bluuebunny/crossref_metadata_2025 huggingface dataset:
The Relationship of Soils to Molybdenum Toxicity in Cattle in Nevada
Authors: Kubota Joe , Lazar Victor A. , Langan L. N. , Beeson Kenneth C.
Published: July 2010

The relationship of soil factors associated with reported areas of Mo toxicity in cattle in seven agriculturally important valleys in Nevada was investigated. The level of Mo in the plant was selected as a measure of the soil factors, but Cu, Co, S and P were also determined in a large number of the forage samples.

The Mo content varied both with plant species and soils. Under Nevada conditions, alfalfa contains about two‐thirds as much Mo as does the clover, and sedge about one‐sixth as much where the Mo content are very high. Grasses and sedges with high levels of Mo commonly have correspondingly low levels of Cu, Co, or P.

The Mo levels were low in forage plants from the naturally well‐drained soils, and the levels of Cu, Co, S and P were considered to be adequate. Neither lithology nor physiography—alluvial fan or floodplain and terrace—is an important factor in well‐drained soils.

Both high water table and surface organic accumulation, common soil characteristics of poorly drained soils, affect the Mo levels in the plant. The magnitude of their effect varies with kind of parent material. The exceedingly high (300 ppm.) Mo levels were found in forage from some granitic alluvial fans.

The relationship of problem soil areas in Nevada to other Mo toxic areas is discussed.
Soil Development in Recent Loess in the Matanuska Valley, Alaska
Authors: Rieger Samuel , Juve Robert L.
Published: July 2010

Most 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

Several 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

The 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

A 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

Soil 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

Single 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

Maintaining 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

A 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

Two 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

A 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

In 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

Unsaturated 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

Fixation 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

Several 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

Diffusion 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

The 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

The 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

The 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

Clay 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

A 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

Results 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

Laboratory 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.
Estimation of Relative Value of Phosphate Rock and Superphosphate to Plants on Different Soils
Authors: Peaslee D. E. , Anderson C. A. , Burns G. R. , Black C. A.
Published: July 2010

The relative value of phosphate rock and superphosphate as sources of P for plants was evaluated by a test crop of sorghum on 19 soils in greenhouse cultures. The results were expressed as availability‐coefficient ratios. In the laboratory, three sets of measurements were made of P extractable from untreated soil, phosphate‐rock‐treated soil, and superphosphate‐treated soil: (1) P extracted by 0.025N HCl, 0.03N NH4F solution used in a ratio of 1 part of soil to 50 of solution by weight (method of Bray and Kurtz modified by Smith and Grava) after a 30‐day incubation period, (2) P extracted by an anion‐exchange resin without prior incubation, and (3) P extracted by an anion‐exchange resin after incubation for 30 days. Methods 2 and 3 were modifications of the method of Amer et al. The results were expressed as extractability‐coefficient ratios. The correlation between availability‐coefficient ratios and extractability‐coefficient ratios was highest with method 2 and lowest with method 1. The correlation between soil pH values and availability‐coefficient ratios was equally as close as that obtained between availability‐coefficient ratios and extractability‐coefficient ratios by method 2.
Measurements of Soil Moisture Diffusivity from Tension Plate Outflow Data
Authors: Bruce R. R. , Klute A.
Published: July 2010

A tension plate apparatus was designed for measuring volume of water outflow from samples of porous material as a function of time. Volume outflow was measured from samples of glass beads and sand at moisture tensions < 200 cm. of water. In the calculation of moisture diffusivity, published theory and procedures were used. The experimental volume outflow of water in the low moisture tension range of all porous materials studied did not agree with that predicted by presently developed theory. Agreement with theory apparently improved in the higher tension range. This disagreement of theory and experiment is not presently explainable. Values of moisture diffusivity were calculated by fitting the outflow data near (Q∞ ‐ Qt)/Q∞ equals 0.5. Although the accuracy of these moisture diffusivity values is uncertain, the general nature of the moisture diffusivity‐moisture tension relationship is shown.
Effects of Temperature and Moisture on Phosphorus Uptake from a Calcareous Saskatchewan Soil Treated with Several Pelleted Sources of Phosphorus
Authors: Beaton J. D. , Read D. W. L.
Published: July 2010

The effects of temperature, moisture, and P source during the initial soil‐fertilizer reaction period on subsequent P uptake by oats were investigated in a growth chamber. Phosphorus‐treated soil with moisture adjusted to four different tensions was stored at 5°, 16° and 27°C. for 1 week and for 7 weeks. Following these storage intervals, P uptake by oats was measured using a shortterm method.

