bluuebunny/crossref_metadata_2025_split huggingface dataset:
Interspersed Salt‐Affected and Unaffected Dryland Soils of the Lower Rio Grande Valley: II. Occurrence of Salinity in Relation to Infiltration Rates and Profile Characteristics
Authors: Wiegand C. L. , Lyles Leon , Carter D. L. 
Published: July 2010

AbstractThirteen variables including chemical and physical characteristics, topographical features, and water table depth measurements were statistically analyzed for differences between seven saline and adjacent nonsaline soil profiles of Lower Rio Grande Valley salt‐affected dryland soils. Cumulative intake and final intake rate, electrical conductivity of soil saturation extract, exchangeable sodium percentage, clay percentage, relative elevation, sand percentage, soil surface slope, and cation‐exchange capacity were the variables most consistently different between saline and nonsaline soils. Profile salinity and water intake were both significantly correlated with profile sand and clay content and with soil surface elevation, In addition water infiltration was a function of profile salinity. Consideration of the effects of clay content, ground surface elevation, and soil slope on the processes of runoff and infiltration lead to the conclusion that the observed salinity pattern is due to differential infiltration of rainfall which results in differences in leaching between saline and nonsaline areas.
Influence of Mulches on Runoff, Erosion, and Soil Moisture Depletion
Authors: Adams John E. 
Published: July 2010

AbstractA 3‐year study was conducted on Austin clay at Temple, Texas, to determine the effect of mulches of straw, gravel, and soil treated with dioctadecyl dimethyl ammonium chloride (DDAC) on runoff, erosion, and evaporation. Mulches were applied to 0.01‐acre plots on a 4% slope. Plots were fallowed 2 years and planted in grain sorghum (Sorghum vulgare) the third year. Runoff and erosion were greater from DDAC‐treated soil than from bare‐check soil. A surface cover of straw or gravel reduced runoff significantly and essentially eliminated erosion. Both the 2‐inch straw mulch and the bare DDAC‐treated soil reduced evaporation significantly from the 0‐ to 6‐inch depth during a hot, rainless 10‐day period. Straw, gravel, and DDAC‐treated soil mulches were about equally effective in evaporation control over periods of a month or more. During high rainfall periods, straw and gravel mulches increased infiltration and movement of excess water below 54 inches. The effect of chemical treatments on runoff and erosion should be considered in addition to their ability to reduce evaporation of soil moisture.
Response of Corn to Zinc as Affected by Nitrogen and Phosphorus Fertilizers
Authors: Terman G. L. , Allen S. E. , Bradford B. N. 
Published: July 2010

AbstractResponse of 2 successive crops of corn (Zea mays L.) forage to fine zinc sulfate mixed with 2 soils was measured in greenhouse pot experiments. Zinc sulfate was also incorporated into −9 + 16‐mesh granules of each of four phosphates, ammonium nitrate (AN), and ammonium sulfate (AS) fertilizers. Large amounts of fine dicalcium phosphate (DCP), concentrated superphosphate (CSP), monoammonium phosphate (MAP), and ammonium polyphosphate (APP) depressed the pH of Hartsells fine sandy loam (limed to pH 7.1) increasingly in the order listed. Depression in soil pH was closely related to response of corn to 6 and 12 mg of applied Zn per pot (2 and 4 ppm of Zn). In Nolichucky sandy clay loam (pH 7.3) and Hartsells soil limed heavily to pH 8.0, soil pH remained high and response to Zn with the APP, MAP, and CSP sources of P was similar and greater than with DCP. Forage yields and uptake of Zn were in the order: Zn mixed alone with the soil > Zn in AN or AS granules > Zn in phosphate granules > no applied Zn. Results with Zn in DCP granules were poorest. Reciprocal Relationships between concentrations of P and Zn in the corn were largely related to yield levels dependent on sufficiency of Zn.
Surface Tension and Water Contamination as Related to the Selection of Flow System Components
Authors: Topp G. C. 
Published: July 2010

