bluuebunny/crossref_metadata_2025_split huggingface dataset:
NCSOIL, A Model of Nitrogen and Carbon Transformations in Soil: Description, Calibration, and Behavior
Authors: Molina J. A. E. , Clapp C. E. , Shaffer M. J. , Chichester F. W. , Larson W. E. 
Published: July 2010

AbstractNCSOIL is a submodel of a larger program NTRM (nitrogen‐tillage‐residue management). NCSOIL computes short‐term dynamics of carbon and nitrogen organics, ammonium, and nitrate which result from the processes of residue decomposition, mineralization, immobilization, nitrification, and denitrification. Both total and isotopic nitrogen are considered. NCSOIL is built on the concept of catenary sequence of heterogenous substrates. The active soil organic phase is divided in two pools which are dynamic, defined by their kinetic rate constants and their position in the model structure. Residues are defined in terms of their chemical or morphological nature. A double feedback loop in the carbon flow adjusts the rate of residue decomposition and the efficiency factor to the availability of inorganic nitrogen. NCSOIL was calibrated with, and its behavior contrasted against published and unpublished data from an experiment reported by Chichester et al. in Soil Science (see p. 455, vol. 120): “Relative Mineralization Rates of Indigenous and Recently Incorporated 15‐N labeled Nitrogen.” Experimental results of the Chichester et al. experiment were discussed in view of computer‐simulated flow rates and substrate concentrations.
Effects of Heating on Soil Chemical Properties and Growth and Nutrient Composition of Corn and Millet
Authors: Kitur B. K. , Frye W. W. 
Published: July 2010

AbstractHeating or burning has a wide variety of effects on soils, the magnitude of which is determined largely by the temperature to which the soil is heated and on soil properties. In parts of Africa, the practice is used on soils in the field to improve crop production. The objective of this study was to determine the effect of heating Alfisol and Mollisol soil materials on their chemical properties and on the early growth and nutrient composition of corn (Zea mays L.) and millet (Setaria italica) grown in the greenhouse. Heating the soils to 110°C decreased pH, but the pH increased when the soils were heated to 200 or 250°C. Organic matter and extractable Mg decreased while extractable NH+4 and Mn and electrical conductivity (EC) increased greatly with heating. The effects on soil‐test P and K and extractable Ca were small and variable, but the soils were already higb in these elements. Increases in extractable NH+4 and Mn, EC, and pH probably came from both the destruction of soil organic matter and release from inorganic compounds in the soils. Heating soils to 110°C resulted in greater growth of both corn and millet, but heat treatments of 200 and 250°C suppressed growth. The increase in the growth of corn and millet was attributed primarily to moderate increases in extractable NH+4 at 110°C. The suppression of growth with heat treatments of 200 and 250°C was thought to be due largely to excessive amounts of NH+4. Extensive work on NH+4 shows that certain levels of this form of N may be toxic to plants. Heating of soil was shown to be both heneficial and detrimental to the growth of plants. Crops may benefit from nutrients released when soils are heated, provided the amounts are not excessive. The detrimental effects observed in this study would not usually be noticeable under field practice, because only a small proportion of the soil volume is heated.
Relative Effectiveness of Tillage and Natural Forces in Alleviating Wheel‐Induced Soil Compaction
Authors: Voorhees W. B. 
Published: July 2010

AbstractWheel‐induced soil compaction can have detrimental consequences in reduced tillage systems if off‐season weathering forces are not very effective in ameliorating a compacted soil. Field studies were conducted on a Nicollet silty clay loam (Aquic Hapludoll) in Minnesota on plots with a history of controlled wheel traffic. After 5 years of autumn tillage, the plots were split, with one‐half of each plot moldboard plowed or reduced tilled (chisel plow or tandem disk) and the other one‐half remaining untilled over the winter period. Bulk density, penetrometer resistance, soil water content, aggregate size, and clod density were measured to assess the relative effect of natural forces and tillage on amelioration of wheel track‐compacted soil. Moldboard plowing in the autumn effectively ameliorated compaction of the bulk tilled layer. Reduced forms of tillage such as chisel plow or tandem disk were only slightly more effective than natural weathering forces which reduced penetrometer resistance by 20 to 50%, but had little effect on bulk density. The structure of individual soil aggregates and clods was not changed much by either tillage or natural weathering. Thus, a no‐till system may result in higher bulk density, aggregate density, and penetrometer resistance because of incomplete amelioration of compacted soil by natural forces during the winter season. Potential consequences include seedbed preparation problems, uneven germination, lower hydraulic conductivity, and undesirable early root growth environment.
Modeling Infiltration into Crusted Soils by the Green—Ampt Approach
Authors: Ahuja L. R. 
Published: July 2010

