bluuebunny/crossref_metadata_2025_split huggingface dataset:
Volatilization of Oxides of Nitrogen from Nitrate‐Treated Black Spruce Raw Humus
Authors: Mahendrappa M. K. 
Published: July 2010

AbstractRaw humus sods covered with sphagnum (Sphagnum sp.) and feather (Pleurozium sp. and Hypnum sp.) mosses were treated with various forms of nitrate and then incubated in glass tanks with air passing over the sods. Oxides of nitrogen removed from the glass tanks by air were absorbed by two traps containing alkaline permanganate solution.Volatilization of oxides of nitrogen was observed in all cases. The quantities of oxides of nitrogen evolved decreased with the treatments in the order: Al(NO3)3 > Ca(NO3)2 > NH4NO3 > KNO3. In all the treatments, the proportion of added nitratenitrogen trapped as oxides was very small (average of 0.005%). The L and F layers of raw humus became more acid with nitrate treatments.
A Simple Apparatus for Obtaining Multiple Soil Atmosphere Samples from a Single Bore Hole
Authors: Jorgensen Jacques R. 
Published: July 2010

AbstractSoil atmosphere samples for analysis by gas chromatography can be obtained from reservoirs of Micro‐Por 100, a porous plastic tubing. These reservoirs have a large surface area through which diffusion can occur to obtain representative samples from specific soil areas. The apparatus is simple, low cost, and easily installed. In a loblolly pine (Pinus taeda L.) plantation, CO2 concentrates in the soil atmosphere increased from ambient at the surface to 1.2% at a depth of 60 cm.
A Two‐Phase Model for the Miscible Displacement of Reactive Solutes in Soils
Authors: Skopp J. , Warrick A. W. 
Published: July 2010

AbstractMiscible displacement is studied by considering the flow regime to be composed of separate mobile and stationary phases. Solute transfer through the mobile phase occurs only by convection, whereas adsorption or reaction by the soil matrix is diffusion limited and occurs normal to the mobile‐stationary interface. The model is unique in that a specific rate law is not assumed, but the solution is exact. Results are presented graphically as a function of two parameters which are compared with experimental results of other workers. The displacement of calcium by magnesium was more closely in agreement with theoretical predictions than was adsorption of picloram.
Measurement of the Transport Coefficients for Coupled Flow of Heat and Moisture in a Medium Sand
Authors: Jury W. A. , Miller E. E. 
Published: July 2010

AbstractA two‐column experiment was designed to measure the primary and cross‐coupling transport coefficients for the simultaneous flow of heat and moisture through a medium sand (Plainfield sand) in the liquid‐dominated regime of moisture flow. Values for the moisture diffusivity and thermal conductivity were obtained in the range from 20% to 90% of saturation. Thermal conductivity values fell within ± 7% of a curve calculated by the method of de Vries. In addition, the coefficient for transport of heat under gradients of moisture content was found to be zero within the accuracy of the experiment. The experiment was not sufficiently accurate to yield quantitative estimates of the coefficient for transport of moisture by temperature gradients, so a different experiment was performed to measure this coefficient indirectly. In this latter experiment the dependence of soil water potential upon temperature was found to be as much as five times larger than predicted by the surface tension model used by Philip and de Vries. These large values suggest that thermal effects should be considered for long‐term movement of soil moisture, and perhaps in certain circumstances for shorter term simulations in moist soil.
Models for Predicting Volatilization of Soil‐Incorporated Pesticides
Authors: Mayer R. , Letey J. , Farmer W. J. 
Published: July 2010

AbstractIn the absence of appreciable mass transfer due to water movement, diffusion processes in the soil account for the movement of pesticides to the soil surface to replace that lost by volatilization. Published solutions for heat flow equations have been applied to the volatilization of lindane and dieldrin from Gila silt loam for a number of different initial and boundary conditions. Predicted fluxes agreed well with experimental values. Five models have been proposed to describe various environmental conditions found in the field. Models I, II, and III assume pesticide concentration at the soil surface is maintained at zero concentration by air movement. Model IV assumes surface pesticide concentrations greater than zero with air turbulence sufficient to maintain zero pesticide concentration gradient in the air above the soil. Model V assumes a nonmoving air layer of various depths above the soil surface so that the pesticide concentration gradient in the air controls the rate of volatilization.
Effect of Salts and Salts Plus Nitrogen‐15‐Labeled Ammonium Chloride on Mineralization of Soil Nitrogen, Nitrification, and Immobilization
Authors: Westerman R. L. , Tucker T. C. 
Published: July 2010

