bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Effect of Soil Surface Conditions on Evaporation of Soil Water
Authors: Benoit G. R. , Kirkham D. 
Published: July 2010

AbstractA laboratory study investigating the comparative effectiveness of a dust, a ground corncob and a gravel mulch in inhibiting the evaporation of soil water from prepared 15‐inch long soil cores 3 inches in diameter under various conditions of radiation (0, 200, or 450 ft‐c.) and air movement (0.5 and 7.5 feet per second) showed the gravel mulch to be more effective than either a dust or a ground corncob mulch. The dust mulch proved to be the least effective. For example, the rate of loss from the mulched cores under conditions of 450 ft‐c. of radiation and air movement of 7.5 feet per second was 0.089, 0.146, and 0.170 g. per hour for the gravel, the corncob and the dust mulch, respectively. It was also observed that the rate of evaporation from the cores increased with both radiation and air movement levels. By the end of 600 hours unmulched cores had lost 1.25 to 5 times as much water as had mulched cores.A concurrent study of the soil moisture distribution that develops with depth as evaporation of soil water proceeds was conducted. The study indicated that the soil moisture distribution in the mulched cores and for the 6‐ to 15‐inch depth of unmulched cores remained essentially constant with depth.
Soil Moisture Interface Effects upon Readings of Neutron Moisture Probes
Authors: Lawless G. Paul , MacGillivray Norman A. , Nixon Paul R. 
Published: July 2010

AbstractMeasurements of soil moisture by the neutron scattering method are inaccurate when made in the presence of abrupt moisture changes. The effects of air‐soil interfaces and of wet‐dry soil interfaces were investigated using neutron probes of four different designs. Three of the probes were used to study the effects of wet soil layers within dry soil masses.Readings taken at shallow depths were found to have the greatest errors. These errors were always negative. Absolute error and depth within the soil to which this effect occurs were related to soil moisture content. Some means of correcting such errors should be used. Errors in determining moisture content of soil zones containing wet‐dry interfaces or wet layers were not as serious, and could be neglected in many practical applications. This was especially true when depth reading increments of 6 inches or less were used. These errors were usually negative. Neutron probes tend to underestimate soil moisture content at interfaces or in stratified profiles.Probe depth reading increments of 1, 3, and 6 inches all gave about the same accuracy of moisture determination. Twelve‐inch reading increments gave errors of as much as 6 times greater than those of the smaller increments.The influence of probe geometry upon neutron meter readings is also discussed. When compared on a basis of equivalent source strength, in uniform soils, the probe with end placement of the source was found to be considerably more efficient than the probes with center placement of the source.
Hydrolysis and Exchange Reactions of the Aluminum Ion in Hectorite and Montmorillonite Suspensions
Authors: Frink C. R. , Peech Michael 
Published: July 2010

AbstractThe hydrolysis and exchange reactions of the aluminum ion in hectorite and montmorillonite clay suspensions were studied in an attempt to characterize the nature of exchangeable and nonexchangeable aluminum. In agreement with theoretical considerations of the effect of charge on the electrostatic adsorption of ions, the degree of hydrolysis of the aluminum ions adsorbed on the clay was found to be lower than that in the equilibrium dialyzate. The degree of hydrolysis of the aluminum ions in the dialyzate was, in turn, shown to be lower than that of an aqueous aluminum chloride solution having the same total concentration of aluminum as the dialyzate. The hydrolysis of aluminum ions in clay suspensions is thus suppressed rather than increased as has been suggested. Consistent with this observation, virtually all of the exchangeable aluminum was found to be present in the form of trivalent aluminum ions without any evidence for the formation of basic polymeric aluminum ions even upon addition of moderate amounts of base. It was also shown why the region of maximum buffer action of an Alsaturated clay may differ markedly from that given by the pK value corresponding to the first‐stage hydrolysis of the aluminum ion. The fixation of aluminum by clays in nonexchangeable form was not found to produce any substantial reduction in exchange capacity, and was, therefore, attributed to precipitation of aluminum hydroxide.
Temperature Fluctuations at a Wetting Front: III. Apparent Activation Energies for Water Movement in the Liquid and Vapor Phases
Authors: Anderson Duwayne M. , Linville A. , Sposito Garrison 
Published: July 2010

