bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mineral‐Weathering Correction for Estimating the Sodium Hazard of Irrigation Waters
Authors: Rhoades J. D. 
Published: July 2010

AbstractAn equation previously proposed by Bower (2, 4) for evaluating the Na hazard of irrigation waters has been modified to include the effect of soil‐mineral weathering on the changes that occur in the SAR values of waters applied to soils. The modification involves the incorporation of a coefficient which reduces the predicted soil drainage‐water SAR values by various amounts, depending upon the mineral properties of the soil and the leaching regime used. The value of the coefficient required in the equation can be determined by simple laboratory procedures. The modified equation was tested on a calcareous soil by comparing the SAR values predicted from the equation with values actually obtained in a controlled lysimeter experiment. The applicability of the equation is supported by the excellent correspondence obtained between the calculated and observed SAR values.
Self‐Diffusion of Phosphorus in Clays and Soils: II. The Effect of pH
Authors: Place G. A. , Phillips R. E. , Brown D. A. 
Published: July 2010

AbstractThe effect of pH on the self‐diffusion coefficient of 32P was measured in kaolinite, montmorillonite, illite, Dundee silt loam, and Sharkey clay. Six fractions of soil phosphorus were evaluated and related to the effect of pH on the self‐diffusion coefficients of 32P by multiple linear regression analysis. The free iron oxide content was determined in each medium and related to the variation in self‐diffusion coefficients between media.The self‐diffusion coefficients were significantly affected by pH in all media. A multiple regression analysis for individual clays and soils where self‐diffusion was the dependent variable and water soluble‐P, Al‐P, Fe‐P, occluded Fe‐ and Al‐P, and Ca‐P were the independent variables revealed that water soluble P in kaolinite was positively correlated (R2 = 0.673) and occluded Al‐P in montmorillonite was negatively correlated (R2 = 0.402). There were no significant terms in the other media. The magnitude of the self‐diffusion coefficients between media was kaolinite > montmorillonite > Dundee silt loam > illite > Sharkey clay. When the self‐diffusion coefficients and phosphorus fractions were averaged over all pH values, self‐diffusion increased as the water soluble‐ and Al‐P concentrations increased and the Fe‐P and free ion oxide contents decreased.
Determination of the Solubility Product of Soil Constitutents Such as Gypsum
Authors: Rance Joan M. , Davey B. G. 
Published: July 2010

AbstractThe solubility product of gypsum at 20C was calculated using a converging cyclic procedure which involved the use of a published value for the dissociation constant of gypsum, an experimentally determined value for total Ca concentration, and the second approximation of the Debye‐Hückel equation.Total Ca concentration of filtered saturated extracts was determined using atomic absorption spectroscopy.From this method the solubility product of CaSO4 at 20C was found to be 2.46 × 10‐5 and 32.1% of total soluble Ca was found to be present as ion pairs.
Detachment of Soil Particles in Simulated Rainfall
Authors: Mazurak Andrew P. , Mosher Peter N. 
Published: July 2010

AbstractSoil materials were fractionated into 20 separates ranging from 4,760µ to < 2µ in diameter. These separates were packed into splash‐cups and exposed to simulated rainfall intensities of 2 to 12 cm/hr. Raindrops were 5.1 mm in diameter and fell 11.33 m onto the surface of soil materials. Soil particles detached from the surface by the raindrops were oven‐dried and weighted.The amount of detached soil particles from surfaces of all separates was linearly related to simulated rainfall intensity. Linearity was significant at the 0.01 level of probability, except for the coarsest and finest separates. Slope of the line is used to characterize the susceptibility of soil materials to detachment from the surface by raindrops. The slope is measured as milligrams of particles per cm3 of water hitting the surface of soil materials.Detachment of soil particles exposed to simulated rainfall increased from 2.2 mg/cm3 of water for separates 4,760–3,360µ in diameter to a maximum amount of 288 mg/cm3 of water for separates 210–149µ and 149–105µ in diameter. Then, the amount of detached particles decreased with decreasing diameter of particles. Detachment for < 2µ diameter particles was 11 mg/cm3 of water.High‐speed movies showed that splash of raindrops from surfaces of separates > 105µ in diameter consisted of much smaller water drops than from separates < 105µ in diameter. Splash from the surfaces of separates < 105µ in diameter exhibited a crown effect and then broke into smaller drops.
Particle Size Analysis of Soils Compared by Sodium Metaphosphate and Sodium Carbonate Dispersion Methods
Authors: Dixon J. B. , McCracken R. J. , Peele T. C. , Rich C. I. 
Published: July 2010

