bluuebunny/crossref_metadata_2025_split huggingface dataset:
Soil Aggregation in Relation to Various Soil Constituents
Authors: Chesters G. , Attoe O. J. , Allen O. N. 
Published: July 2010

AbstractThe relative importance of diverse factors affecting aggregation in four Wisconsin soil types was studied by multiple regression analyses. Single and combined effects of pH and contents of organic matter, microbial gum, clay, and free iron oxide were considered.In general the most important single factor was the microbial gum. However, in the Kewaunee soil which has a relatively high content of clay and iron oxide, the iron oxide was of prime importance in aggregate formation. In all the soils, iron oxide showed a marked effect on aggregation with a tendency to be more important in the smaller aggregate size range. The effect of clay, however, was very small with the exception of the high clay soil (often > 30% clay), in which its effect was only exceeded by that of the free iron oxide. In the multiple correlation analysis the effect of organic matter was considered separately from that of microbial gums. By this statistical analysis only a slight positive relationship existed between organic matter and soil aggregation, i.e., the effect of organic matter was conditioned largely by its content of microbial gum; pH 6.5 was optimum. No relationship existed between soil aggregation and the rate of decomposition of organic matter as measured by CO2 evolution from the soil.
Distribution of the Forms of Nitrogen in Some Soil Profiles
Authors: Stevenson F. J. 
Published: July 2010

AbstractThis paper presents a preliminary report of studies dealing with the chemistry of the nitrogen in the profiles of different soil types. Total, amino acid, and ammonia nitrogen determinations were made on acid hydrolysates of soil collected from 10 profiles representative of 8 great soil groups. The proportion of amino acid nitrogen to total nitrogen was found to decrease with depth in nearly all of the profiles examined, while the proportion of the nitrogen released as ammonia by acid hydrolysis was found to increase with depth. The magnitude of these changes was dependent on soil type. The results afford an explanation of the well‐known phenomenon that the C/N ratio of most soils decreases with increasing depth in the profile. Some practical and theoretical aspects of the findings are considered.
Results from Subsoiling and Deep Fertilization of Corn for 2 Years
Authors: Robertson W. K. , Fiskell J. G. A. , Hutton C. E. , Thompson L. G. , Lipscomb R. W. , Lundy H. W. 
Published: July 2010

AbstractData on six soil types in North and West Florida for 2 years were used to evaluate subsoiling and deep placement of fertilizer. Lime, fertilizer, fertilizer plus lime, and fertilizer plus lime plus minor elements placed in the subsoil were compared with subsoiling alone and surface fertilization at low and high rates. Corn yields, root distribution and the chemical composition of ear leaves were used to measure responses.Where organic hardpans existed, as on the Leon fine sand, Ona fine sand, and combinations of these soil types with related soils, yield increases were obtained for subsoiling alone and fertilizer, lime and/or minor elements placed in the subsoil. Responses to fertilizer were related to the chemical composition of the soil profile and rainfall distribution. Better responses were obtained when moisture stress periods occurred during the first part of the season. The Norfolk loamy fine sand, Ruston fine sandy loam and Red Bay fine sandy loam soils contained compact clay zones or plow soles beneath the surface. When drought periods were of short duration, subsoiling and deep placed fertilizer improved corn yields above the check. When the drought period was of 25 days' duration the advantage of having a deeper root system and a larger corn plant was lost.On the Klej fine sand where there was nothing in the profile to impede roots, fertilizer on the surface was as good as. deep placement and subsoiling alone was of no benefit.The residual effects of the subsoiling treatments were generally small. There was some indication that it would be necessary to subsoil annually even though additional fertilizer in the subsoil may not be needed.
Chelating Ability of Soil Organic Matter
Authors: Himes Frank L. , Barber Stanley A. 
Published: July 2010

AbstractIt was discovered that organic matter reacted with divalent metal ions in a manner similar to chelation reactions. Radioactive zinc was used to facilitate the adsorption measurements. Multiple regression was used to develop a prediction equation to determine the amount of zinc adsorbed as influenced by zinc added, pH, and ionic strength of the solution.Removal of organic matter by oxidation with hydrogen peroxide destroyed the ability of the soil to chelate zinc. Removal of hydrous silicates did not influence the retention of zinc by the soil.The organic matter was fractionated into the humic and fulvic fractions. Both fractions reacted with zinc in a manner similar to the untreated soil. Methylation of the organic matter was used to determine the functional groups involved in the chelation reaction. Carboxyl groups did not appear to be important.The stability constant for the zinc soil complex was investigated by two independent methods. For a Maumee sandy loam soil at pH 7 and 2N KCl it was found to be 5.6.
Adsorption of Hydrolyzed Polyacrylonitrile on Kaolinite: I. Effect of Exchange Cation and Anion
Authors: Mortensen J. L. 
Published: July 2010