AbstractThe effects of 0.0, 0.01, 0.1, and 1.0M concentrations of sodium, copper and calcium chloride salts added to a Pima clay loam with and without 15NH4Cl on mineralization of soil nitrogen, nitrification, and immobilization were measured over a 49‐day period. Dilute concentrations of salt, 15NH4Cl, and dilute salts plus 15NH4Cl stimulated mineralization of soil N. The “priming effect” was shown to be real and not just a simple exchange. Nitrification of native ammonium nitrogen and 15N‐labeled ammonium decreased with increasing concentrations of salt. High concentrations of copper and calcium chloride salts inhibited nitrification of 15N‐labeled ammonium more than sodium salts. Immobilization of 15NH4+‐N was decreased significantly by high concentrations of salt. Gaseous loss processes were decreased with increased salts.
Mechanism of Fire‐Induced Water Repellency in Soil
Authors: Savage S. M. 
Published: July 2010

AbstractOrganic soil litter collected under Manzanita (Arctostaphylos sp.) was burned over a sand column. Ottawa sand was used in the column. Temperatures were monitored by means of thermocouples in the litter layer, at the sand surface, and 1 cm deep in the sand. Two basic types of experiments were conducted. In one type the burned litter layer was allowed to remain on the sand until cool. In the other type, the burned litter layer was removed immediately after the burning period. This second type of experiment was conducted to prevent heat moving into the sand from the litter after burning. The results showed that the maximum temperatures reached in the sand, and the water repellency produced in the sand, were lower in the experiment where the burned litter layer was removed. The substances causing the water repellency in the 0 to 1‐cm depth were also more subject to extraction in the experiment where the litter layer was removed. The organic carbon content of the sand was quite similar in both experiments.When a recently ground quartz sand was used in the sand column, the substances causing water repellency were extractable. The fractionation of the extracted substances showed that the polarity of the molecules of the substances causing water repellency decreased with depth in the sand.Heating studies on three individual fractions indicated differences in volatility among the fractions. The chemistry of the substances in two fractions was altered by heating 20 min at 300C.The primary conclusions of the study were that the primary movement of organic substances from the burning litter layer into the underlying sand occurs during the fire. After the burning, heat moves down through the underlying sand “fixing” some of the more polar hydrophobic substances and revolatilizing the less polar substances, thereby broadening the water‐repellent layer. The temperature required for the “fixing” and the revolatilization appears to be greater than 250C.
Water Repellent Soil Mulch for Reducing Fertilizer Nutrient Leaching: II. Variables Governing the Effectiveness of a Siliconate Spray
Authors: Snyder G. H. , Ozaki H. Y. , Hayslip N. C. 
Published: July 2010

AbstractNitrogen and potassium leaching from a fertilizer band in sand soils was reduced by creating a mulch of water repellent soil over the band using a siliconate spray. Best results were obtained using a 1% siliconate spray in quantities sufficient to penetrate about 3 cm over a region 20 cm wide, on the flat surface of raised vegetable beds. Mulches created on peaked beds were ineffective in reducing leaching, probably due to erosion of the mulch. Sweet corn (Zea mays var. rugosa) yields were comparable to those obtained by protecting N and K with plastic mulch or by applying N and K in split applications.
Reactions among Calcium Carbonate, Carbon Dioxide, and Sodium Adsorbents
Authors: Cruz‐Romero G. , Coleman N. T. 
Published: July 2010

AbstractEquations for Na‐Ca ion exchange, CO2 and CaCO3 solubility and H2CO3 ionization were solved to describe and predict conditions existing in aqueous systems containing Na‐Ca adsorbent, CaCO3, CO2 and salt. Data from systems containing Dowex‐50 or hydrobiotite and having CEC‐H2O ratios approaching those occurring in soils were in reasonable agreement with the theory. For initially Na‐saturated systems, the pH varied from 7.5 at PCO2 = 0.1 atm to 10.5 at PCO2 near zero. Corresponding solution concentrations of NaHCO3·Na2CO3 were 55 and 16 meq/liter. Extremely low Ca concentrations were predicted and observed for high Na saturation and low CO2 pressure. The NaHCO3 concentration and pH varied predictably with initial Na saturation, PCO2, NaCl concentrations and relative adsorption affinity for Na and Ca. The demonstrated predictive ability may be useful in considering plant nutrition and soil reclamation problems.
Nitrogen Fixation by Blue‐Green Algae‐Lichen Crusts in the Great Basin Desert
Authors: Rychert R. C. , Skujiņš J. 
Published: July 2010

