bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chemical and Mineralogical Properties of the Fragipans of the Cincinnati Catena
Authors: Steinhardt G. C. , Franzmeier D. P. 
Published: July 2010

AbstractThis is a study of fragipan soils on two transects on the Illinoian till plain of southern Indiana. These soils were thought to be formed in 50 – 100 cm of loess over Illinoian Age till. In the soils sampled for this study, the surface of Sangamon Age paleosol in Illinoian till was located at a 2‐m depth. Two other parent materials above the paleosol were described. The surface parent material may be loess, but the parent material above the paleosol is too sandy to be completely loess.In sodium citrate‐bicarbonate‐dithionite extracts, SiO2 contents reached a maximum in the fragipan horizons. The Al2O3 contents were highest in the argillic horizon. Extraction of natural clods from the fragipan matrix by various solutions under vacuum showed that extractants that removed Fe and Al did not affect the cohesion of the fragipan matrix. Silica was extracted by sodium hydroxide which also broke down the fragipan matrix. Carbonate and bicarbonate solutions also broke down the fragipan matrix and may have caused a reaction between soluble Si and the soil material. Thus we consider Si to be the binding agent, along with clay, that produces the characteristic brittleness of the fragipan horizon.
Factors Affecting Release and Plant Availability of Sulfur‐Coated Micronutrients
Authors: Ryan John , Prasad J. Devi 
Published: July 2010

AbstractThe agronomic effectiveness of S‐coated micronutrients and factors influencing their dissolution were studied in the green‐house and laboratory. Grain sorghum (Sorghum vulgare L.) was grown for 7 weeks on a calcareous soil incubated individually with S‐coated and uncoated FeSO4·7H2O, MnSO4·H2O, and ZnSO4·7H2O for 0, 1, 2, 3, 5, and 8 weeks. Dry matter yield was not significantly affected, but Fe and Mn uptake decreased with time of incubation prior to cropping. Values from S‐coated materials were initially higher than from uncoated materials but showed little differences after 8 weeks of incubation.Coated materials were incubated for up to 9 weeks at varying moisture contents (8–32%), temperature (8–35°C), Ca(OH)2(1–10%) and sucrose (0.5–2 g). DTPA‐extractable Fe, Mn, and Zn in treated soils decreased with incubation time and with increasing moisture, temperature and Ca(OH2) levels while the effect of sucrose additions was variable. With continuous extraction of the granules in water and in soil by DTPA at 4‐day intervals for 71 days, most of Fe, Mn, and Zn was released during the 1st month. Oxidation of the S‐coatings enhanced native micronutrient availability. Unless improvement in coating materials is made, S‐coated micronutrients are unlikely to have a significant impact in micronutrient fertilization.
Atrazine Degradation and Residue Distribution in Soil
Authors: Dao T. H. , Lavy T. L. , Sorensen R. C. 
Published: July 2010

AbstractDegradation and its effect on atrazine leaching were observed in soil in the laboratory. Degradation of 1.5 ppmw (wt/wt) of ring labeled 14C‐atrazine (2‐chloro‐4‐ethylamino‐6‐isopropylamino‐s‐triazine) over time periods up to 8 months was predominantly a nonbiological process in three nonsterilized soils at 0.1 bar moisture content, although there was evidence that the atrazine molecule was dealkylated simultaneously. Between 4 and 17% of the applied 14C was present as nonpolar compounds after 1 month of incubation at 30°C. The amount of 14CO2 evolved was cumulatively less than 0.05% of the added radiocarbon at 5 and 30°C. Desorption of atrazine from soil treated and incubated for 0.5 hour; 1 and 2 weeks; 1, 2, 4, and 8 months showed a steady increase in the unextractable fraction remaining in soil with time. In the soil extract, a tolueneinsoluble fraction increased as time passed, and made up between 24 and 62% of the extracted radiolabeled fraction of the three soils after 1 month of incubation at 30°C. The ratio of polar compounds to nonpolar compounds steadily increased with time of incubation. Major possible metabolites of the toluene‐soluble fraction were identified by thin layer chromatography as monodealkylated products. During elution of atrazine from soil columns saturated with water, decreasing the water flow rate from 2 cm/hour to 0.08 and 0.04 cm/hour greatly reduced the downward movement and enhanced degradation of the herbicide.
Fluorine in Agricultural Soils of Southeastern Pennsylvania
Authors: Gilpin Lawrence , Johnson Arthur H. 
Published: July 2010

