bluuebunny/crossref_metadata_2025_split huggingface dataset:
Biological Assay of Pumice Soil Fertility
Authors: Youngberg C. T. , Dyrness C. T. 
Published: July 2010

AbstractThe fertility of pumice soils is difficult to assess by laboratory analysis. A biological assay of growth responses yields more meaningful information. Four pumice soils common in central Oregon were assayed in the greenhouse using ponderosa pine as an indicator species.A composite experimental design was used involving additions of N, P, K, Ca, and S. There were no responses to either K or Ca. Nitrogen appeared to be the most deficient nutrient element since it was the only one tested that gave large responses when added alone. Combinations of N and P and N and S gave better responses than N alone. Best growth resulted from addition of N, P, and S in combination. The experimental design used was very satisfactory for this type of assay, particularly in evaluating various nutrient interactions.
Water Permeability of Saturated Soils as Related to Air Permeability at Different Moisture Tensions
Authors: Aljibury F. K. , Evans D. D. 
Published: July 2010

AbstractThe relationship among soil moisture tension, air permeability, and water permeability at saturation was determined for several disturbed soil samples ranging in texture from coarse sand to clay loam. A typical graph of tension versus air permeability shows that a slight tension is necessary before the air permeability is different from zero. With increasing tension, air permeability increases sharply until it levels off near the value of water permeability. The air and water permeabilities are nearly the same for tensions > 100 cm of H2O, unless cracking occurs. Then air permeability greatly exceeds water permeability.Air permeability at field moisture percentages and water permeability of saturated soil were determined for soil cores of known soil moisture tension. As with disturbed samples, the two permeabilities were nearly the same at tensions of 100 cm of H2O.
Variation in Foliage Composition and Diameter Growth of Yellow Birch with Season, Soil, and Tree Size
Authors: Hoyle M. C. 
Published: July 2010

AbstractFoliage samples and diameter measurements were taken periodically from yellow birch (Betula alleghaniensis) trees on well‐drained Hermon and poorly drained Whitman soils. Foliar analyses were made to determine seasonal changes in composition, and differences between trees and soil series. Leaf weights increased with season and were higher on the Whitman. Leaf moisture trends reflected soil moisture regimes. Nutrient percentages decreased during early June. Thereafter N, P, S, and K percentages flucturated slightly until September, then decreased until abscission, while Mg fluctuated considerably and Ca increased steadily. Absolute amounts of all six elements increased during June. Nitrogen, P, S, and K varied slightly during summer and decreased prior to leaf yellowing. Total Mg reached peak values in August and then decreased while total Ca increased continually. Total P, K, and S was comparable on both soils. Total N, Ca, and Mg was higher on the Whitman. Greater diameter increments of study trees were also recorded on the Whitman soil. The total content expression provided more meaningful information than nutrient percentages. Specific periods of sampling birch foliage are given.
Influence of Different Diffusivity‐Water Content Relations on Evaporation of Water from Soils
Authors: Hanks R. J. , Gardner H. R. 
Published: July 2010

AbstractEstimates of the influence of variations in the diffusivity‐water content relation on evaporation showed that where the diffusivity was changed at high water contents, evaporation was changed accordingly. However, variations in the D(θ) relation at lower water contents showed little influence on cumulative evaporation.Estimates were also made for layered soils with the D(θ) relation for one layer 10 times that of the other layer. Cumulative evaporation increased significantly, if the diffusivity of the bottom layer was greater, as the depth of the surface layer decreased, provided the surface layer depth was less than half the total depth of the soil. Where the diffusivity was greater for the surface soil, cumulative evaporation increased as the depth of the surface layer increased.All of the estimates were made based on the assumption that a diffusion‐type equation is valid for evaporation.
Migration of Interlamellar Water During Freezing and Thawing of Wyoming Bentonite
Authors: Anderson Duwayne M. , Hoekstra Pieter 
Published: July 2010

