bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Manure and Irrigation on Sodium Bicarbonate‐Extractable Phosphorus
Authors: Pratt P. F. , Laag A. E. 
Published: July 2010

AbstractData for the NaHCO3‐extracted P in soil samples taken at the end of a 4‐year field experiment on a Hanford sandy loam (Typic Xeror‐thent) are presented. The main variables consisted of six rates of manure combined with two rates of irrigation water. The extractable P in the 0‐ to 0.3‐m depth increased for all manure rates. At the 0.3‐ to 0.6‐m and 0.6‐ to 0.9‐m depths, increases were found for only the highest rates. At the 0.9‐ to 1.2‐m depth there was a statistically significant increase only with the highest rate for the low irrigation treatment. The extractable P was consistently lower in the 0‐ to 0.3‐m depth for the high irrigation. At the lower depths there was a suggestion of higher extractable P with the high irrigation, but this effect was not consistent. The P in a fresh liquid manure appeared to move more readily into lower soil depths than a solid corral weathered material.
Phosphorus‐Enriched Soil Nodules Detected by Energy‐Dispersive X‐ray Spectrometry
Authors: McKeague J. A. 
Published: July 2010

AbstractMarked enrichment in phosphorus (P) was found in 22 of 160 iron (Fe)‐rich soil nodules analyzed by scanning electron microscopy along with energy‐dispersive x‐ray analysis (SEM‐EDXRA). Estimated P levels of 10% occurred in certain areas of some nodules, and levels of 2 to 5% were common. Most of the P‐rich nodules occurred in mottled albic horizons overlying argillic horizons of imperfectly or poorly drained soils, but some were in C horizons.
Parent Materials and Paleosols in the Teays River Valley, Ohio
Authors: Thompson Michael L. , Smeck Neil E. , Bigham Jerry M. 
Published: July 2010

AbstractSoils in the preglacial Teays River Valley of southern Ohio were studied to identify their parent materials and to investigate the presence of paleosols. At each of four sites, soils formed partly in a mantle identified as loess. The loess mantled the landscape to a uniform depth of 50 to 60 cm and was characterized hy 45 to 50% medium silt on a clay‐free basis as well as by Ti/Zr values of 10 to 12 in the total silt fraction. At sites near the old valley walls, the sola extended into colluvium. At sites near the center of the valley, the sola extended into silty alluvium or colluvium. Clay‐free particle‐size profiles and total silt Ti/Zr values generally supported the field identification of a lithologic discontinuity between the loess and underlying material. Finally, the soils were underlain by a third material: either lacustrine clay (Minford Clay), old alluvium (Gallia Sand), or weathered sandstone bedrock, depending on position in the valley.Paleosols were developed in materials underlying the loess. In the field, paleosols were identified by continuous argillans on ped surfaces. Laboratory determination of total clay revealed the presence of two argillic horizons in the soils: (i) in the loess (22 to 26 % clay), and (ii) in the underlying materials (27 to 35% clay). More intense mineral weathering in the paleosol compared to overlying or underlying horizons was indicated by its higher ratios of mica weathering products to mica in the clay fractions, higher exchangeable Al, and lower K/Zr values in the fine silt fractions. The presence of a paleosol in one pedon was supported by two subsurface accumulations of amino acid nitrogen.
Growth Response of Young Douglas‐Fir to Repeated Application of Nitrogen and Phosphorus
Authors: Steinbrenner E. C. 
Published: July 2010

AbstractA heavily thinned (to 200 trees/ha) stand of young Douglas‐fir [Pseudotsuga menziesii (Mirb.) Franco] in southwestern Washington was treated with repeated applications of nitrogen (N) and phosphorus (P) over the 15‐year period from 1955 to 1969. Nitrogen treatments resulted in a 20‐year growth response of 24% over the controls for the lower application rates (1,120‐kg N/ha) and 46% for the higher application rates (2,016‐kg N/ha). All nitrogen treatments combined averaged 40% greater volume growth than controls. Plots that received 1972‐kg N/ha over the first 10 years of the study still showed 25% greater volume growth than the controls after 10 additional years without nitrogen applications. Phosphorus applications, either alone or in combination with nitrogen, did not increase tree growth rates.
Fallow Tillage Effects on Evaporation and Seedzone Water Content in a Dry Summer Climate
Authors: Hammel J. E. , Papendick R. I. , Campbell G. S. 
Published: July 2010