AbstractThree fractions of fluorine were measured in a variety of Pennsylvania soils using a fluoride electrode. Mean total, soluble and resin‐extractable F values for 55 samples were 377±27, 0.38±0.5 and 21.7±1.6 ppm, respectively, in a variety of soils typical of the Piedmont and Triassic Lowlands of southeastern Pennsylvania. Each of the F fractions was related to soil pH. Selected soils were leached with a standard F solution and found to retain substantial amounts of F.
Application of Elovich Equation to the Kinetics of Phosphate Release and Sorption in Soils
Authors: Chien S. H. , Clayton W. R. 
Published: July 2010

AbstractExperimental data on the phosphate release and sorption in soils, when inadequately described by a first‐order kinetic reaction, are often interpreted as a combination of two or three simultaneous first‐order reactions. A simple modified Elovich equation in the form: q = (1/β) ln (αβ) + (1/β) ln t was derived to fit the reported experimental data in literature that failed to conform to a single first‐order kinetic equation. In this equation, q is the amount of phosphate released or sorbed, and α and β are constants. The equation successfully described the data as a single straight line that covers the entire course of reaction time. It also appears that constants of α and β may be used for comparison of reaction rates of phosphate release or sorption in different soils.
Phosphate Fractions in Calcareous Soils as Altered by Time and Amounts of Added Phosphate
Authors: Hooker M. L. , Peterson G. A. , Sander D. H. , Daigger L. A. 
Published: July 2010

AbstractTie‐up of water‐soluble P is very rapid in calcareous soils. To determine the residual effect of high rates of applied P several experiments were established on soils ranging from 0.1 to 16.5% calcium carbonate equivalents (CCE). At each location an experiment was established with four rates of P (25, 50, 100, and 500 kg/ha). The soils were sampled annually for periods of up to 5 years. These soil samples were fractionated to determine the concentration of P in the various inorganic P fractions, using the techniques of Syers et al. (1972), as affected by rate of P application and time after application.Over time there was a decrease in the more soluble, plant‐available fractions indicating a shift of P from extractable to nonextractable forms. Also the various P fractions were correlated with two of the more commonly used soil methods, Bray and Kurtz no. 1 and the Olsen NaHCO3. As the CCE of the soils increased the correlation of the Bray and Kurtz no. 1 method with the fractions considered most available to plants decreased while the correlation of the Olsen method remained high.
Physical Characteristics of Some Minesoils
Authors: Pedersen T. A. , Rogowski A. S. , Pennock R. 
Published: July 2010

AbstractStudies were conducted to evaluate physical properties of spoils resulting from surface‐coal mining and reclamation operations in Clearfield County, Pennsylvania. Bulk density, evapotranspiration, water retention, infiltration, and hydraulic conductivity values were determined at 10 sites randomly located within a 4‐ha experimental area. Average bulk density of the surface 0.5‐m layer of minesoil was 1,763 kg/m3 while specific surface at most sites averaged 31 m2/g. Microlysimeter data indicated that evapotranspiration (ET) on minesoil could be approximated by class‐A pan evaporation or by model results. A large amount of spatial variation was observed in infiltration, water retention and hydraulic conductivity values. In the uppermost 0.75 m of the profile most minesoils on the average retained 35 mm of water, between 10 and 1,500 kPa, compared to 136 mm for the adjoining soils. When water was avaliable ET approached potential, however, hydraulic properties of the minesoil would likely lead to droughty conditions and extended periods of plant stress.
Soil Genesis as Affected by Topography and Time in Highly Calcareous Parent Materials Under Semiarid Conditions in Iran
Authors: Abtahi Ali 
Published: July 2010