AbstractParticle size data obtained by the Na2CO3‐centrifuge method can be used for soils free of carbonates as a substitute for those obtained by the “standard” NaPO3‐pipette method. Dispersion by NaPO3 and Na2CO3 boiling was essentially the same for 13 soil samples. Differences of a few percent clay were common between soil samples analyzed by the NaPO3‐pipette and Na2CO3‐centrifuge methods.
Quantitative Analysis for Nonionic Surfactants in Soil Leachates
Authors: Valoras N. , Letey J. 
Published: July 2010

AbstractTwo methods for quantitatively analyzing nonionic surfactant concentration in soil leachates were investigated. A colorimetric technique was found to produce good results for several nonionic surfactants (including two which have been marketed primarily for soil use) without interference from extraneous materials extracted from the soil in the leachate. A turbidity technique was found to apply for surfactants diluted in distilled water, but was not useful for the analysis of surfactant in soil leachates.
Reactivity of Montmorillonite Surfaces with Weak Organic Bases
Authors: Swoboda Allen R. , Kunze G. W. 
Published: July 2010

AbstractThe adsorption of organic amines and pyridines was used to study the reactivity of magnesium and calcium‐saturated montmorillonite surfaces. The ability of clays to chemisorb organic bases of different pkb values was used as a measure of the acid strength of their surface. Chemisorption and physical adsorption of the organics were differentiated by infrared analysis of the organic‐clay complex. Nontronite and Otay bentonite are the most reactive of the montmorillonites studied, being able to chemisorb bases with pkb values greater than 11.4. The active sites on Wyoming bentonite were found to be heterogeneous with respect to acid strength. The majority of the sites reacted with organic bases with pkb values of 8.8 and below, but chemisorbed only a small amount of aniline and m‐chloroaniline which have pkb values of 9.4 and 10.5, respectively. Hectorite chemisorb bases with pkb values of 8.8 and below but did not chemisorb a base with a pkb of 9.4.
The Movement of Zinc to Plant Roots
Authors: Wilkinson H. F. , Loneragan J. F. , Quirk J. P. 
Published: July 2010

AbstractPrevious workers have classified nutrients on the basis of their movement patterns to plant roots, as shown by autoradiographic techniques, together with calculations using soil and plant nutrient levels and transpiration ratios. Autoradiographs of 65Zn depletion were similar to those shown by other workers for 32P. No difference was observed in zinc levels in tops or roots when transpiration ratios were trebled (from 49 ml/g to 173 ml/g), indicating that zinc absorption is not dependent on mass flow of solution to the roots.
Morphology and Genesis of Some Grayish Claypan Soils in Oklahoma: I. Morphology, Chemical and Physical Measurements
Authors: Culver James R. , Gray Fenton 
Published: July 2010

AbstractGrayish or grayish‐brown soils with thin silty A horizons over clayey argillic horizons occurring in the Reddish Prairies of Oklahoma are described. Four profiles, two of the established Waurika series and two of the proposed Nardin series were characterized by detail profile descriptions and by physical and chemical analyses. Particle‐size distribution, bulk density, cation exchange capacity, extractable cations, pH, and organic matter were determined by soil horizons. Attempts were made to classify the pedons studied according to the 7th Approximation to ascertain the validity of the proposed Nardin series.These soils have thin silty A2 horizons with abrupt thick argillic horizons ranging from 42 to 55% clay. Clay, fine silt, organic matter, and carbonates were lost from the A horizons and were accumulated in the Bt horizons. The soils have high base status with Ca and Mg the dominant cations. A secondary maximum of organic matter accumulation occurs in the B2t horizons.
Profile Distribution of Nonexchangeable Mg in the <1µ Clay in Seven Loess‐Derived Soils
Authors: Protz R. , Riecken F. F. 
Published: July 2010

AbstractThe nonexchangeable Mg content of the <1µ clay in seven loess‐derived soils representing a wide range of soil development decreases with depth. A direct relationship exists between the nonexchangeable Mg content of the <1µ clay and exchangeable Mg/g of <2µ clay. An inverse relationship is present between nonexchangeable Mg in the <1µ clay and exchangeable H/g of <2µ clay. The montmorillonite/kaolinite ratio increases sharply with depth to 50 cm, below which the ratio remains constant. It is concluded that Mg has not been built into the clay fraction during soil profile development.
Reactions between Fulvic Acid, a Soil Humic Compound and Inorganic Soil Constituents
Authors: Schnitzer M. 
Published: July 2010