AbstractEarly fall establishment of winter wheat is essential for high yields and erosion control following fallow in the Pacific Northwest, USA. Successful early stands require tillage management that minimizes water loss from the seedzone during the relatively dry summer. A numerical model was developed to investigate the dynamic aspects of heat and water flow in the upper soil layers with emphasis on effects of conventional tillage fallow and no‐till (chemical fallow) on these processes and ultimately the seedzone water content. After 15‐day simulations used to verify the model with measured values of meteorological variables and soil properties, predicted and measured water content distributions across the seedzone generally agreed within 0.01 kg/kg. Exclusion of thermally induced vapor flow from the model gave a higher predicted evaporative water loss and poorer agreement between measured and simulated soil water content distributions. The values for characterizing the atmospheric boundary layer resistance were also critical for correctly simulating soil temperature and water content profiles. Evaporative water loss for no‐till over a 90‐day simulation period using measured meteorological inputs was 70% higher than for conventional tillage, resulting in water contents in the seedzone that were too low for successful stand establishment under chemical fallow. Thus, for the climatic conditions and the soil studied here, some tillage may be necessary for retention of adequate seedzone water for early fall‐winter wheat establishment.
Nonmicrobial Nitrite‐to‐Nitrate Transformation in Soils
Authors: Bartlett Richmond J. 
Published: July 2010

AbstractNitrate formation in soils equilibrated with nitrite at 0.5° C was directly related to soil level of reactive managanese (Mn) oxides. It was demonstrated that synthetic Mn oxides can oxidize nitrite to nitrate and become reduced in the process. Nitrite oxidation, nitrate formation, and MnO2 reduction were stoichiometrically related reactions in the presence or absence of atmospheric O2. Nitrite reduced Mn(IV) to either Mn(II) or Mn(III), but when MnO2/nitrite ratios were high, reduction to Mn(III) appeared to predominate. This mechanism of nonmicrobial conversion of nitrite to nitrate may explain why nitrite seldom accumulates in soils, even when Nitrobacter numbers are low and conditions for their growth are unfavorable.
Kinetic Model for Phosphate Transport and Transformation in Calcareous Soils: I. Kinetics of Transformation
Authors: Enfield Carl G. , Phan T. , Walters David M. , Ellis Roscoe 
Published: July 2010

AbstractPhosphorous in concentrations exceeding those generally observed through agricultural activities has been encountered at land application wastewater treatment sites. To predict the environmental impact of these systems, a model was developed to describe the reaction of orthophosphate with mineral soils. The model is based on instantaneous reversible absorption theory plus time‐dependent solubility theory. It was assumed, in the model, that first‐order kinetics would adequately describe the formation or dissolution of phosphate minerals. Statistical regression analyses were performed on batch sorption data for 14 mineral soils where two equilibrium compounds were considered. The two compounds considered were hydroxyapatite (Ca10HPO4·2H2O) and dicalcium phosphate dihydrate (CaHPO4·2H2O). Comparisons of correlation coefficients between this model and previous models using a common data set indicate the current model with a mean correlation coefficient of 0.93 is more accurate in describing phosphate reactions in calcareous soils than earlier models with mean correlation coefficients ranging from 0.75 to 0.91.
Kinetic Model for Phosphate Transport and Transformation in Calcareous Soils: II. Laboratory and Field Transport
Authors: Enfield Carl G. , Phan T. , Walters David M. 
Published: July 2010

AbstractA first‐order kinetic model was employed to predict, for selected soils, the response of the soil to phosphorus (P) applied in solution with 0.01M CaCl2 in the laboratory, and the response of P in municipal wastewater at two rapid infiltration wastewater treatment systems. The one‐dimensional steady‐state hydraulic model appears to accurately predict (±50% of estimate) both the concentration of P in the solution phase as well as the accumulation of P in the solid phase.
Thermodynamics of Potassium Exchange in Soil Using a Kinetics Approach
Authors: Sparks D. L. , Jardine P. M. 
Published: July 2010

