bluuebunny/crossref_metadata_2025_split huggingface dataset:
Physico‐chemical Properties of Sols and Gels of Na‐montmorillonite with and without Adsorbed Hydrous Aluminum Oxide
Authors: Davey Brian G. , Low Philip F. 
Published: July 2010

AbstractSodium‐montmorillonite was prepared with and without adsorbed hydrous aluminum oxide and called Na/Al‐clay and Na‐clay, respectively. The two clays were mixed with 10‐4N NaCl solution in different proportions. Measurements of shear stress at different shear rates showed that the clay content at which gelation began, as indicated by an increase in viscosity and the initiation of non‐Newtonian and hysteretic behavior, was lower for the Na/Al‐clay than for the Na‐clay (∼ 2% clay vs. 4% clay). Theoretical considerations indicated that both strong and weak bonds were present in the gels but only weak bonds were present in the sols.Specific heat capacities of the mixtures were determined in a Calvet microcalorimeter and were found to differ from those calculated from the known proportions and specific heat capacities of clay and water. Differences were greater for the Na/Al‐ than for the Na‐clay. A detailed analysis indicated that these differences could be attributed to clay‐water interaction.EMF measurements, made with sodium glass and Ag/AgCl electrodes, showed that the relative partial molar free energy of NaCl changed with clay content in somewhat different ways for the Na/Al‐ and Na‐clay mixtures. The changes were correlated with changes in other properties of the mixtures. It was concluded that adsorbed hydrous aluminum oxide does influence the physico‐chemical properties of sols and gels of Na‐montmorillonite.
Fractionation of Inorganic Phosphate in Calcareous Lake Sediments
Authors: Williams J. D. H. , Syers J. K. , Harris R. F. , Armstrong D. E. 
Published: July 2010

AbstractInorganic orthophosphate (inorganic P) added with NH4F reagent to calcareous Wisconsin lake sediments was recovered in the NH4F (0–32%), citrate‐dithionite‐bicarbonate (18–23%), and first HCl (38–63%) reagents of an inorganic P fractionation scheme. Calcium fluoride, formed during NH4F extraction of calcareous materials, sorbed inorganic P, presumably resulting in the formation of a CaF2‐orthophosphate complex; inorganic P was also sorbed by CaCO3 and CaF2 in an NaOH system. Consequently, the values of NH4F‐P and first NaOH‐P underestimated the amount of inorganic P released from secondary Al‐ and Fe‐containing sediment components during the NH4F and first NaOH extractions, whereas the values for “reductant‐soluble P” (citrate‐dithionite‐bicarbonate‐extractable) overestimated the amount of P occluded within Fe oxides, and the P extracted subsequently by HCl overestimated the amount of acid‐extractable Ca‐P present. Because of the side reactions with CaCO3, the NH4F reagent was omitted in subsequent fractionation studies. Added inorganic P sorbed from 0.1N NaOH solution by CaCO3 in pure form or in calcareous sediments was essentially quantitatively recovered in a subsequent citrate‐bicarbonate extraction. A proposed inorganic P fractionation scheme for calcareous materials, based on successive single extractions with NaOH, citrate‐dithionite‐bicarbonate, and HCl reagents, removed approximately 90% of the total inorganic P in the sediments. Native inorganic P released in the NaOH extraction originated from Fe‐ and Al‐bound P but not from Ca‐bound P, and P released in the subsequent citrate extraction was largely, if not wholly derived from P resorbed during the preceding NaOH extraction. Phosphorus released in the following HCl extraction was derived from Ca‐bound P. Previous inorganic P fractionation schemes have underestimated nonoccluded Fe‐ and Al‐bound P and overestimated Cabound P and, frequently, occluded Fe‐bound P in calcareous soils and sediments.
The Metal Complexing Capacity and the Nature of the Chelating Ligands of Water Extract of Poultry Litter
Authors: Tan K. H. , Leonard R. A. , Bertrand A. R. , Wilkinson S. R. 
Published: July 2010

