bluuebunny/crossref_metadata_2025_split huggingface dataset:
Argixerolls on Late Pleistocene Surfaces in Northwestern Oregon
Authors: Gelderman F. W. , Parsons R. B. 
Published: July 2010

AbstractArgixerolls in the Yamhill Valley in Polk County, Oregon, have characteristics that are determined by the age, topography, and parent materials of three late Pleistocene geomorphic surfaces. The newly defined Bethel surface is in the highest topographic position. Four Willamette‐like pedons were sampled as representative of three topographic positions on the Senecal and Bethel surfaces. The Senecal surface is characterized by level and nearly level valley terraces and the Bethel surface by low, rounded hills that are graded to the level, intermediate Calapooyia surface. The soils of the upper slopes of the Bethel surface have characteristics of Ultic Argixerolls. Those on the nearly level Senecal and Calapooyia surfaces and the lower slopes of the Bethel surface have characteristics of Pachic Ultic Argixerolls. The soils on the level to depressional hill crests of the Bethel surface and level valley terraces of the Senecal surface have characteristics of Aquultic Argixerolls. Characterization of the soils emphasized similarities among them. Subgroup differences are due primarily to topographic position and are related to the stratigraphy of the region.
An Evaluation of Zonal Centrifugation as a Research Tool in Soil Science: II. Characterization of Soil Clays
Authors: Francis C. W. , Tamura Tsuneo 
Published: July 2010

AbstractData revealed little resolution in banding is gained in centrifuging for 40 compared to 17 hours in a conventional centrifuge (force field less than 623 × g). On the other hand, the resolution obtained by centrifuging in an ultracentrifuge is considerably better than that obtained in a conventional refrigerated centrifuge. The clay fraction from a Dodge silt loam banded into nine fractions after centrifuging at 15,000 rpm (38,500 × g) for 17 hours. Characterization of each band allowed a much more extensive evaluation as to the quantities of each specific clay mineral present than the conventional estimates presently being made by examining X‐ray diffractograms of the total clay fractions.
Measuring Chloride in Effluent Flowing from a Soil Column
Authors: Mansell R. S. , Elzeftawy Atef 
Published: July 2010

AbstractAn inexpensive flow cell and combination chloride electrode system is described for continuously recording the chloride concentration in effluent flowing from a soil column. The response was observed to be sufficiently fast for monitoring effluent at flow rates normally encountered in column studies of soils. Break‐through curves for three different volume “slugs” of chloride solution displaced through a column of glass beads were in close agreement with corresponding breakthrough curves obtained by argeniometric titration of aliquots collected from the same effluent.
Systematic and Random Errors in Dual Gamma Energy Soil Bulk Density and Water Content Measurements
Authors: Gardner Walter H. , Campbell Gaylon S. , Calissendorff C. 
Published: July 2010

AbstractSoil bulk density and water content may be obtained concurrently through measurement of the attenuation of gamma photons from two different gamma ray sources and simultaneous solution of the resulting attenuation equations. Errors in the soil bulk density and water content measurements result from random emission from the sources, random errors in attenuation coefficients and soil column thickness measurements, presence of a small, higher energy peak in the 241Am spectrum, and counting equipment dead time. Using gamma photons from 241Am at 0.060 Mev and from 137Cs at 0.662 Mev, attenuated in 10‐cm soil columns, the standard deviation in both water content and bulk density measurements is primarily due to random emission and is about 0.007 g/cm3 for 106 counts measured in air and about 0.005 g/cm3 for 2.5 × 106 counts. However, as larger counts are used the precision of measurement of column thickness and soil and water attenuation coefficients becomes limiting. If, by obtaining large counts, the variance due to random emission is reduced to the same magnitude as that associated with measurement of column thickness or attenuation coefficients, precision limit would be about 0.0035 g/cm3 at midrange values of water content and bulk density. At high count rates instrument dead time corrections are made to get accurate counts. Gamma rays scattered down from the small 0.103 Mev peak in the 241Am spectrum result in attenuation dependent attenuation coefficients for which appropriate corrections must be made. For narrow collimating slits the spatial resolution is only a little greater than slit thickness. Collimater and shielding requirements are shown.
Seepage Through Soil Bedding or a Hillside Due to a Steady Rainfall: II. Soil Surface of Arbitrary Shape
Authors: Selim M. Sami , Kirkham Don 
Published: July 2010

