bluuebunny/crossref_metadata_2025_split huggingface dataset:
Estimating Bulk Density from Organic‐Matter Content in Some Vermont Forest Soils
Authors: Curtis Robert O. , Post Boyd W. 
Published: July 2010

AbstractA close relationship between organic‐matter content and bulk density was found in the acid till forest soils of the Green Mountains of Vermont. Reasonably good estimates of bulk density can be made from determinations of organic matter content. Thus, the difficulties of direct determination of bulk density in these stony soils can be avoided. A method of determining bulk density, including a correction for stone content, is described for use in these stony soils.
Variations in Bulk Density and Moisture Content Within Two New Jersey Coastal Plain Soils, Lakeland and Lakehurst Sands
Authors: Reigner Irvin C. , Phillips John J. 
Published: July 2010

AbstractTo determine how manipulation of vegetative cover affects soil‐moisture storage, 8 plots were laid out in a 50‐acre block on the Coastal Plain of New Jersey, 4 on Lakeland sand and 4 on Lakehurst sand. Each plot, about 1/100 acre in size, was subdivided into 3 subplots, each of which was sampled gravimetrically 42 times over a period of 3 growing seasons.A relationship between bulk density and soil depth plus stone content was developed. From this, bulk density was estimated for each sample in five 1‐foot layers. Moisture content by weight for each 1‐foot layer was converted to moisture content by volume by applying the respective estimated bulk densities. Variations within and between the relatively close‐spaced plots are presented for estimated bulk density and moisture content by voulme for each of the 1‐foot layers.
Determination of Total Nitrogen and Carbon in Soils by a Commercial Dumas Apparatus
Authors: Stewart B. A. , Porter L. K. , Beard W. E. 
Published: July 2010

AbstractA modified Dumas procedure is presented, which extends its application to soils of high organic matter content. The modification eliminates the interference of CH4 that often causes values to be from 5 to 20% higher than Kjeldahl values. The instrument used for the Dumas procedure can be easily converted to determine C in soils. Changes necessary for this conversion are presented.
Oxidative Changes of Polyphenols as Influenced by Allophane
Authors: Kyuma Kazutake , Kawaguchi Keizaburo 
Published: July 2010

AbstractOxidative changes of polyphenols as influenced by allophane were studied in relation to humus‐forming processes in Ando soils. A chestnut tannin‐containing substrate was incubated for varying lengths of time with an allophanic material, and changes in the shape of ultraviolet (UV) and infrared (IR) spectra and in neutralization capacity of the polyphenols were traced with time. As compared with control materials, the allophanic material adsorbed large amounts of organic carbon (8 to 10 times as much at the end of 22 weeks), and the adsorbed organic matter kept incubated for only 2 weeks showed the following features: (1) No sharp peaks in UV spectrum at the 280 mµ region which is characteristic of tannin, (2) High optical density (about 20 times as high at 400 mµ as that of tannin), (3) High neutralization capacity (416 me. per 50 g. carbon, which is about 3 times as high as that of tannin), and (4) Strong 5.8 to 5.9 µ band in IR spectrum instead of a weak shoulder as for tannin. All these remarkable changes occurring in a very short period of time suggested that allophane might have some catalytic effect on oxidative changes of polyphenols, and a manometric determination of oxygen absorption confirmed this supposition. Such catalytic effect exerted by allophane would have great significance in humus formation and accumulation in Ando soils.
Some Chemical Characteristics of the Organic Matter Extracted from the O and B2 Horizons of a Gray Wooded Soil
Authors: Schnitzer M. , Gupta Umesh C. 
Published: July 2010

AbstractOrganic matter extracted from the O and B2 horizons of a Gray Wooded soil was characterized by ultimate and functional group analyses and by infrared spectroscopy. The analytical data were compared with those obtained by the use of the same methods on Podzol O and Bh organic matter.The experimental data indicated that Gray Wooded humic and fulvic acids were chemically similar to Podzol humic and fulvic acids except that Gray Wooded organic matter contained more phenolic hydroxyl groups. In analogy with Podzols, approximately 70% of the organic matter extracted from the Gray Wooded O horizon was humic acid, while 90% of the extract from the B2 horizon consisted of fulvic acid.Gray Wooded organic matter was difficult to extract and purify because of intimate association with clay and possibly other inorganic constituents.
Acidification of a Forest Tree Nursery Soil
Authors: Mullin R. E. 
Published: July 2010