AbstractThe changes in air‐water interfacial tensions caused by contaminants leached from 16 different materials were measured. This was an attempt to find noncontaminating components for a water flow system. A modification of the Wilhelmy slide method using a small volume of water was adopted to measure surface tensions. Only seven of the materials tested showed no measureable effect on the surface tension of the water. In addition to a reduced surface tension caused by the nine remaining materials there was an increased contact angle.
Porosity of Surface Soil Aggregates at Various Moisture Contents
Authors: Voorhees W. B. , Allmaras R. R. , Larson W. E. 
Published: July 2010

AbstractPorosity of individual surface soil aggregates at moisture contents ranging from saturation to air‐dry was determined by glass bead displacement. Measurements were made on aggregates having a diameter range from 0.5 to 10 mm at air‐dry moisture content and 2.0 to 10 mm at suctions ≤ 15 bars. The coefficient of variation for a determination of aggregate density (g cm‐3) ranged from 1 to 11% depending on diameter and moisture content. The major contributor to precision loss was heterogeneity of soil aggregates and not precision errors of the method.More than a 50% decrease in specific total pore volume (cm3 g‐1 of oven‐dry aggregate) upon desorption from saturation to air‐dry was found for three aggregate sizes each from a Chernozem and a Chestnut soil. In both soils, the percentage of pores having diameters > 29 µ increased as aggregate diameter increased. The volume fraction of air at a given moisture content increased as the diameter of aggregate increased. For all aggregate sizes, the volume fraction of air was ≥ 0.10 at 0.33 bar suction. The two soils exhibited different types of shrinkage curves.
The Importance of Illite as a Source of Potassium in Nebraska Soils
Authors: Abed Fawzi M. A. H. , Drew James V. 
Published: July 2010

AbstractThe uptake of nonexchangeable K by alfalfa (Medicago sativa L.) from samples of the surface layers of 8 Nebraska soils in a greenhouse experiment was more closely related to illite contributed to the soils by fine silt (r = 0.85) than to K‐bearing minerals contributed to the soils by other separates. Measurements of exchangeable K may underestimate the K‐supplying power of Nebraska soils for alfalfa when relatively large amounts of illite are contributed to the soils by fine silt.
Soil Phosphorus in South Dakota: II. Comparisons of Two Availability Tests with Inorganic Phosphorus Fractions Among Soil Series
Authors: Westin F. C. , Buntley G. J. 
Published: July 2010

AbstractLinear correlations are presented to compare the Bray and Olsen availability tests for soil phosphorus with four inorganic P fractions, clay content, and pH. The soils represent two great soil groups, several general profile textures, several parent materials, and three horizons.Although trends are indicated when general profile textures, parent materials, and horizons are considered separately, the clearest relationship between the availability tests and the four inorganic P fractions is with great soil group. When all Chernozem samples are considered together the Bray method gives higher positive correlations with the P fractions than the Olsen method. For Chestnut soils considered together the Olsen method gives higher positive correlations than the Bray method. Only one correlation among the Chernozem and Chestnut soils had a significant z value, however. Among the Chernozems when the r values of the textures, parent materials, and horizons are placed within their appropriate great soil group the Bray method has higher r values for 28 of the 31 positive correlations involved. Two of these had significantly higher r values as determined by the z test. When this procedure is followed for the Chestnuts the Olsen method has higher r values for 18 of the 29 positive correlations involved. Eleven of these correlations had significant z values.Clay content, pH, and Ca‐P generally were involved in more negative than positive correlations with the Olsen and Bray methods with the Chernozem and Chestnut soils. The difference in the behavior of the Bray and Olsen reagents between the Chernozem and Chestnut soils used in this study probably is related to climate and its influence on the degree of development of the two great soil groups involved.
Periodic Sedimentation and Soil Formation on an Alluvial‐Fan Piedmont in Southern New Mexico
Authors: Gile L. H. , Hawley J. W. 
Published: July 2010

