bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pedogenic and Geomorphic Relationships of Associated Aqualfs, Albolls, and Xerolls in Western Oregon
Authors: Parsons R. B. , Simonson G. H. , Balster C. A. 
Published: July 2010

AbstractThe distribution of Willamette, Woodburn, Amity, Concord, Holcomb, and Dayton soils is related to deposits and geomorphology of the main floor of the Willamette Valley. Claytextured alluvium was the parent material for the formation of Dayton, Concord, and Holcomb B horizons. Amity soils occur on low knolls where clay was not deposited. Willamette, Woodburn, and Holcomb soils have thick Al horizons partly as a product of overbank alluvial deposition along natural levees.Soil formation has resulted in organic accumulation, base eluviation, iron and manganese segregation into concretions, and argillic horizons. The soils contain one or more discontinuities and have not been derived from the weathering in place of “Willamette Silts” as previously reported. Chemical properties may reflect initial differences in the parent materials as well as subsequent soil development.
Detection of Saturated Interflow in Soils with Piezometers
Authors: Betson R. P. , Marius J. B. , Joyce R. T. 
Published: July 2010

AbstractPiezometers were used as saturated interflow detection devices in a study of partial watershed contribution to storm runoff. Saturated interflow was detected along the AB‐horizon interface in clay loam soils with shallow A horizons. The results of the study showed that at least under some soil conditions piezometers can be useful in determining the extent of saturated flow within a watershed. The occurrence of this flow will normally be confined to the shallow A‐horizon regions.
Effects of Organic Matter, Flooding Time, and Temperature on the Dissolution of Iron and Manganese from Soil in situ
Authors: Meek B. D. , MacKenzie A. J. , Grass L. B. 
Published: July 2010

AbstractA field plot study was conducted to determine the effects of added alfalfa, four flooding times, and two temperatures on EH (Oxidation‐reduction potential) and dissolution of iron and manganese from a silty clay soil. With no alfalfa added, flooding caused only a small decrease in EH at either temperature. The addition of alfalfa at the higher temperature resulted in a reduction in EH to −100 millivolts. Flooding time had no significant effect on EH until the third day, when the soils subjected to shorter flooding periods began to dry out. Flooding without organic matter increased the Mn2+ and Fe2+ concentrations in solution to maxima of only 3.7 and 2.1 ppm, respectively; while the combination of flooding, organic matter and high temperature increased the levels to 46 and 30 ppm. Flooding time had no effect on the dissolution of iron and manganese. The results of this study show the importance of temperature and organic matter on dissolution of iron and manganese and the relation between EH and soluble iron and manganese.
Determination of Organochlorine Insecticides in Soils and Waters
Authors: Pionke H. B. , Chesters G. 
Published: July 2010

AbstractPertinent references on the determination of organochloride insecticides in soil and water samples are reviewed. The particular methods are chosen because of their applicability to heterogeneous systems which often provide problems due to coextraction of indigenous components. The review is divided into three principal sections, i.e., extraction of organochlorine insecticides from soils and waters, cleanup of soil and water extracts, and analysis of purified soil and water extracts. Criteria used in evaluating extraction procedures were based on methods of equilibrating the insecticide with the soil sample and the control of possible insecticide losses through degradation and volatilization. In the section on cleanup procedures special attention is devoted to chromatographic methods, particularly column and thin‐layer chromatography. A large portion of the methods of final analysis of purified extracts is given over to gas‐liquid chromatographic techniques because of the preponderance of its use for insecticide determination. The gas‐liquid chromatographic methods are discussed on the basis of peak resolution, detection and measurement of the insecticides, and confirmation of their identity. Thin‐layer chromatographic, spectrophotometric, and other methods of determination of organochlorine insecticides in purified extracts are evaluated.
Cation Exchange Selectivity of Some Clay‐Sized Minerals and Soil Materials
Authors: Dolcater D. L. , Lotse E. G. , Syers J. K. , Jackson M. L. 
Published: July 2010