AbstractArtificial acidification of nursery soils for coniferous seedling production is being studied on soils which have become alkaline through continuous use. Three methods of acidification are being examined, acidification of the irrigation water, incorporation of acid peat, and incorporation of powdered S. The experimental work is being done on red pine (Pinus resinosa, Ait.) seedbeds used for production of 3‐0 shipping stock. The experiment is in three sections, starting in consecutive years, each running for three years in the nursery, and providing trees for observations in the laboratory and after outplanting. Acidification of the irrigation water, to pH 6.0 by automatic injection of H2SO4 has shown no measurable effect on soil pH or seedlings. Addition of acid peat, 60 cubic yards per acre, at about pH 5.0, showed some reduction in soil pH but not to the level desired, and no effect was determined on the seedlings. Addition of powdered S at 750, 1,500 and 2,250 pounds per acre has been most effective. The soil pH has been reduced proportionately, with that of the heaviest treatment to about pH 5.0, with some fluctuation, and the effect has not diminished after more than three years. The S treatment of 2,250 pounds caused mortality in the seedbeds, whereas the lesser treatments caused an increase in survival. Sulphur addition also resulted in taller, thicker, heavier seedlings with the first level causing a large increase, the second a minor (plateau effect), and the high level a large increase again. Information on the planting success of the seedlings is not yet available.
Water Vapor Diffusion in Relatively Dry Soil: II. Desorption Experiments
Authors: Jackson Ray D. 
Published: July 2010

AbstractWater vapor diffusion during desorption was measured in three soil materials at water contents corresponding to a relative pressure range of 0.97 to about 0.05. The data were obtained from a transient desorption experiment conducted at 27°C. Diffusivities, calculated from analysis of water content distribution curves, increase and then decrease with increasing water content. The desorption diffusivity‐water content curves exhibit a less distinct maximum, with the maximum occurring at a higher water content than do the sorption diffusivity‐water content curves.
Adsorption of Phosphate by Aluminum and Iron in Soils
Authors: Hsu Pa Ho 
Published: July 2010

AbstractA slightly acid soil was treated with dilute phosphate solutions of pH 7 to study the mechanism of phosphate fixation. Two reactions operating at different rates were recognized. The one which proceeded more rapidly is believed to be due to surface adsorption of phosphate on the amorphous aluminum hydroxides and iron oxides already in this soil. The other, a much slower reaction, is due to the surface adsorption on similar amorphous hydroxides and oxides developed during the experiment. Experimental work showed that the solubilities of variscite, of synthetic Al(OH)2H2PO4, and of synthetic Fe(OH)2H2PO4 were considerably increased in the presence of this soil indicating that these compounds are not likely to be the products of fixation under these conditions.
Some Aspects of Ammonia Sorption by Soil Surfaces
Authors: Coffee R. Clifford , Bartholomew W. V. 
Published: July 2010

AbstractRates of sorption of NH3 through soil surface boundaries, the extent of penetration into thin surface strata, and relative sorbing capacities of surface layers were determined for soil materials from several Coastal Plain and Piedmont soils. NH3 sorption through soil surface boundaries was rapid from aerial applications ranging from 1.3 to 1.9 mg. NH3‐N per cm.2 of surface area. Specific rate of sorption was directly proportional to the concentration of NH3 remaining above the soil surface. NH3 nitrogen sorbed by soil in the surface strata did not penetrate more than 10–20 mm. into the soil when applied at rates ranging from 0.17 to 1.00 mg. NH3‐N per cm.2 of surface. The depth distribution of NH3 changed with time of contact with NH3 without appreciable change in total NH3 sorbed. In general clay soils sorb more efficiently than sandy soils, soils with low pH more efficiently than those with high pH, and soils with high organic matter contents were less efficient than mineral soils with similar cation‐exchange capacities.
Influence of Sorbed Hydroxyl and Sulfate on Liming Efficiency, pH, and Conductivity
Authors: Mehlich A. 
Published: July 2010

AbstractSoils having different values of permanent charge (CECp), variable charge (CECv), and anion‐exchange capacity (AEC) were treated with hydroxyl, sulfate and hydrogen saturated exchange resins. The AEC was then principally OH‐ or SO42‐ saturated while CECp was principally saturated with aluminohydronium and CECv with covalently bound H. To these systems were added increments of Ca(OH)2 and the release of SO42‐, Ca2+ sorption efficiency, pH, and conductivity measured. Soils containing sorbed SO42‐ had lower Ca2+ sorption efficiency, higher lime requirements, lower pH's and higher specific conductivities than those containing sorbed OH‐. These effects were the result of replacement of sorbed SO42‐ by OH‐ according to the reaction: Soil‐SO4 + Ca(OH)2 → Soil‐(OH)2 + CaSO4
Sulfate‐Sulfur Concentration as an Indicator of Sulfur Status in Various California Dryland Pasture Species
Authors: Jones Milton B. , Martin W. E. 
Published: July 2010