AbstractThe study deals with infiltration of water through a stable surface crust, wherein the water content at the crust‐soil interface increases with time for a long period, and remains below the saturated value. An approximate Green‐Ampt‐type formulation derived from a physical basis, containing a time‐dependent capillary drive term and a profile shape factor, is evaluated by comparisons to a similarity solution and a finite‐difference numerical solution of the problem. The exact nature of the derived Green‐Ampt formulation is established for early to intermediate stages for certain reasonable conditions. Calculations of cumulative infiltration with time made by the above approach, with the profile shape factor set equal to unity, were within tolerable error from the numerical solution results for one soil and a set of experimental data for another. A previously reported piecewise application of the conventional form of the Green‐Ampt equation is also developed to enable its use from time zero, as an independent predictive method. This method, which includes some implicit correction for the profile shape, gave slightly better calculations of the cumulative infiltration. The above simple methods should also be applicable to related unsaturated flow problems, such as infiltration through a transient crust‐seal resistance and into a layered soil having a fine material overlying a coarse material.
Fixation Kinetics in Potassium‐Aluminum‐Orthophosphate Systems
Authors: Kim Y. K. , Gurney E. L. , Hatfield J. D. 
Published: July 2010

AbstractThe rate of removal of phosphate and potassium from solution was studied by contacting an aluminum‐impregnated, cation exchange resin with solutions of monopotassium phosphate in concentrations of 0.05 to 0.25M and with atomic ratios Al:P from 0.25 to 4.0. The removal of both K and P from solution followed first‐order reaction models for all experimental conditions, the K being removed faster than the P. The rate constants for K and P removal increased as the ratio Al:P increased, but were affected to a lesser extent by the initial concentration of KH2PO4. The concentration of Al with time agreed with a consecutive first‐order reaction model involving cation exchange and precipitation. The rate constants for each experimental condition were evaluated by nonlinear regression analysis, and the reaction model represents the data well. The precipitate (prepared in 0.25 or 1M KH2PO4 solution) was identified as potassium aluminum taranakite by chemical and x‐ray analysis. The phosphate retained in the resin was negligibly small and perhaps was occluded in the beads. Phosphate was removed from solution by the precipitation of taranakite. The taranakite precipitation rate constant, k4, varied directly with the atomic ratio Al:P and inversely with the initial KH2PO4 concentration, Co, by the correlation k4 = 1.09 (Al:P)1.066 (Co)‐0.401.
Determination of Inorganic Sulfate in Foliage with Barium Chloranilate
Authors: Richter D. D. , Johnson D. W. 
Published: July 2010

AbstractFoliage samples were extracted in 0.01M HCl at room temperature and extracts analyzed indirectly for sulfate (SO2‐4) with a barium chloranilate procedure. The method was tested with foliage of coniferous and deciduous tree species, and sulfate recovery was comparable to that obtained by hydriodic acid reduction. Similar amounts of sulfate were recovered from foliage by both acid and salt extractions, and it was concluded that foliar sulfate in the species tested was inorganic and did not include appreciable amounts of hydrolyzable organic sulfates. The barium chloranilate procedure requires equipment available to most soil and plant analysis laboratories and can be readily applied in evaluating sulfur nutrition in plant‐soil systems.
Simulation of Landsat Multispectral Scanner Response of Soils using Laboratory Reflectance Measurements
Authors: Thompson D. R. , Pitts D. E. , Henderson K. E. 
Published: July 2010