AbstractMean flow rates for water movement in the liquid and vapor phases were measured at several temperatures in three representative porous media. Apparent activation energies, calculated by means of a form of the Arrhenius equation, were found to vary from 4.3 to 6.1 kcal. per mole. A comparison of these values with the magnitudes of the potential energy barriers encountered in several relevant phenomena led to a postulation of the rate‐limiting processes for the two flow situations. The rate of advance of the liquid front was concluded to be limited partly by the viscosity of thin films of water at the leading edges of menisci and partly by the rate of extension of the air‐water interface. The rate of vapor movement was concluded to be determined primarily by the evaporation rate at the wetting front.
Determination of Anion Adsorption by Clays
Authors: de Haan F. A. M. , Bolt G. H. 
Published: July 2010

AbstractIn interpreting the experimentally observed interaction between anions and clays two aspects should be recognized, viz, (1) the negative adsorption of anions by negatively charged sites, and (2) the positive adsorption on other sites (probably the edges). A generalized equation was developed describing the contribution of the negative adsorption. With regard to experimental methods the need of the use of radionuclides to detect small quantities of positive adsorption is discussed. Data obtained support the applicability of the derived equation to montmorillonite systems and indicate that a small amount of positive adsorption of SO42‐ is present.
Chemical and Mineralogical Properties of an Orangeburg Profile
Authors: Nash V. E. 
Published: July 2010

AbstractThe Orangeburg soil used in this study was formed from unconsolidated sand of the Kosciusko formation. Weathering of this profile has been intense due to the porous nature of the sand and warm, humid climatic conditions. Methods used in this study consisted of X‐ray diffraction, DTA, an alkali differential dissolution technique for amorphous constituents, heavy mineral analysis of sand, total elemental analysis of the clay fractions, and surface area measurements. Minerals present in clay fractions are kaolinite, amorphous material, mica, a 14Å. montmorillonite‐vermiculite‐chlorite intergrade and quartz, in approximate order of abundance. Kaolinite and amorphous material increases whereas quartz decreases with profile depth in the coarse clay fraction. According to Jackson's weathering sequence this would place the lower horizons in a higher weathering stage than the surface horizon. The evidence gained in this study suggests that coarse quartz particles are being broken down to smaller particles resulting in this apparently anomalous sequence. The 14Å. intergrade mineral is more prevalent and stable in the surface horizons and apparently forms from montmorillonite.
Soil Water Relations During Rain Infiltration: II. Moisture Content Profiles During Rains of Low Intensities
Authors: Rubin J. , Steinhardt R. , Reiniger P. 
Published: July 2010

AbstractDuring transient‐state infiltration of steady, low intensity rain into laboratory soil columns, moisture contents at increasing soil depths tended with time to approach a constant level. This level, as well as the observed rates of wetting‐front advance, were higher in cases of more intense rain. For the conditions studied, soil moisture contents and wetting‐front advance rates associated with ponded‐water infiltration were generally considerably higher than those of rain infiltration profiles.The differences between the observed and the theoretically predicted rain infiltration profile data were insignificant for rains of low intensity but significant for those of higher intensity. The wetting front advance observations confirmed certain aspects of the theory presented in part I of this paper.
Nitrogen Transformations in Soil as Related to Structure, Moisture, and Oxygen Diffusion Rate
Authors: Brandt G. H. , Wolcott A. R. , Erickson A. E. 
Published: July 2010

AbstractThe aeration status of a Brookston clay loam was varied by varying aggregate size, moisture content, and moisture tension. Moisture tensions ranged from saturation to about field capacity. Determinations for pH, NH4+, NO3‐ and oxygen diffusion rate were made periodically during 2 months' incubation at 35°C. Oxygen diffusion rate was determined amperometrically, using platinum electrodes 4 mm. long by 0.8 mm. in diameter. Average rates associated with aggregate size and moisture content ranged from 3 to 43 g. O2 × 10‐8 cm.‐2 minute‐1.Fluctuations in oxygen diffusion rate with time paralleled changes in concentrations of NH4+ and NO3‐ and appeared to reflect changes in metabolic demand for oxygen by components of the microbial population other than the nitrifiers.Large discrepancies between NH4+ disappearance and NO3‐ accumulation made it necessary to distinguish between nitrification as the biological oxidation of reduced forms of nitrogen and net nitrification as the observed accumulation of nitrate.Net nitrification varied with apparent delay period and rate of NH4+ oxidation, and with losses of nitrified N. Rates of ammonium oxidation were related directly to the general level of oxygen supply as measured grossly with the platinum electrode. Apparent delay periods were influenced primarily by anaerobic metabolism in microenvironments too small to be differentiated by the electrodes which were used. Mineral N deficits appeared to be due primarily to enzymatic denitrification at oxygen diffusion rates less than 20; at higher levels of oxygen supply, chemical instability of NO2‐ appeared to become increasingly important because of an accompanying decrease in pH.
Dioctahedral Vermiculite and Chlorite in Highly Weathered Red Loams in Victoria, Australia
Authors: Jones L. H. P. , Milne A. A. , Attiwill P. M. 
Published: July 2010

