bluuebunny/crossref_metadata_2025_split huggingface dataset:
Instrument for Automatic Recording of Rainfall and Pan Evaporation
Authors: Dixon R. M. , Degn R. M. 
Published: July 2010

AbstractAn economical combination rain gage and evaporation pan has been developed to provide a useful and dependable tool for soil and water management studies. Two simple direct‐acting float devices were designed to provide alternate methods for sensitive water level control. The simpler of these devices controlled water level to ± 0.22 mm, whereas the more complex device controlled the level to ± 0.01 mm. This instrument, with minor modification, can be used to automatically monitor water supplied to a ponded‐water infiltrometer or to a watertable lysimeter.
Lack of Evidence for ZnSiO3 in Soils
Authors: Norvell W. A. , Lindsay W. L. 
Published: July 2010

AbstractThe solubility constant for ZnSiO3 reported in the literature is based on invalid thermodynamic data. The agreement between Zn2+ concentrations in some soils and the invalid solubility constant for ZnSiO3 is coincidental. The presence of this compound in soils is very unlikely.
Analysis of Radial, Steady‐State Solution, and Solute Flow
Authors: Whisler Frank D. , Klute Arnold , Millington Richard J. 
Published: July 2010

AbstractRadial, steady‐state solution and solute flow to a root can be described as flow in a hollow cylinder. The analysis was broken into two parts: the solution flow and solute flow. The equation for the solution flow was solved analytically to obtain the soil solution tension distribution subject to fixed tensions at the inner and outer boundaries. From the tension distribution, the solution content distribution and solution flux were derived. The solution flux approaches a finite limit as the tension across the cylinder increases. The equation of flow for the solute was solved seminumerically, subject to fixed inner and outer concentration boundary conditions. The solute diffusion coefficient was assumed to be dependent upon the solution content. The convective part of the solute flow equation was dependent upon the solution flux. For most cases a good approximation would be the use of a constant solute diffusion coefficient, only dependent upon a mean solution content. As the solution flux increased, the solute concentration gradient increased at the root for both plant uptake or salt sieving of the solute.
Predicting Moisture Distributions in Rewetted Soils
Authors: Staple W. J. 
Published: July 2010

AbstractComputed and measured soil moisture distributions were compared during second and third cycles of infiltration and redistribution. In order to obtain acceptable agreement, the hydraulic conductivity had to be reduced to about one‐half of the value used in the first cycle for freshly packed soil. Two methods were adopted in obtaining adequate conductivity data. One method was to correct the conductivity by trial and error. The other was to measure the conductivity of the soil after it had been carried through an initial wetting and drying cycle.Hysteretic effects on rewetting were minimized by adding sufficient water to the partially dried soil to bring it back to its initial wetted condition. The independent domain theory was found satisfactory for providing wetting tension data during the brief infiltration period.Modified tension scanning curves for drying were used in second‐cycle computations for clay soil but the original curves for freshly packed columns were used for sand. Changes in scanning curves due to consolidation during the first drying cycle were not studied in detail. Successive rewetting was predicted satisfactorily only after the boundary condition for infiltration was changed from ponded water at the surface to an applied flux which was below the maximum infiltration rate.
Hydraulic Conductivity of an Isotropically Compressed Soil
Authors: Waldron L. J. , McMurdie J. L. , Vomocil J. A. 
Published: July 2010

AbstractHydraulic conductivities (K) of disturbed samples of Yolo loam were measured under isotropic confining pressures of from 0.1 to 3.2 kgm/cm2 in a triaxial test cell. Solutions of 1, 10, and 100 meq/liter of NaCl or CaCl2 produced marked differences in K, slight effects on compressibility, and no effect on soil dispersibility. The Kozeny‐Carman equation showed the same pattern of failure reported for clays and soils compressed anisotropically, i.e., K declined much more with decreasing porosity than predicted. Hypothetical K versus depth profiles calculated from K versus confining pressure data support a hypothesis that the K decreases with depth reported in texturally homogeneous soils may be attributable to overburden pressure.
Selenium Concentrations in Phosphorus Fertilizer Materials and Associated Uptake by Plants
Authors: Robbins C. W. , Carter D. L. 
Published: July 2010

