bluuebunny/crossref_metadata_2025_split huggingface dataset:
Soil Development in Recent Loess in the Matanuska Valley, Alaska
Authors: Rieger Samuel , Juve Robert L. 
Published: July 2010

AbstractMost well‐drained soils in the Matanuska Valley, Alaska, are developing in loess which is still being deposited. In deep loess close to the river floodplains that are its source, the soils are Regosols. Farther from the floodplains, in shallower loess, soils are Regosol‐Podzol intergrades, and, at still greater distances, they are Podzols. In the Regosols it is likely that the rate of accretion of loess exceeds the rate of horizon differentiation, but that in more distant areas with a lower rate of dust accumulation podzolization can proceed. There are indications of development of more distinct Podzols in both the Regosols and Regosol‐Podzol intergrades at an earlier time during a pause or reduction in rate of loess deposition, and there is evidence of incipient podzolization even in the Regosols at the present time.
Changes in the Clay Content, Calcium Carbonate Equivalent, and Calcium/Magnesium Ratio With Depth in Parent Materials of Soils Derived from Calcareous Till of Wisconsin Age
Authors: Wenner Kenneth A. , Holowaychuk N. , Schafer George M. 
Published: July 2010

AbstractSeveral depth samplings of parent materials (medium and moderately fine‐textured calcareous till) of each of 42 soil profiles were analyzed for clay content, CaCO3 equivalent and the quantities of Ca and Mg extractable with acid. As a rule the clay content decreased, and the CaCO3 equivalent content and the Ca/Mg ratio increased with depth in the upper 30 inches. Little or no variation in the respective values of these properties were observed below this depth. On basis of this work, samples for characterization of calcareous Wisconsin till materials should be collected at about 30 inches below the point of initial effervescence.
Tension Lysimeter Studies of Ion and Moisture Movement In Glacial Till and Coral Atoll Soils
Authors: Cole D. W. , Gessel S. P. , Held E. E. 
Published: July 2010

AbstractThe alundum tension lysimeter originally described was modified to allow installation in shallow soils and to facilitate collection of the leachate. The lysimeter plates were located at various depths in two contrasting soil types to study the ion content of the gravitational water. In addition, the influence of potassium (added as KCl) and nitrogen (added as (NH4)2SO4) on ion movement in the soil was studied.The ion content of the gravitational water changed markedly with soil type, depth, month of the year, and daily weather conditions. KCl and (NH4)2SO4 soil additions distinctly altered established soil dynamics, increasing movement of other soil elements including the radionuclide cesium137 from local fallout in 1954 on Rongelap Atoll soils.
A Double Tube Method for Measuring Hydraulic Conductivity of Soil in Situ above a Water Table
Authors: Bouwer Herman 
Published: July 2010

AbstractA method for measuring hydraulic conductivity of soil in situ above a water table is proposed. The method consists essentially of saturating a limited soil region below an auger hole in which two concentric tubes are placed. Hydraulic conductivity is calculated from measurements of the rate of change of the water level in the inner tube. The procedure is based on separating the flow between the tubes due to different water levels in the tubes from the total flow, which includes continued intake of water by the soil. Dimensionless parameters describing the flow component due to different water levels in the tubes are used in the calculation of the conductivity. These parameters were determined with a resistance network analog for three soil conditions, a uniform soil, a soil underlain by material of much lower conductivity, and a soil underlain by material of much higher conductivity. The depth to the material of different conductivity was taken as a variable. The method is illustrated with an example.
Influence of Low pO2 on Denitrification Processes and Products
Authors: Cady F. B. , Bartholomew W. V. 
Published: July 2010

AbstractSoil samples were incubated in a laboratory apparatus constructed to maintain constant partial pressures of oxygen. The effect of oxygen on “aerobic denitrification” was studied using N15‐tagged nitrate as a tracer material. Periodic analyses of the gaseous phase for oxygen and volatile nitrogen products were made on a mass spectrometer.A marked effect of oxygen on the rate of denitrification was exhibited. Losses after a given period of time with 7 to 8.5% oxygen by volume were approximately 20% of those at 4 to 5.7% and 4% of the losses at 1.0% to 1.6%. Both atmospheric oxygen and combined oxygen (nitrate) were utilized but the decreased gaseous loss of nitrogen at the higher levels of free oxygen disclosed a preferential use of the former. The amount of denitrification was closely associated with the level of the biological pressure or need of oxygen by the microbial population. Studies showed that only under conditions of high levels of carbonaceous material, an available nitrate supply, and an oxygen level of < 7% by volume would an appreciable amount of nitrate be reduced to gaseous forms.Nitrous oxide (N2O) was produced in the aerobic systems. Processes leading to gaseous losses of nitrogen in the presence of oxygen are discussed.
Response of Slash Pine to Colloidal Phosphate Fertilization
Authors: Pritchett W. L. , Swinford K. R. 
Published: July 2010