AbstractRed loams from an old divide in Victoria, Australia, have been examined by optical, X‐ray diffraction, chemical, and thermal methods. The soils have developed on intrusive granodiorite and associated metamorphosed Silurian rocks. The clay fractions of the surface soils on the metamorphosed rocks contained dioctahedral vermiculite with interlayer alumina and the clays of the surface soils on the granodiorite contained dioctahedral chlorite. The chlorite decomposed when heated between 300° and 400°C. which corresponds to the temperature at which gibbsite decomposes. The chlorite also decomposed when treated (with KOH and KCl) to remove interlayer alumina. The weathering in the red loams is correlated with the mineralogy of the sand fractions and the parent rocks.
Buffer Curves of Acid Clays as Affected by the Presence of Ferric Iron and Aluminum
Authors: Coleman N. T. , Thomas G. W. 
Published: July 2010

AbstractBuffer curves of Al‐ or Fe‐montmorillonites and hectorite in 1.0N KCl had appreciably smaller slopes between pH 5 and 8.5 than did curves for corresponding H‐clays. Aluminum or ferric hydrous oxide‐clay complexes gave buffer curves indicative of almost no exchangeable Al, Fe, or H on permanent‐charge sites, but rather showed a regular increase in pH with additions of NaOH. The behavior of the clay‐sesquioxide complexes is thought due to the existence, at pH below about 5, of hydroxy‐Al or Fe‐ions on exchange sites, with the progressive conversion of these to the corresponding hydroxides upon the addition of base. That such a reaction can result in apparent pH‐dependent cation‐exchange capacity (CEC) was shown by the reasonably good correspondence between CEC's measured at various pH values and the amounts of base necessary to titrate the complexes to those pH's. It is suggested that the pH‐dependent CEC's of some soils may be due to the presence of clay‐sesquioxide complexes. In other cases, apparent pH‐dependent exchange capacity can be “created” during the neutralization of Al‐ or Fe‐clay, through the interaction of positively charged metal ion‐hydroxy complexes with exchange sites. Aluminum‐ or Fe‐hydroxy complexes with montmorillonite were not stable upon digestion in dilute salt solutions, but underwent dismutation to produce the corresponding metal ion and hydroxide. While sesquioxide‐montmorillonite complexes resembled many acid soils so far as titration behavior and pH‐dependent CEC are concerned, the chlorite‐like complexes were far less stable than those found in soils.
Phosphorus and Zinc Concentrations in Russet Burbank Potato Tissues in Relation to Development of Zinc Deficiency Symptoms
Authors: Boawn Louis C. , Leggett G. E. 
Published: July 2010

AbstractRusset Burbank potatoes were grown on field plots and in nutrient solutions at levels of Zn and P nutrition that would produce plants ranging from no Zn deficiency to severe Zn deficiency.Increasing the supply of P induced a growth disorder that could be eliminated by an increased supply of Zn. Neither the development of the deficiency nor the elimination of the deficiency was well correlated with changes in the concentration of Zn in stem and leaf tissues. High concentrations of P in tissues resulting in high P/Zn concentration ratios appear to offer a better explanation for the metabolic upset. Healthy plants tended to have P/Zn concentration ratios < 400, whereas in deficient plants the ratio was generally > 400.The data obtained indicate a mutual antagonism between P and Zn in their uptake and accumulation in the plant.
Field Experiments on Sealing Permeable Fine Sand With Bentonite
Authors: Rollins M. B. , Dylla A. S. 
Published: July 2010