AbstractGullies cut in alluvial‐fan piedmont deposits at the southern end of the Jornada del Muerto basin, New Mexico, reveal evidence of periodic sedimentation and soil formation. The gullies show a succession of four major sediments, each of which has a distinct soil, indicating that each period of sediment deposition was followed by a period of stability and soil formation. The two youngest sediments are restricted primarily to a broad drainageway position and have soils with relatively weak Bt and carbonate horizons. The next older sediment, buried in the broad drainageway, has a soil that has prominent textural B and carbonate horizons and that emerges at the land surface on either side of the drainageway. Towards the basin axis the sediments thin and there is mergence of the land‐surface soil with the oldest soil exposed in the gullies.The land‐surface soils overlie much older soils and in places are so thin that the buried soils must be considered in classification of the land‐surface soils. Gradual mergence zones of major sediments can conceal complexities greater than might be suggested by the generally smooth relief. Filling of channels in old sediments by younger sediments can cause prominent and abrupt soil changes not suggested by the smooth relief and uniform slope which crosses the soil boundaries. These phenomena are especially prevalent in and adjacent to drainageways and in areas of thinning of major sediments.
Selection of Characteristics for Numerical Classification of Soils
Authors: Sarkar P. K. , Bidwell O. W. , Marcus L. F. 
Published: July 2010

AbstractEighteen hundred and thirty product‐moment correlation coefficients were used to select characteristics from 61 given soil characteristics for numerical classification by electronic computer of 26 soils representing nine Orders of the new soil classification system (7th Approximation). Correlated characters were eliminated successively to 51, 40, 33, and 22 soil characteristics according to decreasing levels of the product‐moment correlation coefficient over soils.The correlation method is an objective procedure for eliminating members of groups of similar characteristics that might produce undue weighting in the numerical classification. It is superior to the heretofore used, and often criticized, method of selection based on subjective evaluation of the characteristics in soil classification.
Relation of Field‐Plot Runoff to Management and Physical Factors
Authors: Wischmeier W. H. 
Published: July 2010

AbstractThe detailed data for runoff analysis were assembled from nearly all erosion plot studies in the United States. Individual study averages of runoff from cropped plots have ranged from 3% to 36% of total precipitation, from 1 to 14 inches annually. Analyses indicted factor relations valuable for predicting water yields from cropland areas. Improved soil and crop management reduced average plot runoff about 40%. An inverse, curvilinear relation of runoff from growing and maturing corn (Zea mays L.) to crop yield was highly significant. At moderate fertility level, runoff reduction by contour tillage averaged slightly more than 15%. Under natural field conditions, runoff from row crops averaged a 10% increase for each additional percent slope. The relationship is expressed by: log W = 0.521 + .041s, where W is inches runoff and s is percent slope. Slope effect decreases as the surface becomes smooth and approaches zero for dense meadow or saturated soils. Effect of slope length on annual runoff was usually insignificant, but some transmission losses in the growing season and acquisitions in the dormant season were indicated. For 35 fallow soils with sand contents ranging from 4% to 66%, runoff was inversely proportional to organic matter content but was little affected by differences in particle size distribution.
Formation of Surface Coatings on Limestone Particles in Soils
Authors: Barrows H. L. , Simpson E. C. , Tu H. Y. 
Published: July 2010

AbstractHigh‐purity, 12‐ to 14‐mesh calcite limestone was mixed into acid soils containing relatively large amounts of either P, Al, or Mn. These mixtures were equilibrated for 12 months, undergoing wetting and partial drying cycles. Samples of each mixture were withdrawn periodically, and the limestone particles were recovered and examined.The surface of particles equilibrated in the high‐P soil developed a porous, white granular coating. Ater 7 months' equilibration, this coating varied from about 0.03 to 0.1 mm in thickness. It was concluded that the coating formed through the combined processes of weathering, recrystallization of calcite, and adsorption and/or precipitation of phosphates from the soil.
Effect of Sulfur Content of Straws on Rates of Decomposition and Plant Growth
Authors: Stewart B. A. , Porter L. K. , Viets F. G. 
Published: July 2010

AbstractSulfur deficiency must be considered in management of crop residues. With adequate N, P, and K, the decomposition rate of straw in soil low in sulfates depended on the S content of the straw. Incubation studies showed that unless S fertilizer is added, the S content of straw must exceed about 0.15% for a maximum rate of straw decomposition. Growth of winter wheat (Triticum aestivum L. ‘Wichita’), in the greenhouse, on a NPK‐fertilized soil was governed by the S content of straw mixed in the soil. Straws with < 0.15% S added to soil depressed wheat growth, but straws with a higher S content increased yields compared to the no‐straw treatment. When S was added along with N, P, and K, the S content of the straws had no effect on wheat growth.
A Technique for Continuous Monitoring of pH in Soil Systems
Authors: Papendick R. I. , Giordano P. M. 
Published: July 2010