AbstractSingle applications of 0.5 to 2 tons of colloidal phosphate per acre, made at time of planting of slash pine (Pinus elliottii Engelm.), resulted in significant increases in tree growth over a 15‐year period. Results from replicated treatments, applied in 1945 near Gainesville and Welaka, Florida, indicate the commercial feasibility of fertilizing slash pine on acid “flatwood” soils.Neither tree survival nor wood density were significantly influenced by treatment. Average dbh and volume per merchantable trees were significantly greater in fertilized plots than in controls at both locations. The best treatment, considering treatment costs and timber value at the end of 15 years, was 0.5 ton of colloidal phosphate per acre applied in alternate 4‐foot strips and disked. Cordwood volumes in this treatment averaged 45% greater than in the untreated controls. Disking of the soil following the application of the phosphate material increased yields by about 3 cords per acre over yields obtained from phosphate alone.Extractable soil phosphorus and phosphorus content of needles from treated plots were higher than from control plots in the Gainesville experiment, but not in the Welaka experiment.
Effect of Tillage and Chemical Weed Control Practices on Soil Moisture Losses during the Fallow Period
Authors: Army T. J. , Wiese A. F. , Hanks R. J. 
Published: July 2010

AbstractMaintaining surface residues with stubble‐mulch tillage or chemical weed control significantly improved moisture conditions in the seed zone and markedly reduced surface crusting. Field and laboratory studies showed the drying rate of the 0‐ to ½‐inch portion of the soil profile was greatly reduced by plant residues on the soil surface. However, under field conditions soil moisture content below 2 inches was not materially increased by surface residues. The value of surface residues to increase moisture storage during the fallow period is discussed.
Hardpan Formation as Affected by Soil Moisture Loss
Authors: Gerard C. J. , Bloodworth M. E. , Burleson C. A. , Cowley W. R. 
Published: July 2010

AbstractA hypothesis based on laboratory investigations is proposed to explain hardpan conditions which occur in cultivated and virgin soils in the Lower Rio Grande Valley. Hardpan formation, as influenced by various soil and moisture treatments, was evaluated. The hardpans produced in the laboratory were not of the intensity of field hardpans but were characteristically similar to those found in the field. The penetrometer was particularly adapted for evaluating the influence of laboratory treatments on hardpan formation. Moisture loss by evaporation, after surface drying, appears to be an important factor in formation of hardpans. Laboratory findings indicate that tillage practices influence the rate of moisture loss which influences the depth and intensity of hardpan formation in certain soils.
Phosphorus and Aluminum Interactions in the Acidification of Soils
Authors: Pratt P. F. 
Published: July 2010

AbstractTwo soils containing relatively large amounts of basic Ca phosphates were acidified from neutrality to pH 3.5. Acidification produced high P solubility and because of this the A1 solubility remained < 1.0 ppm. for one soil and < 0.5 ppm. for the soil that had the greatest P solubility. Maximum P solubility was obtained at pH 4.2 with both soils. The high P solubility did not prevent accumulation of exchangeable A1 when the pH of the soil decreased to pH 3.5. During acidification the Ca phosphate fraction decreased about 50% in one soil and about 80% in the other. This decrease was largely balanced by an increase in NH4F‐extractable P or A1 phosphates. Acidification of these types of soils to pH values as low as 4.7 should produce little if any A1 toxicity.
Mathematical Description of Diffusion Processes in the Soil‐Plant System
Authors: Bouldin D. R. 
Published: July 2010