AbstractSulfate‐sulfur values in subclover and soft chess under high N fertilizer were approximately equal over a wide range of S fertilizer levels. With no fertilizer N the SO4‐S values of annual grasses including soft chess were higher than those of rose or subclover. Hardinggrass was particularly high in SO4‐S. Where no N was applied the SO4‐S concentration in subclover decreased as the plants advanced from early vegetative to flowering stage. When plants began to wilt at the end of the season, the SO4‐S values increased over SO4‐S levels at flowering. Subclover and rose clover, sampled during the flowering period but before wilting, appeared to be the best plants for determining the S status of dryland pastures in California.
Chloride‐36 Diffusion during Stable and Unstable Flow through Glass Beads
Authors: Biggar J. W. , Nielsen D. R. 
Published: July 2010

AbstractThe effect of the properties of solution on the mixing occurring in porous material has been examined in glass beads using Cl36. Matched NaCl solutions of 0.01, 0.1, and 4N concentration with either the displacing or displaced solutions identified by Cl36 were displaced from a 30‐cm. column. Displacements were made in the horizontal and vertical direction at two flow velocities. For solution density and viscosity differences of 0.0034 g. per ml. and 0.003 centipoise, respectively, between the displacing and displaced solution, unstable flow was clearly demonstrated. In the simple glass bead porous system, unstable flow may be of greater significance than the concentration dependent nature of the diffusion coefficient.
Oxygen Requirements of Cotton Seedling Roots for Penetration of Compacted Soil Cores
Authors: Tackett J. L. , Pearson R. W. 
Published: July 2010

AbstractCotton root growth and activity was determined at different levels of subsoil bulk density and O2 concentration. Subsoil cores of desired bulk density were aerated leaving both the soil moisture content intact and the surface soil exposed to diffusion of gases from the atmosphere. Measurements of root growth and activity in the subsoils included depth of root penetration, root yield, water uptake, and carbon dioxide production in the subsoil.Mechanical impedance was more detrimental than low O2 for root growth in the subsoils at bulk densities above 1.5 g. cm.‐3. At lower densities root growth was depressed at O2 levels below 10%, and there was a strong interaction of O2 and bulk density.
Ion Adsorption on Charged Surfaces
Authors: Heald Walter R. , Frere Maurice H. , de Wit C. T. 
Published: July 2010

AbstractA model, based on ion pair formation, for the adsorption of ions on charged surfaces is developed. This approach results in a two‐layer system analogous to the Stern‐Gouy model. Relations between the charge density, the fraction of the ions in the diffuse double layer, the concentration of the ions in the bulk solution, and a formation constant K are derived. The K describes the equilibrium reaction across the boundary between the two layers without defining the exact position of the boundary. Dowex‐50 resin, which has a high charge density and consequently a relatively small fraction of ions in the diffuse double layer, was used to test the above model. The following ratios of K's were calculated from data obtained from adsorption experiments in dilute solutions: KRb/KNa = 1.71, KRb/KK = 1.26, KK/KNa = 1.37, (K′Sr)½/KNa = 3.31 (eq. per liter)½, (K′Sr)½/KLi = 5.88 (eq. per liter)½, (K′Sr)½/KH = 4.00 (eq. per liter)½, KNa/KLi = 1.89, KNa/KH = 1.35, KSr/K′Ca = 1.56.
Relationships Between Soil Cation‐Exchange Capacity and the Toxicity of Ammonia to the Nitrification Process
Authors: Smith J. H. 
Published: July 2010

