bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hydrolysis of Condensed Phosphates in Soils
Authors: Allmaras R. R. , Black C. A. 
Published: July 2010

AbstractHydrolytic degradation of the condensed phosphates of fertilizer‐grade calcium metaphosphate (CMP) in soils involves several steps, including formation of a dense, viscous liquid from the vitreous portion of the CMP. Experiments indicate that the rate‐controlling step in the early stages of transformation of condensed P to orthophosphate in soils treated with solid particles of CMP was the degradation of the viscous liquid and not the hydrolysis of the condensed P in the solution derived from the viscous liquid.
Loess Composition in Southeastern Illinois and Southwestern Indiana
Authors: Fehrenbacher J. B. , White J. L. , Beavers A. H. , Jones R. L. 
Published: July 2010

AbstractPeorian loess in southeastern Illinois and southwestern Indiana varied more in composition among the Wabash, Ohio, and Mississippi river source areas than did soils developed in the upper portion of the loess.Very low magnetic susceptibility was found in the gray, basal (Iowan or Morton) Peorian loess in the Wabash valley. Carbonate content was lower in Peorian loess of the Ohio valley than in that of the Wabash valley. Peorian loess was lower in clay and higher in silt content than Farmdale or Loveland loesses. Composition of the silt fraction, other than carbonates, did not vary greatly in Peorian loess of the three major source areas. Opal phytoliths and sponge spicules were present in all calcareous Peorian loess samples, and one unidentified microfossil was found in the Wabash valley loess. Illite was the dominant clay mineral in Peorian loess of the Ohio and Wabash valleys and expandable 2:1 minerals were dominant in Mississippi river loess. A high proportion of the expandable minerals in all samples was vermiculite. Chlorite and kaolinite were comparable in the Peorian loess of the three valleys.In comparison with the Peorian, the Farmdale loess had somewhat similar magnetic susceptibility, only secondary carbonates, and greater clay content. In the silt fraction, the Farmdale had lower Fe and Mn contents, less opal phytoliths, and similar sponge spicule content as the Peorian. The Farmdale was lower in illite, equal to or slightly higher in expandable clay minerals, and somewhat higher in chlorite and kaolinite contents than the Peorian.In comparison to the overlying Farmdale, the Loveland loess had strongly developed soils and less secondary carbonates. The silt fraction was lower in K2O and CaO contents, and lacked sponge spicules. The Farmdale and Loveland appeared to have similar clay mineral composition.The Ohio valley loess was most weathered and the five Wabash valley loess soils were least weathered as indicated by CaO/ZrO2 molar ratios of the A horizons. Alford and Sylvan soils, developed in Peorian loess of the Wabash, Ohio, and Mississippi valleys, appear to have no real differences in clay mineral composition in the B2 horizons, although illite may be higher than expandable clay minerals in the Ohio valley loess soils. A high proportion of the expandable clay minerals in all of the B2 horizons appeared to be vermiculite. The rather marked similarity of the clay of B2 horizons of the loess soils in contrast to the varied clay mineral composition of underlying loess, suggests that the surficial loess may have varied less than that deeper in the sections.
Rooting Volume of Corn and Alfalfa in Shale‐Influenced Soils in Northwestern Illinois
Authors: Fehrenbacher J. B. , Ray B. W. , Edwards W. M. 
Published: July 2010

AbstractCorn roots (Zea mays L.) did not penetrate calcareous Maquoketa shale (IIC) horizons appreciably in four soils derived from thin loess on shale in northwestern Illinois. Alfalfa roots (Medicago sativa L.), in contrast, penetrated the shale horizons to considerable depths. This difference in rooting behavior of the two plants probably explains the better adaptation of a perennial taprooted plant such as alfalfa to these soils than an annual plant such as corn. The shale (IIC) horizons had low total porosities (<38%), very low noncapillary porosities (<1.5%), high bulk densities (>1.69 g/cc), and were impermeable to water. Bulk density slightly greater than 1.80 g/cc and intraped porosity of slightly less than 32% of discrete peds in the IIC horizons appear to be limiting to corn root penetration. Seepage and erosion problems on these soils are related to the impermeable nature and depth to the underlying shale.
Influence of Plowing, Disking; Cultivation, Previous Crop and Surface Residues on Corn Yield
Authors: Van Doren D. M. 
Published: July 2010