AbstractThe metal complexing capacity and the nature of the chelating ligands of organic matter extracted from broiler house litter were studied by ion‐exchange equilibrium and dissolution methods and infrared spectroscopy.The water extract of broiler house litter appeared to exhibit a significant chelating effect on the cations Cu2+, Zn2+, Mg2+, and Al3+. The amount of organic matter complexed by one mole of metal and the stability of metal complexes increased with increasing pH in the cases of Cu‐, Mg‐, and Al‐complexes, but were unaffected by changes in pH in the case of Zn‐complexes. With respect to the divalent ions, the amount of organic matter chelated and the stability of the divalent metal‐complexes decreased in the order Cu > Zn > Mg.Dissolution studies with insoluble Al2O3 and Fe2O3 powders showed that both Al and Fe were chelated in the aqueous extract, but 10 times more Al than Fe was dissolved in a given time period.Infrared analysis revealed spectrograms of the ligands similar to those obtained for polysaccharides. However, since the freeze‐dried extract contained 9% N, some NH2 groups must have been present, although bands of these groups were not resolved from overlapping O‐H bands. Functional group frequency vibration comparisons at 3,500, 3,200, 1,650, and 1,400 cm‐1 showed that the formation of stable metal‐complexes involved carboxyl electrovalent linkages and probably hydroxyl and/or amino coordinate linkages.
Grass Cycling of Calcium, Magnesium, Potassium, and Sodium in Solodization
Authors: White E. M. 
Published: July 2010

AbstractInsufficient Na is cycled to the soil surface by the blue grama (Bouteloua gracilis), buffalograss (Buchloe dactyloides), western wheatgrass (Agropyron smithii), and bromegrass (Bromus inermis) to retard the solodization of a solonetz soil. Sodium, Ca, and Mg contents in plant tops were about the same as in the roots, while tops contained more K than the roots. The ratio of Ca to Mg in the plants was less than the ratio of exchangeable Ca to exchangeable Mg in the soil. Proportionately more Mg than Ca is cycled to the upper part of the soil by these plants. This cycling may be a factor in the genesis of solodized soils with considerable exchangeable Mg.
The Effect of Hydrophobic Substances on Water Movement in Soil during Infiltration
Authors: DeBano Leonard F. 
Published: July 2010

AbstractThe effect of hydrophobic substances on water movement was studied by infiltrating water horizontally and vertically into soil columns packed with wettable and water repellent soils. Horizontal infiltration was 25 times slower in water repellent soil than wettable soil. In the water repellent soil, the water content decreased 20 to 25% between the water source and the wetting front. In contrast, water content dropped 10% in the same region of the wettable soil. Diffusivities calculated for the two types of soil suggested that hydrophobic substances had the greatest effect on water movement at the lower water contents. The orientation of the columns during water entry affected the shape of the soil‐water profiles in the water repellent soil, but not in the wettable soil. The diffusivities calculated from horizontal infiltration experiments were not useful for predicting soil‐water profiles during vertical infiltration into either the wettable or water repellent soils.
Effect of Different Anions on the Crystallization of Aluminum Hydroxide in Partially Neutralized Aqueous Aluminum Salt Systems
Authors: Ross G. J. , Turner R. C. 
Published: July 2010

AbstractThe effect of Cl‐, NO3‐, and ClO4‐ ions on the crystallization of Al(OH)3 was studied in 0.2M, 80% neutralized AlCl3, Al(NO3)3, and Al(ClO4)3 systems at 25C. In the presence of 0.6M Cl‐ no crystalline Al(OH)3 formed during 2 year's reaction; instead, an aluminum hydroxychloride solid of composition Al(OH)2.5Cl0.5·xH2O crystallized. In the presence of 0.6M NO3‐ a poorly crystalline aluminum hydroxynitrate of approximate composition Al(OH)2.5(NO3)0.5 · xH2O formed initially, but gibbsite crystallized eventually after 9½ month's reaction. In the presence of 0.6M ClO4‐ nordstrandite initially crystallized and was present after 3 week's reaction. These results support the hypothesis that the rate of Al(OH)3 crystallization is inversely related to the tendency of anion inclusion in aluminum hydroxide precipitates, and that this tendency decreases with an increase in size and structural complexity of monovalent inorganic anions.The incorporation of anions, especially NO3‐, in hydrous aluminum solids may have agronomic importance.
Diffusion of Iron and Iron Chelates in Soil
Authors: O'Connor G. A. , Lindsay W. L. , Olsen S. R. 
Published: July 2010