AbstractHomoionic, clay‐water pastes of Wyoming bentonite were studied at near freezing temperatures by X‐ray diffraction. On freezing, the initial high d(001) spacings of the lithium‐ and sodium‐bentonite pastes decreased, first to about 19A and at about −10C to 16A. When the temperature was raised the d(001) spacings of the frozen clays increased substantially; on melting, the d(001) spacings quickly expanded to their initial high values. The behavior of the hydrogen‐aluminum‐, potassium‐, and calcium‐bentonite was similar except that spacings greater than about 20A did not occur. All the normally observed diffraction maxima of ordinary ice were present after lattice collapse. No anomalous diffraction maxima suggesting the presence of ice having an unusual crystallographic structure were detected. Evidently, when bentonite‐water pastes are frozen all but two or three monomolecular layers of the interlamellar water migrates into the pore space to form ordinary ice. The remaining interlamellar water therefore must correspond to the “unfrozen” water of previous investigations.
Diffusion of Potassium‐40 Into an Illite During Prolonged Shaking
Authors: de Haan F. A. M. , Bolt G. H. , Pieters B. G. M. 
Published: July 2010

AbstractThe diffusion of K40 into the clay crystal lattice of an illite was studied at equilibrium concentrations comparable to those occurring under field conditions. Time of equilibration was extended over 16 months. The self‐diffusion constant was found as roughly 1–3 × 10‐23 cm2 sec‐1; the equivalent depth of penetration during the period of investigation amounted to a few Angstroms only.
Yield and Nutrient Uptake by Corn (Zea mays L.) for Silage on Two Soil Types as Influenced by Fertilizer, Plant Population and Hybrids
Authors: Robertson W. K. , Hammond L. C. , Thompson L. G. 
Published: July 2010

AbstractThe influence of corn hybrid on forage yield, nutrient composition, uptake of nutrients and percentage recovery from the fertilizer were studied at three plant populations and four fertilizer rates. Multi‐eared hybrids yielded more forage than single‐eared hybrids but tall growing hybrids did not always produce more than shorter growing hybrids. Increasing plant population had no significant effect on nutrient composition but did increase yields and uptake of N, P, and K. Corn hybrids differed widely in the amount of fertilizer they recovered. For 7 hybrids of corn, averaging 13,900 lb of dry forage/acre the average uptake of N, P, and K was 177, 25, and 242 lb, respectively. On nonirrigated soils a tall‐growing hybrid did not respond to fertilizer or plant population as did a short‐growing hybrid.
Retention of Acetate by Montmorillonite
Authors: Bingham F. T. , Sims J. R. , Page A. L. 
Published: July 2010

AbstractAcetate retention was measured by treating suspensions of montmorillonite with C14‐labeled acetate solutions, removing excess acetate by washing with methanol, and determining the acetate remaining by C14 assay of the clay. The amount of acetate retained by montmorillonite was found to be dependent upon the concentration of salt used, pH of the system, and concentrations of competitive anions.Maximum acetate retention (0.05 meq acetate/g clay) occurred over the pH range of 2 to approximately 6. Increases in pH above 6 resulted in marked reductions in acetate retention. Under uniform conditions of pH (≅ 5.5), concentrations of approximately 2n acetate salts were required to attain maximum retention, irrespective of salt source. Release studies showed OH‐, F‐, and H2PO4‐ to be effective in removing sorbed acetate. On the other hand, SO42‐ was only partially effective while NO3‐ and Cl‐ were ineffective in releasing acetate.
Effects of Crop Residue, Soil Temperature, and Sulfur on the Growth of Winter Wheat
Authors: Stewart B. A. , Whitfield C. J. 
Published: July 2010

AbstractThe interrelations of wheat straw, fertility levels, and three soil temperatures on the growth and nutrient status of winter wheat were investigated. When only N and P were added, the decomposition of straw incorporated with the soil immobilized a portion of the available S and caused a reduction in yield. When S was added with the N and P, the incorporation of straw had no effect on yield.Ratios of total N to total S and protein N to protein S were determined on the wheat tissue. Indications are that a total N/S ratio of these elements can be used as a very good criterion in assessing the S status of plants. A total N/total‐S ratio of about 17:1 or less suggests that S is not limiting, while a greater ratio points out that S is limiting the formation of protein. The N‐S relation in soil organic matter is also discussed in relation to its abilities and limitations in supplying S for plant growth.
Contribution of Adsorbed Cations to Diffusion in Clay‐Water Systems
Authors: van Schaik J. C. , Kemper W. D. , Olsen S. R. 
Published: July 2010

