bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hydraulic Conductivity of Clays During Shrinkage
Authors: de Jong E. 
Published: July 2010

AbstractThe ratio of unsaturated to saturated hydraulic conductivity was determined for mixtures of glass beads and clay, and for a clay soil. In shrinking soils, the relative hydraulic conductivity remained fairly high over a wide range of mositure contents, while in nonshrinking soils the relative hydraulic conductivity rapidly approached zero with decreasing moisture content.
The Relationship of Soil Properties to Exchangeable and Water‐Soluble Copper and Molybdenum Status in Podzol Soils of Eastern Canada
Authors: Gupta Umesh C. , MacKay D. C. 
Published: July 2010

AbstractThe exchangeable and water‐soluble Cu and Mo contents were investigated from soils of the Podzol region of Eastern Canada. Average exchangeable Cu and water‐soluble Cu content varied from 1.06 to 19.30, and 0.09 to 0.46 ppm, respectively. Soils derived from Permo‐carboniferous rocks were lower in exchangeable Cu than those of other geologic origin.In general the exchangeable Cu content was lower on sandy soils but did not vary much in other soil series. Water‐soluble Cu was not related to any of the soil properties. Exchangeable Cu did not seem to follow any continuous pattern with organic matter or pH.Average exchangeable Mo content of different soil series ranged from traces to 0.227 ppm and was much lower in the soils derived from Permo‐carboniferous rocks. The Mo content was higher in soils with pH values > 6.0, and a significant positive correlation coefficient was observed between the two variables. Its amount was significantly higher on the fine‐textured soils than on the coarse‐textured sandy soils.
Polar Desert Soils
Authors: Tedrow J. C. F. 
Published: July 2010

AbstractThe northern extremeties of ice‐free land are mantled primarily with Polar Desert soils. Polar Desert soils are sparsely colonized by vascular plants and in many instances the organic component scarcely enters the soil system. Low temperature, relatively dry soil conditions, a desert pavement, mildly acid to alkaline reaction, and salt efflorescences commonly characterize the Polar Desert soils.
Effect of Bare Fallow, Barley, and Grass on Salinity of a Soil Over a Saline Water Table
Authors: Sandoval Fred M. , Benz L. C. 
Published: July 2010

AbstractConsiderable acreage in the semiarid to subhumid upper midwestern USA is affected by excessive salinity, which occurs mainly on nonirrigated lands with high water tables where methods for improvement are limited. In northeastern North Dakota a 4‐year study was conducted to compare effects of bare fallow, perennial grass and barley culture on salinity of land affected by a highly saline, shallow water table that ranged in depth from 0.5 to 3 m during the study period. Land use did not appreciably influence salinity of the surface 15 cm. However, by the end of the first season, 46% of the soluble salts were leached out of the 15‐ to 60‐cm depth under fallow. Salinity increased slightly under barley, and definitely increased under perennial grass. Two consecutive years of fallow removed 60% of the soluble salts in 15‐ to 60‐cm depth. Salinity reductions continued under fallow through the third year. Under grass, salinity fluctuated considerably, but generally increased, under barley, salinity fluctuated less. Quantities of ions most often moved where: Na+ > Mg2+ > Ca2+, and Cl‐ > SO42‐.
Cation‐Exchange Characteristics of Forest Floor Materials
Authors: Wells C. G. , Davey C. B. 
Published: July 2010

AbstractThe CEC of forest floor materials from pine, hardwood, and mixed stands was highly dependent upon the saturating cation used in the determination and somewhat less dependent upon the replacing cation. Barium saturation and Ca replacement seemed to be the best cations for CEC determination. Base titration of electrodialyzed samples indicated a 4‐min period of rapid H release followed by a decreasing rate of release. Cation‐exchange capacity of the different materials increased proportionally with pH of the saturating solution, even though the materials differed in source and composition. Buffering properties of the forest floor organic materials were strongest primarily at slightly acid to alkaline reactions. Regardless of the tree species and state of decomposition, correlation of CEC with N content of the material was highly significant. The forest floor may have a higher total CEC than several inches of underlying mineral soil.
An Evaluation of Mogilevkina's Method of Determining Fixed Ammonium in Soils
Authors: Nelson D. W. , Bremner J. M. 
Published: July 2010