AbstractBlue‐green algae‐lichen crusts (Atriplex confertifolia, Eurotia lanata, and Artemisia tridentata sites) from the Great Basin Desert have a laboratory potential of fixing atmospheric nitrogen at rates up to 84 g of N ha‐1 hour‐1. Nitrogen fixation is optimal when the crust is moistened to ‐⅓ bar pressure, temperature is 19 to 23C, and the light intensity is 200 microeinsteins m‐2 sec‐1 with incandescent light. The acetylene reduction technique provided a useful assay to measure in situ nitrogen fixation which was correlated with potential values obtained in the laboratory under optimum conditions. Nitrogen fixation was found to be reduced under desert shrub canopies possibly due to allelopathic effects of the shrubs. Aqueous leaf extracts of desert shrubs significantly inhibited nitrogen fixation. Annual nitrogen fixed was estimated at 10 to 100 kg of N ha‐1 year‐1, depending upon microenvironmental conditions.
Residual Availability of Fertilizer Zinc
Authors: Boawn Louis C. 
Published: July 2010

AbstractResidual availability of fertilizer Zn was measured over a period of 5 years. Three variables were evaluated: Zn rate, free carbonates, and wheat straw residue. Zinc was applied at 0, 5.6, 11.2, 16.8, and 22.4 kg Zn/ha as ZnSO4 · H2O to a noncalcareous soil and a subsoil containing 4.3% lime. The residue variable was imposed by making three annual applications of wheat straw of 11.2 metric tons/ha. Measurements were made annually for extractable soil Zn and the utilization of Zn by sweet corn (Zea mays L., ‘Golden Cross Bantam’ hybrid).Percentagewise, conversion of fertilizer Zn to forms unextractable with 0.005M DTPA solution or 0.1N HCl was comparable for all rates of Zn application. There was a relatively rapid conversion of Zn to nonextractable forms during the first year, followed by a declining rate during the second and third year. The percentage of Zn extractable was essentially unchanged during the fourth and fifth years. At equilibrium, 85 to 90% of the fertilizer Zn was unextractable with 0.005M DTPA. In terms of a desirable Zn soil test of at least 0.8 ppm, a Zn application of 5.6 kg/ha was adequate for not more than 2 years, whereas 11.2 kg/ha was satisfactory for about 4 years. Neither extractable Zn nor Zn uptake by sweet corn indicated an adverse effect of free carbonates on residual availability. The effect of straw residue on residual availability of Zn was too minor to have significance in terms of fertilization practices.
Soil Classification and Land Sale Prices
Authors: Westin F. C. 
Published: July 2010

AbstractOver 4,800 verified land sales in South Dakota covering a period of 1967–1972 were located on the South Dakota Soil Association Map (scale 1:500,000). The first‐named soil in the association was classified in the U. S. Comprehensive Soil Classification System as to order, suborder, great group, subgroup, and family and related to the average price paid per acre. Using coefficient of variation as a measure of homogeneity of a classification category, the most homogeneous units in South Dakota at each level of classification are: Mollisols, Borolls, Haploborolls, Glossic Natrustolls, and Typic Argiustolls, fine, mixed, mesic. In general not all units at the same categorical level are defined with the same precision, but climatically defined units were more homogeneous. In comparing categories, two of seven suborders were more homogeneous than the most homogeneous order, three of ten great groups were more homogeneous than the most homogeneous suborder, nine of twenty‐seven subgroups were more homogeneous than the most homogeneous great group and two of thirty‐seven families were more homogeneous than the most homogeneous subgroup. Some precision was gained at each level, with the greatest gain in homogeneity appearing between order and suborder and the least between subgroup and family.
Calcite and Dolomite as Developmental Criteria in Young Soil Derived From Dolomitic Materials
Authors: Raad A. T. , Protz R. 
Published: July 2010

AbstractGenetic development of five weakly‐developed soils derived from dolomitic materials on five different glaciofluvial landforms was measured using indices. A calcite‐leaching index was calculated from the maximum calcite percentage below the solum/calcite percentage in soil horizons, and a dolomite‐weathering index to measure the degree of dolomite weathering was calculated from the dolomite content at the bottom of the solum/dolomite content in soil horizons. Both indices could be successfully used to measure genetic development of the five soils.
Physical and Chemical Properties of Soil Associated with Heavy Applications of Manure from Cattle Feedlots
Authors: Tiarks A. E. , Mazurak A. P. , Chesnin Leon 
Published: July 2010

