bluuebunny/crossref_metadata_2025_split huggingface dataset:
Use of Soil Survey Information to Assess Regional Salinization Risk Using Geographical Information Systems
Authors: Bui Elisabeth N. , Smettem Keith R. J. , Moran Chris J. , Williams John 
Published: July 2010

AbstractPrevious experience in southern and western Australia has shown that tree clearing alters the water balance in a landscape, leading to increased deep drainage and consequent rises in phreatic water tables. Assessment of the risk of regional salinization involves integration of hydrology, hydrogeology, soil and land management issues. An example of the use of soil survey data, integrated with water resources and digital elevation data in a GIS, to estimate the risk of salinization after tree clearing is illustrated for the upper Burdekin river basin in the wet/dry tropics of North Queensland. Soil map unit descriptions include information on soil‐landform relations, parent material, soil thickness, depth to bedrock and dominant and subdominant soil types. Such information can be used to qualitatively estimate permeability and drainage classes (high, medium, or low) and to determine likely recharge and discharge areas in the landscape. Analysis of the spatial association between surveyed electrical conductivity measurements and estimated recharge and discharge areas was used to cross‐check this qualitative classification. The distributions of saline soils and shallow water tables are used to assess the salinity hazard of the region. Where % total soluble salts (TSS) are >0.25% and water table >6 m deep, a salinity hazard is present. This hazard can translate into a salinity problem if the hydrologic balance is altered so that the salt is remobilized and redeposited in the landscape. An estimate of the likelihood and amount of increased recharge to groundwater after tree clearing was obtained using water balance models with soil physical parameters measured at key sites. Where physical data were not available, surrogate physical properties were estimated from the soil survey data. Results suggest that tree clearing may increase deep drainage by up to 10 times and that in watersheds where shallow unconfined aquifers are present and where %TSS > 0.25%, recharge areas should not be cleared.
GIS Modeling of Recharge on a Watershed
Authors: Rogowski A. S. 
Published: July 2010

AbstractThe study describes a model developed to delineate primary recharge contributing areas on a large watershed based on the field‐measured parameters. The procedure uses measured values of soil water content, bulk density, hydraulic conductivity, and depth to water at 31 locations, to generate kriged overlays of input in a Geographic Information Systems (GIS) framework. The number of locations was a compromise between sampling efficiency and requirements of the geostatistical analysis. Mathematical operations on the overlays are carried out on a pixel‐by‐pixel basis to predict distributions of water flux from below the root zone, travel time to the groundwater, and recharge flux pulse at the water table. Comparison with field data suggests that flow may occur through ouly a portion of total pore space. Field application is illustrated on a 123 km2 catchment in Pennsylvania.
Uncertainty of Groundwater Vulnerability Assessments for Agricultural Regions in Hawaii: Review
Authors: Loague Keith , Bernknopf R. L. , Green R. E. , Giambelluca T. W. 
Published: July 2010

AbstractThere are important challenges associated with assessing potential groundwater vulnerability hazards that may result from regional scale applications of agrochemicals. The increasing availability of Geographic Information System (GIS) software to those involved in assisting with landuse decisions has resulted in the widespread production of multicolored risk management maps for many environmentally sensitive issues. Soil‐based GIS's have recently been coupled to various solute‐leaching models to make near‐surface groundwater vulnerability assessments for guidance in pesticide regulation in several states. In general, these assessments rest on soil, climatic, and chemical data that are extremely sparse and contain considerable uncertainty. It is also important to acknowledge the uncertainty associated with the transport/fate processes that are not accounted for by the modeling approach used to make the assessment. In this paper, we review the results from a series of papers that have focused on characterization of uncertainty in pesticide mobility estimates, using the attenuation and retardation indices (AF and RF), for the Pearl Harbor Basin on the Hawaiian island of Oahu. Relative to data error uncertainties, we discuss the impacts of: (i) soil, climatic, and chemical data base uncertainties, (ii) reductions in data base uncertainties, (iii) extrapolation of soil data base information based on soil taxonomy and soil survey, and (iv) importing information from outside the region of interest. Relative to model error uncertainties, we compare pesticide leaching estimates from the simple AF and RF mobility indices with simulations from the EPA's Pesticide Root Zone Model (PRZM) and field observations. Finally, we outline a Regional Integrated Risk Assessment approach for characterizing regional scale groundwater vulnerability for near‐surface nonpoint sources.“Hey farmer farmer put away that DDT” Joni Mitchell, “Big Yellow Taxi”
Use of Soil Survey Data for Modeling Solute Transport in the Vadose Zone
Authors: Bouma J. , Booltink H. W. G. , Finke P. A. 
Published: July 2010

