bluuebunny/crossref_metadata_2025_split huggingface dataset:
Properties of Natraqualfs in the Upper Coastal Plain of Mississippi
Authors: Pettry D. E. , Brent F. V. , Nash V. E. , Koos W. M. 
Published: July 2010

AbstractNatraqualfs were studied on poorly drained, silty, fluvial terraces in the humid Coastal Plain region of Mississippi. They are underlain by contrasting geologic formations of different ages. The soils have fine‐loamy and fine‐silty textural families. Soil reaction of pedons ranges from extremely acid to strongly alkaline. Acid Natraqualfs are dominant on older geomorphic surfaces, and they are deeper to natric horizons than alkaline pedons. Argillic subhorizons have a SAR > 13 and an exchangeable sodium percentage (ESP) > 15 to qualify as natric horizons. Exchangeable Ca + H is greater than Mg + Na in the acid Natraqualfs. Soil extracts have relatively low electrical conductivities and electrolyte concentrations. Sulphate and chloride are the dominant water‐soluble anions. Barite is a common mineral constituent of the natric horizons.
The Influence of Soil Water Potential and Soil Texture on the Survival of Rhizobium Japonicum and Rhizobium Leguminosarum Isolates in the Soil
Authors: Mahler R. L. , Wollum A. G. 
Published: July 2010

AbstractWater stress and differences in soil texture are thought to be primary factors in inoculation failure in the southeastern United States. There is, however, a lack of quantitative data relating the effect of soil water potential on rhizobia survival in soils of differing textures.The objectives of this study were to investigate the effect of soil water potential on the survival of slow‐ and fast‐growing rhizobia in soils varying in texture. Rhizobium japonicum serogroup isolates 122 and 123 and Rhizobium leguminosarum serogroup isolates WA‐01 and WA‐02 were incubated in seven different soils maintained at water potentials of −0.3, −1.0, −5.0, and −15.0 bars for periods to 7 weeks. The most probable number (MPN) technique and plant infectivity tests were used to enumerate rhizobia.Soil water potential and soil texture were both found to play important roles in the survival of the four rhizobia isolates. Rhizobia populations were always greatest at −0.3 bars. Populations were proportional to decreasing water potentials to −15.0 bars. Populations were lowest in the sands and clay loam soils. Conversely, populations were usually highest in the sandy loams, silt loams, and sandy clay loam soils.Differences between the four isolates were also observed. Rhizobium japonicum serogroup isolates 122 and 123 survived in greater numbers than the R. leguminosarium isolates during the initial incubation period. R. leguminosarum isolate WA‐02, however, performed as well as or better than the R. japonicum isolates after 1 week for most soil textures and water potentials. Rhizobia populations declined during the first week of incubation and increased, in most cases, by the seventh week.
Effect of Electrolyte Concentration and Soil Sodicity on Infiltration Rate and Crust Formation
Authors: Agassi M. , Shainberg I. , Morin J. 
Published: July 2010

AbstractThe effects of electrolyte concentration and soil sodicity on the infiltration rate and extent of crust formation of a calcareous and a noncalcareous soil were studied using a rain simulator. The infiltration rate was more sensitive to the sodicity of the soil and to the electrolyte concentration of the applied water than was the permeability of the underlying soil. The mechanical impact of the raindrops and the relative freedom for particle movement at the soil surface may account for the greater sensitivity of the infiltration rate. These observations suggest that crust formation is due to two mechanisms: (i) a physical dispersion of soil aggregates caused by the impact action of the raindrops, and (ii) a chemical dispersion which depends on the soil exchangeable sodium percentage (ESP) and the electrolyte concentration of the applied water.
Devarda's Alloy Method for Total Nitrogen Determination
Authors: Liao Christina F. H. 
Published: July 2010