AbstractIn a companion paper (I), the authors presented a theoretical solution for the seepage of steady rainfall through soil bedding or a hillside, with constant slope soil surface. In the present work, the case of an arbitrarily shaped soil surface is investigated. Two different shapes for the soil surface are considered in detail. The first shape is taken as part of the boundary of an ellipse, and the second is an arbitrary shape that includes ponded water‐depressions. The depth of water standing in the ponded depressions and drainage furrows is taken into account. Flow nets, seepage velocities, and infiltration rates are determined. As in paper I, but now for the new conditions, the seepage patterns show that some of the rainwater seeps into the soil on the uphill part of the slope and then flows through the soil more or less parallel to the soil surface. The water then seeps upward out of the soil on the downhill part of the slope. In one example, the inward and then outward flow occurs three times. With an elliptical shaped water table, the upward seepage occurs over a smaller portion of the bedding than for rectilinear (constant slope) bedding. The in and out seepage of water may cause leaching of nutrients and other chemicals from the soil.
Solubility of Silica in Soils
Authors: Elgawhary S. M. , Lindsay W. L. 
Published: July 2010

AbstractA solubility diagram was developed that shows the activity of various ionic and molecular species of Si in equilibrium with amorphous silica as a function of pH. Below pH 8.0 only uncharged Si(OH)4 contributes significantly to total soluble Si.The solubility of Si was measured on two soils in which equilibrium was approached from both undersaturation and supersaturation over a 50‐day period. In this study, 0.02M CaCl2 was included in all suspensions during their equilibration to flocculate colloidal Si and preclude its inclusion as soluble Si. The acid Paxton soil supported approximately 19 ppm of Si in solution while the calcareous Ulysses soil supported 25 ppm. These levels are intermediate between the solubility of quartz (2.8 ppm Si) and amorphous silica (51 ppm Si) and lie very near the level predicted for equilibrium between kaolinite and montmorillonite based on Kittrick's thermodynamic calculations.
Volatility of Organochlorine Insecticides from Soil: I. Effect of Concentration, Temperature, Air Flow Rate, and Vapor Pressure
Authors: Farmer W. J. , Igue K. , Spencer W. F. , Martin J. P. 
Published: July 2010

AbstractThe volatilization of dieldrin from Gila silt loam as influenced by soil pesticide concentration was determined in the laboratory at two air flow rates at 20 and 30C. The influence of pesticide vapor pressure on volatilization was measured by comparing the volatilization from Gila silt loam of dieldrin with that of lindane and DDT. No net water movement to or from the soil occurred during any of the volatilization processes.The vapor density of the soil‐applied pesticide was the main factor controlling volatilization. The rate of volatilization of dieldrin from Gila silt loam increased with increasing soil pesticide concentration until the soil dieldrin concentration reached approximately 25 µg/g. This is the soil dieldrin concentration required to give a maximum saturation vapor density equivalent to that of the pure compound. An increase in temperature of 10C increased the rate of volatilization approximately fourfold. Increasing the rate of air movement over the soil surface from 0.005 to 0.018 mile/hour increased the rate of volatilization twofold. The order of rate of volatilization of three insecticides was: lindane > dieldrin > DDT. This is the same order for increasing vapor pressures of the three insecticides. The increase in rate of volatilization of the three insecticides was less than the increase in saturation vapor density of the pure compounds. This resulted because the concentrations of lindane and dieldrin in the soil rapidly decreased below that required to give a maximum vapor density of the pesticides. The maximum volatilization rates obtained represent potential losses of lindane, dieldrin, and DDT from soils of 202, 22, and 5 kg/ha/year, respectively. The volatilization rates decreased rapidly as soil pesticide concentration decreased. Extrapolation of the laboratory data to field situations suggests that the rate of volatilization could account for a significant proportion of these applied pesticides lost under normal field conditions.
Nitrogen Mineralization Potentials of Soils
Authors: Stanford George , Smith S. J. 
Published: July 2010