AbstractLaboratory soil reflectance measurements from surface soil samples representing 246 soil series within 39 of the 48 contiguous states of the USA were used to simulate Landsat MSS (multispectral scanner) digital counts for two atmospheric conditions. The resulting Landsat MSS digital counts were within the range of values for soils seen in Landsat data. The importance of accounting for the soil background in various spectral vegetation indexes is demonstrated. Spectral curve forms for different soils are shown to be generally separable within greenness and brightness vector space for the various reflectance values and simulated Landsat MSS values and atmospheres. Organic matter content could be stratified into 0 to 2 and > 2% with > 80% accuracy. The ability to convert reflectance data from controlled experiments to simulated Landsat MSS digital counts will allow researchers to account for the effect of the soil on crop‐spectral relationships, conduct sensitivity analyses of the effect of soil on spectral models, and to develop a better understanding of the relationship of spectral and physical‐chemical properties of soils and advance the application of remote sensing for soil survey and classification.
A Method for Maintaining Constant Soil Moisture Availability for Potted Plants
Authors: Schwaegerle Kent E. 
Published: July 2010

AbstractA method was developed to reduce labor time in experiments in which soil moisture is to be periodically adjusted by observed changes in pot weight. In an experiment involving 420 pots of Phlox species, a pair of modified balances was used daily to fill pots with water automatically to a precise weight. To achieve six different levels of soil moisture availability six weights of equal volume were placed in the pots. Pots displayed daily changes in soil moisture of 0.9 to 2.3%. Daily watering of all pots required only 75 to 90 min. This system proved effective for analysis of plant growth response to different soil moisture levels in experiments where statistical considerations demand large sample sizes.
Furrow and Trickle Irrigation: Effects On Soil Oxygen and Ethylene and Tomato Yield
Authors: Meek B. D. , Ehlig C. F. , Stolzy L. H. , Graham L. E. 
Published: July 2010

AbstractThis study was conducted to determine whether low soil oxygen levels or high soil ethylene reduce tomato (Lycopersicon esculentum) yield in clay soil, when high temperatures are combined with trickle or furrow irrigation. Treatments were daily or weekly trickle irrigations (100 or 120% of pan evaporation) and furrow irrigations (5‐ or 10‐d intervals). Soil oxygen and ethylene levels and soil matric potentials were measured at the 20‐ and 40‐cm depths immediately before and during part of the fruiting cycle. Daily trickle irrigations (100 or 120% of pan evaporation) resulted in oxygen levels of 3 to 6% and matric potentials of 0 to −7 kPa. Furrow irrigation or weekly trickle irrigations resulted in oxygen levels that were about double the values measured for the daily trickle irrigation, and in soil matric potentials of −1 to −60 kPa. Irrigation frequency or rate did not have a significant effect on yield of tomatoes. Soil ethylene levels were low for all treatments (< 1 ppm). Because of higher oxygen level, weekly trickle or furrow irrigation would be preferable to daily trickle irrigation when oxygen may be limiting or when the crop grown is oxygen sensitive.
A Method for Estimating the Standard Free Energy of Formation of Borate Minerals
Authors: Mattigod S. V. 
Published: July 2010

AbstractAn empirical method has been developed to estimate the standard free energy of formation (ΔGof,298) values for hydrated borate minerals. The method is completely general, and the only parameter used in the computation is the number of born atoms in the polyanion unit of a mineral. The standard free energy of formation values estimated by this method are within ± 10 kJ of the experimental data obtained from the literature. This method has fewer limitations than the structural method of Bassett.
The Influence of a Microalgal Conditioner on Selected Washington Soils: An Empirical Study
Authors: Metting Blaine , Rayburn William R. 
Published: July 2010

AbstractChemical and physical analyses of four Columbia Basin soils were used to evaluate the effects of repeated annual inoculation with the mass cultured microalgal soil conditioner Chlamydomonas mexicana ‘Lewin’. Carbohydrate concentrations were consistently, though not significantly, greater in both the surface 10 mm and in the upper 300 mm of treated portions of a Quincy loamy fine sand, a Quincy loamy sand, and a Warden silt loam compared to untreated portions from the same soil mapping units. Treated soil samples from the two Quincy soils contained from 0.12 to 0.40 g/kg more carbohydrate than did untreated samples, while differences of about 1.0 g/kg of soil were measured in the Warden silt loam. Using locations as replicates, increases in water retention from treatments were significant (0.05% level), ranging from 2 to nearly 5% above untreated soils. Wet sieving of 0.92‐ to 1.68‐mm natural aggregates showed striking differences (significant at 0.1% level) between treated and untreated samples of the three soils. Stability in water was increased from 54.4 to 76.1% for the Quincy loamy fine sand, from 44.5 to 63.4% for the Quincy loamy sand, and from 82.1 to 86.1% for the Warden silt loam. Disruption of natural 0.92‐ to 1.68‐mm aggregates by rotary dry sieving was significantly different (0.05% level) between algal‐treated and untreated samples. Disruption to particles < 0.42 mm was 75.1 and 87.2% of treated and untreated samples, respectively, of Quincy loamy fine sand. Corresponding values for the Quincy loamy sand were 81.3 and 97.6%, and for the Warden silt loam, 60.9 and 78.8%. Moisture is implicated as the factor most likely controlling growth and polysaccharide production by the microalgal inoculum from the fact that differences in these chemical and physical properties could not be measured between treated and untreated samples from a dryland Ritzville silt loam.
Effect of Slope on Water Balance Under Center‐Pivot Irrigation
Authors: Hanna A. Y. , Harlan P. W. , Lewis D. T. 
Published: July 2010