AbstractThermodynamics of potassium (K) exchange using a kinetics approach was investigated in Ca‐saturated samples from the Ap and B21t horizons of a Matapeake soil from Delaware. Kinetics of adsorption and desorption were determined at temperatures of 0, 25, and 40°C on each soil horizon using a miscible displacement technique. Energies of activation for adsorption and for desorption (Ea and Ed, respectively) ranged from 3.83 to 5.52 kcal mol−1. The Ed values were higher than the Ea values, indicating that more energy was needed to desorb K than to adsorb K. Thermodynamic and pseudother‐modynamic parameters were determined using Gibbs' and Eyring's reaction rate theories. The free energy for K exchange (ΔG°) values were negative (ranging from 1,155 to 1,294 cal mol−1) and increased with increasing temperature. The free energy of activation values were higher for K desorption (ΔGd‡) than for K adsorption (ΔGa‡), suggesting a greater free energy requirement to desorb K. The excellent agreement between ΔG° calculated from Gibbs' theory and from Eyring's reaction rate theory indicated that pure thermodynamic parameters could be calculated using a chemical kinetics approach. The enthaply (ΔH°) values were exothermic and indicated stronger binding of K+ ions in the B21t horizon than in the Ap horizon of the Matapeake soil. The latter was related to the difference in external surface‐to‐interlayer surface‐charge ratio in the two horizons. The enthalpy of activation (ΔH‡) values in both horizons were higher for desorption (ΔH‡d), than for adsorption (ΔHa‡), suggesting the heat energy required to overcome the K desorption barrier was greater than for that of K adsorption.
Characteristic Variations in Reflectance of Surface Soils
Authors: Stoner E. R. , Baumgardner M. F. 
Published: July 2010

AbstractSurface soil samples from a wide range of naturally occurring soils were obtained for the purpose of studying the characteristic variations in soil reflectance as these variations relate to other soil properties and soil classification. A total of 485 soil samples from the U.S. and Brazil representing 30 suborders of the 10 orders of Soil Taxonomy was examined. Spectral bidirectional reflectance factor was measured on uniformly moist soils over the 0.52 to 2.32 µm wavelength range with a spectroradiometer adapted for indoor use.Five distinct soil spectral reflectance curve forms were identified according to curve shape, the presence or absence of absorption bands, and the predominance of soil organic matter and iron oxide composition. These curve forms were further characterized according to genetically homogeneous soil properties in a manner similar to the subdivisions at the suborder level of Soil Taxonomy. Results indicate that spectroradiometric measurements of soil spectral bidirectional reflectance factor can be used to characterize soil reflectance in terms that are meaningful to soil classification, genesis, and survey.
Soluble Salt Concentrations in Runoff Waters from Soils Previously Cropped to Rice
Authors: Gilmour J. T. , Marx D. B. 
Published: July 2010

AbstractSoluble salt damage to rice in Arkansas has been evident in recent years. In order to adequately model salt balances for Crowley silt loam soil (Typic Aibaqualfs) cropped to rice (Oryza sativa L.) and soybean (Glycine max L. Merr.) in the Grand Prairie region of Arkansas, a description of soluble constituents in runoff water was needed. Three fields were monitored for soluble salts in runoff and irrigation water as well as runoff volume. As cumulative runoff increased, a logarithmic decline in the concentration ratio of runoff water salt concentration to irrigation water salt concentration was found for electrical conductivity (EC), Ca, Mg, Na, SO4, and Cl for the first 10 cm of runoff after removal of the rice floodwater. The equation in which the logarithm of the concentration ratio was the dependent variable and cumulative runoff was the independent variable had a common slope among fields for the solution variables studied. A common intercept was found for Ca and Na but not for EC, Mg, SO4, and Cl. A second linear relationship was developed where the intercept in the above for SO4 and Cl was found to be a function of irrigation water concentration. At one field where sufficient data were available the concentration ratio stabilized after 10 cm of runoff and could be predicted using the concentration ratio equation where cumulative runoff was set at 10 cm.
Ammonia Volatilization from Lime Urea Ammonium Nitrate Suspensions Before and After Soil Application
Authors: Winter K. T. , Whitney D. A. , Kissel D. E. , Ferguson R. B. 
Published: July 2010