AbstractStudies using soils and ammonium‐saturated clay minerals showed that Mogilevkina's method of determining fixed ammonium gave much lower values than HF methods and was unsatisfactory. The heat treatment used in this method for removal of organic‐N and exchangeable ammonium‐N leads to loss of fixed ammonium, and the Kjeldahl procedure used to determine the nitrogen in the residue from this treatment fails to recover this nitrogen quantitatively.
Evaluation of the Evaporation Zone in Soil by Measurement of Heat Flux
Authors: Gardner H. R. , Hanks R. J. 
Published: July 2010

AbstractHeat flux plates were employed to measure the movement of heat within a soil column during the process of water evaporation. The movement of the zone of evaporation was followed for a bare soil column with and without a surface treatment of hexadecanol. Under these conditions the evaporation zone was approximately 1 cm thick, and equal rates of evaporation were found for the check and hexadecanol treatments when the zones were at the same depth after the treated zone had been passed. Diurnal fluctuation of applied heat energy slowed the evaporation process but the evaporation zone movement was still evident.
Availability and Fractionation of Residual Phosphorus in Soils High in Aluminum and Iron
Authors: Robertson W. K. , Thompson L. G. , Hutton C. E. 
Published: July 2010

AbstractThe fate of applied P has been studied on two soils high in Al and Fe using the method of Chang and Jackson (2). Water soluble‐P, Ca‐P, Al‐P, and Fe‐P fractions were determined. The “occluded” and organic P were not determined but were considered to be the difference between the above forms and the total P.Single applications of concentrated superphosphate (CSP) and rock phosphate (RP) up to 175 and 349 lb of P/acre respectively were made to Norfolk loamy fine sand, and corn (Zea mays L.) was used as an indicator crop. Annual applications of ordinary superphosphate (OSP) to the same plots using the split‐plot technique gave significant yield responses in all but 3 of the 5 years following P application. Only a small part of the increase in total P due to the initial P application could be accounted for in the Al‐P, Fe‐P and Ca‐P fractions after 8, 11 and 13 years cropping. Apparently much of the P had been converted to occluded P. This may account for the need for currently applied P.After 2 years 220 lb of P/acre from CSP applied to Red Bay fine sandy loam raised the total P 95 lb/acre above that of a 110 lb/acre application. Of this amount 54, 28 and 5 lb/acre (92%) were in the Al‐P, Fe‐P and Ca‐P forms, respectively. An 108 lb of P/acre increase in total P due to an application of OSP 8 years before raised the Al‐P, Fe‐P and Ca‐P, 17, 15 and 3 lb/acre (32%), respectively. Assuming that CSP reacted in the soil like OSP, it was apparent that P was converted to other forms with time similar to Norfolk loamy fine sand. The formation of Fe‐P from Ca‐P in Red Bay fine sandy loam was related to total P 2 and 8 years after application.After 2 years there was 4.1 and 1.5 times as much Al‐P and Fe‐P, respectively, in the soil following CSP than RP treatments for Red Bay fine sandy loam. Plant uptake data using P32 also showed P from CSP was more available than from RP.
Effect of Added Plant Tissue on Decomposition of Soil Organic Matter Under Different Wetting and Drying Cycles
Authors: Arsjad Sitanala , Giddens Joel 
Published: July 2010

AbstractThe so‐called priming effect occurred during the first 22 days when C14 labeled soybean (Glycine max) stems or leaves were added to Cecil and Bladen soils under constant moisture and under wetting and drying cycles. After 96 days the effect of added plant tissue upon native soil organic matter decomposition was significant for Cecil but not for Bladen soil Wetting and drying greatly increased soil organic matter decomposition and increased the priming effect in the Bladen soil for the first incubation period but decreased this effect in the Cecil soil.
Characterization of a Streptomyces sp. Isolated from Root Nodules of Ceanothus velutinus Dougl.
Authors: Wollum A. G. , Youngberg C. T. , Gilmour C. M. 
Published: July 2010