AbstractThe rate and extent of adsorption of hydrolzed polyacrylonitrile (HPAN) on kaolinite was determined, using HPAN labelled with C14. Continuous mixing in the presence of univalent exchange ions gave steady state adsorption within 4 hours. Langmuir type adsorption isotherms resulted. Saturation adsorption was 2.6 me. HPAN per 100 g. H‐Cl‐kaolinite.The exchange cation affected the extent of adsorption of HPAN in approximately the same order as such cations reduce the zeta potential of kaolinite, i.e., Th4+ > Ca2+ > Ba2+ > H+ > NH4+ > K+ > Na+. An anomalous increase in adsorption in the presence of polyvalent exchange cations suggested adsorption at the site of base exchange salt formation. Anions of sodium salts sorbed on kaolinite increased adsorption of HPAN in the order F‐ > OH‐ > H2PO4‐ > Cl‐ > CH3COO‐ > NO3‐ > HPAN.HPAN was apparently adsorbed as a monolayer on a single set of sites which are most likely “positive spots” on the edge of the kaolinite crystal or which arise from adsorbed or colloidal sesquioxide impurities.
Characteristics of Eolian Influenced Soils in Connecticut: I. Physical Properties
Authors: Ritchie A. , Colby W. G. , Swanson C. L. W. , Tamura T. 
Published: July 2010

AbstractField and laboratory studies were made on soils strongly influenced by loess in the Central Lowland of Connecticut. Laboratory samples were obtained from 10 profiles located on a grid sampling system in an area east of the Connecticut River. Depth of the loess mantle had an important influence on the particle size composition of the profiles. The greater amounts of coarse particles in the shallower profiles are believed to be due to mixing with the underlying unconformable materials, probably through frost action and tree throw. An increase in coarse particles from the underlying material in the profile results in reductions in water‐holding capacity, capillary pore volume and penetrability, and increases in bulk density and non‐capillary pore volume, but with only a small change in permeability.
A Portable Rainfall‐Simulator Infiltrometer and Physical Measurements of Soil in Place
Authors: Adams John E. , Kirkham Don , Nielsen Donald R. 
Published: July 2010

AbstractA portable rainfall‐simulator and infiltration cylinder are described for applying artificial rainfall to soil in place for making infiltration, runoff, and soil erosion measurements. Raindrops are formed by glass capillary tubes protruding through the base of the water supply tank. Each tube has chromel wire suspended in the capillary to reduce the rate of flow. The rainfall is delivered over a circular area 5 ¾ inches in diameter delimited laterally by a cylinder 6 inches long, driven vertically into and flush with the soil surface. The soil surface area is small and replications are easy to obtain. Air permeability measurements may be made before and after rainfall application. The equipment can be carried, set up, and operated conveniently by one man and offers a fast, economical means of evaluating the soil factor in runoff and soil erosion problems. Field data, obtained on the Edina silt loam after 30 minutes of artificial rainfall, showed that the infiltration rate for corn in a corn‐oat‐meadow rotation (0.70 in./hr.) was nearly twice as great as for continuous corn (0.36 in./hr.) Wash erosion, or sediment in suspension, reached a maximum value for both systems between 5 and 10 minutes after the start of rainfall. During the next 5 minutes, wash erosion decreased rapidly although runoff continued to increase.
Swelling Pressure of Montmorillonite
Authors: Warkentin B. P. , Bolt G. H. , Miller R. D. 
Published: July 2010

AbstractA montmorillonite suspension was placed in a miniature compression chamber bounded on one side by a cellulose membrane supported by a water saturated porous Alundum disk, and on the other by a rubber film. Changing the ambient pressure on the film caused water to move across the membrane until the swelling pressure of the suspension equalled the applied pressure.Existing theory, based upon the Gouy‐Chapman description of the diffuse double layer and upon its anticipated osmotic activity, was used to predict swelling pressures for different suspensions.During initial compression, measured swelling pressures of both Na‐ and Ca‐montmorillonite exceeded predicted values. Subsequent decompression and recompression cycles were reversible except for a slight but measurable hysteresis, but the position of the reversible portion of the curve depended upon the terminal pressure of the initial compression. When the latter was large (25 to 50 atm.), measured swelling pressures of decompression‐recompression cycles for Na‐montmorillonite agreed quantitatively with theory over the range 0.2 to 50 atm. Under similar conditions, Ca‐montmorillonite exhibited pressures appreciably less than predicted by theory.
Annual Lupines and Other Cover Crops for the Forest Nurseries of the Lake States
Authors: Stoeckeler J. H. 
Published: July 2010