AbstractSoil surveys have now been completed in many countries and qualitative interpretations in terms of soil suitability for different forms of land use, which are part of most soil survey reports, are being used widely. These interpretations are, however, essentially based on expert judgement and they are inadequate to answer many modern questions about ecological and environmental aspects of alternative forms of land use. Simulation modeling of solute transport and plant growth has become an operational tool in land use studies and soil survey databases can be an important source of basic soil and landscape information to be used in modeling. Still, many data are not in a form that can be used directly and an effort has to be made to transform soil survey data into a usable format, by developing pedotransfer functions. In discussing soil survey data, a distinction can be made between point‐ and area data. Case studies for leaching of nitrates (NO−3) and growth of potato (Solanum tuberosum L.) in a loamy and clayey soil, illustrate use of different types of class‐pedotransfer functions for functional soil horizons. Monte Carlo techniques are used to illustrate the effect of variability of hydraulic basic data on results obtained. Soil surveys define soil data and interpretations for areas of land by considering “representative” soil profiles for delineated areas on the map. Internal variation is expressed only in qualitative terms. Geostatistical techniques can be used to interpolate point data to areas of land, allowing quantitative expressions including error statements. The effects of upscaling of point data to cells of different sizes on leaching of NO−3 and growth of potato are illustrated for data derived from a Dutch field. All illustrations demonstrate the crucial role of Geographic Information Systems (GIS) in storing and manipulating basic soil and landscape data.
Treatment of Fish Farm Wastewater Using Sand Filtration
Authors: Kristiansen Rolv , Cripps Simon J. 
Published: July 2010

AbstractThe treatment of aquaculture wastewaters typically consists of screening suspended particles from the primary flow, producing a sludge that must be disposed of. Two experiments were conducted to determine the feasibility of using sand to renovate, stabilize, and dry salmon farm sludge. Data from a preliminary laboratory experiment were used to quantify and design a pilot‐scale study facility linked to a salmon farm. The pilot study comprised coarse sand‐filled infiltration beds loaded with either an artificial fish farm wastewater (AFW), backwash water from a microsieve (BW), or sedimented microsieve backwash water (SBW) collected daily from a settling chamber. A large reduction in hydraulic capacity was caused by the establishment of a clogging mat on the sand filter surface. About 60% of the sludge total organic C was removed by the filters. Nitrogen in the effluent from the SBW loaded filters was predominately organic, and nitrate concentrations were insignificant (<0.03 mg NO3‐N L−1). Effluent ammonium concentration decreased from 97% of the effluent total nitrogen (TN) after 1 mo of loading, to 10% after 2 to 3 mo, with an attendant increase in nitrate to about 65% of the TN. The P binding capacity of the test sand volume was exceeded after 1 to 2 mo of SBW loading. This capacity was not exceeded during the experiment, using the two other effluent types (BW and AFW). Filter effluent P concentrations were about 1.4 mg L−1. At a SBW loading of 1 cm d−1, to a coarse sand, with a hydraulic head of >10 cm, it is expected that 2 to 3 mo loading can be conducted before maintenance or change of filter surface sand is required, as a result of hydraulic malfunction. The use of sand infiltration for treating salmon farm sludge was therefore shown to be feasible.
Application of a Lumped, Nonlinear Kinetics Model to Metal Sorption on Humic Substances
Authors: Yu Y. Shane , Bailey George W. , Xianchan Jin 
Published: July 2010