AbstractA procedure using a 20% solution of H2O2 as the sterilizing. agent was developed which allowed the isolation of a Streptomyces sp. from the root nodules of C. velutinus. This was repeated 17 times and a total of 136 similar streptomyces sp. were isolated from the nodules of this nonleguminous, nitrogen‐fixing plant. Further characterization by standard bacteriological procedures suggested that the isolates belonged to a single species, which did not correspond to any previously recognized Streptomyces sp The inoculation of sterilized, germinated seeds with some of the isolates showed that they were capable of initiating the infection of root hairs on C. velutinus. Infection and nodulation of C. velutinus occurs in at least three distinct phases. At first there is a swelling at the tip of the root hair, which is followed by a marked swelling. As infection continues the root hair becomes swollen to its base. Shortly after this point has been reached the final phase of the process is recognized as the formation of visible nodules on the root surface. In the presence of some isolates and a sterile nodule extract, the infection process has been observed to the point where the entire root hair has become swollen. Without the sterile extract the infection was not as complete and progressed much slower. When the isolate is omitted and the seedling inoculated with the sterile nodule extract, a slight swelling at the root hair tip occurs. Despite the similarity of the isolates, infective ability of the isolates which appears to be a unique feature of the endophyte, no species name should be proposed until the demonstration of nodule formation with the isolate. Also it was suggested that some predisposing agent(s) may be required for the rapid initiation of the infection process in C. velutinus seedlings.
Mechanisms for the Movement of Mn, Fe, B, Cu, Zn, Al and Sr from One Soil to the Surface of Soybean Roots (Glycine max)
Authors: Oliver S. , Barber S. A. 
Published: July 2010

AbstractThe role of root interception, mass‐flow and diffusion in supplying ions to soybeans growing in a leached subsoil was investigated. Root interception was the main mechanism for the supply of Cu, Al and Sr to the soybean roots. Mass‐flow was the most important for B and diffusion was the most important for Mn, Fe and Zn.The most significant mechanisms will likely vary with the crop grown, climate and soil.
A Culturing Unit to Evaluate Sodic Influence on Calcium Nutrition of Alfalfa
Authors: Nightingale H. I. , Smith R. L. 
Published: July 2010

AbstractA culturing unit was constructed whereby the influence of exchangeabe sodium on the growth and mineral uptake of established alfalfa (Medicago sativa) could be determined. Two compartments, separated by a membrane through which roots could penetrate, were placed one above another. The top compartment contained a calcareous nonsodic soil to which Ca45CO3 was added. The lower compartment contained complete nutrient solution.Following the establishment of the plants in the nonsodic soil and complete nutrient solution, four levels of exchangeable Na percentage, 0.9, 14.9, 35.4, and 54.9, were established by adding solutions of Na2CO3 to the soil. The yield and Ca content of leaves was reduced by the sodic influence even though sufficient Ca was available to the plant through the nutrient solution. This decreased Ca uptake was compensated for by greater uptake of Mg.
Comparison of Fragipan and Bisequal Profiles of the Gulf Coastal Plain with Soils of Southern Loess Belt
Authors: Vanderford H. B. , Shaffer M. E. 
Published: July 2010

AbstractBisequal profiles with fragipans have been studied in the Southern Loess Belt by several research workers. The purpose of this paper is to compare morphological, physical and chemical properties of silty soils that developed in the Gulf Coastal Plain with features of similar soils in the Loess Belt. Bisequal profiles with fragipans are common in the Coastal Plain which are similar in morphology to bisequal soils that are found in the Southern Loess Belt. The bisequal expression varies with drainage with the maximum development in somewhat poorly drained profiles. The leached A′2 horizon above the firm fragipan attains a thickness of 3 or 4 inches in some soils, and seems to grow upward into the B2 horizon and downward by tongues and cleavage streaks into the fragipan. It appears to be the most highly weathered horizon in the profile and clay particles migrate from this zone into the fragipan by way of the gray streaks. As this process continues a cambic layer forms above the A′2 horizon in the moderately well and somewhat poorly drained profiles. The genesis of these soils in the Gulf Coastal Plain appears to be similar to the genesis of bisequal profiles of the Loess Belt. Knowledge of the genesis and nature of the bisequal profiles will aid in classifying these soils in the new system of classification.
The Persistence of Decaying Wood in the Humus Layers of Northern Forests
Authors: McFee W. W. , Stone E. L. 
Published: July 2010

AbstractThe amount, composition, and persistence of decaying wood in humus layers was examined in yellow birch (Betula alleghaniensis Britton)‐red spruce (Picea rubens Sarg.) stands in the Adirondack Region of New York. The wood is initially attacked by brown rot fungi, but thereafter decomposes very slowly and may persist in the humus layer for a century or more. Separable wood residues weighed as much as 41,800 lb/acre and composed 14 to 30% of the forest floor. These residues were significantly lower in N and P content than the surrounding humus.
Simultaneous Determination of Surface Area and Cation‐Exchange Capacity
Authors: Bower C. A. , Hatcher J. T. 
Published: July 2010