AbstractSoil formation as affected by topography and time was studied in highly calcareous parent materials under the semiarid conditions of southern Iran. Soils of the 95,000‐ha Sarvestan basin were considered for this purpose.Topographic features of the Sarvestan basin were related to variations in soil texture and salinity. Slightly saline, coarse‐textured soils occurred at high elevations, whereas fine‐textured soils of higher salinity occurred at low elevations. Based on salinity status, these two general soil types were classified as Inceptisols and Aridisols, respectively.Soils comprising a chronosequence differed mainly in the redistribution and accumulation of carbonates. They ranged from those developed in Holocene alluvium (Typic Xerofluvents) and lacking any evidence of carbonate redistribution to those developed on Lower or Middle Pleistocene surfaces (provisionally classified as Petrocalcic Xerochrepts) and showing distinct petrocalcic horizons.X‐ray and electron optical analyses indicated a clear gradation in the relative contents of palygorskite and smectite clay minerals within this chronosequence. Palygorskite increased as smectite decreased in older soils.
Alfalfa for Hydrologic Control of Saline Seeps
Authors: Halvorson A. D. , Reule C. A. 
Published: July 2010

AbstractSaline seeps affect extensive dry cropland areas in the northern Great Plains and methods need to be devised to control them. The effectiveness of alfalfa (Medicago sativa L.) in controlling saline seepage on northern Great Plains small grain dryland farms was studied from 1971 to 1977.Alfalfa, when grown on about 80% of the recharge area, reduced the deep percolation of soil water and provided hydrologic control for two seep areas within 1 year after its establishment in recharge areas. As the perched water table receded, the soil surface in the discharge (seepage) area dried allowing passage of farm implements, soil salinity decreased, and weeds, grasses, and crops grew better in the seepage area.In contrast, a buffer strip of alfalfa (occupying about 20% of recharge area) on the upslope side of a saline seep did not provide hydrologic control. Greenhouse data indicated that alfalfa yields will decrease rapidly if soil salinity increases to high levels above a saline water table. Reduced plant growth resulted when salts accumulated in the root zone as water moved upward by capillary action. When in situ root zone soil salinity reached an EC of 38 mmho/cm, alfalfa growth essentially ceased.We concluded that alfalfa can effectively control the hydrology of saline seep areas if it is grown on a major portion of the recharge area.
Effects of Fire on Nitrogen in Forest Floor Horizons
Authors: Mroz G. D. , Jurgensen M. F. , Harvey A. E. , Larsen M. J. 
Published: July 2010

AbstractThe effects of burning no nitrogen (N) losses and transformations in red pine (Pinus resinosa Ait.), eastern hemlock [Tsuga canadensis (L.) Carr.], and Douglas‐fir (Pseulotsuga menziesii)/western larch (Larix occidentalis Nutt.) forest floor were investigated. Organic horizon samples were burned at 400°C for 30 min in a top‐heating oven to simulate field conditions. Measurements taken immediately after burning showed total and available N losses from the O1 horizons but gains in total and available N in underlying layers. After burning, the litter was incubated for 5 weeks and analyzed for ammonium and nitrate concentrations and changes in acidity. Each forest floor type displayed varying patterns of ammonification, nitrification and immobilization of N. The N changes appeared related to the differing initial N contents of the organic material.
Aqueous‐ and Sediment‐Phase Nitrogen Yields from Five Southern Pine Watersheds
Authors: Schreiber J. D. , Duffy P. D. , McClurkin D. C. 
Published: July 2010

AbstractNitrogen (N) in solution and associated with suspended sediments in stormflow from five reforested watersheds (1.5–2.8 ha) in northern Mississippi was determined during the 1975 water year. Samples were collected using Coshocton wheel samplers set below 0.91‐m H‐flumes. Mean yearly solution NH4‐N and NO3‐N concentrations, 0.20 and 0.01 mg/liter, respectively, did not differ among watersheds. Sediment‐N concentrations ranged from 2,410 to 6,080 µg/g and were 5.4 to 10.0 times those in the watershed soils. The N enrichment of sediment relative to soil was attributed to selective erosion of fine sediments (clay) and/or deposition of coarse sediments in transport. Significant differences in sediment N yields among the five watersheds were related to stormflow volume, sediment concentration, and sediment N concentration. Nitrogen was transported from the watersheds about equally in the sediment and solution phases. Mean solution NH4‐N and NO3‐N yields for the water year were 422 and 28 g/ha, respectively, for the five watersheds; mean sediment N yield was 395 g/ha. For the year, 8–17% of the precipitation was measured as stormflow; the remainder was deep seepage and evapotranspiration since there was essentially no baseflow.
Compression of Agricultural Soils from Eight Soil Orders
Authors: Larson W. E. , Gupta S. C. , Useche R. A. 
Published: July 2010