AbstractThe Se concentration of seven Florida Land Pebble deposit phosphate rocks ranged from 0.7–7.0 ppm. The range was 1.4–178 ppm Se in seven samples from the western phosphate field. The Meade Peak phosphatic shale member of the Phosphoria formation contains more Se than rock from other phosphatic formations. Normal and concentrated superphosphates made from phosphatic rocks containing 100 ppm Se can be expected to contain about 60 and 40 ppm Se, respectively. Laboratory‐prepared concentrated superphosphate containing 23 ppm Se applied to an alkaline soil that normally produced alfalfa (Medicago sativa L.) low in Se at a rate of 156 ppm P increased Se concentration in alfalfa above the minimal requirements to protect livestock from white muscle disease. Concentrated superphosphate and single superphosphate prepared from phosphate rock containing 178 ppm Se and applied at a rate of 80 ppm P increased the Se concentration in alfalfa compared to the same amount of P applied as Se free concentrated superphosphate. Normal phosphate fertilizer practices can provide required Se for livestock provided the fertilizer is prepared from phosphate rock containing sufficient Se.
Use of the Leco Automatic 70‐Second Carbon Analyzer for Total Carbon Analysis of Soils
Authors: Tabatabai M. A. , Bremner J. M. 
Published: July 2010

AbstractStudies with surface and subsurface soils containing 0.3–34% organic carbon and with carbonate standards showed that the Leco automatic 70‐second carbon analyzer is satisfactory for determination of total carbon in soils. The Leco procedure evaluated involved high‐temperature combustion of soil with a high‐frequency induction furnace in a stream of purified oxygen and measurement of the carbon dioxide evolved by a thermal‐conductivity technique providing automatic readout of the carbon content of the sample.With all soils analyzed, the results of total carbon analysis by the Leco analyzer agreed closely with, and were as precise as, those obtained by the wet‐combustion method of Allison. Total carbon analysis of soils by the Leco analyzer is very simple and rapid, and a single operator can easily perform more than 150 analyses in a normal working day.
Effects of Lime upon Soil and Plant Manganese Levels in an Acid Soil
Authors: White R. P. 
Published: July 2010

Abstract‘Charlottetown 80’ and ‘Herta’ barley (Hordeum vulgare L.), ‘Charlevoix Red Kidney’ and ‘French Horticultural Bush’ beans (Phaseolus vulgaris, L.), and ‘Century’ peas (Pisum sativum L.) were planted in an acidic podzol soil (pH 4.7) after application of dolomitic limestoen at rates of 0, 375, 750, and 1,500 ppm. Soil and tissue samples obtained at bloom (beans and peas) and at heading and maturity (barley) indicated that soil Mn extracted with H2O and with neutral 1N NH4OAc as well as plant tissue Mn levels were markedly reduced by liming. Soil Mn levels were well correlated with pH and tissue Mn levels. Manganese toxicity symptoms were observed at tissue Mn levels of approximately 1,000 ppm in beans, 550 ppm in peans, and 200 ppm in barley.Charlevoix Red Kidney beans appeared a good indicator plant for Mn toxicity studies.
Influence of Rainfall Energy on Soil Loss and Infiltration Rates: II. Effect of Clod Size Distribution
Authors: Moldenhauer W. C. 
Published: July 2010

AbstractVarious clod size distributions were subjected to drop impact from a water drop applicator that delivered only 5‐mm drops. Clod beds were exposed to drops in 30‐ by 45‐cm pans. Point of “failure” of the clod bed was the accumulated energy when runoff began. Increasing the maximum clod size from 20 to 40 mm did not delay the time for runoff to begin on four silt loam to silty clay textured Iowa soil samples taken from continuous‐corn plots. Removing the < 2‐mm clods from the < 40‐mm sample had little effect on the time to runoff on continuous‐corn soils, but did increase the time to initial runoff on the silt loam soil from meadow. Removing the fraction < 8 mm from the < 40‐mm sample significantly increased the rainfall energy required to initiate runoff in all instances tested. Removing the fraction < 30 mm from the < 40‐mm sample nearly doubled the energy to initial runoff. However, clod beds of this 30‐ to 40‐mm size range from continuous corn did not withstand 0.18 joules cm‐2 of rainfall energy—the energy that occurs in western Iowa during the critical erosion period. Clod beds of the 30‐ to 40‐mm size range from continuous meadow, in contrast to clod beds from corn land, did withstand 0.18 joules cm‐2 of rainfall energy.
Arsenic Sorption by Soils
Authors: Jacobs L. W. , Syers J. K. , Keeney D. R. 
Published: July 2010