AbstractCattle feedlot manure at 0, 90, 180, or 360 metric tons ha‐1 year‐1 was incorporated with Sharpsburg silty clay loam to depths of 10, 20, and 30 cm. For plots tilled 10‐cm deep, the heaviest applications increased the soil organic carbon content from 2 to 5% after 2 years. Particle density decreased from 2.63 to 2.50 g cm‐3 and bulk density decreased from 1.05 to 0.90 g cm‐3. Geometric mean diameter of water‐stable aggregates increased from 80 to 800 µm. Modulus of rupture of soil cores decreased from 0.60 to 0.08 bars. Hydraulic conductivity of undisturbed soil cores increased five fold. Manure applications reduced the hydraulic conductivity of disturbed soils sampled in the fall, but there was no effect on spring samples. The heaviest application of manure increased the electrical conductivity of the hydraulic conductivity leachates from 0.8 to 3.2 mmhos cm‐1 in the fall samples and from 0.4 to 1.2 mmhos cm‐1 in the spring samples. The effects of manure on soil properties decreased with increased depth of tillage.
Scanning Electron Microscopic and X‐ray Diffraction Study of Natural Weathering of Phlogopite Through Vermiculite to Saponite
Authors: Jackson M. L. , Sridhar K. 
Published: July 2010

AbstractThe weathering of phlogopite mica through vermiculite to saponite was demonstrated by X‐ray diffraction (XRD), quantitative mineralogical analysis and electronoscopic studies. The sand grain sized flakes showed highly crystalline (high intensities at 10Å with K saturation) minerals with a high degree of interstratification of mica‐vermiculite (12.4Å) and mica‐saponite (27.5Å) as well as discrete mica (10Å), vermiculite (14.9Å), and saponite (19.2Å) phases with Mg saturation and glycerol solvation. The saponite increased from 48% in the coarse clay to 70 to 72% in the fine and medium clay, while vermiculite decreased from 34% in the coarse clay to 12 to 17% in the fine and medium clay fractions. Scanning electron microscopy (SEM) of Li+‐saturated, electrical double‐layer‐swollen, freeze‐dried macroflakes of phlogopite revealed that saponite layers glided out from interstratified sites within the mica and folded at the mica‐vermiculite grain boundary. Authigenic mica needles were observed at some flake margins. A visual model of the formation of the expansible phyllosilicate clays, vermiculite and saponite, from mica is provided. Significant amounts of 137Cs+ fixation and 90Sr2+ trapping is to be expected in such systems.
A Simple, Inexpensive Apparatus for Simultaneous Collection of CO2 Evolved from Numerous Soils
Authors: Weaver R. W. 
Published: July 2010

AbstractAn apparatus was constructed from polyvinylchloride pipe and 30‐gauge disposable hypodermic needles for measurement of microbial activity in soil. The apparatus was compact, easy to construct, and adaptable to any number of samples. It has been used in our laboratory for simultaneous collection of CO2 from 250 soil samples.
Two‐Dimensional Water Infiltration from a Trench in Unsaturated Soils
Authors: Sawhney B. L. , Parlange J.‐Y. 
Published: July 2010

AbstractTwo‐dimensional infiltration of water from finite trenches was observed in three soil samples with different textures. The vertical infiltration is slowed by the lateral infiltration and the slowing is inversely proportional to the width of the trench. Furthermore, the vertical infiltration is about twice as fast as the lateral infiltration for all soils tesed. At the same relative distance from the trench, the soil was drier beside than below the trench. Our observations and interpretations agree with numerical simulations of Selim and Kirkham.
Limitations of the Instantaneous Profile Method for Field Measurement of Unsaturated Hydraulic Conductivity
Authors: Baker F. G. , Veneman P. L. M. , Bouma J. 
Published: July 2010