AbstractA technique is described for continuous in situ measurement of pH in soil systems. The instrumentation consists of several minature combination electrodes connected through a stepping switch arrangement to an amplifier and a single‐point recorder. The unit is not subject to external disturbances and is applicable to situations where information concerning rate and degree of pH change is desired. A description of the system and an experimental example of its use are discussed.
Effect of Phosphorus on Some Physical Properties of Soils: II. Water Retention
Authors: Lutz J. F. , Pinto Rafael A. , Garcia‐Lagos Ricardo , Hilton H. Gill 
Published: July 2010

AbstractField studies showed that the use of phosphate fertilizers increased the amount of water present in the soil and facilitated tillage. Crop yields were closely related to the increased water content. Laboratory studies showed that P appreciably increased the water‐holding properties of soils. This was found to be directly related to the increase in the negative charge of the soil particles and the charge was closely related to the Al‐phosphate/Fe‐phosphate ratio. In general increases in water‐holding capacity were caused only by the larger rates of P, but in some instances 50 ppm P gave significant increases.
Determination and Isotope‐Ratio Analysis of Different Forms of Nitrogen in Soils: 2. A Simplified Procedure for Isotope‐Ratio Analysis of Soil Nitrogen
Authors: Cheng H. H. , Bremner J. M. 
Published: July 2010

AbstractA procedure for isotope‐ratio analysis of soil nitrogen is described which eliminates the ammonium distillation stage of the customary procedure. The nitrogen in the soil sample is converted to ammonium by Kjeldahl digestion without use of a catalyst, digestion being accomplished by heating the sample with sulfuric acid containing a high concentration of potassium sulfate (ca. 0.7g/ml of H2SO4). An aliquot of the digest is partially neutralized and treated in vacuo with alkaline hypobromiteiodide solution, and the N2 liberated by this treatment is analyzed by the mass spectrometer. This simplified procedure eliminates problems encountered in distillation and concentration of ammonium samples for N15 analysis and gives the same results as the customary procedure.
Nutrition of Corn (Zea mays L.) on a Calcareous Soil: III. Interaction of Zinc and Boron with Plant Population and the Relationship between Grain Yield and Leaf Composition
Authors: Fuehring H. D. 
Published: July 2010

AbstractA field experiment on corn with N, Zn, Mn, B and plant population as variables resulted in important positive interactions of plant population with applied Zn and with applied B indicating that limited Zn or B may be part of the reason for the severe yield decrease resulting from planting corn too thickly. High rates of applied Zn or B (90–180 kg/ha) were depressing to grain yield at low plant populations (40,000–53,333 plants/ha) but increased yields at high plant populations (80,000–93,333 plants/ha).The logarithm of the nitrate‐N concentration of the midrib of the sixth corn leaf at the silking stage was found to be closely correlated with grain yield up to about 1,000 ppm. The relationship between the total N concentration of the leaf blades and grain yield was less distinct. The phosphate‐P concentration of the midrib and the total P concentration of the leaf blades were significantly increased by increasing applications of N. The B concentration of midribs at the point of maximum yield varied from < 60 ppm at low plant population to 120 ppm at high plant population.
Clay‐Suspension Root‐Coating as Antidesiccants and Rhizospheric Nutrient Sources
Authors: Tabor C. A. , Davey C. B. 
Published: July 2010

AbstractSuspensions of kaolinitic and montmorillonitic clays were applied to roots of loblolly pine seedlings (Pinus taeda L.). Survival and growth effects of these clay‐suspension, root‐coatings were evaluated in a series of greenhouse experiments. Preplanting exposures to adverse atmospheric conditions of clay‐treated seedlings showed positive effects of the clays as antidesiccants. Clay coatings did not appreciably influence early growth under conditions of either high or low soil moisture stress. Seedlings from three known mother trees were grown in subirrigated sand cultures using Ca2+‐, Mg2+‐, K+‐, and Na+‐saturated clays as sources of the specific cation of each treatment. Seedling responses varied according to the clay used, the cation charge, the physiological role of the cation, and the genetic source of the seed. The higher cation exchange capacity (CEC) clay, montmorillonite, appeared to have a potential use as a rhizospheric nutrient source.
The Effect of Interactions of Salts and Clays on Unsaturated Water Flow
Authors: Christenson D. R. , Ferguson Hayden 
Published: July 2010