AbstractThe effects of slope on soil water storage and other water balance components under center‐pivot irrigation were studied in Gage County, Nebraska. Soil water, surface runoff, precipitation, and irrigation were measured for soils of low infiltration on slopes of 2, 4, and 8% under corn (Zea mays L.). Evapotranspiration was calculated. Soil water content (0‐ to 137‐cm depth) during the growing season was higher in soils on 8% slopes than in soils on slopes of 2 and 4%. Runoff from all slopes was not associated with sprinkler irrigation in the crop production system studied. As slope increased, surface runoff caused by rain increased, and internal drainage beyond the 137‐cm depth decreased at approximately the same rate. The overall water depletion during the growing season was not significantly affected by slope.
Origin of Red Clay over Dolomite in the Loess‐Covered Wisconsin Driftless Uplands
Authors: Frolking T. A. , Jackson M. L. , Knox J. C. 
Published: July 2010

AbstractRed clays associated with Prairie du Chien and Sinnipee (Galena) dolomites and loess were studied stratigraphically and geomorphically at 10 locations. The clay content (< 2 µm, 82 ± 9.1%; < 0.2 µm, 70 ± 10.4%, n = 15) relative to the overlying loess (< 2 µm, 28 ± 4.4%; < 0.2 µm, 16 ± 4.9, n = 4) and the dolomite insolubles (< 2 µm, 47 ± 11%; < 0.2 µm, 34 ± 9.6%, n = 7) indicate fine clay enrichment. Smectite‐rich oriented clay coatings on dolomite sands suggest illuviation. Undisturbed chertlines from dolomite through red clay bodies necessitate a volume‐for‐volume replacement. Periglacial activity during the Wisconsinan frequently produced loess (i), over a mixed zone of loess and red clay (ii), over in‐situ red clay (iii), and dolomite (iv). For the 1‐to 10µm quartz; euhedral grains indicated by x‐ray diffraction I(100)/(101) = 0.23, 0.54, 1.02, 0.70, respectively; nine trace element contents = 2.15 ± 0.40, 1.61 ± 0.18, 0.78 ± 0.10 relative to dolomite (1.0); and oxygen isotopes expressed as δ18O = 18.6, 19.7, 26.9, 26.4%. The values for the mixed zone (ii) fall between those for the loess (i) and insitu red clay (iii). Optical data for the morphology of the fine sand fractions (50–250 µm) were corroborative. The silt and sand of in‐situ red clay (protected in karst depressions and by chert lag gravels) are from the dolomite.
Mineralogy and Acidity of an Inland Acid Sulfate Soil of Texas
Authors: Carson C. D. , Dixon J. B. 
Published: July 2010

AbstractThe Aubrey soil occurs in the East Cross Timbers Region of north‐central Texas. It has developed in an acid clayey shale of the Lewisville member of the Woodbine geologic formation of Upper Cretaceous age. Jarosite [KFe3(OH)6(SO4)2] occurs in localized concentrations in the lower horizons. Selected particles form the C horizon were 87.6% jarosite and served as a reference mineral for the soil. Jarosite content of the B3 and C horizons was 1.6 to 6.7% and was detectable by thermal and x‐ray diffraction analyses of the whole soil. Scanning electron microscope examination indicated that the jarosite occurred as cubes and octahedra. These isometric forms suggest jarosite formation from pyrite present in the parent material. Smectite and kaolinite are the major clay constituents and they are both more poorly crystalline in the major A and B horizons than in the lower three horizons. The pH in water ranges from 5.0 in the upper B horizon at the 8‐cm depth to 4.0 in the C horizon to the 152‐cm depth. Exchangeable and nonexchangeable acidity increase with depth into the C horizon. The Aubrey soil has developed an accumulation of free Fe oxides above the jarosite zone, which is characteristic of an acid sulfate soil.
Distribution of Silica, Sesquioxides, and Clay in Quebec Podzolic Soils and Their Effects on Subsoil Cementation
Authors: De Kimpe C. R. , Laverdiere M. R. , Dejou J. 
Published: July 2010