AbstractThe importance of diffusion in moving Fe to plant roots was estimated by theoretical calculations. In plant studies chelates increased the diffusion and uptake of Fe by increasing the concentration gradient of diffusible Fe to sorghum roots (Sorghum vulgare). Uptake of Fe increased linearly with the concentration of Fe in solution.Self‐diffusion coefficients of Fe and Fe chelates were determined in both aqueous media and soil. In aqueous media, the diffusion coefficients were 6.2 × 10‐6 cm2sec‐1 for Fe, 5.4 × 10‐6 cm2sec‐1 for FeEDDHA, 4.2 × 10‐6 cm2sec‐1 for FeDTPA, and 3.9 × 10‐6 cm2sec‐1 for FeEDTA. In soil, a correction factor was used to adjust the apparent porous system self‐diffusion coefficients. The corrected diffusion coefficients in soil were 1.5 × 10‐7 cm2sec‐1 for Fe and 1.85 × 10‐7 cm2sec‐1 for FeEDDHA.
Solution Ion Activity and Plant Growth
Authors: Khasawneh F. E. 
Published: July 2010

AbstractThe relation of ion uptake to soil solution composition is discussed. Uptake of a given ion depends not only on its activity in solution, but also on the activity of other ions and the relation that exists between solution ions and exchangeable or solid‐phase ions. Methods of combining all these factors are reviewed and evaluated. A dimensionless plot, suggested by Howard and Adams, which related relative plant growth to the ratio of the ion activity to the sum of ion activities in solution, ai/Σn1ai, seems to have a wide range of applicability that extends from uptake from a nutrient solution in a beaker to uptake from soil solution in situ.
Problems Associated with the Determination and Application of the Solubility Product Constant
Authors: Nakayama F. S. 
Published: July 2010

AbstractDifficulties encountered in estimating the solubility product constants of CaSO4 · 2H2O and CaCO3 from analytical measurements are discussed. A major factor involved is the formation of complexes between the constituent of the dissolving solid and other ionic species in solution. Conversely, when the solubility product principle using these constants is applied for predicting the precipitation of ions or the dissolution of a solid in fairly dilute solutions containing various ionic constituents, adequate accounting of all possible combinations of ion association must be made. Prediction problems are still present for solutions at high salt concentrations.
Loess Distribution in Central and Eastern Kentucky
Authors: Barnhisel R. I. , Bailey H. H. , Matondang Sahat 
Published: July 2010

AbstractThe loess distribution along a transect from Louisville to eastern Pike County, Kentucky was studied. The parameters used to determine the extent and depth of loess were particle size analyses, titanium content of—and relative amounts of feldspar in—the coarse, medium, and fine silt fractions. The best criterion was the expression of data on the percent silt on a clay‐free basis. It was determined that the loess mantle extends about 148 km (92 miles) eastward from the Ohio River. Beyond this distance the loess was either too thin to be recognized due to mixing with residuum or loess was not present. The entire soil profile was developed in loess up to 68 km (42 miles) from the source and from 84–148 km (52–92 miles) along the transect, the upper part of the solum was in loess, the lower part was developed in residual material. It appeared that loess of two ages associated with the glaciation periods, was present in the initial part of the transect, up to 84 km (52 miles) from the Ohio River.
Furrow Infiltration Rates as Affected by Incorporation of Straw or Furrow Cultivation
Authors: Miller D. E. , Aarstad J. S. 
Published: July 2010

AbstractEither straw incorporation or cultivation of the furrow bottom greatly increased furrow infiltration into a sandy loam soil during a 3‐year study period. Straw incorporation became less effective as the season progressed. A single straw application of 13.4 tons/ha lasted until midway into the second irrigation season. The cultivation treatment caused serious erosion when furrow inflow rates were about 6 liters/min or more. The straw prevented erosion at all inflow rates (up to 8 liters/min). Organic matter contents were significantly increased by the incorporation of straw. Aggregate stabilities followed the same trend, but differences were not statistically significant.
Limitations on Scaling by Contact Angle
Authors: Philip J. R. 
Published: July 2010

AbstractThe prevalent notion that the (static and dynamic) behavior of liquids in porous media such as soils may be scaled by contact angle depends on the over‐simplification that such media are bundles of long cylindrical capillaries. Observations on such media yield, at best, apparent contact angles which cannot be related directly to contact angle at interfaces within the medium. In some circumstances scaling by apparent contact angle may hold approximately, but this is of only limited value, since apparent contact angle depends not only on the true liquid‐solid contact angle, but also on properties of the internal geometry of the medium. These matters are illustrated through the counter‐example of a (somewhat more realistic) conical‐pore model; and an interpretation is offered of some data of Mustafa et al. (4).
Soil and Plant Relationships of Inositol Phosphate Stereoisomers; the Identification of D‐Chiro‐ and Muco‐Inositol Phosphates in a Desert Soil and Plant System
Authors: L'Annunziata Michael F. , Fuller Wallace H. 
Published: July 2010