AbstractA modified semimicro‐Kjeldahl procedure for total nitrogen (N) determination to include No3‐‐N, NO2‐‐N, or both is described. The method involves use of Devarda's alloy as a reducing agent in the pretreatment procedure to convert NO3‐‐N, or NO2‐‐N, into NH4+‐N in 6N H2SO4 with subsequent Kjeldahl digestion of the sample using a mixture of K2SO4 − Se and concentrated H2SO4. The proposed method was effective in recovering NO3‐‐N or low‐level NO2‐‐N from water, soil, plant, and organic N compounds in total N determinations. The method gives essentially the same or slightly higher values for total N in a variety of soils when compared with other commonly used methods. The advantage of the proposed method is that it includes both NO3‐‐N and low‐level NO2‐‐N in one single pretreatment procedure and gives a smooth digestion during the subsequent Kjeldahl analysis.
The Soil Sequence of Late Pleistocene Glacial Outwash Terraces from Spokane Floods in the Idaho Panhandle
Authors: Parsons R. B. , Weisel C. J. , Logan G. H. , Nettleton W. D. 
Published: July 2010

AbstractGlacial Lake Missoula was the source of the catastrophic Spokane Floods through northern Idaho, eastern Washington, and the main stem of the Columbia River. About 2,000 km3 of water was impounded behind ice dams that were repeatedly breached. Giant current ripples, huge gravel bars, coulees, and dry cataracts attest to the enormity of the floods.The sequence of five late Pleistocene outwash terraces and a Holocene terrace were studied in the Hoodoo Valley of Bonner County, Idaho. The geomorphic surfaces document that there were at least five Spokane Floods. Kootenai taxadjunct, Bonner, and Rathdrum soils occur on each of the outwash terraces, have different topographic positions within the giant current ripple microrelief, and have contrasting thicknesses of reworked volcanic ash over the flood deposits. Similar soils on the five terraces indicate that the time factor of soil genesis is negligible and that the flood events occurred in rapid succession.
Laboratory Evaluation of Soil Mixtures for Sports Turf
Authors: Taylor D. H. , Blake G. R. 
Published: July 2010

AbstractThe suitability of soil mixtures for sports turfgrass areas is often determined by measuring physical properties of laboratory‐packed samples. The objectives of this study were (i) to establish a basis for choice of laboratory packing conditions for preparing test samples; and (ii) to determine whether physical properties of soil mixtures after in‐situ settling on sports turfgrass areas were correlated to physical properties of the same mixtures packed and tested in the laboratory.Seven soil mixtures varying from 76 to 97% sand by weight were packed in the laboratory by applying impact energies of 3.0, 4.5, and 6.0 J/cm2 to samples at water potentials of −30, −100, −330 mbar. Comparisons of Ksat and bulk density of laboratory‐packed samples with sustained infiltration rate and bulk density of mixtures after turf growth and compaction under greenhouse conditions indicated a packing combination of 3.0 J/cm2 packing energy to a sample at −100 mbar water potential was equal or preferable to any other combination.Using this laboratory packing combination, Ksat, bulk density, and air porosity at −30, −40, −60, and −100 mbar water potentials of undisturbed cores from golf greens were compared to corresponding properties on disturbed samples taken from the greens and packed in the laboratory. Laboratory‐packed samples were not indicative of the properties of soil mixtures after settling in situ on greens. Sand content was a better measure of the physical qualities of soil mixtures in the field than were physical properties of laboratory‐packed samples.
A Physicoempirical Model to Predict the Soil Moisture Characteristic from Particle‐Size Distribution and Bulk Density Data
Authors: Arya Lalit M. , Paris Jack F. 
Published: July 2010

AbstractA model to predict the moisture characteristic of a soil from its particle‐size distribution, bulk density, and particle density parameters is presented. The model first translates a particle‐size distribution into a pore‐size distribution. Then, the cumulative pore volumes corresponding to progressively increasing pore radii are divided by the sample bulk volume to give the volumetric water contents, and the pore radii are converted to equivalent soil water pressures using the equation of capillarity.To compute the pore volumes and the pore radii, the particle‐size distribution curve is divided into a number of segments. The solid mass in each segment is assumed to form a matrix with a bulk density equal to that of a natural‐structure sample. For a unit of sample mass, an equivalent pore volume for each segment is computed from Vvi = (Wi/ϱp)e and the corresponding pore radius from: ri = Ri[4eni(1‐α)/6]1/2, where Vvi is the pore volume, Wi is the solid mass, ϱp is the particle density, e is the void ratio, ri is the mean pore radius, Ri is the mean particle radius, ni is the number of particles, and α is an empirical constant ranging in value from 1.35 to 1.40. The formulation for the pore radius is based on spherical particles and cylindrical pores.Model predictions for several soil materials show close agreement with the experimental data.
Soil and Geologic Mapping Over Mafic and Ultramafic Parent Materials in Maryland
Authors: Rabenhorst M. C. , Foss J. E. 
Published: July 2010