AbstractIn previous work it was found that Cl repulsion by arid‐zone soi's from a solution having a high and uniform concentration of Cl is closely related to surface area as measured by ethylene glycol retention. Based on this information, a measurement of Cl repulsion has been incorporated into the NaOAc method for determining cation‐exchange capacity. As a result, values for surface area, as well as cation‐exchange capacity, can be obtained with but little additional analytical work, except for soils high in kaolinite and sesquioxides.
Osmotic Efficiency Coefficients Across Compacted Clays
Authors: Kemper W. D. , Rollins J. B. 
Published: July 2010

AbstractMovement of solution through clays in response to salt concentration differences and in response to hydraulic pressure differences was measured. Rate of movement of solution in response to an “osmotic pressure” difference was divided by the rate of movement in response to an energywise equal hydraulic pressure difference to obtain osmotic efficiency coefficients. These osmotic efficiency coefficients are increased by saturating the clay with monovalent rather than divalent cations, using divalent rather than monovalent anions, decreasing the water content of the clay plug and by decreasing the average concentration of the outside solution. Effects of these factors on the osmotic efficiency are predicted by diffuse layer theory (negative adsorption of salt) and hydrodynamic considerations.
Determination and Isotope‐Ratio Analysis of Different Forms of Nitrogen in Soils: 4. Exchangeable Ammonium, Nitrate, and Nitrite by Direct‐Distillation Methods
Authors: Keeney D. R. , Bremner J. M. 
Published: July 2010

AbstractMethods of determining exchangeable ammonium, nitrate, and nitrite in soils which do not require extraction of the soil sample are described. The soil sample is treated with 2M KCl (5 ml/g of soil) and analyzed directly by steam‐distillation methods involving use of magnesium oxide for liberation of ammonium, ball‐milled Devarda alloy for reduction of nitrate and nitrite to ammonium, and sulfamic acid for destruction of nitrite. The methods are rapid, specific, and precise, and they permit nitrogen isotope‐ratio analysis of exchangeable ammonium, nitrate, and nitrite in N15‐tracer studies of nitrogen transformations in soils. Results of soil analyses by these direct‐distillation methods are practically identical to those obtained by extraction‐distillation methods.
Quenching the High Phosphorus Fixation of Hawaiian Latosols
Authors: Younge O. R. , Plucknett D. L. 
Published: July 2010

AbstractHawaii aluminous‐ferruginous latosols are severely deficient in total and available phosphorus and have very high phosphorus fixation capacities. This severely limits croup production. Results of 6‐year field experimentation indicate that the problem of phosphorus fixation and low yields can be overcome by a heavy initial phosphorus treatment which quenches the fixation complex, and thus diverts the extra phosphorus to maximum yield production. Additional phosphorus must be added every few years to replace depletion by crop removal, erosion and slow residual fixation. Long‐term yields indicate the costs of reclamation may be readily amortized over a 10‐ to 20‐year period.
Colorimetric Determination of Iron of Mixed Valency by Orthophenanthroline
Authors: Murti G. S. R. Krishna , Volk V. V. , Jackson M. L. 
Published: July 2010

AbstractA colorimetric method for the determination of Fe in a mixed Fe3+ and Fe2+ valency system has been proposed. Complete reduction of Fe3+ to Fe2+, which was essential for the formation of a stable colored complex with orthophenanthroline, was obtained when the iron solution, buffered at pH 3.5 with sodium acetate, was heated for 1 hr at 65C with 5% hydroxylamine hydrochloride. This reduction procedure was found to be suitable even for solutions at a higher pH where iron was present either as Fe3+ or as a hydroxylated complex. The organe color complex was found to be stable at pH values 2 to 9 for at least 20 hr and no interference of citrate ion was observed in the stability or the formation of the color.
Ionic Balance and Growth of Sixteen Plant Species
Authors: Noggle J. C. 
Published: July 2010