AbstractRetention of As against extraction by NH4OAc and Bray P‐1 reagents from Wisconsin soils equilibrated with As (0, 80, and 320 µg As/g added as Na2HAsO4) increased as the sesquioxide content increased. Similarly, the amount of As sorbed from solution increased as the free Fe2O3 content of the soils increased. Removal of amorphous Fe and Al components by treatment with oxalate eliminated or appreciably reduced the As sorption capacity of the soil. Amorphous Fe and Al components preferentially sorbed added As, as evidenced by the quantitative removal of added As from equilibrated soils by a single oxalate extraction and the essentially complete recovery of added As by NH4F and NaOH reagents during chemical fractionation. Because As released during extraction with NH4F is sorbed by soil components during the same extraction, NH4F‐As is underestimated unless a correction for resorption is made.
Occurrence of Amino Sugars in Extracellular Polysaccharides of the Genus Rhizobium and Some Observations Regarding Their Distribution in Somatic Components
Authors: Stevenson F. J. , Clapp C. E. , Molina J. A. E. 
Published: July 2010

AbstractChromatographic analysis of amino sugars in hydrolysates of some extracellular polysaccharide preparations from the genus Rhizobium revealed the occurrence of at least six amino sugars, of which three (glucosamine, galactosamine, and muramic acid) were positively identified. Not all of the amino sugars could be accounted for as structural components. Analysis of phenol‐extractable polysaccharides and proteins from intact cells showed that the various species of Rhizobium differed greatly in the kinds and amounts of amino sugars they synthesized.
Selective Dissolution Effects on Cation‐Exchange Capacity and Specific Surface of Some Tropical Soil Clays
Authors: Reneau R. B. , Fiskell J. G. A. 
Published: July 2010

AbstractSoil clays from eastern Panama and Wyoming bentonite changed in CEC and specific surface after sequential selective dissolution treatments. Dithionite‐citrate treatment of the clays resulted in a small increase in CEC at both pH 4.8 and 8.2 and a decrease in ethylene glycol retention. Free Fe2O3 ranged from 2% to 9% of the clay weight and substantial Al2O3 and SiO2 were also removed. Further treatment with hot 0.5N NaOH for 2 minutes again followed by citrate‐dithionite resulted in 20% to 40% loss in clay weight as SiO2 and lesser amounts of Al2O3 and Fe2O3. This treatment resulted in an increase of 7 meq in CEC at both pH ranges of soil clays and 20 meq for the bentonite. This was attributed to removal of interlayer material blocking exchange sites but there was a mean decrease in specific surface after this treatment. Clays treated with acid NH4F‐NH4Cl reagent for 10 minutes decreased sharply in specific surface and loss in clay weight was from 9% to 17% with SiO2 > Al2O3 > Fe2O3. After Na saturation and careful washing, Na replacement by 1N NH4OAc at pH 4.8 also removed high amounts of F and Al making CEC estimation impractical because NaF and/or Na3AlF6 was occluded in the process of Na saturation.
Effect of Gibberellic Acid in Fertilizer Packets on Growth of Cottonwood and Silver Maple
Authors: Rasson F. L. , Attoe O. J. , Boyle J. R. 
Published: July 2010

AbstractAddition of fertilizer packets containing 0.5% or 2% gibberellic acid to potted soil significantly increased height growth rates of cottonwood (Populus deltoides Marsh.) cuttings over that for packeted fertilizer alone. Plant weight increases were significantly higher for 0.5% gibberellic acid in the two‐packet treatment but not in the one‐packet treatment. Similar treatments with gibberellic acid in the field did not increase the height or diameter growth rates of cottonwood cuttings, and caused a significant decrease in growth rate of silver maple (Acer saccharinum L.) plantings for the two‐packet treatment with 0.5% gibberellic acid. The latter treatment reduced survival of this species to 60% from 95% for fertilizer alone.
Wind Erosion Equation: Computer Solution and Application
Authors: Skidmore E. L. , Fisher P. S. , Woodruff N. P. 
Published: July 2010