Uptake of P from soil treated with mono‐ and diammonium phosphates was greater following reaction of the fertilizer with soil at 5°C. than at either 16 or 27°C. No significant differences between 16° and 27° were observed.

Moisture tension during the I‐week reaction period did not influence P uptake. Following the 7‐week reaction period, uptake of P was favored by the 2.0‐bar moisture tension treatment. It was lowest from soil reacted at 0.4 bar. Water‐soluble sources such as monocalcium phosphate and mono‐ and diammonium phosphates were the most sensitive to differences in moisture.

Availability of the source decreased in the order mono‐ammonium phosphate > diammonium phosphate > mono‐calcium phosphate > dicalcium phosphate dihydrate > anhydrous dicalcium phosphate > check.
The Leaching of Radiostrontium and Radiocesium Through Soils
Authors: Miller J. R. , Reitemeier R. F.
Published: July 2010

Sr90 and Cs137 are hazardous, long‐lived, nuclear fission products. Experiments were conducted in the greenhouse to determine their downward movement in soils under intensive leaching. The five soils (Norfolk, Hagerstown, Miami, Fort Collins, and Huntley series) selected for the investigation represented a wide range of soil properties, and the leaching treatments consisted of 30 inches and 300 inches of deionized water, 0.005N NaCl, and 0.005N CaCl2. There was little downward movement of Cs134 when the soils received the applications of deionized water, NaCl, or CaCl2. Radioactive assays of the soil columns showed that 96.6 to 100% of the Cs134 was in the surface two layers of the soil columns (average depth 1.4 inches) after 300 inches of leaching. In the leaching experiment with Sr, the CaCl2 produced the greatest movement of Sr89 and deionized water the least. The maximum distance Sr89 penetrated into the soils when leached with 30 inches of water was 1.3 inches, and with 300 inches of water the distance was 4.3 inches. In general, there was more movement of Sr89 in the Norfolk soil and least in the Huntley, with the other soils being intermediate.
Decay of Phosphate Fertilizer Reaction Products in an Acid Soil
Authors: Taylor A. W. , Gurney E. L. , Lehr J. R.
Published: July 2010

Complex iron and aluminum phosphates that may be formed by the reaction of concentrated acidic phosphate solutions with soil minerals were incubated in a moist acid soil for 10 months. Potassium ferric phosphate, H8KFe3(PO4)6·6H2O, and calcium ferric phosphate, H4CaFe2(PO4)4·5H2O, dissolved incongruently with release of part of their phosphate to the soil and formation of strengitic residues. Potassium taranakite, H6K3Al5 (PO4)8·18H2O, was more stable; it persisted throughout the incubation period and released smaller amounts of phosphate. Amorphous iron and aluminum phosphates also persisted throughout the incubation period, and their rates of dissolution appeared to be controlled by the rate of diffusion of their phosphate into the surrounding soil.
Metallo‐Organic Interactions Associated with Podzolization
Authors: Wright J. R. , Schnitzer M.
Published: July 2010

Leaching a calcareous soil parent material with a chelating agent caused the mobilization, transport, and redeposition of iron and aluminum resulting in the formation of a profile similar to those of certain podzolic soils. Under natural conditions, fulvic acid is considered to be the dominant ligand effecting the translocation of iron and aluminum in the podzolization process. Oxidative degradation studies and infrared and functional group analyses suggest that fulvic acid consists of an aromatic “nucleus” to which carboxyls, hydroxyls, and carbonyls are attached as the main functional groups. There is a strong possibility that on its path down the profile this fulvic acid forms, at first, water‐soluble multidentate chelates with metals such as iron and aluminum, etc., and that precipitation of these metallo‐organic complexes lower in the profile is effected by further reaction with the same metals and by extremely small amounts of ionic Ca2+ and/or Mg2+.
Effect of Soil Temperature on Corn Plant Development and Yield: II. Studies With Six Inbred Lines
Authors: Jones J. Benton , Mederski H. J.
Published: July 2010

Six inbred lines of corn were grown in the field under heated and normal soil conditions. Heating was accomplished using electric heating cables placed under the row. Heating had a marked effect upon the early growth rate and uptake of K, P, and Ca. Heating tended to shorten the period from emergence to silking. All of the inbred lines on the heated rows were shorter than those in the unheated rows at maturity. A differential yield (ear and fodder) response to soil heating was obtained among the inbreds. The differential response among the inbreds may explain why varying yield responses to soil heating which have been obtained in different investigations. Inbred lines may be unique plants to use for determining the factors related to the heat stimulus effect.
Soil Water Relations During Rain Infiltration: I. Theory
Authors: Rubin J. , Steinhardt R.
Published: July 2010

Soil moisture content changes and rates of water entry during rain infiltration into a semi‐infinite soil column are analyzed mathematically. The model considered involves, principally, the following assumptions: Darcy's and continuity equations are applicable; the soil's hydraulic conductivity and diffusivity are unique, positive, and monotonically increasing functions of soil moisture contents; rainfall entering the soil can be considered as a continuous body of water.