AbstractThe influence of plowing, disking, cultivation, previous crop, and organic matter residue management on corn grain yield has been measured on structurally unstable Wooster silt loam soil for two years. Precipitation during the growing season was 8.6 and 10.5 inches per year. On plowed soil, disking reduced yield by 6% and cultivation increased yield by 6%. When the soil was not plowed, management systems providing a high percentage of organic residue surface cover or which included cultivation increased yield much more than disking or previous crop per se. The top producing nonplowed treatments yielded 13% more corn than the best plowed treatments. Of the lowest yielding treatments, nonplowed conditions produced 17% less corn than the plowed treatments.
Variation in the Ability of Slash Pine Progeny Groups to Absorb Nutrients
Authors: Walker Laurence C. , Hatcher Robert D. 
Published: July 2010

AbstractTwenty‐seven variables were tested to determine whether five slash pine (Pinus elliottii var. elliottii) progeny groups of known parentage differed in ability to absorb and efficiently utilize nutrients. Fertilization × progeny group interactions were significant for N and K in needles and stems, and for CO2 absorption by needles during the first year of growth in an environmental control room. Phosphorus‐32 in stems varied between progeny groups, and relative amounts of P32 absorbed were ascertained from radioautographs.
Nutrient Relationships Between Soils and Needles of Loblolly Pine (Pinus taeda)
Authors: Wells C. G. 
Published: July 2010

AbstractHighly significant correlations were found between nutrients in the soil and needle content of 5‐year‐old loblolly pine for all seasons and needle age classes. Mineralized N was more highly correlated with percentage N in the needle than was total N. Available P by the Truog and Bray no. 2 methods was more closely related to percentage P in the needles than was total P. Percentage exchange capacity saturated with K accounted for more of the variability in percentage K in the needles than did either exchangeable K or acid‐extracted K. Exchangeable Ca and Mg were more closely related to percentages of these elements in the needles than was percentage saturation with these elements. Antagonism interactions were indicated between K and Ca or Mg but not between Ca and Mg. Needle samples of the previous year's first growth flush collected in late winter from the upper crown were best for relating nutrient content of needles to soil fertility.
Phosphate Fractions in Some Texas Grumusols and Their Relation to Soil Weathering and Available Phosphorus
Authors: Hawkins R. H. , Kunze G. W. 
Published: July 2010

AbstractThe phosphate fractions were determined in nine profiles of Grumusols from Texas, representing four soil series. Soil weathering and available P were shown to be related to certain of these fractions.The distribution percentages for Ca‐P, Al‐P, and Fe‐P serve as sensitive indicators of the weathering environment. These show Beaumont clay to be the most weathered and Victoria and Houston Black clay to be the least and about equally weathered. Lake Charles clay occupies an intermediate position, through none of the four have undergone much weathering.Free salts, particularly soluble sulfate salts, were found to affect the distribution percentages of Ca‐P and Al‐P in the Victoria profiles.Available P was correlated with Al‐P in all but the Victoria profiles where Ca‐P was correlated with available P. Indications are that the correlations between Al‐P and available P are fortuitous and more realistically reflect small amounts of mineralized organic phosphates extracted by the initial extraction for Al‐P.The C/P ratios of the organic matter in the A horizons of the Grumusols range from 27 to 295. The higher ratios are associated with the Beaumont and Lake Charles soils, whereas the majority of the values for the A horizons of Victoria and Houston Black soils are below 75. The lack of response to applied P on these soils is attributed to the large amounts of organic P and accompanying low C/P ratios. Decomposition of organic matter in these soils results in mineralization of significant amounts of organic phosphates which are then available for use by the plant.
Effect of Liming and Flooding on Manganese Toxicity in Alfalfa
Authors: Graven E. H. , Attoe O. J. , Smith Dale 
Published: July 2010