AbstractLimestone suspensions provide a means of uniformly applying finely divided liming materials to raise soil pH. Water has usually been the suspending medium, but N fertilizer solutions may be used.The objective of this research was to measure ammonia (NH3) losses that might occur while a lime and urea‐ammonium nitrate (UAN) suspension is being prepared and potential losses after the suspension is applied to soil.Ammonia volatilization was measured in the laboratory from lime‐UAN suspensions formulated with lime sources containing various amounts of CaO. Suspension pH's, rates of loss, and total NH3 losses were directly proportional to the CaO content of the lime material and ranged up to approximately 90% of the ammoniacal fraction of the UAN after 4 hours. Losses were not influenced greatly by the initial pH of the UAN materials used in the study.Ammonia volatilization from the surface of two acid soils was also measured after lime‐UAN suspensions were applied at a rate of 840 kg/ha effective calcium carbonate [CaCO3; (ECC)] and 112 kg N/ha. Lime applied with the UAN increased NH3 volatilization, but less on Grundy sicl (Aquic Argiudoli) than on Parsons sil (Mollic Albaqualf) with a lower cation exchange capacity (CEC). Up to 17% of total N was lost with the lime‐UAN treatments on Parsons soil with a CEC of 10.2.Results indicate substantial losses of NH3 may occur while lime‐UAN suspensions are being prepared only if the lime contains CaO. After soil application, NH3 losses can occur in the absence of CaO if the lime‐UAN is allowed to remain on the soil surface.
Wetting Moisture Characteristic Curves Derived from Constant‐rate Infiltration into Thin Soil Samples
Authors: Perroux K. M. , Raats P. A. C. , Smiles D. E. 
Published: July 2010

AbstractAlthough procedures are available for obtaining the wetting moisture characteristics of soils, they often involve lengthy equilibration periods. A simple and quick laboratory method is described for obtaining the wetting moisture characteristic using constant flux infiltration into a thin section of soil. A theoretical analysis of the process is tested by comparing predicted and observed times for pressure heads to develop in a fine sand sample. The technique is demonstrated using a fine sand, a loam, and a silty clay loam, and comparison is made with data obtained by other methods.
Trace Metal Chemistry in Arid‐zone Field Soils Amended with Sewage Sludge: II. Comparative Study of the Fulvic Acid Fraction
Authors: Sposito Garrison , Holtzclaw Kenneth M. , LeVesque C. S. , Johnston Cliff T. 
Published: July 2010

AbstractThe elemental composition, infrared spectrum, and proton titration curve were determined for (i) the fulvic acid fraction of a Domino soil which had received applications of composted sewage sludge for three years in a field experiment, and (ii) a commercially available fulvic acid extracted from a spodosol. Data showed that the Domino fulvic acid more resembled a typical sludge‐derived fulvic acid than a fulvic acid extracted from natural soil organic matter. The distinguishing features of the Domino fulvic acid which led to this conclusion were: (i) a high total sulfur (S) content and the presence of sulfonyl groups, (ii) a significant content of anionic surfactants and S‐containing amino acids, (iii) a low glucosamine/galactosamine ratio, and (iv) more than two classes of acidic functional groups. However, the Domino fulvic acid had a much larger content of carboxyl and other acidic functional groups than a typical sludge‐derived fulvic acid, evidently because of partial oxidation of the sludge in the Domino soil.
Stabilization and Incorporation into Biomass of Phenolic and Benzenoid Carbons during Biodegradation in Soil
Authors: Kassim Ghiath , Stott Diane E. , Martin J. P. , Haider K. 
Published: July 2010