AbstractNitrification was studied in Red Bay sandy loam and Iredell clay loam treated with increments of sand to produce a range of cation‐exchange capacities (CEC). The soils were treated with 1% additions of alfalfa particles of three particle sizes. Analyses were made at intervals for ammonia, nitrate, nitrite, and pH.The nitrification rate of ammonia from alfalfa particles decomposing in soil was decreased when the exchange capacity of the soil was decreased by dilution with sand. The mechanism involves less exchange sites for NH4+ at low CEC and the resulting increase in soil solution pH producing an NH3 concentration that is toxic to Nitrobacter. The same effect was produced by decreasing the distance between the alfalfa particles in the soil, thereby reducing the interparticle zones of low NH3 concentration where nitrification could proceed.A steep ammonia concentration gradient develops around the alfalfa particles when adequate exchangeable hydrogen is present. In the areas between alfalfa particles, where NH3 concentration is low, nitrification proceeds without inhibition. As the exchangeable hydrogen concentration is reduced or the alfalfa particles are placed closer together, the zones where NH3 is not toxic decrease in size until most of the soil has reached the concentration of NH3 toxic to nitrification.
Moisture Relations of Soil Inclusions of a Texture Different from the Surrounding Soil
Authors: Grover Ben L. , Cahoon Garth A. , Hotchkiss C. W. 
Published: July 2010

AbstractThe rates of wetting and drying of soil inclusions, showed that the rate of rise of soil suction in the inclusion when compared to the surrounding soil was greatest with Ducor clay. The other soils followed in order of decreasing clay content. The rate of wetting was also greatest in the Ducor clay inclusion; the others were in the following order Coachella loamy sand > Ramona loam > Chino loam. The inclusions consisted of the soil ball on commercial nursery‐grown citrus trees. The ball was wrapped in burlap in the usual manner. The Chino loam inclusions took 3 times as long to wet as the surrounding soil when they were placed in either the clay or sand. The data indicated that extra caution must be used in orchard operation when the texture of the nursery soil is different from the field soil.
The Influence of Vegetation on Soil Thermal Regime at the San Dimas Lysimeters
Authors: Qashu Hasan K. , Zinke Paul J. 
Published: July 2010

AbstractSoil temperatures for four lysimeters (bare, grass, scrub oak, and pine) during a 7‐year period (1952–1959) were studied. Observed temperature data of each lysimeter was subjected to harmonic analysis reducing the temperature time curves to a series of Fourier coefficients and the following empirical equations:

Tz = 62.70 + 18.53 exp (−0.1273z) sin (30t − 8.15 [3] −7.98z) °F. for the bare lysimeter

Tz = 58.20 + 16.02 exp (−0.1240z) sin (30t − 16.17 [4] −7.22z) °F. for the scrub oak lysimeter

Tz = 60.44 + 18.32 exp (−0.1167z) sin (30t − 15.48 [5] − 7.05z) °F. for the Coulter pine lysimeter

Tz = 60.96 + 17.43 exp (−0.1179z) sin (30t − 16.15 [6] −7.19z) °F. for the grass lysimeter

Presence of vegetation has altered the soil temperature regime by reducing mean annual soil temperature and temperature amplitudes. Vegetation has introduced patterns of time delay in the soil temperature profile characteristic of the vegetation cover and directly related to the soil moisture regime. When the lysimeters with vegetation cover are compared, the influence of vegetation is of varying magnitude as shown by marked differences in soil temperature regime and soil thermal properties.With exception of the top 6 inches of soil, observed data for the average annual cycle of temperature agrees well with calculated values using the theory of heat flow. The slight difference in average monthly temperatures are much smaller than the natural differences from year to year.
Landform Parameters Correlated to Soil Drainage
Authors: Troeh Frederick R. 
Published: July 2010

AbstractQuantitative means of describing land surfaces were developed in this study and related to soil drainage. Hundreds of elevations were determined on each of 40 plots representing 6 soil series. The 3‐dimensional equations developed to approximate these elevations assume radial symmetry and a parabolic relationship between elevation and distance from the symmetry axis. An electronic computer was used to solve and test equations for several positions in each plot. Areas that crossed soil boundaries were excluded. The equations of 75% of the remaining positions closely approximated the data and were used in this study. Parameters representing slope, rate of change of slope, and radius of curvature were obtained from the equations. These parameters were used to classify the shapes of the land surfaces both qualitatively and quantitatively. Three‐dimensional plots of these parameters correctly predicted the drainage class of 90% of the positions with usable equations. Surfaces having equivalent drainage at all points were defined by equations in terms of radius, slope, and rate of change of slope.
Persistence and Biological Reactions of Pesticides in Soils
Authors: Alexander M. 
Published: July 2010