AbstractBentonite has excellent sealing powers. Treating permeable fine sand with bentonite saved up to 99% of the water previously lost through seepage. From less than 1 up to 2 pounds of bentonite per square foot of sand surface was applied by adding a prepared bentonite suspension to the water or by mixing it dry with the sand.After drying for 1 month and then rewetting, the seals were 75 to 80% effective. Winter weather and particularly severe winds damaged the bentonite seals still further, reducing them to between 30 and 60% effectiveness. At the close of 2 years of experimentation, including five wetting and drying cycles, the bentonite seals were 27 to 44% effective.It is estimated that one bentonite seal would cost about the same as the annual cost of 4 inches of concrete amortized over a 30‐year period at 6% interest. Therefore, bentonite does appear favorable as a competitive sealer, since one application of bentonite may be effective for more than 1 year.Simple and effective methods of establishing bentonite seals must be further developed before this sealing method can be fully utilized to effectively reduce seepage losses.
Seepage into Stratified Water‐Saturated Soil from Idealized Vertical Mulch Channels
Authors: Swartzendruber Dale 
Published: July 2010

AbstractA general theoretical method of approximating the steady‐state, two‐dimensional seepage rate in stratified porous media is applied to the problem of water flow into stratified water‐saturated soil in the presence of idealized subsoil channels. The approximation, for the present problem estimated to be accurate within 10%, is obtained by considering the stratified system in 3 special, mathematically degenerate cases for which exact solutions are available. When a less permeable surface soil stratum overlies a more permeable stratum, the flow effect of the channels always exceeds that found for channels in a uniform soil and becomes quite marked if the channels penetrate the upper, less permeable stratum and extend into the more permeable stratum below. If the more permeable stratum overlies the less permeable stratum, the flow effect of the channels is less than in a uniform soil.
Ammonia and Ammonium Reactions with Some Layer‐Silicate Minerals
Authors: Young J. L. , McNeal B. L. 
Published: July 2010

AbstractRetention of NH3 and fixation of NH4+ by 16 specimen layer‐silicate minerals was investigated using anhydrous and aqua NH3, NH4Cl, and different degassing and fixing conditions.Despite a much greater partial pressure differential, vacuum degassing (to remove excess and physically sorbed NH3) greatly accentuated the retention and apparent NH3 fixation as compared with diffusion degassing.The great bulk of NH3 initially sorbed by anhydrous NH3‐treated layer‐silicates was rapidly dissipated (few hours to < 3 days) when samples were exposed to the atmosphere. Redisplacement by competitive water vapor evidently was a principal driving force. The equivalent of tons of NH3 per acre‐furrow‐slice, however, was retained longer than 3 days by the expandable layer‐silicates. The major portion (68 to 99+%) of retained NH3 was KCl leachable in all except the vermiculitic samples in which > 90% was fixed.Wide variability in basal spacing changes resulted from ammoniation and wetting treatments. Physical changes as reflected by X‐ray diffraction were in general accord with chemical data.Vermiculitic minerals under wet or air‐dry conditions fixed quantities of NH4+ greatly in excess of amounts fixed by other minerals. Metabentonite 38 and biotite 33 fixed moderate quantities under these conditions.In a comparison of N sources under wet fixing conditions, less than 20% as much N was fixed by vermiculite from aqua NH3 as from NH4Cl. All other minerals fixed roughly equivalent amounts from both sources.Montmorillonites fixed very small quantities of NH3 or NH4+ under wet or air‐dry conditions but showed a roughly 20‐fold increase in NH4+ fixation resulting from drying at 105°C.Anomalous retention and mechanisms of NH3 retention and fixation are briefly discussed. Results re‐emphasized need for continued restraint to minimize overextrapolation of data from a few type minerals to complex mixtures as generally encountered in soils.
Contrasting Release Characteristics of Potassium in Alluvial and Associated Upland Soils of Indiana
Authors: Binnie R. R. , Barber Stanley A. 
Published: July 2010

AbstractThe uptake of K from alluvial soils was similar to that from associated upland soils under low cropping intensity. Under the high intensity cropping of a Neubauer experiment, the alluvial soils released more K. Within the exchangeable K range 40 to 180 ppm., K uptake was 67 ppm. greater from the alluvial soils than from the associated upland soils at the same exchangeable K level. The reduction of exchangeable K in the soil due to crop removal was greater in the upland than in the alluvial soils. There was no statistical correlation between the mineralogical composition of the soil and the K released.
Relationships between Ammonia Volatilization, Ammonia Concentration and Water Evaporation
Authors: Chao Tyng‐Tsair , Kroontje Wybe 
Published: July 2010