AbstractIncubation and greenhouse studies showed that regardless of soil pH, flooding increased the content of exchangeable Mn and the Mn content of alfalfa (Medicago sativa L.) grown in a Kellner loamy sand. In the absence of a source of easily decomposable organic matter, Mn mobilization by flooding was considerably slower at a soil pH of 4.7 than at 7.3. Where alfalfa was grown in the soil or where finely milled oat straw was added, flooding mobilized more Mn in the acid than in the neutral soils. Liming promoted immobilization of Mn on the resumption of normal soil moisture relations after flooding. Seventy‐two hours of flooding increased the Mn content of the alfalfa on the unlimed soil from 426 ppm to more than 6,000 ppm. Excess Mn tended to accumulate in the leaves and growing points of the plants. The results suggest that the well‐known susceptibility of alfalfa to Mn toxicity may also account for its sensitivity to poorly aerated soils.
Multiple Working Hypothesis in Soil Genesis
Authors: Arnold R. W. 
Published: July 2010

AbstractCurrent theories of soil genesis emphasize variable rates of processes in the differentiation of soils, and include the implication that soils of similar morphology may have travelled different pathways. Multiple hypotheses, proposed as explanations of observed soil features, may be expressed as sequential models, each depicting an alternate mode of development.The genesis of neo‐skeletans in subsoils of some Udolls is examined in four models. Soil morphology, empirically related to different environmental conditions (state factors), is interpreted as the consequence of a combination of variable rate genetic processes. It is concluded that polygenesis is likely involved in the development, maintenance, and/or preservation of neo‐skeletans in Udoll subsoils. Regardless of the genetic pathway, the resulting soils are believed to be youthful entities within a genetic spectrum whose striking morphological features have been dominantly influenced by translocations of inherited clay.
An Evaluation of Imipramine Hydrochloride as a Reagent for the Quantitative Determination of Nitrate in Plant Material and Soil Extracts
Authors: Simpson Elmer C. , Barrows Harold L. 
Published: July 2010

AbstractA qualitative determination for nitrates was investigated for possible use as a rapid, routine, quantitative, colorimetric procedure for nitrates in soil extracts and plant material. The inherent difficulties and the limitations of the procedure are shown and discussed.
Phosphate—Ammonium—Moisture Relationships in Soils: II. Ion Concentrations in Leached Fertilizer Zones and Effects on Plants
Authors: Blanchar R. W. , Caldwell A. C. 
Published: July 2010

AbstractRadioactive fertilizer pellets MCP32, MCP32 + NH4Cl, and MCP32 + KCl were placed in a Dakota sandy loam and allowed to react for 2 weeks. The pots containing the fertilizer were then leached with 0, 2, 4, and 8 cm of water. Corn (Zea mays) was grown on these pots for 2 weeks and analyzed for total and radioactive P. Results showed only trace amounts of fertilizer P taken up from all nonleached pots. Leaching the pots with 2 or more centimeter of water resulted in a significant uptake of fertilizer P. When the pots were leached with 4 cm of water, P uptake from MCP + NH4Cl pellets was nearly 3‐fold that of either MCP or MCP + KCl. Measurement of water‐soluble P and other conditions in the fertilizer zone indicated no differences between MCP + NH4Cl and MCP + KCl pellet zones. It was concluded that ammonium increased the capacity of the plant to absorb P and did not affect the availability of P in the soil.
A Computer Technique for Prediction of CaCO3 Precipitation in HCO3‐ Salt Solutions
Authors: Tanji K. K. , Doneen L. D. 
Published: July 2010

AbstractFive salt solution systems containing HCO3‐ were concentrated by evaporation, in contact with laboratory atmosphere, to simulate 2‐to 10‐fold reduction in volume. The amounts of CaCO3 precipitated, final pH, and final solute concentrations were comprehensively predicted from the initial solute concentrations, degree of concentration of initial solution volume, and final PCO2. A flow diagram of the computational scheme is presented for IBM 7040 Data Processing System. The basic equilibrium relationships in the CaCO3 and HCO3‐‐CO32‐ cycles are applicable to any aqueous systems which precipitate CaCO3 due to changes in solute concentration, partial pressure of CO2 or ambient temperature.
A Soil Salinity Sensor of Improved Design
Authors: Richards L. A. 
Published: July 2010