AbstractCompression curves (bulk density vs. log applied stress) determined on 36 world agricultural soil samples at a given water content were linear over the range of stresses from about 1 to 10 kg cm−2. Compression curves determined for soils at different water contents were approximately parallel to each other over the range of initial pore water potentials from −0.05 to −1.0 bar. The compression index, C (slope of the compression curve), increased approximately linearly as clay content of the soil increased up to about 33% and then remained approximately constant as clay content further increased. The maximum C value was 0.55 for soils with predominantly 2:1 type clays and 0.50 for soils with predominantly kaolinite or iron oxides in the clay fraction. If the compression curve at one water content is known, a procedure is suggested to predict compression curves at other water contents.
A Simulation Model for Predicting Infiltration into Cracked Clay Soil
Authors: Hoogmoed W. B. , Bouma J. 
Published: July 2010

AbstractInfiltration into dry cracked clay soil was simulated by combining two existing physical simulation models for vertical and horizontal infiltration, using boundary conditions for horizontal infiltration that were defined by morphological data. Vertical flow into the cracks occurred when the application rate exceeded the calculated vertical infiltration rate of peds between cracks. Calculated horizontal infiltration from the cracks into adjacent dry peds was limited because it had to occur from a few small vertical bands along which the water moved. The contact area (S) of all bands had been determined in situ in 0.5‐m2 plots per 10‐cm depth interval using morphological staining techniques. S was a function of the applied flow regime. “Short‐circuiting,” which was defined as preferential movement of free water along large pores through unsaturated soil, was predicted well by the model. Short‐circuiting increased when the initial moisture content of the soil was higher.
The Effect of Crushed Basalt Scoria on the Cation Exchange Properties of a Highly Weathered Soil
Authors: Gillman G. P. 
Published: July 2010

AbstractSoil from the surface horizon of a highly weathered soil (Acrohumox) from tropical Queensland was mixed with crushed basaltic cinders and incubated in a moist condition for 12 months in the laboratory. The cation exchange capacity (CEC) increased from 9 to 14 meq/100 g in direct relationship to the rate of application and degree of fineness of the scoria, as well as to the duration of incubation. The increase in CEC was accompanied by an increase in exchangeable calcium, magnesium, and potassium. The results suggest that crushed basaltic scoria could be successfully used to prevent cation nutrient losses from highly weathered soils of the tropics.
Measurement of Adsorption on Solids by the Axial Filter; Linear Vs. Nonlinear Isotherms
Authors: Egozy Yair 
Published: July 2010

AbstractUse of the axial filter for adsorption measurements and evaluation of distribution coefficient is described. Adsorption of Sr(II), Co(II), and Cd(II) on Na montmorillonite from solutions of a wide range of NaCl concentration was measured by the axial filter and compared with results obtained by other experimental methods. Agreement was found for Sr(II) and Cd(II) systems. Disagreements between batch and axial filters results for Co(II) adsorption appear to rise mainly from the slow kinetics of the Co(II) adsorption.Adsorption of Sr(II) on alumina was used to demonstrate the application of the axial filter method for a nonlinear isotherm case. The nonlinear isotherm, obtained by a batch method, was used to explain the behavior of the system in an axial filter experiment. Good agreement was obtained between the predicted and the experimental axial filter results.
Greenhouse Evaluation of Four Phosphorus Soil Tests in Relation to Phosphate Buffering and Labile Phosphate in Soils
Authors: Holford I. C. R. 
Published: July 2010

AbstractFour soil P tests — Olsen, Colwell, Bray, and Mehlich — were evaluated in a greenhouse experiment in relation to plant uptake, relative yield, labile P, and buffer capacity on 30 soils varying in pH from 5.4 to 8.1. The Olsen and Colwell tests were most highly correlated with plant uptake, and the Olsen and Bray tests with relative yield. When the soils were stratified into weakly, moderately, and strongly buffered groups, it was found that extraction of labile P was depressed by increasing buffer capacity most in the Bray test, followed by the Olsen test, and least in the Colwell test. The Bray test tended to overcompensate for the effects of buffering on plant uptake and therefore underestimated the amount of available P in strongly buffered soils, whereas the Colwell method tended to overestimate it in strongly buffered soils. The Olsen test appeared to be correctly sensitive to buffering and therefore gave the highest correlations with both plant parameters. The Mehlich test extracted large amounts of nonlabile P in soils with pH >6.0 and was therefore weakly correlated with plant uptake and relative yield. The results showed that in a successful soil test, increasing buffer capacity will depress the extraction of labile P in the same way as it depresses uptake by plants.
Movement and Distribution of Ammonium‐N Following Deep Placement of Urea in a Wetland Rice Soil
Authors: Savant N. K. , De Datta S. K. 
Published: July 2010