It is shown analytically that an incessant rain eventually results in ponding if and only if rain intensity, R, exceeds the saturated soil's hydraulic conductivity, K(wsat). For R ⩽ K(wsat) it is proven that as infiltration proceeds soil moisture contents at increasing depths tend to approach a constant level. At this level the soil's hydraulic conductivity equals the rain intensity. For R > K(wsat) it is indicated how to estimate the water uptake at incipient ponding.

A difference method for solving approximately the differential equation of the model in question is described. An illustrative numerical example of this method's results is presented.
Thermal Response of a Dry Surface to Shading Cycles of Short Period
Authors: Federer C. A. , Tanner C. B.
Published: July 2010

An experiment is presented on the thermal response of a nonevaporating surface (concrete) to square‐wave pulses of solar radiation with half‐periods ranging from 2 to 20 minutes. Heat flux into the concrete accounted for most of the net radiation but the data was inconsistent due to inadequate temperature sampling. The amplitude ratio of sensible heat to net radiation was 0.01 to 0.10, increasing with period, surface roughness, and wind velocity in agreement with Lettau's theory for sinusoidal net radiation. The amplitude ratio of surface temperature to net radiation (ΔT0/U0) increased from 1 to 6°C.ly.‐1 min. with increased period. The predicted decrease of ΔT0/U0 with increased roughness was approximately that of the experimental results; however, the observed decrease of the ratio with increased wind speed was greater than that predicted by theory.
A Suggested Mechanism for Sulfate Adsorption by Soils
Authors: Chang Monica L. , Thomas Grant W.
Published: July 2010

Equilibrium experiments with SO4‐Cl mixtures suggested that the quantity of anions held by a Cecil subsoil increases with time. Further experiments with K2SO4 confirmed the “time” effect on two Cecil subsoils and on Fe‐treated Georgia kaolinite. On the basis of the time effect and other observations made on SO42‐ adsorption a suggested mechanism is proposed. The mechanism envisions the replacement of OH‐ ions by SO42‐ and the hydrolysis of Al (in the presence of salt) to form H+ ions. Thus, the OH‐ ions are neutralized by H+ ions and anion adsorption proceeds apace.
The Effect of Gamma Radiation on the Availability of Nitrogen and Phosphorus in Soil
Authors: Eno Charles F. , Popenoe Hugh
Published: July 2010

The effects of several levels of gamma radiation ranging from 0 to 2,048 kiloroentgens on the availability of N and P from three fine sands and one peat soil were investigated. Nutrient release was measured chemically and by plant uptake. Irradiation increased the availability of N and P in soils evaluated immediately following irradiation, and after 2 weeks of incubation. This was shown by both chemical and plant uptake measurements. The release of N and P was closely related to soil type and more particularly to its organic matter content. In each case the soil containing the largest amount of organic matter showed the largest increase in extractable N and P after irradiation. An evaluation of the ammonium acetate (pH 4.8) extractable Ca, Mg, and K data indicated that there were no measurable changes in the availability of these elements that could be directly related to irradiation of the soil. The release of N and P, in many soils, will be a significant nutritional factor when plants are grown on irradiated soil.
The Reactions of Extracts from Maple and Oak Leaves with Iron and Zinc Compounds
Authors: Himes F. L. , Tejeira R. , Hayes M. H. B.
Published: July 2010

A water extract of oak leaves solubilized more iron from freshly precipitated ferric hydroxide at three pH's than the extract of maple leaves. The influence of the hydrogen‐saturated extracts on the equilibrium of iron and zinc between solution and sodium‐saturated Dowex resin were studied. More iron was solubilized when the extract was present than when absent, and the two extracts were similar. The influence of the extracts on equilibrium with zinc was very small. With paper strip electrophoresis, the iron moved with the extract toward the anode and the zinc moved toward the cathode. The higher molecular weight substances precipitated when the pH of the solution was raised to 5.2. The infrared spectra of the hydrogen‐saturated and iron‐saturated extracts indicate that carboxyl groups are involved in the reaction of iron with the organic constituents of the extract. Since zinc did not react with the constituents in the extract but iron did react, phenolic groups were probably involved in the reactions with iron.
Moisture Retention by Soil with Coarse Layers in the Profile
Authors: Miller D. E. , Bunger Wm. C.
Published: July 2010

The effects of coarse strata on the moisture retention characteristics of soil profiles were evaluated. A sandy loam soil was underlain at various depths by sand or gravel and the moisture status of the soil was observed for 2 months following a heavy irrigation.