AbstractComparisons were made of soil and geologic mapping in regions of mafic and ultramafic lithology. Samples from 39 locations were collected and analyzed for weak acid‐extractable Ca and Mg. Identification of parent materials was facilitated by mineralogical examination of the < 20‐µm fraction of the subsoil by x‐ray diffraction techniques. Comparisons and analyses indicate that some serpentine soil units have been mapped over nonserpentine mafic rock. The Ca/Mg ratios of serpentine soils differ significantly at the 0.01 level from those soils formed from nonserpentine mafic rocks. In areas where mafic and serpentinitic parent materials occur in association, weak acid‐extractable Ca/Mg ratios can be used as an aid in distinguishing soils formed from these parent materials. In such areas, soils with Ca/Mg ratios < 0.10 have a 98% probability of having formed from serpentinitic rather than from nonserpentine mafic parent materials.
Effects of Pyrophosphate, EDTA, and DTPA on Zinc Sorption by Montmorillonite
Authors: Asher L. E. , Bar‐Yosef B. 
Published: July 2010

AbstractThe effects of pyrophosphate (PP), pH, ionic strength, EDTA, and DTPA on zinc (Zn) sorption by montmorillonite were studied in order to evaluate the role of pyrophosphate in Zn solubilization. In such a system PP dissolution of organic matter and its subsequent complexation of Zn was limited and would not affect the interpretation of the results. The effectiveness of PP in complexing Zn was dependent on the levels of Ca, initial PP concentration, and pH of the montmorillonite suspension. Decreased sorption of PP with increasing pH, as well as markedly greater sorption of PP by Ca‐montmorillonite than by K‐montmorillonite, suggests the existence of a sorption process which could include surface adsorption and precipitation.At initial PP concentrations of 1.92 mM, Zn solubilization decreases monotonically with increasing pH, while at 9.6 mM initial PP, a minimum in Zn solubilization is observed at about pH 6.0. This trend of solubilization could be attributed to decreased Zn sorption and increased Zn complexing with PP. At pH greater than about 7.5, PP is comparable to EDTA and DTPA in Zn solubilization, but only at PP molar concentrations some 40 times greater than the organic ligands. Equilibration time (2 to 192 hours) had little effect on PP concentration or on Zn concentration. Regardless of which of the ligands was used, the sorption of Zn reached completion in most cases within 2 hours. For EDTA and DTPA, provided that their concentration was greater than Zn concentration, sorption of Zn was found to be a relatively slow process. Approximately 40% (EDTA) and 20% (DTPA) of the initial Zn was sorbed after 192 hours.
Field Testing of a Two‐dimensional Soil Moisture Model Simulating Water Table Fluctuations
Authors: Fayer Michael J. , Hillel Daniel 
Published: July 2010

AbstractAn attempt has been made to test the validity of a two‐dimensional model of soil‐water dynamics in a sloping field, with respect to groundwater level fluctuations during several infiltration‐drainage cycles. The data from rain recorders, runoff plots, water table wells, tensiometers, and an evaporation pan were used to describe the various initial and boundary conditions. Soil hydraulic properties were determined from undisturbed cores and in situ methods. Comparisons of the predicted and measured water table positions were used to judge the model's capabilities. After two one‐week periods of no rainfall, during which the actual water table fell 11 and 79 cm, the predicted water table levels were within 1.5 and 8 cm, respectively, of the measured levels. Before and immediately after periods of rainfall, the predicted water table levels were usually within 2 cm of the measured levels. As the water table rose in response to the rainstorm, however, the predicted rise was only one‐half that measured in the field. Altering the shape of the moisture characteristic programmed in the model nearly doubled the predicted rise. Hence the discrepancy between prediction and observation may be due to insufficient accuracy in determination of the soil moisture characteristic in the very wet range, or to failure to account for air occlusion or hysteresis.
Revised Methods for Rapid Quantitative Determination of Minerals in Soil Clays
Authors: Karathanasis A. D. , Hajek B. F. 
Published: July 2010