AbstractExposure assessment models are needed to predict the sorption behavior of metal ions with humic substances. To address this need, a lumped parameter nonlinear kinetics model based on the Langmuir‐Hinshelwood kinetic model—dC/dt = k1C/(1 + k0C)—is introduced and evaluated. The model was applied to a mixture of seven metal ions— Cr(III), Pb(II), Cu(II), Cd(II), Co(II), Ag(I), and Li(I)—reacted with three individual humic substances. The lumped parameter model employs a dimensional analysis technique (i.e., uses dimensionless parameters), Laplace transforms, gamma functions, and gamma distributions to produce analytical solutions for the kinetic equation of metal ion sorption to humic substances. During the initial reaction period, the most reactive species—Cr(III) and Pb(II)—dominated the lump parameter value, and the mixture behaved like a first‐order reaction. At longer periods, the lump followed a second‐order decay if there were less reactive species involved. The lumped parameter model provides valuable information about the overall kinetics behavior of metal ion mixtures with humic substances and could serve as a simulation tool to investigate the transport of metal ions in and out of landfill sites and the transport/retardation of metals in contaminated soils and aquifers.
Movement of Pesticides under Two Irrigation Regimes Applied to Turfgrass
Authors: Starrett S. K. , Christians N. E. , Austin T. Al 
Published: July 2010

AbstractCurrent public concern has focused attention on the environmental effects of chemical applications to turfgrass areas. Our objective was to investigate the movement of isazofos ([O‐[5‐chloro‐1‐(1‐methylethyl)‐1H‐1,2,4‐triazol‐3‐yl]O,O‐diethyl phosphorothioate]), chlorpyrifos ([0,0‐diethyl‐0‐(3,5,6‐trichloro‐2‐pyridinyl) phosphorothioate]), metalaxyl [N‐(2,6‐dimethylphenyl)‐N‐(methoxyacetyl) alanine methyl ester], and pendimethalin [N‐(1‐ethylpropyl)‐3,4‐dimethyl‐2,6‐dinitrobenzenamine] when applied to Kentucky bluegrass turf established on 50‐cm long and 20‐cm diameter undisturbed soil columns of Nicollet (fine‐loamy, mixed, mesic Aquic Hapludolls) in which the macropore system remained intact. This study was conducted for 28 d and used a heavy (four, 2.54‐cm applications) and a light (16, 0.64‐cm applications) irrigation regime. Average isazofos, chlorpyrifos, metalaxyl, and pendimethalin recovered (by extraction) from soil columns under the heavy irrigation regime, plus that collected in the leachate, were 8.8, 11.5, 23.8, and 7.9%, respectively. Isazofos, chlorpyrifos, metalaxyl, and pendimethalin recovery from soil columns under the light irrigation regime, plus that collected in the leachate, averaged 3.4, 6.6, 13.9, and 4.6%, respectively. On average, 6.3, 0.5, 7.7, and 0.2% of the applied isazofos, chlorpyrifos, metalaxyl, and pendimethalin, respectively, were measured in leachate from soil columns under heavy irrigation in contrast to 0.4, 0.0, 0.2, and 0.0%, respectively, from soil columns under light irrigation. Comparing the four applied pesticides, metalaxyl is most likely to be leached because of a low soil sorption, followed by isazofos, pendimethalin, and chlorpyrifos. Metalaxyl was found in the highest percentage in the leachate followed by isazofos, pendimethalin, and chlorpyrifos. From this research, we conclude that irrigation practices (frequency and depth of application) can have an impact on the movement of pesticides through soil profiles.
Side Effects of Rimsulfuron on the Microbial Biomass of a Clay‐Loam Soil
Authors: Perucci P. , Scarponi L. 
Published: July 2010

AbstractThe effect of Rimsulfuron treatment on soil microbial biomass was studied in a clay‐loam soil under field and laboratory conditions. Field trials were performed at the usual field rate (0.005 ppm; FR) and 10 times the field rate (10FR). In addition to FR and 10FR, one hundred (100FR) times the field rate was also assayed in laboratory experiments. Determinations of microbial biomass‐C content, fluorescein diacetatehydrolysis activity (FDA hydrolysis) and protease activity were carried out 0, 1, 2, 4, 7, 10, 15, 25, and 45 d after herbicide application. In the field trials there were no significant side effects on the investigated parameters at either rate. Conversely, laboratory experiments showed decreases in microbial biomass‐C levels and increases in FDA‐hydrolysis and protease activity at 10FR and 100FR within the first 10 d. As increases in the activity of FDA hydrolysis and protease were concomitant with the decreases in the microbial biomass‐C content a toxic effect on soil microrganisms with a consequent release of hydrolytic enzymes from cell lysis has been hypothesized. This effect was transitory and only at the higher rates of rimsulfuron was it significant.
Soil Response to Acid Percolation: Acid‐Base Buffering and Cation Leaching
Authors: Hartikainen Helinä 
Published: July 2010