AbstractNet mineralization of N in 39 widely differing soils was determined over a 30‐week period at 35C, using incubation intervals of 2, 2, 4, 4, 4, 6, and 8 weeks. Mineral N was leached from the soils before the first incubation and following each of seven incubations by means of 0.01M CaCl2 and a minus‐N nutrient solution. Soil water contents were adjusted by applying suction (60 cm Hg), and losses of water during incubation under aerobic conditions were negligible. With most soils, cumulative net N mineralized was linearly related to the square root of time, t½. The pH of soils changed very little in the course of 30 weeks' incubation. Because of the generally consistent results, the data were employed in calculating the N mineralization potential, No, of each soil, based on the hypothesis that rate of N mineralization was proportional to the quantity of N comprising the mineralizable substrate. Values of No ranged from about 20 to over 300 ppm of air‐dry soil. The fraction of total N comprising No varied widely (5 to 40%) among soils. Mineralization rate constants did not differ significantly among most of the soils. The most reliable estimate of the rate constant, k was .054 ± .009 week‐1. The time required to mineralize one‐half of No, t½, was estimated to be 12.8 ± 2.2 weeks. Results suggest that the forms of organic N contributing to No were similar for most of the soils.
Wheat Response to Different Soil Water‐Aeration Conditions
Authors: Anaya M. G. , Stolzy L. H. 
Published: July 2010

AbstractA graphical yield surface was constructed for wheat (Triticum aestivum L.) grown on Yolo silt loam with 13 different soil water‐aeration combinations. The experiment was conducted in a growth chamber under controlled environmental conditions. Oxygen over the soil surface was maintained at different percent O2 concentrations from 0.9 to 21%. Various soil water regimes were obtained by irrigation at different soil suctions from 8 to 99 centibars (cbars). The highest grain yields were obtained in two treatments, one of 9.6% O2 watered at a soil suction of 15 cbars, and another treatment of 4.3% watered at 8 cbars. The lowest production was in the treatment of 0.9% O2 weatered at 99 cbars, and the difference between the highest and lowest yields was 347%. From the data, the regression equation for grain yield was: Y = 15.94 − 0.1324 X1 + 3.1813 X2 − 0.1297 X22, where Y = grain yield in g/pot, X1 = soil suction in cbars, and X2 = percent O2. The maximum predicted yield calculated from the equation is at a level of 12.0% of O2 irrigated at a soil suction of 8 cbars. However, the maximum production recorded was obtained at 9.6% O2.There was a high correlation coefficient (0.94) between water consumption and grain production. An inverse relationship existed between grain yield and protein content. The highest level of grain protein content (22.6%) was obtained in the lowest producing treatment, while the lowest level of grain protein content (16.5%) occurred in the highest producing treatment. The difference in grain protein content between treatments was 37%.
Adsorption Interactions of Monosilicic and Boric Acid on Hydrous Oxides of Iron and Aluminum
Authors: McPhail Malcolm , Page A. L. , Bingham F. T. 
Published: July 2010

AbstractReactions of monosilicic acid and boric acid with hydrous oxides of aluminum and iron were studied. Adsorption of B by hydrous iron oxides was satisfactorily described by the Langmuir equation over the range of equilibrium solution concentrations investigated (0–14mM). Adsorption by hydrous aluminum oxides conformed to the Langmuir equation at equilibrium solution concentrations less than 6mM B. Maximum adsorption of boric acid by aluminum hydrous oxides was found to occur at approximately pH 7.5. Aging freshly precipitated hydrous aluminum and iron oxides up to 12 hours markedly reduced B adsorption; beyond 12 hours the effects of aging diminished.Successive treatments with 1.4mM solutions of Si(OH)4 were applied to freshly precipitated aluminum‐ and ironhydrous oxides until an apparent saturation was attained. The adsorption of Si followed the Langmuir equation, with maximum adsorption of 2.96 and 2.67 millimoles of Si per gram of aluminum and iron hydrous oxide, respectively. Boric acid at concentrations of 1.85 and 18.5mM were applied to individual samples after each Si(OH)4 treatment. Aluminum‐ and iron‐Si complexes retained less B as the amount of adsorbed Si on these hydrous oxides increased.
Effect of Storage Conditions on Activities of Urease, Invertase, Amylase, and Dehydrogenase in Soil
Authors: Pancholy Sunil K. , Rice Elroy L. 
Published: July 2010

AbstractThere were no significant decreases in the activities of urease, invertase, and amylase after 30 days' storage of an Oklahoma mollisol at 4C. However, storage at room temperature (21C) was unsatisfactory. Significant loss in activity was noted in the case of dehydrogenase after 15 and 30 days of soil storage at both 4C and room temperature. Fresh soil was used for assay of dehydrogenase.
Dynamics of Ion Transport During Moisture Flow from a Douglas‐Fir Forest Floor
Authors: McColl J. G. 
Published: July 2010