AbstractA set of quantitative mineralogical methods was revised and evaluated for routine and rapid mineralogical characterization of clays from southern soils and sediments. The procedures adopted consist of soil dispersion in a pH 9.5 suspension by ultrasonics, centrifuge fractionation to give 300 mg of clay, K‐ and Mg‐saturation by millipore filtration for x‐ray diffraction (XRD), x‐ray emission spectroscopy (XRES), differential scanning calorimetry, and thermogravimetric analyses. Smectite, vermiculite, kaolinite, halloysite, gibbsite, and calcite were quantified from thermal data, hydroxyinterlayered vermiculite and quartz from XRD, using indigenous kaolinite determined by thermal methods as an internal standard, and free iron oxides and mica from XRES analysis. The mean total recovery on 79 samples was 99.9 ± 0.6%. Very good agreement and small average deviations were obtained between mineral quantities determined by these procedures and values reported by other laboratories for several of the same samples. Because the accuracy of the data exceeded most quantitative mineralogical interpretative needs, these methods can be used for routine quantitative mineralogical characterization of most southern soils.
A Differential Model for One‐dimensional Cation Transport in Discrete Homoionic Ion Exchange Media
Authors: Persaud N. , Wierenga P. J. 
Published: July 2010

AbstractThe heterogeneous system at equilibrium consisting of an aqueous solution of a counterion, I, in contact with a cation exchanger saturated with another counterion, J, was treated as a Donnan system. An equation was thus developed to describe the equilibrium adsorption isotherm of the cation I, as a function of the concentration of I and J in the equilibrium solution. This equation adequately described experimental “batch” equilibrium isotherms for selected cations on a synthetic cation exchange resin and on a natural soil material. The equation was incorporated into a differential convective‐dispersive solute transport model, and the resulting differential equations were integrated numerically using an implicit finite difference scheme. Simulations were done to test the ability of the transport model to describe the elution curves for Na+, Li+, and Cs+ from miscible displacement experiments in water‐saturated and water‐unsaturated laboratory columns packed with the materials used for the adsorption studies. The model was successful in predicting the results of these experiments in the water‐saturated columns. It was successful in predicting only the general shapes of the experimental elution curves in the water‐unsaturated columns. These latter experimental curves were shifted to the right or left of the simulated curves and showed extensive tailing. It was concluded that other physical and chemical effects not accounted for in the transport model, such as diffusion kinetics between “mobile” and “immobile” water in the water‐unsaturated columns were responsible for these discrepancies.
Infiltration as Affected by Long‐term Use of Sodic‐Saline Water for Irrigation
Authors: Hadas A. , Frenkel H. 
Published: July 2010

AbstractInfiltration rates and hydraulic conductivity of two fields were determined to evaluate the long‐term impact of irrigation with saline‐sodic water [electrical conductivity (EC) = 5.6 mmho/cm and sodium adsorption ratio (SAR) = 26] and the benefit of gypsum treatments. Field 1 had been irrigated for 2 years and field 2 for 8 years. Infiltration rates were measured by a constant head method and hydraulic conductivity by Bower's method using distilled water (to simulate rainwater) and the saline‐sodic irrigation water. Results indicated that the infiltration rates of the gypsum‐treated plots were higher than the nontreated plots for each field, and the infiltration rate of the soil irrigated with sodic‐saline water for 8 years was greater than the infiltration route of field irrigated for 2 years. The latter difference was related to different crust structures found in the two fields. Hydraulic conductivities and infiltration rates of soil crusts were calculated for rainfall and for irrigated conditions. The results are discussed in view of the existence of CaCO3 and gypsum in the original and treated soil, respectively. Some estimates of calculated final infiltration rates under rainfall conditions are presented.
Bacterial Utilization of Simple Alcohols and Their Influence on Saturated Hydraulic Conductivity
Authors: Frankenberger W. T. , Troeh F. R. 
Published: July 2010