AbstractThe total concentration of inorganic cations (K+, Na+, Ca2+, Mg2+) exceeds the total concentration of inorganic anions (NO3‐, H2PO4‐, SO42‐, Cl‐) in most plant tissue, and the difference between the two is an estimate of the organic anion concentration. Previous investigations have shown that vegetative growth of barley with high fertilization rates was regulated to some extent by the organic anion concentration. In this study, 16 plant species were grown in the greenhouse to test the consistency of this relation with different ion accumulation patterns. The inorganic anion content of the plant tissue was varied by applying either SO42‐ or Cl‐ to the soil. All Cl‐treated plants had a higher inorganic anion concentration than the SO4‐treated plants. The organic anion concentration in 10 of the plant species was lower in the Cl‐treated plants. The lower yield of each plant species was associated with the plants that had the higher total inorganic anion concentration. The results of this study, with one possible exception, are consistent with the concept that reducing the organic anion concentration in plants reduces growth.
Cation‐Exchange Capacity as a Function of Organic Matter, Total Clay, and Various Clay Fractions in a Soil Toposequence
Authors: Wilding L. P. , Rutledge E. M. 
Published: July 2010

AbstractSoil cation‐exchange capacity (CEC) as determined for A and B horizons of Miami, Celina, Crosby, and Brookston soils was statistically partitioned using multiple linear regression analyses into the following sets of components: [1] organic matter (OM) and total clay; and [2] OM, 2‐0.2µ, and <0.2µ clay. Coefficients of multiple correlation (R) for independent variables used in regression components [2] are of larger magnitude but not significantly different from components [1]. R values for components [1] range from .76 to .87 and for components [2] from .78 to .92. Organic matter contributes most to the CEC in A horizons whereas <0.2µ clay contributes greatest to the CEC of B horizons for soils of this toposequence. With one exception, 2–0.2µ clay is not significantly correlated with CEC in either A or B horizons. The average CEC of OM for Brookston A horizons is lower than for other toposequence members (154 vs. ca. 200 meq/100 g), whereas for B horizons it is considerably greater (361 vs. ca. 290 meq/100 g). The average CEC of fine clay in B horizons progressively increases with decrease in drainage class, varying from about 70 meq/100 g in Miami to 121 meq/100 g in Brookston.
Forces Involved in Ion Fixation by Vermiculite
Authors: Kittrick J. A. 
Published: July 2010

AbstractThe temperature at which vermiculite loses or gains an interlayer of water molecules was compared for a number of interlayer ion saturations. Results indicate the difference between contracting and expanding forces in vermiculite to be dependent upon interlayer ion charge, distance, and hydration energy. Important interlayer forces therefore must be electrostatic attraction between the negatively charged layers and the positive interlayer ions, and expansion due to ion hydration. Basically, ion fixation appears to occur when electrostatic forces of attraction exceed those of hydration
Reactions of Selenite‐Selenium Added to Soils That Produce Low‐Selenium Forages
Authors: Cary Earle E. , Wieczorek George A. , Allaway W. H. 
Published: July 2010

AbstractAlfalfa (Medicago sativa L.) absorbed Se in concentrations potentially toxic to livestock from four of seven soils treated with radioactively labeled Se at a 2.5‐ppm rate as a selenized concentrated superphosphate. When the Se rate was 0.5 ppm, only the first few crops from one soil contained toxic amounts. Subsequent alfalfa crops from all seven soils receiving 0.5 ppm and six of seven soils receiving 2.5 ppm contained nearly constant, nontoxic levels of Se that would protect animals from Seresponsive diseases.After 1 year of cropping soils in pots in a greenhouse, up to 40% of the residual Se could be removed by isotopic exchange with selenite. Further fractionation indicated that organic Se compounds and elemental Se or selenides are also probably present in the residual Se.
Analysis of Gamma‐Ray Spectra From Soils and Plants: I. Computer Program With Correction for Gain‐Shift and Sample Bulk Density
Authors: Elfield Mark , Franklin R. E. 
Published: July 2010

AbstractA computer program and counting techniques used in analyzing complex gamma spectra were developed. The program computes a standard spectrum for each radioisotope based on the bulk density of the sample and then corrects for differences in the energy equation of reference and sample spectra. A solution is then obtained by the method of least‐squares.In addition to a numerical solution, the program provides logarithmic plots of the unknown spectrum, the solution, and the individual components. The approximate execution time is 10 to 15 seconds on an IBM 7094 computer. The program presently has a capacity of 16 standard spectra (512 channels each). This program has been applied successfully to the analysis of complex gamma spectra obtained from soils and plants.