AbstractInositol phosphate stereoisomers were isolated from a forest soil and its surface organic horizon of undecomposed ponderosa pine (Pinus ponderosa) needles, and also from a desert soil and its surface plant matter of undecomposed velvet mesquite (Prosopis juliflora var. velutina) leaves. Qualitative and preparative paper chromatography, mass spectrometry, infrared (IR) and nuclear magnetic resonance (NMR) spectroscopy were the principal methods used to identify the stereochemistry of the inositol moieties. Nuclear magnetic resonance spectroscopy proved to be the most useful means of differentiating among the soil and plant inositol phosphates. Myo‐ and “DL”‐chiroinositol phosphates (optical rotation unknown) were found in the pine needles of P. ponderosa and its underlying soil. Myo‐, D‐chiro‐, and muco‐inositol phosphates were found in the leaves of P. juliflora var. velutina; however, only myo‐ and D‐chiroinositol phosphates were identified in the underlying desert soil. The presence of D‐chiro‐inositol phosphate but absence of muco‐inositol phosphate in the desert soil poses questions concerning the fate of the latter in the soil. Epimerization reactions involving a cyclic ketone intermediate are considered, which could occur between the muco‐ and D‐chiro‐inositol moieties and also between the myo‐ and D‐chiro inositol moieties, in which the isomers in both cases differ in the stereochemistry of only one carbon atom.
Trace Element Correlation of Volcanic Ash Soils
Authors: Borchardt G. A. , Harward M. E. 
Published: July 2010

AbstractNeutron activation of volcanic ash followed by gamma‐ray detection with a Ge(Li) semiconductor detector and 4096 multichannel analyzer produced rapid analysis for 19 elements. This was demonstrated to be useful for correlating soil parent materials. The trace element compositions of volcanic glass from C horizons of soils along a 450‐km transect in Oregon correlate with known ejecta from Mt. Mazama. Concentration of transition metals in upper horizons relative to C horizons occurred in the order Cr > Co > Fe = Sc. Ratios of Na/Fe and Na/Co increased with depth. The abundances of Hf, Th, and the rare earth elements, as well as Sc/Fe ratios, were relatively constant with depth. Stable elemental ratios unique to Mazama ash aided correlation of weathered soil horizons. Some of the soils of northeastern Oregon may have small amounts of St. Helens ash in upper horizons in addition to the predominant Mazama ash.
Formation of Vesicular Structure in Soil
Authors: Miller D. E. 
Published: July 2010

AbstractVesicular structure observed under irrigation furrows of several high‐silt soils is described. The structure is induced by the succession of wetting and drying cycles that accompany irrigation. The degree of drying before irrigation, the number of irrigations and the surface tension of water are important factors in the structure formation. The vesicular structure is probably caused by capillary pressure within the air‐filled voids surrounded by water. The soils involved are unstable when nearly saturated, and the capillary pressure is sufficient to form the trapped air into spheres. Swelling and shrinking accompany the wetting and drying, so that more air is trapped each cycle and the volume of vesicles increases with number of irrigations. The size of vesicles increases with number of irrigations as small vesicles merge to become larger ones, and thus decrease the surface area per unit volume.
The Effect of Sprinkling Intensity and Soil Type on Oxygen Flux During Irrigation and Drainage
Authors: Gornat B. , Enoch H. , Goldberg D. 
Published: July 2010

AbstractThe effect of sprinkling intensity on oxygen flux in sand, loam, and clay soil was measured with platinum electrodes. In all three soils, the interval between two consecutive irrigations could be divided into four periods: (i) From the beginning of irrigation until the wetting front reached the electrode, the reduction current was unrelated to oxygen flux and the measurements were meaningless. (ii) When the wetting front reached the electrode, high values were recorded. From then on, the oxygen flux decreased to a minimum value by the end of the irrigation. (iii) Shortly after irrigation and until drainage had almost ceased, flux increased to a new peak. (iv) Hereafter, the reduction current decreased although the real oxygen diffusion presumably increased.Oxygen flux was higher at the low irrigation intensity, which is attributed to a lower soil moisture content during infiltration at this rate. Aggregate breakdown and crust formation on the soil surface due to the high irrigation intensity inhibit gas exchange.
Infiltration from a Trickle Source: I. Mathematical Models
Authors: Brandt A. , Bresler E. , Diner N. , Ben‐Asher I. , Heller J. , Goldberg D. 
Published: July 2010