AbstractThe biodegradation, incorporation into biomass, and stabilization in humus of specific carbons of ferulic, p‐hydroxycinnamic, anisic, and benzoic acids and catechol were followed in Steinbeck loam (pH 5.0) and Greenfield sandy loam (pH 7.0). Biomass was estimated by the fumigation procedure. The least incorporation into biomass was noted for the three‐side chain carbon of ferulic acid (1.0 to 1.4%) and the greatest for the two‐side chain carbons of either ferulic or p‐hydroxycinnamic acids (10.9 to 17.6%). Greater amounts of carbon were evolved as carbon dioxide (CO2) and incorporated into the biomass in the acid soil than in the neutral soil. Approximately 74% of the ring carbons of catechol were stabilized in the neutral soil after 12 weeks but only 2% of that was in biomass. The amount of residual carbon found in the biomass decreased with time. The amount of residual ring‐carbons of anisic and benzoic acids incorporated into the biomass were 19 and 15%, respectively. As the substrate concentration increased from 1 to 10,000 ppm, the carbon released as CO2 from ferulic acid and glucose ranged from 47 to 85% and from 63 to 85%, respectively. The residual ferulic acid and glucose carbons in biomass ranged from 2.2 to 11% and 19 to 39%, respectively. The study indicated that relatively higher amounts of the phenolic carbons were stabilized in the soil humus while greater amounts of the glucose carbons were incorporated into the soil biomass, and that compared to glucose, greater amounts of the residual carbons of the phenolic compounds were not solubilized by 6N HCl hydrolysis.
Phosphorus Accumulation and Toxicity in Leaves in Relation to Zinc Supply
Authors: Loneragan J. F. , Grunes D. L. , Welch R. M. , Aduayi E. A. , Tengah A. , Lazar V. A. , Cary E. E. 
Published: July 2010

AbstractThe relationship of zinc (Zn) deficiency to phosphorus (P) toxicity was examined in ‘Emerald’ okra [Abelmoschus esculentus (L.) Moench] grown for 21 days (D21) in complete nutrient solution and then transferred to treatments with two levels of P (P1, P2 = 250, 2,000 µM P) and four levels of Zn (Zn1, Zn2, Zn3, Zn4 = 0, 0.25, 1, 2 µM added Zn).No symptoms of “little leaf” or “rosetting” developed in any plants. “Mottle leaf” symptoms developed as chlorotic and necrotic patches in the interveinal areas of the older leaves of Zn1 plants at P1 and in Zn1, Zn2, and Zn3 plants at P2. Thus, increasing the level of P induced symptoms which were eliminated by adding Zn.Treatments had little effect on dry matter at D45 and D63: at D111, low Zn depressed dry weight of P1 tops and even more markedly depressed dry weight of P2 tops, roots, and fruits.Increasing solution P increased the concentration and amount of P in all plant parts at all harvests. At D45 it also depressed Zn concentrations in all parts of Zn1 plants but in no other Zn treatment and in no treatment at later harvests.At Zn1, leaves had relatively low concentrations of Zn and high concentrations of P. Increasing levels of Zn enhanced their Zn concentrations and depressed their P concentrations; at D45 and D63 they also depressed the concentrations and total amounts of P in tops and whole plants but increased them in roots. Thus Zn deficiency markedly enhanced P absorption by roots, transport to tops, and accumulation in leaves.Concentrations of magnesium in plant organs responded to treatments in the same way as did P but to a smaller degree, particularly in the leaves. No other element measured (Ca, K, Na, Fe, Cu, Mn) responded in the same way.The development and intensity of symptoms in old leaves correlated closely with P concentrations. Leaves with faint symptoms had 0.8% P; those with marked symptoms had > 1.5% P; and dead leaves had nearly 5% P. The intensification of symptoms is attributed to accumulation of P to toxic levels in leaves.It is suggested that Zn deficiency interferes with P metabolism enhancing the amounts of P absorbed by roots and transported to tops: under conditions of high P supply, P accumulates to toxic levels in leaves inducing or accentuating symptoms resembling Zn deficiency. This effect of Zn on P metabolism in roots seems to explain previously puzzling observations in which P treatments enhanced symptoms of Zn deficiency without any reduction in Zn contents of plant tops: there is no need to invoke any effect of P in inactivating Zn in leaves.
Quantification of Soil Loss and Sediment Produced from Eroded Land
Authors: Lewis D. T. , Lepele M. J. 
Published: July 2010

AbstractSoil eroded from slopes and sediment added to stream systems as non‐point pollution from a small watershed in southeastern Nebraska were quantified. The watershed studied was within delineation of severely eroded loessial soils. Calculations of soil loss were based on horizonation and clay distribution in eroded pedons as compared to slightly eroded pedons in the same soil series. Thickness and areal extent of soil loss were used to calculate weight and volume of soil moved from the slopes as well as volume and weight of sediment that remained near its source on the landscape. Amount of soil eroded minus that remaining in local storage suggested an amount added from the watershed as non‐point sediment pollution in streams. The method described suggests a way in which soil survey mapping units may be characterized in order to quantify the amount of sediment in storage on the landscape and in stream systems due to past erosion of agricultural land.