AbstractCation exchange selectivity (CES) values for montmorillonite, vermiculite, biotite, muscovite, and micaceous vermiculitic clays from Triangle and Harpster soils were determined by equilibration of each exchanger with a mixed, equinormal solution containing two competing cations. The cation affinity of Na‐saturated materials increased in the order K < Mg < Ca < Sr < Ba for montmorillonite and the soil clays, Mg < K < Ca < Sr < Ba for biotite, Mg < Ca < Sr < K < Ba for muscovite, and K < Ba < Sr < Ca < Mg for vermiculite. Sodium‐saturated micaceous vermiculite gave a K/Ca CES value of 0.2, whereas K‐saturated, dried vermiculite gave a K/Ca CES value of 0.4, indicating that the large number of interlayer wedge sites produced by the structural collapse in K‐saturated and dried vermiculite increased the selectivity for K ions. Potassium‐saturated and dried muscovite having a CEC equal to the similarly treated vermiculite gave a K/Ca CES value of 4.0 compared to 0.4 for the vermiculite, suggesting that layer charge density has a large influence upon K selectivity. The higher CES values for muscovite relative to those for biotite are explained by the smaller ditrigonal holes and the oblique orientation of hydroxyl groups in the muscovite structure.
Canopy Drip: A Source of Mobile Soil Organic Matter for Mobilization of Iron and Aluminum
Authors: Malcolm R. L. , McCracken R. J. 
Published: July 2010

AbstractLeaf leachates, simulating canopy drip during rainfall, were collected from southern red oak (Quercus falcata var. pagodaefoliz Ell.), live oak (Quercus virginiana Mill.), and longleaf pine (Pinus palustris Mill.), which were the principal tree species growing on soils with spodic horizons on the North Carolina Coastal Plain near Ft. Caswell. The samples of canopy drip were immediately chilled, filtered, and freeze‐dried. From the representative canopy drip sampled it was estimated that approximately 20 kg/ha per year of organic matter could be contributed to the soil from this source. In the laboratory, 139 to 1,480µ moles of Fe or 460 to 1,450µ moles of Al/g of freeze‐dried canopy drip were complexed from nitrate salt solutions depending on the concentration of the leachate solution. This amounts to a possible field mobilization of 0.15–1.53 and 0.22–0.70 kg/ha per year of Fe or Al, respectively.The active components responsible for Fe and Al mobilization were determined to be polyphenols, reducing sugars, and organic acids. Paper chromatograms and reducing‐sugar analyses indicated that the polyphenol and reducing‐sugar contributions to soil as canopy drip were approximately 1 kg and 4kg/ha per year, respectively. Organic acids were not quantitatively determined. Thus, canopy drip was shown to be an important source of mobile soil organic matter for podzolization and other pedogenic processes.
Morphology and Genesis of Some Grayish Claypan Soils of Oklahoma: II. Mineralogy and Genesis
Authors: Culver James R. , Gray Fenton 
Published: July 2010

AbstractMineralogical determinations and the suggested genesis of two proposed Nardin soils described in the first paper of this series are presented. Weathered and unweathered material of the clayey Wellington formation, Permian Redbeds were also studied to create two models showing that the proposed Nardin soils formed in either Permian Redbeds or Post‐Permian sediments. Cation‐exchange capacity, nonexchangeable K, ethylene glycol retention, and clay mineralogy based on X‐ray diffraction and differential thermal analysis were determined for the clay fraction.The clays are mainly illitic in the surface horizons and interstratified montmorillonite and illite in the argillic horizons. Coarse clays are largely illitic and fine clays, the dominant fraction, are largely montmorillonitic. It is concluded that the proposed Nardin and Waurika soils are developed from similar pedogenic processes from Post‐Permian sediments.
Hydraulic Conductivity Measurements with a Pressure Transducer
Authors: Overman A. R. , Peverly J. H. , Miller R. J. 
Published: July 2010

AbstractA rapid method for measuring hydraulic conductivities of materials in the range 10‐6 to 10‐10 cm/sec is described. By using a pressure transducer as part of a decreasing head permeameter, the time constant for measurement is reduced. Only small volume transfers of water are required. An example is discussed to illustrate the method.
Hydraulic Conductivity Related to Porosity and Swelling of Soil
Authors: Lagerwerff J. V. , Nakayama F. S. , Frere M. H. 
Published: July 2010