AbstractA mathematical treatment of the process of diffusion of ions through a porous medium to plant roots was derived by assuming the root acts as a cylindrical sink in an infinite, unstirred medium. The concentration dependence of the ion uptake process was coupled to diffusion in the medium by assuming transfer across the root surface was directly proportional to the concentration at the surface. The apporximate value of the proportionality constant for a limited range of concentration was derived from published results of uptake of phosphorus by excised roots in aerated, stirred phosphate solutions. Solutions of the diffusion equation were obtained for values of the diffusion coefficient from 10‐5 to 10‐9 cm.2 per sec.The results indicate flux per unit of root surface area may increase tenfold as the radius of the roots is decreased from 5 × 10‐2 cm. (approximate radius of root cylinder) to 7.5 × 10‐4 cm. (approximate radius of root hairs). Estimates of root hair dimensions and incidence obtained by microscopic examination of roots removed from greenhouse pots indicate that the total flux across root hair surfaces may be 3 to 10 times greater than the flux across the surface of the central root cylinder.
The Effect of Surface Soil Thickness on Corn Yields: II. As Determined by an Experiment Using Normal Surface Soil and Artificially‐Exposed Subsoil
Authors: Engelstad O. P. , Shrader W. D. 
Published: July 2010

AbstractIn an experiment involving corn yield responses to rates of nitrogen fertilizer on artificially exposed Marshall subsoil and normal surface soil, results were obtained in 1958 and 1959 which indicated that equal corn yields could be obtained on either surface or subsoil, provided that adequate nitrogen fertilizer was supplied. Maximum corn yields on both subsoil and normal soils were approximately 100 bushels per acre in 1958 and 125 bushels per acre in 1959. Yields on subsoil control plots (0 N) were 45 to 50 bushels per acre lower than from corresponding surface soil plots. A regression analysis of the data indicated that the production of maximum corn yields on subsoil required 35 more pounds of nitrogen per acre in 1958 and 52 more pounds of nitrogen per acre in 1959 than on normal soil. Nitrogen availability in the untreated surface soil exceeded that in the untreated subsoil by the equivalent of about 70 to 75 pounds of fertilizer nitrogen per acre per year.
Influence of Soil Bulk Density on Matric Potential
Authors: Box James E. , Taylor S. A. 
Published: July 2010

AbstractUnsaturated soil samples were compressed at three different moisture contents and temperatures to evaluate these interrelations with soil moisture matric potential. It was found that in all cases increasing bulk density, at constant moisture content and temperature, resulted in an increase in soil moisture matric potential. The moisture contents were such that all suctions were less than 1 bar. Temperatures of 10°, 25°, and 40°C. were studied. Compression was performed such that only mechanical pressure was applied to the soil; thus, air pressure within the soil sample remained constant and equal to that of the free atmosphere at all times. Mechanical pressures up to 27 bars were studied. Matric potential was measured with a null‐point tensiometer which rendered water flux between the soil and tensiometer systems negligible.An expression is proposed for the chemical potential of soil water which includes the influence of pressure, temperature, moisture content, bulk density, and composition, which includes implicitly all other variables. The term matric potential has been used to describe the residual chemical potential when pressure, temperature, and solute content were constant.It is felt that the proposed expression is more adequate for describing soil moisture matric potential than previous expressions. This expression provides a way for describing, at least in part, hysteresis of soil water that is associated with shrinking and swelling.
Mineral Fixation of Anhydrous NH3 by Air‐Dry Soils
Authors: Young J. L. , Cattani R. A. 
Published: July 2010

AbstractFixation of anhydrous NH3 by the mineral fraction of air‐dry samples from 65 horizons in 17 Pacific Northwest soils was investigated. Soils represented a wide variety of great soil groups. Nitrogen fixed from anhydrous NH3 was compared to (a) nitrogen fixed from aqua‐NH3, (b) indigenous fixed NH4+, and (c) NH3 retention of the whole soil (organic and mineral fraction).Mineral fixation of anhydrous NH3 varied greatly between soils and between horizons within individual profiles. Values ranged from 6 to 1015 ppm. N and appeared large enough to have possible practical significance in some soils. Though small in comparison to NH3 retention, mineral fixation of NH3 caused lattice collapse from 14Å. to 10Å. in some samples. Mineral fixation of anhydrous NH3 by air‐dry samples generally exceeded by severalfold the wet fixation of nitrogen from aqua ammonia.Ammonia retention ranged from 820 to 9190 ppm. N. Of the NH3 retained, from 1 to 8% in the surface and from 2 to 31% in the subsurface horizons was fixed by the mineral fraction.Indigenous fixed NH4+, found in all horizons, ranged from 17 to 125 ppm. N and comprised from 1 to 7.5% and from 2 to 42% of the total N in surface and subsurface horizons, respectively. From 11 to 89% and from 6 to 63% of the total mineral‐fixed NH3 in the surface and subsurface horizons, respectively, was previously satisfied by indigenous fixed NH4+.
Miscible Displacement: III. Theoretical Considerations
Authors: Nielsen D. R. , Biggar J. W. 
Published: July 2010