The moisture retained by soil underlain by sand or gravel was much greater than in similar depths of a uniform soil. The moisture content of the soil above a layer increased as the layer was approached. The moisture content of the soil underlain by sand or gravel changed very little after the first few days following irrigation whereas in the uniform soil moisture moved downward throughout the observation period.

The moisture retention characteristics of the profiles were roughly estimated from laboratory measurements of unsaturated conductivities of the sand and gravel and from a moisture characteristic curve of the soil.
A New Calcium Aluminum Phosphate, CaAlH(PO4)2·6H2O
Authors: Lehr James R. , Frazier A. William , Smith J. P.
Published: July 2010

Descriptions are given of the optical and morphological properties of CaAlH(PO4)2·6H2O, one of five new acidic calcium aluminum phosphates that may be formed by reaction of phosphatic fertilizers with soil minerals. The new salt has a striking resemblance to CaHPO4·2H2O in its morphological and optical properties, but differs markedly in its X‐ray powder diffraction pattern.
The Influence of Fluoride, Temperature, Calcium, and Alcohol on the Reaction of Cobalt With Montmorillonite
Authors: Hodgson J. F. , Geering H. R. , Fellows Martha
Published: July 2010

Pretreatment of montmorillonite with F interferes with the adsorption of Co by montmorillonite. Since the effect is reversible with base, the F is thought to replace surface hydroxyl groups that serve as the adsorption sites for Co. The Co reaction with these sites increases with temperature, indicating that the reaction is endothermic. Therefore, either heat is required to form the Co‐to‐surface bond or the cation is replacing more strongly bound surface hydrogens such as those associated with the hydroxyls mentioned above. While certain other heavy metal cations were previously shown to exchange with adsorbed Co, Ca is found to have no effect on the reaction, except to alter the activity coefficient of Co in solution. This is interpreted as indicating the absence of any charge associated with the bonding site. Alcohol is found to enhance the reaction of Co with montmorillonite in contrast to what would be expected if hydrolysis played a role in the reaction.
Precipitation of Phosphate from Calcium Phosphate Solutions by Iron Oxide and Aluminum Hydroxide
Authors: Taylor A. W. , Gurney E. L. , Moreno E. C.
Published: July 2010

Aluminum hydroxide is the principal reagent in the precipitation of phosphate from fertilizers in acid soils. Iron oxide is much less reactive unless it is very finely divided. In cold phosphate solutions, clay minerals are stable in comparison with hydrated iron and aluminum oxides. The amounts of dicalcium phosphate, calcium aluminum phosphate, and amorphous aluminum phosphate that are precipitated when gibbsite dissolves in potassium‐free acidic calcium phosphate solutions depend upon the rate of dilution of the solution. Amorphous ferric phosphate and calcium ferric phosphate are formed during the dissolution of goethite, but, unless the soil contains a large amount of reactive iron oxide, most of the phosphate will be precipated as aluminum compounds.
Nutrition of Corn on a Calcareous Soil: I, Interrelationships of N, P, K, Mg, and S on the Growth and Composition
Authors: Soofi G. S. , Fuehring H. D.
Published: July 2010

A factorial experiment was carried out with irrigated corn grown on a calcareous soil to determine the effect of N, P, K, Mg, and S, both singly and in combination, on the production of grain and stover, and on the composition of the leaves. Multiple regression equations in quadratic logarithmic form were developed in order to elaborate the effects.