AbstractThe hydraulic conductivity factor in Darcy's equation for viscous flow is analyzed in terms of a modified Kozeny equation. The modifications include a correction for swelling, and the replacement of the cubic exponent of the porosity term by an exponent varying between 0 and 3. The choice depends on the interplay between surface and volume of soil pores, as determined by flocculation‐dispersion conditions. Swelling is calculated from the theory of the diffuse double layer. A theoretical analysis of experimental results on the hydraulic conductivity of two soils for percolants of variable concentration and composition showed that a single value for the electrical potential parameter sufficed to match theoretical with experimental data when the concentration of the percolant ranged from 10 to 100 meq/liter. Taking into account effects of pore size, pore density, effective porosity, and flow matrix on the hydraulic conductivity, the above has been explained in terms of expansive swelling of smaller pores at the expense of larger ones. A number of published studies have been analyzed in the light of the theory proposed. The relevance of the theory with regard to the alleged contrast between grain and pore models of soil has been considered.
Pore Size Distributions as Measured by the Mercury Intrusion Method and Their Use in Predicting Permeability
Authors: Klock G. O. , Boersma L. , DeBacker L. W. 
Published: July 2010

AbstractSeveral equations to predict the permeability of a porous medium from its pore size distribution have been proposed. Pore size distributions of soils are most commonly obtained from soil water release curves. In the present study pore size distributions were obtained by the mercury intrusion method and used in the calculation of intrinsic permeability. The calculated permeability values were compared with measured values for a range of pore size distributions.Permeabilities and pore size distributions of 54 systematically selected particle size classes of glass beads and sand were measured. Limits of the particle size classes ranged from 44–53 to 208–246 microns for the particle diameters. Millington and Quirk's equation was used to calculate the permeabilities. The calculated permeabilities agree with the measured values only when a correction factor is used. Some limitations of the mercury intrusion technique used to obtain pore size distributions are discussed.
Regularity of Interstratification as Affected by Charge Density in Layer Silicates
Authors: Sawhney B. L. 
Published: July 2010

AbstractSuccessively larger sorptions of Cs or K by most Ca‐saturated vermiculites collapsed their alternate layers, producing regularly interstratified mica‐vermiculite layer sequences. Additional sorption then collapsed the expanded layers within the interstratified mineral until the entire sample was collapsed to the mica structure. Sorption of Cs or K by Ca‐saturated montmorillonites, on the other hand, did not collapse their interlayers even when almost half of their exchange sites were occupied by Cs or K. Additional sorption then collapsed some layers producing random, not regular, interstratification.The ease of collapse of interlayers and the subsequent regularity of interstratification was related to the layer charge density of the mineral. The large charge density in vermiculite collapses the layers readily on Cs or K sorption. The collapse in one layer prevents the entry of these cations in the adjacent layer, producing regularly interstratified mica‐vermiculite layer sequences. The lack of collapse and the random interstratification in montmorillonites, on the other hand, is attributed to their small charge density.
Contribution of Metal‐Organic Complexing Agents to the Transport of Metals to Roots
Authors: Hodgson J. F. 
Published: July 2010

AbstractThe movement of many cations in soils can be influenced by the presence of synthetic chelates and soluble organic matter capable of forming metal‐organic complexes. To understand how these complexes may contribute to the nutrition of plants, a means is needed to interpret their thermodynamic properties and behavior in solution culture experiments in terms of their effect on roots growing in porous media such as soils. For this purpose, a theoretical model is proposed to describe the contribution of complexed species to the flux of nutrients to roots. The model is developed from considerations of diffusion in response to concentration gradients, mass flow of water to a simulated root, and chemical equilibria between complexing agents and competing cations, and is evaluated in terms of different boundary conditions. The model illustrates how metal‐complexing can contribute more to the nutrition of plants grown in a porous medium such as a soil than in nutrient solutions. It also shows how competing ions can have a potentially beneficial effect, as well as the obvious deleterious effect, on the contribution of complexing agents to the nutrition of plants.
Reactions of EDTA Complexes of Fe, Zn, Mn, and Cu with Soils
Authors: Norvell W. A. , Lindsay W. L. 
Published: July 2010