AbstractSelf‐diffusion of sodium and calcium ions was measured in bentonites containing various amounts of water and the respective chlorides. The contribution of mobile exchangeable cations to diffusion was calculated from the data by subtracting measured rates of free electrolyte diffusion from the total rate of self‐diffusion measured in these systems. Mobile exchangeable cations accounted for from 3 to over 500 times as much diffusive movement as was accounted for by free electrolyte cations in these systems. The fractions of the exchangeable cations that were in the diffuse layer were estimated from the contribution of exchangeable ions to diffusion, the fluidity of water near clay particles and the calculated concentration distributions of the adsorbed cations. Approximately 70% of exchangeable sodium ions were mobile. Approximately 25% of exchangeable calcium ions were mobile.
Ureolysis, Immobilization, and Nitrification in Black Spruce (Picea mariana Mill.) Humus
Authors: Roberge M. R. , Knowles R. 
Published: July 2010

AbstractThe transformations of urea in black spruce humus from an untreated plot and from a plot fertilized with 400 lb urea‐N/acre 2 years before sampling were studied using incubation tests. Urea‐N (3,500 ppm) added in the laboratory disappeared within 2 days. During the first 3 days, exchangeable ammonium‐N equivalent to about 82% of the added urea‐N appeared and the pH increased by 1.5 units, but no nitrates were formed. Thereafter, and up to 42 days, there was a very small immobilization of the ammonium‐N and a decrease in pH of approximately 0.5 unit. Nitrification occurred only after 28 days, and then only in the field‐treated humus when urea was again added in the laboratory. The addition of (NH4)2CO3‐N (3,500 ppm) had very similar effects except that a slightly greater rise in pH was accompained by somewhat more immobilization of the ammonium‐N than occurred following the addition of urea.It is concluded that ureolysis was very rapid; that, in spite of the high C/N ratio, immobilization was small; and that, in most treatments, nitrification was negligible, and therefore leaching of nitrates following the fertilization of acid forest soils with 400 lb urea‐N/acre is not likely to be a problem.
Effect of Nitrogenous and Potassic Salts with Phosphates on the Yield and Phosphorus, Nitrogen, Potassium, and Manganese Contents of Oats (Avena sativa L.)
Authors: Hamilton Herman A. 
Published: July 2010

AbstractOn a neutral Grey Wooded soil receiving identical rates of N, P, and K from different sources, there were significant differences (at the 5% level) in oat grain yields as well as straw yields. The choice of salts used influenced differently the yields of straw and those of grain. Whereas maximum grain yields were realized with monocalcium phosphate monohydrate (MCP) + (NH4)2SO4 + KCl, maximum straw yields were obtained with MCP + (NH4)2SO4 + K2SO4. With diammonium phosphate (DP) as a source of N and P, there were no significant differences in yield of grain or straw with the use of K2SO4 or KCl, however N, P and K uptake by straw was invariably greater with K2SO4 than with KCl. Despite the equivalence of N, P, and K applied, there were considerable differences in the nutrient composition of grain and straw. With the exclusion of the control treatment, N in straw varied from 0.40 to 0.54%, P from 0.021 to 0.046%, K from 3.38 to 3.94%, and Mn from 9.4 to 63.4 ppm. In a comparison of the nitrogenous sources associated with MCP + KCl, Mn uptake was in the order NH4Cl > (NH4)2SO4 > NH4NO2. While the symptoms of Mn deficiency were most pronounced for the control treatment, these symptoms disappeared in all the fertilized treatments excepting MCP + KNO2.
Plant Responses to Oxygen Supply and Physical Resistance in the Root Environment
Authors: Rickman R. W. , Letey J. , Stolzy L. H. 
Published: July 2010

AbstractLimiting and nonlimiting aeration treatments which were monitored with platinum microelectrodes were applied to soil at two levels of compaction in a greenhouse experiment. Total dry weight of tops and depth of root penetration were used to compare tomato (Lycopersuon esculentum ‘Rutgers’) growth under the various treatments. No difference in top growth was detected between the two levels of compaction when oxygen diffusion rate (ODR) values were nonlimiting in both. Roots penetrated compacted layers in which ODR values were non‐limiting but their rate of extension was slower than in less compacted layers with nonlimiting ODR. Top growth in soils with low ODR values was reduced regardless of compaction. Root extension in the least compacted soil with low ODR values was less than root extension in that soil with high ODR values.
Electrochemical Determination of Diffusion Coefficients in Clay‐Water Systems
Authors: Mokady Raphael S. , Low Philip F. 
Published: July 2010