AbstractA wind‐erosion equation was programmed for computer solution. The relationships among variables are evaluated by the computer, and the general functional relationship between soil loss and independent variables, E = f(I', C', K', L', V), is solved stepwise to give potential average annual soil loss, E, in tons per acre per annum for specified conditions of erodibility, I'; roughness, K'; climatic factor, C'; equivalent field length, L'; and equivalent vegetative cover, V. The computer also can solve the equation to determine field conditions necessary to reduce potential erosion to a tolerable amount and can compare the effectiveness of various combinations of erosioncontrol treatments.
Nitric Oxide Volatilization from a Calcareous Soil and Model Aqueous Solutions
Authors: Steen W. C. , Stojanovic B. J. 
Published: July 2010

AbstractNitric oxide (NO) was volatilized from a laboratory aerobically incubated West Point loam (amended with different rates of urea or ammonium sulfate nitrogen) and from aqueous solutions containing ammonium and nitrate ions. Oxide loss from the soil was dependent upon the source and rate of nitrogen applied. Urea‐treated soil samples fertilized with 50, 100, 200, and 300 ppm of N lost 8.9, 17.8, 26.6, and 35.5 kg N/ha, respectively. Similar NO losses were observed from ammonium sulfate treatments, although these were substantially smaller. Also, losses of NO from sterile soil samples supplemented with ammonium and nitrite in concentrations equivalent to those occurring in the nonsterile soil at the peak of oxide volatilization were comparable to those of the nonsterile soil. Aqueous solutions containing nitrite and ammonium or urea nitrogen, with or without ferrous iron, humic acid, or lignin, which were buffered from pH 6.5 to pH 8.0, volatilized appreciable quantities of NO over the entire pH range tested. A decrease in methyl content of organic matter suggests that methyl nitrite may have been volatilized.
Nitrogen Fixation by Azotobacter paspali in Association with Bahiagrass (Paspalum notatum)
Authors: Kass Donald L. , Drosdoff Matthew , Alexander Martin 
Published: July 2010

AbstractEstablishment of Azotobacter paspali in the rhizosphere of Paspalum notatum grown in sand was consistently successful only with tetraploid varieties of the grass when glucose was added at the time of inoculation. Increases in the nitrogen content of the roots and in the total nitrogen content of the sandplant system were associated with successful Azotobacter colonization. These increases were significant at p < 0.05. There was no evidence for improved growth or for nitrogen gains in the above‐ground portions of the plants resulting from A. paspali establishment.Soils containing tetraploid P. notatum and A. paspali showed considerable nitrogen fixation, as measured by acetylene reduction. The nitrogen gains appeared to be a consequence of growth of photosynthetic microorganisms, since all fixation ceased when soils were incubated in the dark.
Canfield Silt Loam, a Fragiudalf: II. Micromorphology, Physical, and Chemical Properties
Authors: Miller F. P. , Wilding L. P. , Holowaychuk N. 
Published: July 2010

AbstractAlthough cutans comprise less than 1 to 2% of the total soil volume, they impart a disproportionately large influence to the soil as a medium for plant growth. This impact is maximized in the Canfield fragipan where rooting volumes are almost exclusively restricted to polygonal ped interfaces. Sampling these morphological units of fragipan horizons revealed twice as much total clay and three times as much < 0.2µ clay in the cutan segments of the horizon as in the matrix material or bulk horizon sample. Quantities of exchangeable cations were roughly proportional to the clay content, but the exchangeable K and Sr were nearly four and five times more concentrated, respectively, in the cutanic material, suggesting a possible mineralogical difference between the cutan and matrix or bulk mineralogy. X‐ray analysis indicated that the total clay fraction of the cutan material contained a greater proportion of nonexpandable and expandable 14Å and 17Å minerals, as well as interstratified components, when compared to the matrix and bulk clay fraction. Thin section analysis in conjunction with textural analysis and profile descriptions verified the presence of an argillic horizon above the fragipan and revealed the laminar morphology of the polygonal interface. From these data and observations the genetic sequence of the Canfield series is suggested.
The Mobility of Phosphorus, Potassium, and Calcium in a Forest Soil
Authors: Riekerk Hans 
Published: July 2010