AbstractThe Fe, Zn, Cu, and Mn complexes and the Na salt of EDTA (ethylenediaminetetraacetic acid) were reacted with suspensions of acid, neutral, and calcareous soils. The initial concentration of chelate was 1 × 10‐4M or on a soil weight basis, 11.2, 13.1, 12.7, and 11.0 ppm of Fe, Zn, Cu, and Mn, respectively. Suspensions were aerated and shaken continuously for periods of 2 hours to 30 days. At the termination of each reaction period the pH of the suspensions was measured; following centrifugation, the supernatant solutions were analyzed for Fe, Zn, Cu, Mn, Ca, and Mg by atomic absorption spectrophotometry. The concentration of 14C‐labeled EDTA was determined by liquid scintillation.FeEDTA was stable in soil suspensions of pH 5.7 and 6.1, moderately stable at pH 6.75, and unstable at pH 7.3 and 7.85. This behavior was satisfactorily predicted using formation constants to describe equilibria of EDTA with Fe3+, Ca2+, and H+, with the assumption that the Fe3+ concentration was controlled by the solubility of amorphous iron(III) oxides. ZnEDTA and CuEDTA were most stable in suspensions near neutrality. In acid soils Cu and Zn were increasingly displaced by Fe as pH decreased while in calcareous soils these metals were displaced by Ca as pH increased. The loss of Mn from MnEDTA was very rapid in all soils and was essentially complete in less than one day from suspensions of pH 6.1 to 7.85.
Design and Performance of an Osmotic Tensiometer for Measuring Capillary Potential
Authors: Peck A. J. , Rabbidge R. M. 
Published: July 2010

AbstractAn osmotic tensiometer makes use of a confined aqueous solution, instead of pure free water, as the reference state in measuring soil‐water potentials. The membrane separating the confined solution from soil water is highly impermeable to the confined solute (polyethylene glycol, molecular weight 20,000), but exchange of much smaller molecules and ions occurs. Thus the capillary potential of soil‐water is measured unless soil solutes are excluded from the instrument by a vapour gap. The advantage of this instrument over conventional tensiometers is that measurements of capillary potential can be made throughout the range 0‐ to −15‐bar. Tests and observations show that osmotic tensiometers can be useful for measurements of capillary potential at depths greater than about 10 cm during the redistribution of soil water, and its uptake by plants. For accurate data, zero checks should be made when possible, and instrument temperature should be recorded to enable correction for its effect on each reading.
Effect of pH on Labile and Soluble Phosphate in Soils
Authors: Murrmann R. P. , Peech Michael 
Published: July 2010

AbstractA study was made of the effect of varying soil pH, by the addition of either HCl or Ca(OH)2, on the concentration of phosphate in 0.01M CaCl2 extract as well as the amount of labile phosphate, as determined by isotopic exchange, in both acid and limed soils to which liberal amounts of superphosphate had been applied over a long period of time but to which no phosphate had been applied for at least five years prior to sampling.For any given soil, the amount of labile phosphate in the soil and the concentration of phosphate in soil solution both reached a minimum value at about pH 5.5 and increased rapidly as the pH was increased or decreased from this value. When the value of pH + pH2PO4 was plotted against pH — ½pCa on the conventional calcium phosphate solubility diagram, the experimental points did not fall on the solubility isotherm of any known crystalline phosphate compound except when the pH was increased sufficiently to cause supersaturation with respect to octocalcium phosphate at which point octocalcium phosphate began to precipitate and the values of pH + pH2PO4 fell on the octocalcium phosphate solubility isotherm.The observed variation in the amount of soluble and labile phosphate with pH was found to be reversible. The addition of soluble phosphate to a soil also resulted in increases in the amounts of soluble and labile phosphate at any given pH. These findings would support the conclusion that the phosphate concentration in soil solution was determined by the amount of labile phosphate rather than by the solubility of some crystalline phosphate as the pH of the soil varied.
Environmental Factors Influencing the Sorption of Atmospheric Ammonia by Soils
Authors: Hanawalt Ronald B. 
Published: July 2010