AbstractSeveral theoretical models are examined as to their usefulness in describing miscible displacement in porous materials. These descriptions are discussed for glass beads, sieved aggregates and soils at several water contents and for several flow velocities. It is shown that mathematical descriptions which do not include individual mechanisms are unsatisfactory. The mechanisms that must be considered are discussed with specific reference to experimental data.
Phosphate Diffusion to Plant Roots
Authors: Olsen S. R. , Kemper W. D. , Jackson R. D. 
Published: July 2010

AbstractDiffusion of phosphate appears to account for the observed rates of P uptake by corn roots. A diffusion equation was developed which takes into consideration the effect of plant removal of P on the relationship between solution P and solid phase P, in addition to the tortuosity and ionic interaction factors of the porous system. The equation has the same form as the heat flow equation, hence solutions of the latter can be applied to describe phosphate diffusion in soils.
Amendments to the Determination of “Uronic Acids” in Soils With Carbazole
Authors: Dormaar J. F. , Lynch D. L. 
Published: July 2010

AbstractThe release of soil “uronic acids” from four soil profiles was determined using 0.5N NaOH extracting solutions at 22° and 70°C, with an intermediate treatment using N HF‐HCl. The amounts of “uronic acids” released by alkali extractions were compared with the amounts released by either an HCl or H2SO4 hydrolyses of these soils. An exchange resin Amberlite IR‐120 (hydrogen form) and other means were investigated as to their efficiency in removing excessive amounts of iron from these soil solutions. A comparison of recoveries of pure galacturonic acid after hydrolysis with HCl and H2SO4 solutions was also made.Both the extraction and the hydrolytic procedures released large amounts of soil “uronic acids” from the four soils. However, in terms of time and simplicity the hydrolytic methods are to be preferred. Iron was most effectively removed from these soil solutions by an ion‐exchange resin (Amberlite IR‐120). A more rapid rate of decarboxylation of pure galacturonic acid occurred with HCl hydrolyses than similar hydrolyses with equivalent solutions of H2SO4. The content of “uronic acids” ranged from 1.2 to 3.9% of the organic matter in the four soil profiles.
Properties and Genesis of Soils Developed in Very Firm Till in Northeastern Iowa
Authors: Tyler L. E. , Riecken F. F. , Allen J. S. 
Published: July 2010

AbstractThe Cresco and closely associated soil series in northeastern Iowa are known to be less productive than soils formed from similar but less firm parent materials. Lack of information on the properties and genesis of these soils has been an obstacle to assessment of production potential and formulation of management recommendations. Principal soil genesis questions are the nature, origin, and age of the components of a two‐storied parent material and the degree to which each of two kinds of vegetation—trees and grass—have influenced morphology.This paper presents mainly basic morphological, physical, and chemical data on these soils as an aid to a better understanding of the soils themselves. Two profiles each of five soil series were studied, representing a moderately well‐drained biosequence, part of a prairie toposequence, and part of a transition forest‐prairie toposequence. In the prairie toposequence increasing wetness is associated with increasing base saturation. Base saturation relationships suggest that trees probably have occupied all but the poorly drained sites at some time during soil formation. The degree of textural B horizon development increases with increasing evidence of tree occupancy.
Prediction of the Concentration of Solutes in Soil Solutions For Soil Systems Containing Gypsum and Exchangeable Ca and Mg
Authors: Dutt Gordon R. 
Published: July 2010