AbstractThe order of stabilities at pH 5.0 of complexes formed between a water‐soluble Podzol fulvic acid and nine divalent metal ions was Cu > Pb > Fe > Ni > Mn > Co > Ca > Zn > Mg. Log K (stability constant) values ranged from 8.69 for the Cu‐complex to 2.09 for the Mg‐complex and were higher at pH 5.0 than at pH 3.5. The Irving‐Williams series was not followed. Provisional results indicated that log K values for Fe3+‐ and Al3+‐fulvic acid complexes were higher than those for divalent metal‐fulvic acid complexes. Two types of reactions occurred between fulvic acid and metal ions and hydrous oxides: a major one in which both COOH and phenolic OH groups reacted simultaneously, and a minor one involving less acidic COOH groups only. To develop analytical methods for investigating metal‐organic matter complexes occurring in soils, model compounds, containing varying metal to fulvic acid ratios, were prepared. The methods so developed were later used as diagnostic tools for the characterization of metal‐organic matter complexes extracted from natural soils or occurring as distinct horizons in soil profiles.In contrast to unreacted fulvic acid, metal fulvic acid complexes reacted with phosphate via the metal to form fulvic acidmetal‐phosphate. The interlamellar adsorption of fulvic acid by montmorillonite depended on the pH of the medium, the fulvic acid concentration and the type of cation with which the clay was saturated. Fulvic acid was found to have a positive effect on root initiation, which appeared to be related to its metal complexing ability.
Potassium Supplying Power of Iowa Soils at Their “Minimal” Levels of Exchangeable Potassium
Authors: Tabatabai M. A. , Hanway J. J. 
Published: July 2010

AbstractThe plant removal of native K from seven surface soils and seven subsoils from Iowa was studied at their “minimal” levels of exchangeable K. The “minimal” levels of exchangeable K were directly related to the percentages of <2 μ clay present in the surface soil samples. Plant uptake of nonexchangeable K was a linear function of time of cropping for all the soils and was highly correlated with the “minimal” level of exchangeable K. In the 758‐day cropping period, an average of about 24 times as much K was removed by the plants as was present as exchangeable K in the soils at their “minimal” exchangeable K levels. Long‐term K supplying powers of the soils used were highly correlated with their “minimal” levels of exchangeable K.
Hydrolysis and Sorption Reactions of Orthophosphate, Pyrophosphate, Tripolyphosphate, and Trimetaphosphate Anions Added to an Elliot Soil
Authors: Blanchar R. W. , Hossner L. R. 
Published: July 2010

AbstractThe reactions of trimetaphosphate (TMP), tripolyphosphate (TPP), pyrophosphate (PP), and orthophosphate (OP) with an Elliot soil were studied.The hydrolysis reaction TMP→TPP→PP + OP→3 OP was studied by equilibrating TMP added to the Elliot soil at a rate of 400 µg. P/g soil and measuring TMP, TPP, PP, and OP at various times. These measurements showed that TMP persisted less than 1 day and TPP less than 8 days. Less than 10% of the PP formed had been hydrolyzed after 16 days.The sorption of TMP, TPP, PP, and OP in the soil was studied. TMP was not appreciably adsorbed by the Elliot soil. The P adsorption capacities for OP, PP, and TPP calculated from the Langmuir equation were 462, 965, and 706 µg P/g soil, respectively.A method for extracting and determining TMP, TPP, PP, and OP in soils was developed. The method consisted of two extractions (2% EDTA + 0.1N NH4F pH 4.2 and 2% EDTA + 1N NAOH), followed by an anion exchange resin separation of the P forms. Recovery of added P was 94% using these extractants. The average error for the extraction and separation was 17%.Plant uptake of P from soil treated with PP was slightly higher than soil treated with OP.
Infrared Studies of the Mechanism of Adsorption of Urea‐d4, Methylurea‐d3, and 1,1‐Dimethylurea‐d2 by Montmorillonite
Authors: Farmer W. J. , Ahlrichs J. L. 
Published: July 2010

