduced watershed sediment yield 13 to 41%, but increased total P yield by 44 to 113% as compared with CC(OA)AAA‐mFMP. Average annual costs were $11 ha−1 less for these sequences when compared with CC(OA)AAA‐mFMP.
Bioavailability of Copper, Manganese, and Zinc in Poultry Litter
Authors: van der Watt H. v. H. , Sumner M. E. , Cabrera M. L. 
Published: July 2010

AbstractPoultry litter is a useful agricultural by‐product but its potential for environmental pollution requires clarification. A poultry litter from north Georgia containing 1196, 944, and 631 mg/kg Cu, Mn, and Zn respectively was used to study the bioavailability of these metals in a short‐term greenhouse pot experiment. Metal uptake from poultry litter applications equivalent to 0, 15, 30, and 60 Mg/ha were compared on pure quartz sand and Cecil (clayey, kaolinitic, thermic Typic Kanhapludult) and Lakeland (thermic, coated Typic Quartzipsamment) soils at soil pH regimes of ≈5 and 7. Sudax [Sorghum bicolor (L.) Moench)] was used as test crop for metal uptake from 1 kg of soil during a 21‐d growth period. For the litter treatments, the Cu, Mn, and Zn concentrations were in the ranges 5 to 15, 62 to 1933, and 19 to 55 mg/kg. The Cu and Zn plant concentrations were in the normal range, while toxic Mn concentrations (>400 mg/kg) were found only in the case of the more clayey Cecil soil where reducing conditions in the pots may have been responsible for excessive solubilization of Mn. Soil pH was important in determining both ammonium bicarbonate‐DTPA and 0.1 M NaNO3 extractable soil Cu, Mn, and Zn. Significant (P < 0.01) correlations were found between soil Cu, Mn, and Zn extracted by these extractants and plant uptake, while inclusion of soil pH improved the significance of the regressions. Analyses of field soils revealed the build‐up of possible toxic levels of Cu, Mn, and Zn in only one soil which had received 6 Mg/ha of poultry litter per annum for 16 yr.