AbstractThe equilibrium relationships for the solubility of CaSO4 in solution and the exchange of Ca++ and Mg++ between solution and the soil exchange complex may be used in conjunction with the Debye‐Hückel theory to predict the equilibrium concentrations of the ions in solution and ions adsorbed by the exchanger when distilled water or a solution of Ca++ and/or Mg++ salts is used to wet a Ca‐Mg‐soil which contains an excess of CaSO4.The equilibrium concentration of the solution and adsorbed ions have been calculated for mixtures of CaSO4, Yolo soils, containing different ratios of Ca++ to Mg++, and distilled water or 0.05 M MgCl2. The ionic concentration of the equilibrium solution was also determined experimentally for these same mixtures. The theoretical and measured concentrations of the ions in the equilibrium solution are compared.
Properties of Intergradient Chlorite‐Expansible Layer Silicates of Soils
Authors: Dixon J. B. , Jackson M. L. 
Published: July 2010

AbstractClay fractions of soils which contain intergrades of chlorite‐expansible 2:1 layer silicates from three states were studied. The citrate, fluoride, and 400° and 500°C. dehyroxylation‐NaOH methods of removing the interlayer materials were compared. The latter method removed more interlayer material than either of the other two methods as indicated by greater collapse of potassium‐saturated samples heated at various temperatures from 300° to 600°C. The greater effectiveness of the dehydroxylation—NaOH method compared to the other two methods was more evident for clays which contained larger amounts of interlayer material. The Al, Si, and Fe extracted by the dehydroxylation‐NaOH method were determined. The soil clays contained differing amounts of interlayer material, possibly allophanic in part, which varied between about 1 to 2% alumina (400°C. minus 110°C. extractions), corresponding to about 4 to 8% chlorite equivalent. The heat stability of the 14Å. peak increased with quantity of differentially soluble interlayer alumina. The cation‐exchange capacity of the Cookeville Ap horizon, 2 to 0.2µ fraction, increased from 38.0 me. to 61.2 me. per 100 g. while the corresponding increase in specific surface by the mono‐interlayer method was from 79 m.2 per g. to 148 m.2 per g. on dissolution of interlayers.
Rock Phosphate Transformations in Acid Soils
Authors: Chu C. R. , Moschler W. W. , Thomas G. W. 
Published: July 2010

AbstractA study of several Virginia soils revealed that rock phosphate breakdown into both Al‐ and Fe‐fractions decreased with increasing pH. The relationship between pH and Al‐phosphate was essentially the same for all soils studied, whereas the amount of Fe‐phosphate formed varied both with pH and soil free Fe content. From these relationships it appears that soils which respond well to rock phosphate applications are those with low pH and relatively low free Fe content.
Properties of Norfolk and Portsmouth Soils: Statistical Summarization and Influence on Corn Yields
Authors: Nelson L. A. , McCracken R. J. 
Published: July 2010

AbstractResults of chemical, mineralogical, and physical characterizations of 15 profiles each of the Norfolk and Portsmouth soils of the North Carolina Coastal Plain are reported. Purposes of the study were to: (a) determine central tendencies, ranges, and standard deviations of properties; and (b) weight those properties most promising as differentiating criteria for soil classification and characterization. Multiple linear regression techniques were used for this selection and weighting.A mineral index, derived from X‐ray diffraction pattern peaks for determining the relative proportions of intergradational vermiculite‐chlorite and kaolinite in the surface horizon clay fractions, was found to be a promising differentiating criterion. This is based on its relationship to corn yield response to added nitrogen and “maximum” corn yields (corn yield data were available from another study). Nitrate production was also found to be important in the regression studies. Drouth index and several other factors also occur in the multiple regression models.
Organic Matter Decomposition as Influenced by Oxygen Level and Flow Rate of Gases in the Constant Aeration Method
Authors: Parr J. F. , Reuszer H. W. 
Published: July 2010

AbstractLaboratory experiments were conducted to determine the rate of decomposition of wheat straw added to soil when continuous aeration was conducted with N2‐O2 gas mixtures containing 0, 0.5, 1.0, 2.5, 5.0, and 21% oxygen at flow rates of ⅛, ¼, ½, 1, and 2 liters per hour. Rates of decomposition and total decomposition were followed by determination of wheat straw carbon evolved as CO2.Total decomposition at all oxygen levels varied directly with aeration flow rate, except for the 0% level where an inverse relationship was observed.Microbial activity at the 21% oxygen level was greatly stimulated as flow rate increased from ⅛ through 2 liters per hour.A rapid increase in microbial activity occurred for the 0.5, 1.0, 2.5, and 5.0% oxygen levels as flow rate increased from ⅛ through ½ liters per hour, however, little increase in CO2 production was observed at higher flow rates.