AbstractClay‐organic complexes of urea‐d4, methylurea‐d3, and I,I‐dimethylurea‐d2 with montmorillonite were examined by infrared spectroscopy in an effort to add to our understanding of the mechanism of adsorption of the substituted urea herbicides in soils. The complexes were examined in the infrared as dried thin self‐supporting films. Deteration techniques were used to correlate infrared spectra with molecular structure. Urea‐d4 was found to be adsorbed in the interlayer space by montmorillonite through coordination of the carbonyl with the exchange cations. The degree of coordination with the exchangeable cation was least for Ca, intermediate for Ni (II), and largest for Al, representing alkaline earth cation‐clay, transition metal cation‐clay, and acid clay, respectively. Methylurea‐d3 and I,1‐dimethylurea‐d2 reacted with montmorillonite through the carbonyl in a manner similar to urea. The reaction of dimethylurea with montmorillonite was limited by the presence of the methyl groups to the extent that its reaction was the same with Al or Ni as the exchange cation. The amino groups of urea, methylurea, and I,I‐dimethylurea appear relatively inactive as bonding sites.
Separation and Functional Group Analysis of Soil Organic Matter
Authors: Leenheer J. A. , Moe P. G. 
Published: July 2010

AbstractAn investigation was conducted on the Romney silty clay loam and Zanesville silt loam soils to determine an efficient method of separating organic matter from the mineral fraction of the soil with a minimum amount of alteration, and to compare the two soils on the basis of the functional group composition of their organic matter. Soil organic matter was obtained as an organic residue after the sand and silt fractions had been removed from an alkaline soil‐water suspension by sedimentation following dispersion of the soil by ultrasonic vibration, and the remaining suspended clay fraction dissolved by repeated treatments with an HCl‐HF acid mixture. No loss of organic matter was incurred by the physical removal of the sand and silt fractions, but approximately 12% of the Romney organic matter and 37% of the Zanesville organic matter was dissolved by the acid treatments.Various chemical and instrumental techniques were used to quantitatively analyze this organic matter preparation for the carboxyl, aliphatic hydroxyl, phenolic hydroxyl, and carbonyl functional groups. The Romney organic matter was characterized by its high carboxyl and carbonyl content, whereas the Zanesville organic matter exhibited a high aliphate hydroxyl content. This comparison of functional group composition indicates a greater state of humification (oxidation) for the Romney organic matter than for the Zanesville organic matter. This difference in functional group composition is a major factor affecting the chemical interactions each type of organic matter undergoes in the soil.
Test of Constancy of Self‐Diffusion Coefficients
Authors: Phillips Ronald E. 
Published: July 2010

AbstractA method is outlined which allows one to determine the constancy of diffusion coefficients measured by the use of Fick's second law subject to two sets of initial and boundary conditions if the spatial distribution of the diffusing ion is known. The constancy of published self‐diffusion coefficients was analyzed for illustrative purposes; they were found to remain essentially constant throughout the diffusion period. The method can be used to calculate constant diffusion coefficients from experimental spatial‐distributions of the diffusing ions. Diffusion coefficients calculated in this manner were compared with the values calculated by other methods; the values are the same, within experimental error, as predicted by theory.
Lindane Diffusion in Soils: I. Theoretical Considerations and Mechanism of Movement
Authors: Ehlers Wilfried , Letey J. , Spencer W. F. , Farmer W. J. 
Published: July 2010

AbstractEquations are developed to describe the combined vapor and “nonvapor” phase diffusion of a volatile insecticide in soils and compared with the diffusion of lindane in a Gila silt loam in a transient state system. The quantity of diffused lindane appears to increase linearly with increased lindane concentration in the treated soil up to about 20 ppm but deviates from linearity at higher concentrations. The diffusion coefficient of lindane is independent of time until 22 ppm of the initial 80 ppm lindane concentration in the treated soil have diffused into the formerly untreated soil. The diffusion rate then decreases rapidly. The dependency of the diffusion coefficient on concentration and time may be explained by the fact that lindane will reach maximal vapor density in the range of 20 to 30 ppm. After these concentrations are built up in the initially untreated half‐cells by diffusion, vapor diffusion approaches zero and all the diffusion is in the “nonvapor” phase. At a 10% soil water content, 50% of the lindane diffuses in the vapor phase and 50% in the “nonvapor” phase. At near saturation, total diffusion is in the “nonvapor” phase. Lindane diffusion in soils can easily change from “nonvapor” to vapor phase and back to “nonvapor” phase.
Restoring Productivity on Pullman Silty Clay Loam Subsoil under Limited Moisture
Authors: Eck Harold V. 
Published: July 2010