AbstractThe dynamics of ion transport during periods of moisture flow from the forest floor was studied using automated equipment in a second‐growth Douglas‐fir (Pseudotsuga menziesii (Mirb.) Franco) forest in western Washington. This transport process was related to the environmental parameters of temperature in the forest floor, the duration of time before flow, and the amount of moisture flow. Seasonal climatic changes are related to the ion transport process, and changes in solution concentration during a few representative wetting cycles are also presented. The results provide a base for predicting possible effects of manipulating natural forest ecosystems. A warning is given of the possible effects of some common forest‐management practices.
Kinetics of Phosphate Adsorption by Calcium Carbonate and Ca‐Kaolinite
Authors: Kuo S. , Lotse E. G. 
Published: July 2010

AbstractThe objective of the present investigation was to elucidate the time‐dependence of phosphate adsorption by calcium carbonate and Ca‐kaolinite and to suggest a mechanism of adsorption. The phosphate adsorption by calcium carbonate and Ca‐kaolinite at low phosphate concentrations in solution could be described by Langmuir adsorption isotherms, indicating that a monolayer of phosphate is formed on the surface. The calculated maximum surface saturation was 25µg/g for calcium carbonate and 187µg/g for Ca‐kaolinite. A second‐order kinetic equation was developed which considers both the change in phosphate concentration in solution and the surface saturation of the adsorbent during the adsorption process. The rate constant of phosphate adsorption was about 30,000 times greater for calcium carbonate than for Ca‐kaolinite. About 80% of the phosphate adsorption by calcium carbonate was completed within 10 sec. The variation of the second‐order rate constant with phosphate concentration was different in the two systems. The rate constant decreased in the calcium carbonate‐phosphate system and increased in the Ca‐kaolinite‐phosphate system with increasing phosphate concentration. It was suggested that phosphate ions are adsorbed by displacing coordinated water molecules and/or coordinated anions.
Exchange Adsorption of Trace Quantities of Cadmium in Soils Treated with Chlorides of Aluminum, Calcium and Sodium
Authors: Lagerwerff J. V. , Brower D. L. 
Published: July 2010

AbstractThe exchange adsorption of Cd has been studied in Cecil sandy loam (clay fraction 45% kaolinite and 25% vermiculite), Winsum clay loam (clay fraction 80% illite), and Yolo silt loam (clay fraction 47% montmorillonite and 22% mica). Experimental variables were the major cations Al3+, Ca2+, and Na+, salt (chloride) levels (from 5 to 50 meq/liter), and the initial concentration of CdCl2 (from 22 to 170 µeq/liter). The exchange of Cd2+ in Al3+‐ and Ca2+‐treated soils was normal in that the adsorption was greater in the presence of Ca2+ than of Al3+, and decreased with increasing concentration of AlCl3 or CaCl2. In the Na+‐treated, alkalized soils, Cd2+ did not precipitate. The exchange was unusual because the adsorption of Cd2+ decreased as NaCl concentrations decreased. The same behavior was shown by 109Cd2+. At NaCl concentrations decreasing below 30 meq/liter, the adsorption of Ca2+ by Na+‐treated soils also decreased, as did the adsorption of Na+. The result was attributed to decreasing soil exchange capacity with decreasing NaCl concentration due to increased adsorption of products derived from alkaline corrosion of the soil matrix.
Measurement of the Diffusion Coefficient of Boron in Soil Using a Single Cell Technique
Authors: Sulaiman Wan , Kay B. D. 
Published: July 2010

AbstractThe porous system diffusion coefficient, Dp, of boron in a loam soil was measured by means of a single cell technique. Boron diffused from a semi‐infinite medium of uniform initial concentration to a sink of constant concentration which was separated from the soil by a dialysis membrane. A polyethylene glycol (PEG) 6,000 solution circulated through the sink and controlled the soil matric suction osmotically. The diffusive flux at the soil and membrane interface was treated as an evaporative process. The value of Dp was found to be 2.44 ± 0.17 × 10‐6 cm2/sec when the bulk density of the soil and the volumetric moisture content were 1.30 gm/cm3 and 0.31, respectively.The significance of the equilibria between absorbed and solution B on the diffusion rate of B was also studied. Addition to the soil of boric acid solutions of concentrations lower than 1 ppm resulted in a capacity factor and solution B concentration which were lower than the corresponding values when water containing no B was added. As a consequence, the quantity of B diffusing into the sink from the boron‐treated soil was less than that from the untreated soil.
Resistance of Sawdusts, Peats, and Bark to Decomposition in the Presence of Soil and Nutrient Solution
Authors: Maas E. F. , Adamson R. M. 
Published: July 2010