AbstractThree soil profiles containing two types of brittle horizons were extracted using citrate‐hicarbonate‐dithionite (CBD), a modified CBD, and NaOH procedures. The modified CBD method with a low soil‐solution ratio was the most effective extractant for Fe, Al, and, especially, Si. Increases in extractable Si could be associated with the presence of a fragipan‐duripan intergrade horizon, but a similar relationship was not observed with a well‐expressed fragipan.
Estimating Soil Temperature by Linear Filtering of Measured Air Temperature
Authors: Persaud N. , Chang A. C. 
Published: July 2010

AbstractLinear dynamic filtering techniques were used to model the relationship between time series of average daily air temperature and soil temperature at the 10‐cm depth. The data utilized consisted of 730 consecutive daily observations of these two variables measured at Brawley, Calif., for the period 1 Jan. 1962 to 31 Dec. 1963. The soil temperature measurements were made in a bare and level Holtville silty clay soil completely exposed to the sum. Spectral analysis procedures were used to first identify and then to obtain the factors for filtering the frequency components contributing most to the variance of each temperature series. The annual cycle (frequency 2π rad d−1 ÷ 365) contributed 82.30 and 91.10%, respectively, and the semiannual cycle (frequency 2π rad d−1 ÷ 365) contributed, respectively, 2.36 and 1.56%, of the variance of the air and soil temperature series. The analysis also showed that the annual and semiannual cycles of the soil temperature series lagged the corresponding cycles of the air temperature series by 2.5 and 10.4 d, respectively. After removing the annual and semiannual cyclic components from each series, Box‐Jenkins transfer function modelling techniques were used to describe the filter relating the residual stochastic series. The transfer function was then used in conjunction with the results of the spectral analysis to yield a relation for estimating the soil temperature at the 10‐cm depth using the air temperature as input. The residual variance of this estimation was 58.5% less than the residual variance using a linear regression equation.
Numerical Analysis of the Snow‐Plow Effect
Authors: Barry D. A. , Starr J. L. , Parlange J.‐Y. , Braddock R. D. 
Published: July 2010

AbstractA mathematical model describing the snow‐plow effect, i.e. the removal of adsorbed ions from soil particles by an incoming solution with relatively high solute concentration, is analyzed. It is shown that an accurate numerical solution to the model must be obtained to investigate the influence of the parameters entering the problem. The numerical solution helps generate simple rules that allow for straightforward but accurate construction of snow plows in practical situations. The numerical results are also used to evaluate an earlier analytical approximation and are compared to experimental observations.
Selecting Rhizobium meliloti for Inoculation of Alfalfa Planted in Acid Soils
Authors: Lowendorf Henry S. , Alexander Martin 
Published: July 2010

AbstractA study was conducted to obtain Rhizobium meliloti strains suitable for use with alfalfa grown in acid soils. Thirteen strains of R. meliloti were examined for their ability to grow in acidified culture medium, and seven of these were characterized for the ability to survive in acid and limed nonsterile soils or grow in the presence of the host legume, Medicago sativa L. The pH values of the most acid, defined medium that permitted growth of the bacteria from a small inoculum ranged from pH 5.3 to 6.0. For R. meliloti 411SE1 and GH1‐1SE1, the minimum pH that allowed for growth, the critical pH, was not a dependable indicator of survival in a more acid medium. Strains of R. meliloti with relatively low critical pH values survived better in a limed soil but not in acid soils than strains with higher critical pH values. Three strains of R. meliloti previously identified as good inoculants for alfalfa in acid soils did not consistently survive better than other strains in a planted or unplanted acid soil of pH 5.3. However, the plants increased the population densities of these three strains more than other strains. These results suggest that R. meliloti strains suitable for inoculation of alfalfa in acid soils may be selected not by simple saprophytic properties but by their stimulation by the host legume in acid soils.