AbstractPastes containing different concentrations of MCl (M = Li or Na) were prepared by mixing MCl olutions with M‐montmorillonites. The pastes were used in pairs in which the members differed only in NaCl activity. Initially, a Ag‐AgCl electrode and an M‐sensitive glass electrode were inserted into each paste and the emf between them was measured. Then the members of each pair were brought into contact with Ag‐AgCl electrodes inserted in them. The emf's between the latter electrodes were also measured. From the two kinds of emf measurements the transference numbers of the ions in the different pairs were calculated. These transference numbers, along with the measured electrical conductances of the pastes, were used to calculate the ionic mobilities. Finally, the calculated ionic mobilities and the known ionic concentrations were inserted in the Nernst equation to calculate the diffusion coefficients of the respective salts
Volumetric Calibration of Neutron Moisture Probes
Authors: Douglass James E. 
Published: July 2010

AbstractA volumetric method of estimating the slope (b coefficient) of a neutron moisture probe calibration curve is discussed. Coefficients obtained for three probes by this method did not differ significantly between soil series or between horizons within a series. Simply dividing the count rate in water by 100 gave a value virtually identical to the b coefficient determined volumetrically for these probes and soils. Agreement was excellent between measured outflow and outflow predicted from neutron measurements made with a volumetrically calibrated moisture probe.
Kinetics of Cesium Sorption by Clay Minerals
Authors: Sawhney B. L. 
Published: July 2010

AbstractTime course and the processes in the sorption of cesium from dilute solutions by illite, montmorillonite and vermiculite saturated with Ca or K and in the absence of excess saturating cation were investigated.Cesium sorbed by illite and montmorillonite quickly reached an approximate equilibrium; the Cs sorbed by montmorillonite did not change with time while the Cs sorbed by illite changed only slightly. On the other hand, the Cs sorbed by vermiculite did not reach an equilibrium even after 500 hr. Cesium sorbed by Ca‐vermiculite continued to increase while the Cs sorbed by K‐vermiculite decreased.Since the sorption of Cs by illite is limited to the external planar surfaces and interlattice edges only, equilibrium is quickly reached. Equilibrium in montmorillonite is attributed to its expanded lattice which makes all exchange sites equally available and permits exchange readily. The increased Cs sorption by Ca‐vermiculite, on the other hand, is attributed to the different sorption rates by different exchange sites: initial fast sorption on external surfaces and edges followed by slow diffusion into the interlayers. The decreased Cs sorption by K‐vermiculite is perhaps associated with the collapse of the partially hydrated vermiculite in suspension to 10A.
Phosphorus Supplying Capacity of Lowland Rice Soils
Authors: DeDatta S. K. , Moomaw J. C. , Racho V. V. , Simsiman G. V. 
Published: July 2010

AbstractIn a greenhouse experiment with rice (Oryza sativa L.) on four lowland soils, Milfor 6(2), an indica variety from the Philippines, was used to test the relative utilization of soil and fertilizer P (P32‐labelled superphosphate) at various N rates. Added P remaining in solution in six soils was also determined using Ca (H2P32O4)2 at various equilibration times.From 8 to 27% of the total P in the plant was derived from applied P, the amount presumably depending on the availability of soil P under continuous submergence. In general the amount derived was not affected by different levels of N fertilization. The results indicate that, by using the ‘A’ value concept, the rice plant itself gives an indication of the P supplying capacity of some flooded rice soils. Results also show that within 4 days of equilibration the added P remaining in solution was lowest in acid latosolic soils containing kaolin type minerals, moderately high in soils containing mainly montmorillonite, and essentially unaltered in calcareous soil.
Adsorption‐flocculation Reactions of Soil Polysaccharides with Kaolinite
Authors: Saini G. R. , MacLean A. A. 
Published: July 2010