AbstractThe rate of NH3 volatilization and the rate of water evaporation from soils followed different functions. These functions were not affected by differences in soil texture, soil water, speed, or relative humidity of air flowing over the soil surface. A linear relationship was observed between the rate of NH3 applied (up to 600 ppm.) and NH3 volatilized. The NH3 losses from finer textured soils were proportional to their original soil pH's. The larger NH3 losses from the coarse textured soil indicate that soil texture is a key factor in NH3 volatilization.
The Influence of Root Zone Temperature on the Growth and Contents of Phosphorus and Anthocyanin of Corn
Authors: Knoll H. A. , Lathwell D. J. , Brady N. C. 
Published: July 2010

AbstractIn a greenhouse experiment corn plants were grown in sand cultures using a complete nutrient solution in which only the P level varied. Root zone temperatures of 15°, 20°, and 25°C. were used in this experiment. In addition, 2 weeks after emergence, a number of plants were subjected to a sudden change in root zone temperature. The dry weight yield and the P content of the tops and the roots and the anthocyanin content of the tops were determined at 2 and 3 weeks.Low root zone temperature severely restricted the growth of young corn plants. High P levels never fully counteracted this harmful effect. It was likely that reduced P uptake at low root zone temperature was caused primarily by a depression in root growth, induced by the low root zone temperature. Anthocyanin synthesis was stimulated by both a low root zone temperature and a low P level in the nutrient solution indicating that purpling of corn is not necessarily an indication of P deficiency.
Effects of Parent Material and Vegetation on Properties Related to Soil Erosion in Central Washington
Authors: Wooldridge David D. 
Published: July 2010

AbstractIn a preliminary study of physical properties of wild land soils, three soil parent materials were sampled by horizons under forest and adjacent grass cover. Soil properties analyzed were mean water‐stable aggregate, bulk density, organic matter pH, total porosity, and % clay, silt, and sand. Several of the measured soil properties were related significantly to parent material and horizon depth. Effects of vegetative cover were not reflected in overall averages of soil property values. However, these values, broken down by parent materials and horizons, indicated that forest and grass covers were associated with soil property differences, although the relation of these differences to changes in parent materials and horizons is not consistent. Over 40% of the variation in soil erosion hazard (as measured by mean size of water‐stable aggregates) is accounted for by multiple variation in soil organic matter content, pH, total porosity, and bulk density.
Chemical Composition of Foliage from Fertilized Plus Douglas Fir Trees and Adjacent Unfertilized Check Trees
Authors: Beaton J. D. , Kosick R. , Speer R. C. 
Published: July 2010

AbstractShoots of the 1960, 1961, and 1962 growth were removed from two fertilized plus trees and two unfertilized adjacent check trees in April 1963. Each plus tree received 80 pounds of 16‐20‐0 ammonium phosphate sulphate fertilizer in April 1961, and 40 pounds of the same fertilizer in April 1962. The length of the shoots was measured and needle production was determined. Needles from each of the 3 years of growth were analyzed for N, P, K, Ca, Mg and S.Fertilization increased the length of the 1962 shoots. Diameter of the shoots also appeared to be increased. Needles from the fertilized trees seemed to be larger and darker green in color. Weight of needles produced in 1962 was greatly increased by fertilization. Concentration and weight of N in needles was markedly increased by fertilization, particularly in the 1962 growth. Phosphorus concentration was slightly reduced by fertilization. However, the weight of P in the 1962 needles was increased by fertilization. The N/P ratios in all needle samples from the fertilized trees were much greater than those in the unfertilized check trees. Although K concentration was reduced in the foliage from fertilized trees, weight of K was not influenced by fertilization. Potassium percentage tended to be lowest in the oldest tissue, and highest in the youngest tissue of all trees. Concentration and weight of Ca was highest in foliage from the fertilized trees. Calcium concentration increased with age of all foliage samples. Fertilization resulted in an increase in concentration and weight of Mg. Concentration and weight of S was highest in the foliage from fertilized trees. Older needles appeared to have a higher S concentration than the younger needles.