AbstractApplied fertilizer restored grain sorghum (Sorghum vulgare) yields on 10‐cm cut Pullman silty clay loam to 93% of those obtained on uncut soil. On 20‐, 30‐, and 41‐cm cuts, yields were restored to 87% of those on uncut soil. Soil water storage, water use, and water‐use efficiency data revealed that differences in soil water storage and use were responsible for differences in yield when fertility was not limiting. Topsoil removal decreased and fill increased water‐holding capacity of the soil profile. Topsoil removal decreased water loss from fallowed soil, but fill had little effect.N was the only added nutrient required to produce highest yields obtained under limited moisture conditions in this study. Inadequately fertilized treatments used less water than adequately fertilized ones, but water‐use efficiency was greater where plant nutrients were adequate.
Hydrologic and Morphologic Implications of Anisotropy and Infiltration in Soil Profile Development
Authors: Zaslavsky Dan , Rogowski A. S. 
Published: July 2010

AbstractThe concept of anisotropy as a possible factor of soil formation is introduced and the hydrologic and morphologic implications of water infiltration are demonstrated. It is concluded that the magnitude and direction of downhill flux of infiltrating water will depend on the degree of anisotropy as well as on the land slope and its changes. This conclusion may explain in part the greater differentiation of horizons on flat lands than on sloping lands, and the gradual thinning out of the B horizon uphill as the slope increases.
Evaporation from a Simulated Soil Shrinkage Crack
Authors: Adams John E. , Ritchie Joe T. , Burnett Earl , Fryrear D. W. 
Published: July 2010

AbstractA simulated soil shrinkage crack, 46 cm wide and 62 cm deep, was constructed in such a manner that depth could be varied by 15.2‐cm increments and width could be adjusted between 10 and 70 mm by 20‐mm intervals. The walls of the crack were lined with porous ceramic plates connected to a water supply maintained at −5 mb potential. The simulated crack was installed in the floor of a laboratory wind tunnel located in a controlled environment room maintained at 24.0 ± 1.5C air temperature and 43 ± 3% relative humidity. Evaporation from the simulated crack walls (ceramic plates) was determined for all combinations of four crack widths (10, 30, 50, and 70 mm), three crack depths (30, 45, and 60 cm) and five windspeeds (0, 2.2, 4.5, 6.7, and 8.9 m sec‐1).Total water loss (evaporation) from the walls of the simulated crack increased as any one or all of the three variables (windspeed, crack depth, or crack width) increased. These three variables accounted for 99.1% of the variability in total evaporation from the crack walls. Turbulent air movement within the simulated crack was the major factor affecting the evaporation.Both straw and gravel mulches reduced evaporation from the crack walls 85 to 90% with no wind and about 60% at 8.9 m sec‐1 windspeed. The results suggest that evaporation from soil shrinkage cracks may be reduced by closer plant or row spacing or by surface residues such as trash and clod mulches.Total evaporation from a simulated crack 60 cm deep varied from 0.5 cm3 hr‐1 (10 mm wide, 0 m sec‐1 windspeed) to 18 cm3 hr‐1 (70 mm wide, 8.9 m sec‐1 windspeed). In simulated cracks 60 cm deep and 30–70 mm wide, 50–60% of the total evaporation occurred below 15 cm and 30–40% occurred below 30 cm.
Chemical and Biological Weathering in Vermiculite from Transvaal
Authors: Sawhney B. L. , Voigt G. K. 
Published: July 2010

AbstractTransvaal vermiculite flakes were weathered in solutions of salts or acids as well as in nutrient solutions inoculated with water extracts of soils from hemlock (Tsuga canadensis) and tulip poplar (Liridendron tulipifera) forest stands. Morphological changes were studied with a microscope and the structural changes were determined by X‐ray diffraction analysis, while the changes in chemical composition were estimated by an electron microprobe.Weathering of flakes proceeded from edges inward and produced a weathered zone parallel to the flake edges. However, the changes produced by salt solutions were different from those by acids and biological agents.Treatment with salt solution produced the expanded weathered zone with a 14A c‐axis spacing as compared to 10A spacing of the unaltered zone. Electron microprobe analysis revealed that the salt treatment replaced the interlayer K ions by the hydrated cations of the salt. Treatment with acids or biological agents, on the other hand, produced a bleached and fragile weathered border that was amorphous to X‐rays. Electron microprobe analysis showed that the bleached zone was depleted of Fe, Mg, and Al, besides the interlayer K ions; concentration of these cations decreased towards the extremity of the edge. The amorphous nature of the weathered zone is attributed to the loss of the unit cell periodicity resulting from the removal of a portion of the octahedral and tetrahedral cations.