AbstractA study was made to evaluate the movement of nutrient elements in rainwater percolating through a well‐drained Douglas‐fir (Pseudotsuga menziesii (Mirb.) Franco) forest soil. Radiotracers of phosphorus, potassium, and calcium, mixed with stable elements, were applied to the forest floor simulating rainwash input. Leachates from tension lysimeters were collected periodically and analyzed for nutrient and tracer contents. Trees and soil were sampled and analyzed at the end of the experimental period. The data showed large coefficients of variation typical of biological materials. Twenty percent of the labeled phosphorus leached through the forest floor during the year, representing 10% of the total phosphorus movement with rain water. Similarly, 8% of labeled potassium, representing 27% of leached potassium, and 2% of labeled calcium, representing 5% of leached calcium, moved annually with rain water through the forest floor. Comparable leaching values through the top 20 cm of mineral soil were a thousand times less, but with most of calcium and least of phosphorus released. These data were related to forest soil contents and indicated the elemental mobility to be dependent on the physico‐chemical properties of the forest soil, as well as the ionic properties and biological functions of the nutrient elements.
Phosphorus Diffusion in Soils: I. The Effect of Applied P, Clay Content, and Water Content
Authors: Mahtab Samuel K. , Godfrey Curtis L. , Swoboda Allen R. , Thomas Grant W. 
Published: July 2010

AbstractSelf‐diffusion coefficients of 32P (D) were measured in four soils: Miller clay, Norwood loam, and two textural intergrades of these two soils. Clay percentages of the soils were: Norwood, 12.5; Intergrade I, 25.0; Intergrade II, 36.0; and Miller, 59.0. The P rates used were 0, 25, 50, and 100 ppm. The moisture levels were 35, 60, and 100% of the water content between ⅓ and 15 bars tension. The D values averaged over all clay and P levels, increased from 10.25 × 10‐10 to 27.76 × 10‐10 cm2/sec as the water content increased from 35 to 100% of the available moisture. The average D value increased from 5.05 × 10‐10 for the Norwood to 26.59 × 10‐10 cm2/sec for the Miller soil. Likewise, D values increased with increasing rates of added P for all soils. The data indicated reduction in available water has less effect on diffusion rates of P in clay soils than in the lighter‐textured soils. It follows that in order to maintain a given rate of diffusion in a soil, as water content decreases, the amount of added P must be increased.
The Role of Sparingly Soluble Solids and Cation Exchange Reactions in Controlling Conditions in Soil Solutions
Authors: Turner R. C. , Singh S. Shah 
Published: July 2010

AbstractThe application of the principle of solubility products of relatively insoluble solids and exchange reactions to soil problems are discussed. The examples used concern the solubility products of hydroxyaluminum solids, whether thermodynamically stable or metastable, and exchange reactions with clay surfaces involving aluminum and calcium ions.
Effect of Added Salts on Nitrogen Mineralization in Three California Soils
Authors: Broadbent F. E. , Nakashima T. 
Published: July 2010

AbstractThe effect of ammonium sulfate, ammonium chloride, potassium chloride, calcium chloride, aluminum chloride, and copper sulfate added in amounts corresponding to 0.2, 2, and 20 atm concentration on mineralization of soil nitrogen in three soils was measured over a 30‐day period. Significant increases were produced by the ammonium salts which were labeled with 15N to allow distinction between added and soil nitrogen. In Aiken clay loam nitrogen mineralization was also increased by solutions of potassium chloride, calcium chloride, and aluminum chloride, but in Altamont clay loam and Mormon clay increases were not consistent. Copper sulfate depressed nitrogen mineralization in all soils. It was found that the quantity of organic nitrogen brought into solution was related to the concentration of the salt solution.
The Occurrence of 2‐Methoxy‐1,4‐Naphthoquinone in Caribbean Vertisols
Authors: Lambert E. N. , Seaforth C. E. , Ahmad N. 
Published: July 2010

AbstractAn orange colored pigment identified as 2‐methoxy‐1,4‐naphthoquinone was separated and identified from the dark colored 0 to 15‐cm layer of Caribbean Vertisols. Extraction of the pigment was carried out by shaking the soil (> 2 mm) in CHCl3 (1:2) and decanting the supernatant liquid from which the pigment was purified by column chromatography and crystallization from ethanol. Eight kilograms of soil yielded 69 mg of the pigment. Identification of the pigment was determined using a combination of techniques including solubility tests, elemental analyses, melting point, ultraviolet, infrared, NMR, and mass spectroscopy. To the authors' knowledge, the isolation described herein is the first for a nonchlorophyllic pigment occurring in a chemically uncombined form in a tropical soil.