AbstractA gradual soil acidification was simulated in a percolation experiment with two cultivated soils differing markedly in their initial pH. Soil samples were repeatedly eluted with water or 0.002 M H2SO4, and the changes in the eluate and soil chemistry at various stages of soil acidification were monitored. Ion exchange properties responded to acid load more readily than did the eluate chemistry. Cation exchange at variable charge sites and dissolution reactions releasing from the nonexchangeable pool were important mechanisms consuming solution H+ ions. Alkali and alkaline earth saturation degree that was related to the potential cation exchange capacity (AAESpot) decreased in conformity with acid load, whereas that related to the effective cation exchange capacity (AAESeff) did not. In terms of eluate chemistry, two stages of acidification were identified in a circumneutral acid Podzol (CaCl2, pH 6.7). In the first stage, acidification proceeded with small changes in pH as long as buffering by variable charge exchange sites was available (above soil pH 5). In the second stage, percolate pH dropped drastically and the leaching of Al, Fe, and Mn was intensified because of a marked increase in their exchangeable pool. An acid Gleysol (pH 4.9) showed only the feature of the second stage of acidification. The acid‐induced losses of cations in the percolation were markedly lower than in a previous titration experiment. Magnesium was more sensitive to acid than Ca. The monovalent cations were only slightly affected. Response of Mn to acid was similar to the alkaline earth cations, whereas Al was not substantially displaced. Above pH 4.7, complexation by humus reduced the leaching of Al, but below this pH complexed Al began to decrease.
Effects of Initial Water Content on Macropore/Matrix Flow and Transport of Surface‐Applied Chemicals
Authors: Shipitalo M. J. , Edwards W. M. 
Published: July 2010

AbstractPesticides and fertilizers are often broadcast on no‐till fields in the spring when soil water content can be quite variable. Soil water content may influence the contribution of macropores and matrix porosity to water movement and chemical transport in subsequent rainfalls. Therefore, we surface‐applied SrBr2 6H2O, atrazine (2‐chloro‐4‐ethylamino‐6‐isopropylamino‐s‐triazine), and alachlor [2‐chloro‐2′,6′‐diethyl‐N‐(methoxymethyl) acetanilide] on nine, 30 by 30 by 30 cm, undisturbed soil blocks obtained from a no‐till corn (Zea mays L.) field and maintained at three initial moisture levels 1 h before a 30‐mm, 0.5‐h simulated rain. To distinguish applied water from resident water and assess interaction of the rainwater with the soil matrix, RbCl was added to the simulated rain as a tracer. Sequential percolate samples were collected from the base of the blocks in ≈ 10‐mL increments using a 64‐cell grid lysimeter. Flow‐weighted concentrations of Cl− and Rb+, respectively, were 75 and 836% higher in percolate from dry (θ = 0.11 kg kg−1) than from wet blocks (θ = 0.21 kg kg−1), indicating that displacement of resident water and interaction of rainwater with the matrix increased with initial soil water content. As a result, percolate concentrations of the reactive, surface‐applied, constituents (Sr2+, atrazine, alachlor) decreased with increasing soil water content. High block to block variability precluded detection of significant differences in percolate volume and total chemical transport among moisture levels. The relative contribution of macropores to chemical transport and water movement appears to be greatest when the soil is dry and decreases as the soil becomes wetter.
Fate and Transport of Plutonium‐239 + 240 and Americium‐241 in the Soil of Rocky Flats, Colorado
Authors: Litaor M. Iggy , Barth G. R. , Zika E. M. 
Published: July 2010