AbstractTechnical problems and soil profile characteristics may limit the applicability of the instantaneous profile method for field measurement of unsaturated hydraulic conductivities. A modified procedure for tensiometer installation and different methods for measuring moisture contents are discussed. Good agreement was found between moisture contents determined in situ with the neutron‐probe and those indirectly derived from moisture retention curves obtained from measurements of large core samples in a closed assembly. Sloping soils with slowly permeable horizons or with lateral water movement cannot be characterized adequately with this method. The use of the crust test procedure is recommended.
Growth, Mineral Composition and Seed Characteristics of Sesame as Affected by Nitrogen, Phosphorus, and Potassium Nutrition
Authors: Mitchell G. A. , Bingham F. T. , Yermanos D. M. 
Published: July 2010

AbstractSesame (Sesamum indicum L.) was grown to full maturity in three sand culture experiments with variable rates of N, P, and K. Tissue samples of the most recently matured leaves were taken at three stages of growth for chemical analysis and correlation with optimum yield and quality of the seed. Nutrient response curves were obtained along with approximate critical concentrations of N. P, and K.Samples taken at early flowering stage appeared to be best suited for use in establishing diagnostic criteria for the fertility requirements of sesame. The approximate critical concentrations of leaf NO3‐N, total P, and K were 0.51%, 0.52% and 2.4%, respectively.Increasing substrate levels of N, P, and K resulted in increases in all components of yield, while effects on seed quality were mixed. Increased levels of substrate N resulted in increased protein and decreased oil content. Potassium demonstrated a similar, although smaller, increase in protein and corresponding decrease in oil content. Phosphorus alone had no effect on protein or oil content.
A Leak‐Proof Sampling Port in Gas Analyses Studies
Authors: Smid A. E. , Beauchamp E. G. 
Published: July 2010

AbstractUnmodified rubber serum caps frequently used as sampling ports in gas analysis studies, failed to reseal after being punctured. Mean N2 leakage through puncture holes increased from 92 to 5,200 µliters/liter after 24 hours with one puncture and to 12,000 µliters/liter after an additional 24 hours with two puncture holes. Leak‐proof serum caps were devised by sealing silicone rubber septa into them with silicone rubber sealant.
Convergence and Validity of Time Expansion Solutions: A Comparison to Exact and Approximate Solutions
Authors: Parlange Jean‐Yves 
Published: July 2010

AbstractThe convergence of series solutions for the diffusion equation by time expansion is discussed quantitatively, on the basis of the linear and delta function solutions for a spherical cavity. It is shown that convergence alone is a poor criterion to justify the validity of the series solutions. A counter example, diffusion in the presence of an impervious wall, shows that the series may converge for all times but be entirely erroneous. By comparison an approximate integral technique yields a solution which agrees very well with the exact result.
Movement of Two Nonionic Surfactants in Wettable and Water‐Repellent Soils
Authors: Miller W. W. , Valoras N. , Letey J. 
Published: July 2010

AbstractThe movement of two nonionic surfactants (Soil Penetrant 3685, Aqua Gro) and their effect on water flow through wettable and water repellent soils was investigated. Surfactant concentrations of 0, 100, 500, 1,000, 1,600, and 3,200 ppm were applied to the top of vertical soil columns and the concentration of surfactant in the column effluent was measured. When the concentration of surfactant in the effluent did not significantly change with time, leaching of the columns with tap water was initiated. Both surfactants affected the hydraulic conductivity of the hydrophobic soil. The conductivity effects appeared to be related to aggregate destabilization, micelle formation, and particle migration, all of which caused a general decrease of flow rates with time. Adsorptive characteristics were found to affect greatly the shape of the effluent concentration versus time curve. Aqua Gro was shown to be more strongly adsorbed and less subject to leaching than was Soil Penetrant. A theoretical model was tested for its ability to qualitatively predict experimental effluent concentrations. Allowing for the spreading effects of dispersion, there was reasonable agreement between most experimental and theoretical values. The behavior and movement of surfactants in soils are a function of adsorption isotherms, mixing or dispersion due to flow velocities, solute concentration, and the physical and chemical characteristics of the porous medium.
Influence of Soil Microstructure on Water Characteristics of Selected Hawaiian Soils
Authors: Tsuji G. Y. , Watanabe R. T. , Sakai W. S. 
Published: July 2010

AbstractThe higher water‐holding capacity of Oxisols and Ultisols compared to that of the Vertisols and Inceptisols at 15 bars of suction is attributed to the presence of intra‐aggregate void spaces. Existence of such voids was verified with the aid of a scanning electron microscope. These voids are obvious in soils with kaolinitic and oxidic mineralogy but are not evident in soils of montmorillonitic or amorphous oxide composition.