The soil used was inherently fertile and the first order effect of the nutrients was very small for grain and stover yield. The interaction of Mg and S was significantly positive in effect on grain yield. If application of either Mg or S was high, there was a large positive response to the other, while if application of either Mg or S was low, there was a large negative response to the other. However, for yield of stover the Mg‐S interaction was significant and negative or opposite in effect. The contrasting effect between grain and stover yields was further indicated by the interactions between the three anion nutrients, N, P, and S, which were all negative for grain production and all positive for stover production. The interactions of K and Mg on stover production were opposite in effect. The K‐S, K‐P, and K‐N interactions were positive while the Mg‐S, Mg‐P, and Mg‐N interactions were negative; the elemental composition was affected to a considerable extent by various interactions as well as by the first order effects of the elements involved.
Surface Area Determination of Soils by Adsorption of Ethylene Glycol Vapor
Authors: Morin R. E. , Jacobs H. S.
Published: July 2010

Surface area was determined from ethylene glycol (EG) retained by vapor‐wetted soils and clays in equilibrium with EG‐bentonite or ‐resin buffers. The method compared favorably with previously proposed equilibrium and nonequilibrium methods.

Only small excesses of EG are adsorbed by vapor‐wetted samples. This reduces equilibration time, extends buffer life, and eliminates hysteresis on the drying curve at the monolayer point. The determination is independent of sample size; moderate temperature fluctuations; or moisture present in EG, buffer, or sample. Use of redistilled EG is not necessary.

The monolayer end point can be determined using a series of EG‐bentonite buffers independently of other methods. Buffers containing more than a monolayer of EG can be used if suitable corrections are made.
Formation of Clay Mineral‐Rhizobial Polysaccharide Gels and Their Measurement by Torque Viscometry
Authors: Davis R. J. , Heald W. R.
Published: July 2010

The gel‐forming characteristics of several Rhizobial polysaccharides and clay mixtures were studied using a torque‐type viscometer. This method was found to be both a rapid and a precise measure of the total effect of the added compound to clay than was the floc volume. Krillium and dextran were used as comparison compounds. Krillium greatly influenced the viscosity of clay suspensions, but dextran had no effect. All rhizobial poly‐saccharides used had some effect on the properties measured, and most compared favorably with Krillium.
Beta Oxidation of Phenoxyalkanoic Acids in Soil
Authors: Gutenmann W. H. , Loos M. A. , Alexander M. , Lisk D. J.
Published: July 2010

The 2,4‐dichlorophenoxyalkanoic acids with aliphatic moieties ranging from butyric to undecanoic were metabolized by the soil microflora to acids of shorter chain length. Phenoxyalkanoic acids with an even number of carbons in the fatty acids consistently were converted to products with an even number of carbons while compounds with an odd number of carbons in the aliphatic moieties were converted to the corresponding 2,4‐dichlorophenoxyvalerate, propionate, and ultimately 2,4‐dichlorophenol as measured by gas chromatography. The results demonstrate a beta oxidation sequence in the degradation of these pesticides in soil.
The Effects of Soil Temperature and Form and Level of Nitrogen on Growth and Chemical Composition of Italian Ryegrass
Authors: Nielsen K. F. , Cunningham R. K.
Published: July 2010

Italian ryegrass was grown in a clay loam soil in a greenhouse at 3 soil temperatures 11°, 19.5° and 28°C. with 6 levels of N (0 to 500 ppm.) as NH4+ (treated with “N serve”) or NO3‐. Tops grew best at 19.5° and roots at 11°C. At 19.5° yields of tops with NO3‐N were maximal at 100 ppm. and with NH4‐N at 200 ppm. Increasing NO3‐N above 100 ppm. greatly decreased yields of tops, but increasing NH4‐N did not. Yields of tops were larger with NO3‐N than with NH4‐N at low levels of N but were smaller at higher levels.

Root weights were similar with both forms of N, but whereas the roots were well distributed throughout the soil with NH4‐N, with NO3‐N, they were mainly confined to the top half of the soil.

Form of N greatly influenced the composition of the grass. Increasing NO3‐N decreased the concentrations of P, Cl and S, and NH4‐N decreased the concentrations of Ca. Percent N was larger with NO3‐N than with NH4‐N.

Raising the soil temperature greatly increased % Ca and % Mg but had little influence on concentrations of N, P, S, Na, and K. Percent Cl was always largest at 11°C.
Evaluating the Sulfur Status of Soils by Plant and Soil Tests
Authors: Fox R. L. , Olson R. A. , Rhoades H. F.
Published: July 2010

Several methods for evaluating the sulfur status of soils were compared. Among chemical procedures used, water and phosphate extractions gave the best agreement with sulfur A values and total sulfur uptake by alfalfa from Nebraska soils. Water was an inefficient extractant of sulfate from a Hawaiian Latosol. Calcium phosphate solution was a more convenient extractant than KH2PO4 for both Nebraska and Hawaii soils.