AbstractActinides contamination of soils around Rocky Flats, CO, resulted from leaking drums of Pu‐contaminated oil stored at an outdoor site. The transport of these actinides through the soil to groundwater was studied using an advanced monitoring system (MS). The fully automated, remotely controlled MS gathered real‐time data on soil water content, groundwater level, and timing of gravitationally flowing water. Controlled rain simulations coupled with measurements of volume flux and actinide activities provided essential information about the fate and transport of Pu‐239 + 240 and Am‐241. Volume fluxes at most sampling locations were similar, regardless of the antecedent moisture or the duration, frequency, and intensity of the simulated rain. Actinide activities were not correlated with the measured volume flux, or the duration, frequency, and intensity of the simulated rain. Flow was facilitated primarily via macropore channeling. The relatively short residence time precluded a continuous interaction between the soil and the flowing water, which minimized the movement of actinides in the soil. Actinide activities in the interstitial water collected from the upper 20 cm of the soil were significantly higher (P > 0.001) than water collected at deeper sampling depths (20–70 cm). Actinide activity in water samples from the deepest sampling depth (40–70 cm) did not exceed 0.4 Bq/L. These results suggest that, under the experimental conditions, the movement of actinides was restricted to the top 20 cm. A transport mechanism involving discrete Pu oxide particles, coupled with macropore channeling is proposed to explain the observed actinide activities in the soil.
Predicting Long‐Term Decomposition of Biosolids with a Seven‐Day Test
Authors: Gilmour John T. , Clark Mark D. , Daniel Sharon M. 
Published: July 2010

AbstractDecomposition of biosolids (municipal sewage sludge) in soil has been characterized by long‐term (>60 d) studies. This study was conducted to determine if short‐term incubations could be used to estimate long‐term decomposition behavior. Twenty‐four biosolid/soil combinations were incubated at 25°C for a period of about 60 d. Decomposition followed first order kinetics with two fractions, rapid and slow, based on decomposability. The percentage of biosolid C in the rapid fraction (%Rapid), and the rapid and slow fraction rate constants (kr and ks, respectively) were determined using linear regression of log transformed data (sequential decomposition model) and nonlinear regression of the original data (simultaneous decomposition model). Both models adequately estimated the %Rapid, kr, and ks. The sequential model provided the best relationship between %Rapid and the percent decomposition at 7 d, %D7, and the only relationship between kr and %Rapid. The slow fraction rate constants in this study were compared to those estimated using data from other studies. The slow fraction rate constant used in prediction of long‐term decomposition was from one of these other studies. Predictions of long‐term decomposition agreed well with observed values (r2 = 0.76). It is proposed that a single measurement, %D7, could be used to assess long‐term decomposition for biosolids similar to those reported here. The equation should not be applied to biosolids with small rapid fractions (<10%) such as those stored for extended periods or composted or to biosolids not originating from municipalities.
Phosphorus Mobility in Calcareous Soils under Heavy Manuring
Authors: James D. W. , Kotuby‐Amacher J. , Anderson G. L. , Huber D. A. 
Published: July 2010

AbstractConfined animal production systems produce large amounts of manure that are usually disposed on limited land areas in proximity to the source. There is concern that continuous heavy manuring may saturate the soil's capacity to retain manure‐P and result in groundwater contamination with excessive P. The objectives of this research were to determine the fate of waste‐P in heavily manured soils and assess the risk of soil and water quality degradation in turkey (Meleagris gallopavo) and beef (Bos taurus) feed lot production areas. All soils were calcareous throughout the profile. Samples were collected by 30‐cm depth increments to a depth of 210 cm or a limiting layer and were analyzed for NaHCO3‐extractable P (including inorganic and organic), and total soil P. Large amounts of extractable organic P in the surface soil layers decreased to background levels within 2 to 3 yr after manuring ceased. In heavily manured fields extractable inorganic P was well above background concentrations to as deep as 210 cm, apparently because of movement and subsequent mineralization of organic P. Organic matter in these soils was about twofold higher than background levels. There appeared to be no practical limit to the P‐retention ability of these calcareous soils. Under these conditions the risk of groundwater contamination by organic or inorganic P from waste P disposal to land is negligible.