AbstractKemper (1959) showed that an electrical conductivity cell with spaced electrodes in fine‐pored ceramic that is in contact with the film water in soil can provide continuous measurement of the salt concentration of the soil solution. Information is given on an improved sensor of this type. The response time has been reduced to about 1 hour for bulk solutions by using a ceramic plate 1 mm thick for the sensitive element. The effect of external current paths has been eliminated by shielding and insulation, and temperature compensation has been added. Information is given on calibration procedure, along with data on the use of the senor in irrigation tests and the relation of such data to leaching‐requirement theory.
Plant Availability and Form of Residual Phosphorus in Davidson Clay Loam
Authors: Singh R. N. , Martens D. C. , Obenshain S. S. 
Published: July 2010

AbstractThe form and availability of residual P in Davidson clay loam, a Reddish Brown Lateritic soil, was investigated. Various levels of residual P had been established in the soil by annual application of superphosphate for 17 years. In a greenhouse experiment, residual P from annual application of 21 lb P/acre was adequate to supply the P requirement of three successive crops of alfalfa (Medicago sativa L. ‘DuPuits’); application of 10.5 lb P/acre was inadequate. Phosphorus fractionation by the Chang and Jackson procedure (5) showed that native and residual P was present in the soil predominantly as iron phosphate; application of superphosphate resulted in small but significant increases in aluminum and calcium phosphates. A comparison of the inorganic fractions in soil before and after growth of the three crops of alfalfa provided evidence that aluminum, iron, and calcium phosphates were sources of P to the first crop and that iron phosphate was the main source to the second and third crops. The availability of the three fractions was explained on the basis of their composition and soil pH and exchangeable Ca2+ content.
Soil Properties Affecting Dieldrin Toxicity to Drosophila melanogaster
Authors: Hermanson H. P. , Forbes Clifford 
Published: July 2010

AbstractThe toxicity to Drosophila melanogaster Meigen of dieldrintreated soils was measured by bioassay. Under adequate standardization and control of light, temperature, humidity, and soil moisture, the variation in insecticidal activity was closely related to the colloidal properties of the soils. As organic carbon content, specific surface area of the minerals, and soil reaction increase, higher levels of dieldrin were required to maintain the killing power. Cation‐exchange capacity interacts with soil organic carbon content to increase dieldrin effectiveness. The dieldrin activity equation developed shows that often the simplest practical mathematic model of soil pesticide activity should be quadratic.
Neutron Activation Products from Project Sedan in Plants and Soils
Authors: Romney E. M. , Rhoads W. A. 
Published: July 2010

AbstractNeutron activation products of tungsten, scandium, and antimony were among those radionuclides concentrated through roots of plants grown on ejecta from the Sedan thermonuclear cratering detonation. Nuclear reactor‐produced isotopes were used in corroborative experiments to investigate, in greater detail, their behavior in plants and soils. Radiotantalum was also included as a matter of academic interest.Plants concentrated more Sc46, Sb124, and W185 in leaves than in stems, whereas Ta182 was concentrated more in stems. Plant uptake of Sc46, Sb124, and W185 was Influenced by different types of soil. Scandium‐46 and Ta182 were virtually immobile in columns of soil leached with 76 cm of water while Sb124 and W186 moved readily in neutral and alkaline soil, but not in acidic soil. Their behavior was influenced by the kind of clay mineral present, the sodium and potassium content, and the soil pH.
Soil Moisture Characteristics of Sand‐Peat Mixes
Authors: Juncker Paul H. , Madison John J. 
Published: July 2010

AbstractMixtures of Osoflaco sand and screened Canadian peat were examined for bulk density, tension‐moisture relations, wilting tensions and readily available water. As peat content increased, mixtures became lighter (less dense), held more available water, had a lower zone of saturation and approached wilting tensions more gradually. Tension‐moisture curves indicate relatively uniform pore sizes in the sand, but a relatively wide distribution of pore size in the peat.
Molybdate Phase Equilibria in Soil
Authors: Follett R. F. , Barber S. A. 
Published: July 2010