AbstractAlthough microorganisms are often considered to be omnivorous and biochemically omnipotent, they seem unable to destroy at significant rates many synthetic chemicals that enter soil. This unexplained microbial fallibility recently has assumed prominence because of the long persistence of a variety of pesticides. With at least certain compounds, the chemical, physiological, or environmental basis of the biological failings can be established, as illustrated with substituted phenols and phenoxy herbicides.Microorganisms may detoxify pesticide‐treated soil by metabolizing or degrading the added substance. The microflora may also be responsible for the generation of a toxic condition in soil by activation of the applied pest‐control agent. The use of laboratory precedents as guides in investigations of natural transformations is considered, and instances of pesticide metabolism in soil are cited.
Soil Polysaccharides and Aggregation in Crop Sequences
Authors: Webber L. R. 
Published: July 2010

AbstractSoil polysaccharides and aggregation (mean weight‐diameter and aggregate stability) were determined in the corn plots from a rotation project where the preceding crops were corn, oats, alfalfa‐brome, or winter wheat. The residues from these crops did not result in significant differences in the content of soil polysaccharides; only in a two‐year crop sequence, corn and oats underseeded with red clover, were the polysaccharides increased by the addition of manure. Aggregate stability was greater in the rotations that included a grass‐legume; manure improved aggregation over unmanured plots. In a multiple regression analysis, polysaccharides and organic matter together, accounted for 36% of the variation in mean weight‐diameter and 27% of the variation in aggregate stability.The seasonal variation in the content of polysaccharides and aggregate stability showed a marked out‐of‐phase relationship except under oats, which were underseeded with a grass or legume.
Structural Arrangement of Functional Groups in Soil Humic Acid as Revealed by Infrared Analyses
Authors: Wagner G. H. , Stevenson F. J. 
Published: July 2010

AbstractHumic acid from a brunizem soil was subjected to a series of treatments (methylation, saponification, acetylation) to determine the number and arrangement of functional groups when analyzed by a combination of chemical and infrared techniques. One‐third of the COOH groups (total COOH, 390 meq/100 g) occurred in positions close enough to form cyclic anhydrides; two‐thirds of the OH groups (total OH, 290 meq/100 g) were phenolic. Some phenolic OH groups in the samples failed to methylate wth diazomethane. Potassium bromide catalyzed the formation of cyclic anhydrides by mild thermal treatment of acid‐treated and methylated‐saponified humic acids, but not of untreated humic acid. Acetylation gave a small amount of brown material (acetyl content, 20%) whose infrared pattern was characteristic of an acetylated carbohydrate. Tests for quinone and H‐bonded phenolic OH groups were negative.
The Effect of Salts on the Dissolution of Monocalcium Phosphate
Authors: Taylor A. W. , Gurney E. L. 
Published: July 2010

AbstractAdditions of KCl, NH4NO3, or K2SO4 to Ca(H2PO4)2·H2O so complicate the dissolution processes that the final distribution of the phosphate cannot be interpreted in terms of the simple system CaO‐P2O5‐H2O as can the dissolution of Ca(H2PO4)2·H2O alone. In KCl and NH4NO3 mixtures, formation of Ca2KH7(PO4)4·2H2O and Ca2(NH4)H7(PO4)4·2H2O lowers the pH of the initial solutions to < 1 and decreases the initial phosphate concentrations; in the later stages both salts hydrolyze to CaHPO4·2H2O, but the amounts of phosphate remaining as this salt are less than that remaining from pure Ca(H2PO4)2·H2O. In mixtures containing K2SO4, Ca(H2PO4)2·H2O is rapidly decomposed with formation of syngenite, CaK2(SO4)2·H2O, and the phosphate is dissolved as KH2PO4. Sulfate decreases markedly the amount of residual phosphate.
The Effect of Nitrite and Organic Matter on Aerobic Gaseous Losses of Nitrogen from a Calcareous Soil
Authors: Meek B. D. , MacKenzie A. J. 
Published: July 2010

AbstractThe loss of gaseous nitrogen compounds when nitrite accumulates in a calcareous silty clay loam during nitrification was investigated under aerobic conditions.Soil to which either (NH4)2SO4, NaNO2, or (NH4)2SO4 + barley straw was added, was incubated at 28C and 31% moisture for 28 days. Samples were maintained under aerobic conditions in a N‐free atmosphere of 21% oxygen and 79% helium. Gas samples were taken every 7 days from the incubation flasks and analyzed, using a gas chromatograph, for gaseous N products evolved. The accumulation of nitrite was measured on separate soil samples incubated in the same manner as the flasks used to secure gas samples.The gaseous N forms produced were N2O and N2. It was found that losses were low even when large amounts (250 ppm) of nitrite‐N accumulated. The gaseous N loss was 1.3% for (NH4)2SO4 and NaNO2 and 3.6% for the (NH4)2SO4 + barley straw treatment.