AbstractThe ability of sawdusts, peats, and bark to withstand decomposition when used as soil substitutes in greenhouse culture was determined for differing particle sizes, nutrient additions, and admixtures with soil by means of incubation in the laboratory over a 36‐month period. Particle size was not an important factor but the presence of soil greatly increased the rate of decomposition of bark, sawdusts, and sphagnum peats, which shows the necessity of avoiding contamination of these media by soil. The additions of a nutrient solution containing fairly low levels of N, P, and K increased the rate of decomposition greatly in red alder (Alnus rubra Bong.) sawdust, moderately in Douglas‐fir (Pseudotsuga menziesii (Mirb.) Franco) sawdust, but by only a small amount in Douglas‐fir bark, and decreased the rate of decomposition in the peats. The combination of soil and nutrient solution was particularly detrimental to alder and Douglas‐fir sawdusts but had less effect on Douglasfir bark. The addition of sand to Douglas‐fir and alder sawdusts did not increase their decomposition rates either with or without nutrient solution and its inclusion in a growing medium may be useful in facilitating the establishment of new transplants.
Prediction of Runoff and Erosion from Natural Rainfall Using a Rainfall Simulator
Authors: Young R. A. , Burwell R. E. 
Published: July 2010

AbstractField rainfall simulators have been used extensively for runoff and erosion studies. To more accurately interpret and apply the results of studies using simulated rainfall, it is necessary to know the relative effects of natural vs. simulated rainfall.A comparison was made of the soil and water losses from three natural storms and three simulated storms on cultivated fallow plots under similar rainfall and soil conditions. A rainulator was used to apply the simulated storms. Soil losses from the three simulated storms averaged 77% of those from the natural rainstorms. This compares closely, considering that the average EI value for the simulated storms was 78% of that for natural rainstorms. The runoff from the simulated storms compared quite closely to runoff from the natural storms.The study showed that, in general, the rainulator can be used to simulate rainfall for runoff and erosion research with confidence that the results will reflect the runoff and soil loss that would occur under similar conditions of natural rainfall.
Impact of Wetting on Microbial Respiration in Desert Soil
Authors: Macgregor A. N. 
Published: July 2010

AbstractWhen naturally air‐dried soil from the surface layer of the Sonoran Desert was brought into contact with water, there was an immediate release of gases. Carbon dioxide was identified as a major gas component and was released in amounts equivalent to 50µliter/g of dry soil. It was estimated that following rainfall the air‐layer above natural areas of desert may temporarily experience up to a ten‐fold increase in CO2‐concentration due solely to the above phenomenom.Wetted soil immediately proceeded to take up O2 at a rate equivalent to approximately 2.5µliter/g soil/hour over a 5‐hour incubation period. Soil treated only with water had a respiratory quotient of 0.63 and soil treated with 1.0M KCN a respiratory quotient of 0.54.
Water Movement in Undisturbed Swelling Clay Soil
Authors: Ritchie J. T. , Kissel D. E. , Burnett Earl 
Published: July 2010

AbstractHydraulic conductivities of Houston Black clay were measured in two field basins, in 73‐cm and 21‐cm diameter undisturbed cores, and in small cores prepared from sieved soil. Conductivities averaged about 2.5 cm/day for the field basins, about 0.3 cm/day for the undisturbed cores, and 0.1 cm/day for the disturbed soil cores. After steady‐state flow through the larger, undisturbed cores was obtained, water tagged with fluorescein was used to displace water in the cores until tagged water first appeared in the effluent. Examination of cross sections of the cores at different depths showed distinctive isolated areas where tagged water was present in the soil pores. The results imply that most water contained within structural units was inactive in the flow process compared to water flow around the units. The core walls apparently cut off some large pores associated with the soil structure, causing the decreased conductivities. Therefore, only field‐determined hydraulic conductivities are appropriate for use when predicting water flow in natural profiles of a swelling clay soil.