AbstractUnder conditions of controlled temperature and atmospheric ammonia concentration, the sorption rate for atmospheric ammonia by six soils from New Jersey decreased only slightly over exposure periods up to 4 days and averaged 55 to 74 kg of NH3‐N/ha/year. The ammonia sorption rate for these soils increased rapidly with increasing ammonia concentration and moderately with increasing temperature. Calculated energies of activation suggest that sorbed ammonia is held by chemical bonds rather than by physical adsorption. Increasing the velocity of gas flow across the soil surface brings more ammonia into contact with the soil and thus enhances the sorption rate. Soils sorb significant amounts of ammonia from the atmosphere which under some environmental conditions may constitute a major mechanism in the transfer of nitrogen form the atmosphere to soils.
The Formation of Nitrate from Ammonium Nitrogen in Soils: IV. Use of the Delay and Maximum Rate Phases for Making Quantitative Predictions
Authors: Sabey B. R. , Frederick L. R. , Bartholomew W. V. 
Published: July 2010

AbstractEstimation of the amount of nitrate accumulation occurring in soil requires an understanding of the delay period and maximum rate of nitrate accumulation under defined environmental conditions. The actual maximum rates and delay periods of nitrate accumulation varied greatly between soils at several constant temperatures, whereas the relative maximum rates and delay periods were more nearly constant at any one temperature.An equation for estimating nitrate accumulation, which includes maximum rate and delay indexes, is suggested. Temperature‐rate and temperature‐delay indexes are presented for several soils. Values for different temperatures were predicted from actual values determined at only one temperature. The concept of delay periods and maximum rates should help evaluate the influence of other factors on nitrate accumulation.
Interdependence of Water Drop Energy and Clod Size on Infiltration and Clod Stability
Authors: Moldenhauer W. C. , Kemper W. D. 
Published: July 2010

AbstractThe decline of intake rates as successive increments of water drop energy were applied to various sizes of soil fragments of two Iowa and two Colorado soil types is presented. There was a wide spread between intake rate of the 8‐ to 20‐mm size range and those of all other sizes after the first increment (1.25 cm as 5‐mm drops) was applied. The intake rate of the 8‐ to 20‐mm size declined rapidly after the first or second increment. Final intake rates were not correlated with aggregate stability in this study. There was a negative correlation between clay content and final intake rates. Final intake rates after disintegration of large soil fragments in many cases were lower than when initial size ranges were small.
Proton Transfer Reactions at Clay Mineral Surfaces
Authors: Raman K. V. , Mortland M. M. 
Published: July 2010

AbstractThe transfer of protons from a protonated species to an uncharged molecule at the surface of clay minerals is an important process. NH+4, pyridinium, ethylammonium, methylammonium, and protonated‐urea montmorillonite and nontronite complexes were equilibrated over NH4OH, pyridine, methylamine, or with 3‐aminotriazole, and the status of the adsorbed molecule determined using infrared spectroscopy. Proton transfer or retention by a species depends on two factors: (i) the relative basicities of the two interacting compounds and (ii) the relative concentration or activities of the reactants and products. Indications were that the clay mineral altered the basicity of some compounds compared to the others. The relative order of basicity of the compounds studied here were found to be 3‐aminotriazole > ammonia > methylamine = ethyamine > pyridine > urea. Such proton transfer reactions as have been demonstrated here to occur in model clay‐organic complexes are undoubtedly processes of importance in natural systems.
pH‐Dependent Bonding of Potassium by a Spodosol
Authors: Bartlett R. J. , McIntosh J. L. 
Published: July 2010

AbstractA Spodosol Ap high in extractable Al and pH‐dependent CEC was limed to pH 6.3, producing deficiency of K in tomato seedlings. This was evidenced by lowered plant yields and concentrations of K in the tissue, compared with plants grown in acid samples of the soil. Soil chemical studies were undertaken to further examine the magnitude and mechanism of this phenomenon. Treatment of acid soil samples with increasing levels of CaCO3, CaSiO3, CaHPO4, or CaF2 markedly raised CEC along with pH and lowered activity of K and extractable Al.It was hypothesized that hydroxyl, phosphate, or fluoride ions neutralized positive charges on Al. This freed negatively charged exchange sites, and thereby raised CEC. With increased CEC, the percentage saturation of the exchange complex with K (and, therefore, availability of K) was decreased, compared with the untreated soil.