AbstractArtificial soils containing 17.6% dickite or montmorillonite clay minerals were treated to give exchangeable sodium percentages (ESP) of 5.0 and 20.3, and 5.5 and 13.6, respectively. Calcium chloride solutions of 0 or 0.015 meq/ml were applied to horizontal columns of the soils at 2 millibars tension. Deviation of the least squares line fit to data of quantity of water entry or distance of water movement vs. √time from 0 at time = 0 was taken as an indication of swelling. By this criteria, swelling was not a factor in water movement in dickite soil regardless of treatment but was a factor in water movement in montmorillonite soil. Use of 0.015NCaCl2 solution eliminated swelling in the 5.5 ESP montmorillonite soil but only reduced swelling in the 13.6 ESP soil.Water diffusivities were calculated from water content vs. distance curves. Use of 0.015N CaCl2 increased water diffusivity by a factor of at least 1.8 in all soils except montmorillonite ESP 13.6. This is probably associated with a reduced influence of the double layer on water movement as well as a change in pore geometry. By the method of calculations, use of 0.015N CaCl2 did not increase the diffusivity of montmorillonite ESP 13.6 over that of distilled water in spite of reduced swelling.Both water treatments resulted in some Na displacement from the first few centimeters of the columns and movement with the wetted front, but the quantity of Na movement was much greater with the CaCl2 solution.
Infiltration and Redistribution of Water in Vertical Columns of Loam Soil
Authors: Staple W. J. 
Published: July 2010

AbstractA numerical method was used to compute infiltration and redistribution of water in vertical columns of air‐dry Grenville silt loam. Hysteresis was taken into account in that drying tensions and hydraulic conductivities were interpolated from the appropriate scanning curves at each depth in the upper profile as redistribution continued into the dry soil below.Although the computations were not confirmed by independent experiments, results from related measurements showed that the distribution curves were of the right magnitude. The moisture contents reached in the drying zone after 24 to 72 hours' redistribution were in agreement with field capacity data.Computed moisture contents following redistribution in which hysteresis in both tension and conductivity were neglected differed considerably from the accepted hysteresis‐dependent values. Computed moisture contents in which hysteresis in conductivities only were neglected were closer to the accepted values when conductivities for wetting were used.
Surface Mobilities of Cations in Clays
Authors: Cremers A. E. , Laudelout H. 
Published: July 2010

AbstractThe effect of clay content and temperature on the electrica conductivity of two Na‐kao inite clays is investigated. The effect of the type of cation is examined in the Camp‐Berteau montmorillonite. The ionic surface mobilities (i.e. corrected for tortuosity effects) are calculated from the conductivity results. In Na‐kaolinite clays, surface mobility steadily increases with increasing cay content and attains about 40% of its solution value when clay content becomes about 70% by weight. In montmorillonite clays, surface mobility increases until clay content reaches about 35% by weight. Higher clay contents result in nearly constant values for the surface mobilities. In the series of alkali metal cations, surface mobilities increase from Cs+ (attains about 7% of its solution value at 55% clay) to Na+ (attains about 60% of its solution value at 55% clay); activation energies increase from Na+ (4.6 kcal/eq. at 55% clay) to Cs+ (5.6 kcal/eq at 55% clay).The ionic mobilities and activation energies can be correlated with the polarizabilities of the ions. It is suggested that the mobility of an ion along a clay surface is influenced more by crystallographic than by hydrated ionic volume. The large negative entropies of activation, calculated on the basis of the transition theory of rate processes, are interpreted in terms of hydration effects when an ion moves from one site to another.The agreement between self‐diffusion coefficients calculated from the electrical conductivity data and the values which may be found in the literature is very good. The applicability of the electrical conductivity method for investigating purely geometrical effects is discussed.