AbstractThe adsorption of a soil polysaccharide by kaolinite saturated with different exchange cations was determined with polysaccharide tagged with C14. Adsorption followed the Langmiur equation. Adsorption increased with exchange cations with the effect of Fe3+ > Al3+ > H+ > Ca2+ > Mg2+ > Na+.Filtration rates of kaolinite were also increased by saturating with different cations with the effect of Fe3+ > Al3+ > H+ Ca3+, Mg2+ > Na+. In a dispersed system, filtration rates increased with successive additions of polysaccharide and then decreased.It is suggested that a segment rather than the whole polysaccharide molecule competed with the solvent molecule for surface sites whereby a fraction of the total segments was adsorbed and the remaining segments protruding from he interface were attached to free surface on an adjacent soild particle. With subsequent additions of polysaccharide, it is suggested that conditions were created whereby there was insufficient free surface for bridging or possibly the extended segments interfered physically with one another and prevented bridge formation.
Hydration Status of Adsorbed Cations
Authors: Shainberg I. , Kemper W. D. 
Published: July 2010

AbstractEnergies with which cations adsorb water molecules are calulated and discussed. An amendment to the diffuse layer theory is developed which takes into consideration the hydration energy of the ions, position of the negative charge in the clay, and other steric factors. Calculations using this amended theory predict differences in the adsorption characteristics of Li+, Na,+ and K+ which appear to be in general agreement with experimental observations.Calculations for the interacting diffuse layer case indicate that the fraction of the adsorbed ions residing in the first molecular layer of water (Stern Layer) is essentially independent of distance between the platelets when this distance is greater than 2.5A. Pushing the platelets closer together results in a arger portion of the adsorbed ions in the Stern Layer.The various assumptions and estimates involved in the development of the theory and the calculations are discussed.
Micronutrient Cation Complexing in Soil Solution: II. Complexing of Zinc and Copper in Displaced Solution from Calcareous Soils
Authors: Hodgson J. F. , Lindsay W. L. , Trierweiler J. F. 
Published: July 2010

AbstractZinc deficiencies are generally more widespread on calcareous soils than are Cu deficiencies. The concentration and the degree of complexing of Zn and Cu were measured in the soil solution of 20 calcareous soils from Colorado. The Zn levels in solution were generally less than 2 ppb with rarely more than 75% of the Zn being complexed. Copper levels generally ranged from 5 to 16 ppb in the soil solution with 98 to 99% of the Cu present as organic complexes. Thus, complexing increased the total Cu concentration in solution by a factor of about 100, whereas it increased the total Zn in solution by a factor of 4 or less. Compared to acid soils studied previously, soluble Zn levels were much lower and complexing of Cu was somewhat higher in calcareous soils.
Effect of Surface‐Applied Wheat Straw on Soil Water Losses by Solar Distillation
Authors: Greb B. W. 
Published: July 2010

AbstractSoil surface application of 1,120, 2,240, and 3,360 kg/ha of wheat straw (Triticum aestivium L,), equivalent to 30, 60, and 90% soil surface coverage, reduced water losses from a wet soil surface by solar distillation 16, 33, and 49%, respectively, for a 20‐day period compared with no straw. A surface application of 6,720 kg/ha, or 180% soil coverage, reduced soil water loss only slightly more than did the 3,360 kg/ha application. Water losses and effectiveness of straw tended to diminish with time as soil water was depleted. The presence of clear plastic canopy increased daily soil temperature maximums at 2.5‐cm depth by approximately 11.5F. Maximum daily soil temperatures, both with and without plastic, were reduced nearly 3 F/1,120 kg per ha of added straw. The results suggest part of the mechanism by which more soil water is conserved under stubble mulch summer fallow than with clean fallow.
A Technique for Rapid and Precise Positioning of Neutron Depth Probes
Authors: MacGillivray N. A. , Goldberg Irving 
Published: July 2010

AbstractA device is described which replaces the standard cable clamp used for positioning of neutron depth probes. With the technique developed, positioning is accomplished by suspending he probe from brass stops affixed to the cable.Several years experience have demonstrated this technique to be entirely satisfactory, resulting in improvement in precision of probe positioning, as well as in a considerable saving of time.