AbstractThe vertical distribution of NH4+‐N following subsurface placement of different forms of urea was studied in incubated, undisturbed wetland soil cores. For prilled urea, supergranule urea, and prilled urea in mudballs placed at the 10‐cm depth, peak concentration of NH4+‐N was near the placement site and decreased with time, whereas after placement of sulfurcoated urea (SCU‐21) at the same depth, peak concentration of NH4+‐N increased over a period of 4 weeks. With time, the NH4+‐N tended to move downward more than upward from the placement sites, probably because of the mass flow of percolating water.In another experiment, the movement and spatial distribution of NH4+‐N were studied following application of 2‐g supergranules of urea (SGU) and sulfur‐coated supergranules of urea (SC‐SGU) at a depth of 10 cm in transplanted and cultivated wetland fallow plots. After 2 weeks, NH4+‐N concentration gradient for SGU was 1,850 to 32 µg N/cm3 wet soil, over a distance of 10–12 cm from the placement site. The corresponding gradient for SC‐SGU was 287 to 32 µg N/cm3 wet soil, over a distance of 5–7 cm from its placement site. For SGU in transplanted plots, the concentration gradient decreased steadily through 8 weeks, whereas for SC‐SGU it increased during the first 4 weeks and then decreased. The disappearance of NH4+‐N with time and distance from the site of application is attributed to diffusive transport or convective transport, or both, and root‐sink effect. The general movement of NH4+‐N was downward > lateral > upward. The apparent benefits of deep placement of urea in a wetland rice soil are discussed.
Translocation of Nutrients in Soybeans
Authors: Scott H. D. , Brewer D. W. 
Published: July 2010

AbstractTransport of nutrients in plants represents an important area in the pursuit of a greater understanding of plant nutrition. A mathematical model was developed to describe the changes in accumulation of nutrients in soybean [Glycine max L. Merr.] plants during the growing season. The model uses the compartmental approach to describe transport of nutrients between three compartments: soil (including roots), plant (including stems, petioles, and leaves), and pod (including seed). The validity of the model was tested using published data for soybeans grown in the field. The results show that nutrient translocation in soybeans varies with the type of nutrient, growth stage, and growing season.
Soil Aggregates and Primary Particles Transported in Rill and Interrill Flow
Authors: Alberts E. E. , Moldenhauer W. C. , Foster G. R. 
Published: July 2010

AbstractThe size distribution of soil particles detached and transported in rill and interrill flow was determined on a silt loam soil in northcentral Indiana. Eroded soil was separated by field and laboratory sieving into > 2‐, 2‐ to 1‐, 1‐ to 0.5‐, 0.5‐ to 0.21‐, 0.21‐ to 0.05‐, and < 0.05‐mm size classes. The amount of primary clay (< 0.002 mm) transported as discrete particles in rill and interrill flow was also determined.Large differences were found in the size of soil aggregates and primary particles in rill and interrill sediment. Rill flow transported a greater proportion of larger particles as compared with interrill flow because of basic differences in the detachment and transport mechanisms. Less than 5% of the rill and interrill sediment was composed of primary clays, indicating that most eroded clay was transported within soil aggregates.The primary particle composition of the eroded aggregates was also determined. For all sizes > 0.05 mm, the percentage of sand in rill and interrill sediment was considerably higher than that in the matrix soil. The high sand content decreased the percentage of silt in some size classes more than the percentage of clay, indicating that primary clays may either flocculate or adsorb to the surfaces of larger aggregates during transport.Water was added to the top of preformed rills at several rates to simulate various upland slope lengths. Discharge and rill erosion rates were not related for this soil that had not been tilled or cropped for 1 year.