AbstractSolubility product relationships were investigated as a means of determining the possible solid phase forms of Mo which govern the concentration of Mo in the solution phase of soils. The Ksp value for ferrimolybdite was not available in the literature and was estimated to be approximately 10‐52.The activities of Ca, Fe, Mo, and H in the liquid phase after 24 leachings and CaO treatments were used to determine possible solid phase forms in a Maumee sandy loam soil. Calcium molybdate and ferrous molybdate were too soluble for their solid phases to exist in this soil.
Water Flow in an Unsaturated Soil with a Step‐Type Initial Water Content Distribution
Authors: Jensen R. D. , Klute A. 
Published: July 2010

AbstractWater flow against the water content gradient in soil columns composed of two layers of a given soil, with the upper layer at a higher water content than the lower layer, has been reported in the literature. From experiments with columns involving air gaps, control and variation of the temperature gradient, removal of water by evaporation, porous membranes and air‐dry soil, water content and pressure head measurements, it was concluded that vapor movement was the dominant mechanism when water was removed by evaporation. A vapor pressure gradient, originating from the temperature gradient created by the evaporation of water from the soil, provided the driving force for vapor transfer against the water content gradient. Liquid transfer predominated when water was removed isothermally. Initially water moved from the wetter layer into the drier soil in response to the pressure head gradient. After a time, the direction of the pressure head gradient reversed without a corresponding reversal in the water content gradient and water flowed out of the drier soil against the water content gradient.Two phenomena were instrumental in reversing the pressure head gradient. First, disturbance of the soil during the handling procedures caused an increase in the pressure head without a change in the water content. Second, since the driver layer initially gained water and dried thereafter, hysteresis also reduced the pressure head difference between the soil layers. Then removal of only a small quantity of water from the wetter soil made the pressure head smaller in the wetter soil than in the drier layer and the direction of the pressure head gradient reversed.
Interstratification in Vermiculite and Biotite Produced by Potassium Sorption: II. Evaluation by One‐Dimensional Fourier Analysis
Authors: Rhoades J. D. , Coleman N. T. 
Published: July 2010

AbstractThe one‐dimensional Fourier analysis was applied to the determination of the distribution of sorbed potassium in initially magnesium‐ or sodium‐saturated South African vermiculite and Bancroft biotite. It was concluded that while the type of interstratification produced through K sorption by vermiculite was not entirely regular, there was a definite trend in that direction. The biotite sample, on the other hand, apparently underwent zonal segregation upon K sorption when the complementary cation was Mg, whereas random interstratification seemed to be the case for the analogous Na system. Difficulties encountered in the use of this approach were discussed in terms of “skewness” and obscuration of X‐ray diffraction peaks and the apparent intermixing of interstratification types obtained. Information gained from the Fourier analysis was used to speculate on reasons for the observed distribution of K in the materials.
Nitrogen Losses from Urea as Affected by Altering Soil Urease Activity
Authors: Moe P. G. 
Published: July 2010

AbstractLaboratory incubation experiments were conducted to determine whether nitrogen losses from urea could be reduced by manipulating the urease activity of the soil. The natural urease activity of Chalmers silt loam and Plainfield sand was modified directly by applications of either additional urease enzyme or an enzyme inhibitor and indirectly by applications of a decomposing mulch and liming material. Additional urease enzyme increased the rate of urea hydrolysis, the rate of ammonia volatilization during the early part of the incubation period, and also the rate of nitrification during the latter part of the incubation period. The enzyme inhibitor, p‐chloromercuribenzoate, decreased the rate of urea hydrolysis but maintained soil ammonium contents at a high level throughout the entire incubation period due to inhibition of nitrification. Treatments had no significant effect on total volatile ammonia losses.The presence of a corn mulch layer (Zea mays) in the zone of urea application increased urea hydrolysis rates only when the mulch was undergoing rapid decomposition. The mulch layer increased initial rates of ammonia volatilization but reduced leaching losses of nitrogen significantly. Significantly lower volatile ammonia losses were observed when lime and urea were applied together on the surface of a corn mulch than when they were applied to bare soil.