AbstractTheoretical considerations and mathematical tools to analyze multidimensional transient infiltration from a trickle source have been developed. Two mathematical models were considered: (i) a plane flow model involving the Cartesian coordinates x and z; and (ii) a cylindrical flow model described by the cylindrical coordinates r and z. The diffusion‐ type water flow equation in unsaturated soil was solved numerically by an approach that combines the noniterative ADI difference procedure with Newton's iterative method. The numerical results have been compared with Wooding's solution for steady infiltration from a circular pond and with a simple one‐dimensional solution. These comparisons indicate that the method is reliable and can be used with confidence. Typical results are demonstrated to show the effect of trickle discharge on the water content field, the saturated water entry zone, and the water flux at the soil surface.
Infiltration from a Trickle Source: II. Experimental Data and Theoretical Predictions
Authors: Bresler E. , Heller J. , Diner N. , Ben‐Asher I. , Brandt A. , Goldberg D. 
Published: July 2010

AbstractThe theory of transient infiltration from a trickle source, as developed in Part I of this work, was compared with experimental results. Laboratory experiments using a loamy soil were conducted under conditions similar to those assumed in the two‐dimensional plane flow model. Field data were collected from a sandy soil that was wetted by commercial trickles. The field conditions were similar to those assumed in the cylindrical model. The effect of trickle discharge rates on the water content distribution and on the location of the wetting front was considered. The functional relationship between water diffusivity and water content was estimated by a computer technique that complements the conventional method for diffusivity determination. These data, together with the soil water retention curve were used to estimate the hydraulic conductivity as a function of water content. The agreement between theory and experiment, as expressed by water content distribution and location of the wetting front, is generally good and suggests that the theory is applicable to many field situations. Significant discrepancies between observed and theoretical results were obtained only in one case, where the rate of trickle infiltration was large. The theory, as well as the experimental data, indicate that for the conditions studied, an increase in the trickle discharge rate results in an increase in the horizontal wetted area and a decrease in the soil wetted depth.
Nitrate Adsorption: I. In Some Acid Soils of Mexico and South America
Authors: Kinjo T. , Pratt P. F. 
Published: July 2010

AbstractNitrate adsorption by subsoils of Andepts, Oxisols, and Alfisols from Mexico and South America was studied using a batch‐type technique. Nitrate adsorption increased as the acidity of the suspension increased to about pH 3.5. This increase was directly proportional, but not equivalent, to the amount of hydrogen ion added. The adsorption of NO3‐ was concentration‐dependent and was described by a Langmuir type isotherm when NO3‐ concentration was above 0.03N for Andepts and above 0.08N for Oxisols and Alfisols. Adsorption maxima and affinity constants of Andepts were twice as large as those of other soils. A significant correlation was observed between the amount of NO3‐ adsorbed and the content of amorphous inorganic materials extractable with 0.5N NaOH.
Volatilization of Nitrogen‐Containing Compounds from Beef Cattle Areas
Authors: Elliott L. F. , Schuman G. E. , Viets F. G. 
Published: July 2010

AbstractThe release of NH3 plus steam‐distillable organic N compounds to the atmosphere from a small beef feedlot and a pasture was measured. Acid traps placed next to the feedlot and 0.8 km from the feedlot averaged 148 and 16 kg/ha per yr NH3 plus steam‐distillable organic N compounds, respectively. The same traps averaged 21 and 3.3 kg/ha per yr, respectively, of organic N compounds that were not recovered by the 3‐min steam distillation procedure. Feedlot disturbances, such as manure mounding, increased volatilization of N compounds. Ammonia plus steam‐distillable organic N compounds trapped near a cattle pasture and cropland averaged 15 and 11 kg/ha per yr, respectively. Organic N compounds not recoverable by the 3‐min steam distillation were very low in the areas.Normally, steam distillation values represent only NH3; however, in this case, other N‐containing compounds were distilled over and titrated as NH3.