AbstractTwo simple alcohols (methanol and n‐propanol) were used to leach saturated soil columns for 2,000 hours, and changes in saturated hydraulic conductivity (Ksat) over time were determined. For both alcohols and a distilled water treatment, Ksat was found to decrease with time, attaining a constant value after approximately 1,500 hours. The addition of simple alcohols reduced Ksat considerably when compared with the flow rate of distilled water in soils. Initial decreases in Ksat were attributed to structural breakdown of unstable aggregates and expansion of clays, but the final portion of conductivity‐time curves was probably due to microbial action, in which soil pores became clogged with products of growth and cells. The pH values of effluents collected from soils treated with simple alcohols were lower than those of the added influents. Soils leached with distilled water became more acidic than those leached with methanol and n‐propanol. Phosphatase activity was assayed in each soil column, and results showed greater activities in the oxidized zones of soils. The magnitude of phosphatase activities in the oxidized zones of the treated soils were consistently higher in the following order: methanol > n‐propanol > distilled water. The decrease in Ksat of soils treated with simple alcohols was related to acid phosphatase activity, in that, as phosphatase activity increased, Ksat decreased.
Factors Affecting the Mobility and Plant Availability of Boron in Some Western Oregon Soils
Authors: Parker D. R. , Gardner E. H. 
Published: July 2010

AbstractSurface soil from five diverse soil series was used to investigate the influence of soil properties and constituents on the mobility of boron (B) in a greenhouse study. Using pots 16.5 by 18.5 cm in diameter, from 13 to 61% of a 2.0 mg/kg liquid application of B was recovered in 25 cm of leachate. Recovery of B decreased with increased soil organic matter, clay, and free Fe and Al oxide content, but statistical separation of the effects of individual components was complicated by intercorrelations among these soil properties. No effect of soil pH on B mobility over a range of 5.4 to 7.5 was observed.Following leaching, the soils were cropped with New Zealand white clover (Trifolium repens L.). Yield differences were not correlated with hot water‐extractable B levels ranging from 0.47 to 2.34 µg/g or with B applied at planting. Plant B concentrations were high, ranging from 60 to 150 µg/g. As the range in hot water‐soluble B values encompassed current concepts of deficiency levels in western Oregon soils, the merits of investigating soil‐B critical levels under greenhouse conditions are questioned.A balance sheet approach indicated that soils have reserves of leachable and plant‐available B not detected in the conventional hot water extraction. The boron‐supplying power of these soils varied both within and among soil series and depended on soil properties and the amount of B in the soil system.
Soil Fertility Changes following Clearcut and Whole‐tree Harvesting and Burning in Central Michigan
Authors: Adams Paul W. , Boyle James R. 
Published: July 2010

AbstractSoil fertility (available Ca, Mg, K, P, and total N) was evaluated at the time of and 1 and 5 years after clearcut and whole‐tree harvest of adjacent oak‐aspen forests. Surface mineral soil at both sites showed increased K and decreased N concentrations 1 year following harvest. A wildfire that burned both sites shortly thereafter generally increased the nutrient concentrations at each site, but smaller increases occurred at the whole‐tree harvest site. Five years after cutting (4 years after burning) soil Ca and P levels at both sites were higher than the concentrations at the time of harvest, while K and N were similar to original levels. Calcium and Mg concentrations at the clearcut site were 88 and 75% higher than the levels at the whole‐tree site 5 years after harvest. The increased soil fertility observed could provide a valuable nutrient supply to the succeeding forest stand, but net nutrient outputs through harvest and burning could also eventually reduce the already low productivity of these sites.
Electromagnetic Determination of Soil Water Content Using TDR: I. Applications to Wetting Fronts and Steep Gradients
Authors: Topp G. C. , Davis J. L. , Annan A. P. 
Published: July 2010

AbstractThe time‐domain reflectometry (TDR) technique has been demonstrated to be a viable method for determining soil water content in uniformly wet soils. The TDR response in nonuniformly wet soils was examined herein both theroetically and experimentally. An extensive set of experiments was carried out in a controlled laboratory test facility which permitted synthesis of steep water content gradients and wetting fronts. The water content measured by the TDR technique has been found to be the same as the average water content to within 0.01 cm3cm−3 in extremely nonuniform conditions. This result is quite surprising at first but is readily explained by the nature of the dielectric constant and water content relationship. The TDR technique has also been found useful in detecting and monitoring the progression of wetting front advance through a soil.