AbstractBlue, white, and sweet yellow lupines were tested as a green manure crop in forest nurseries in northeastern Wisconsin and in Michigan. Besides lupines; vetch, soybeans, serradella, and rye were also tried. Sweet yellow lupine consistently gave the best performance, producing on the average about 4,392 pounds of oven‐dry bulk per acre with an average nitrogen content of 89 pounds per acre. Hairy vetch gave the best average yield but had the disadvantage of slow initial growth rate.
Moisture Depletion by Forest Cover on a Seasonally Saturated Ozark Ridge Soil
Authors: Fletcher P.W. , McDermott R. E. 
Published: July 2010

AbstractMany broad, flat‐topped ridges in the Ozark Province of Missouri have a subsoil pan horizon at 2 to 4 feet beneath the soil surface. This pan limits the depth of root penetration and restricts water movement to deeper depths. Winter excesses of precipitation are held in and above the pan as a “perched” water table. Records from shallow wells showed that free water occurred within 3½ feet of the soil surface throughout most of the winter months, persisting almost continuously from November, 1954, to August, 1955, where the trees had been cut, and from December, 1954, to June, 1955, in the adjacent undisturbed forest. A dense stand of oak trees, 4 to 8 inches in diameter, having roots in this saturated zone, caused a pronounced diurnal fluctuation in the rate of recession of the water level during April and May. Estimates from this record, together with soil moisture records, indicated that evapotranspiration for this forest stand was 0.175 inches of water daily during rainless periods in April and May.
The Effect of Clay Minerals and Exchangeable Cations on the Adsorption of Ethylene Dibromide Vapor
Authors: Jurinak J. J. 
Published: July 2010

AbstractA study was conducted to investigate the effect of clay mineral and exchangeable cation on the adsorption of ethylene dibromide (EDB) vapor by dehydrated clay. The Brunauer, Emmett, and Teller (BET) equation was applied to the data and the BET parameters Wm, n, and C evaluated. Both the exchangeable cation and the clay mineral had a pronounced effect on the adsorption process. Adsorption, in all cases, was confined to the external surfaces of the mineral systems.The effect of Mg, Ca, and Na ions on the adsorption of EDB by montmorillonite was accredited to the varying amount of moisture retained by the homoionic clay systems after dehydration, the retained moisture being important in determining the extent and nature of the adsorbing surface.The adsorption of EDB per unit surface by Ca‐montmorillonite, ‐illite, and ‐kaolinite indicated that adsorption on Ca‐montmorillonite is more restricted than on Cakaolinite, with Ca‐illite being intermediate. These data and the BET parameters support the view that the effect of clay minerals on EDB adsorption is a manifestation of the physical condition of the clay surface after dehydration. The montmorillonite system presenting a porous aggregate whose capillary dimensions restrict adsorption while the kaolinite system presents a relatively unrestricted planar surface for vapor adsorption.
Characteristics of Some Soils of the Arid Region of Washington
Authors: Gilkeson Raymond A. , Marshall Warren G. , Smith Henry W. 
Published: July 2010

AbstractA study has been made of six soils selected for characterization by laboratory and field methods as representative of soil development in the arid region of south central Washington.The parent materials are derived from several acid igneous, basic igneous, and metamorphic rock types, and range from glacial‐fluvial deposits to loess. The arid microthermal climate, with a mean annual precipitation of 6 to 9 inches, supported a sparse native vegetation of sagebrush and bunchgrasses.The A horizons, as contrasted with the rest of the solum, have some accumulation of organic matter, darker colors, partial removal of bases but a significant increase in exchangeable potassium, and weakly developed granular or platy structure. Development of a B horizon is recognized on the basis of weak blocky or coarse prismatic structure, and, in contrast to the A horizon, higher pH, and lighter colors. Illuviation of clay is not apparent. Lower horizons are characterized by significant increases in exchangeable sodium, lighter colors, and stratified materials. The texture, number of horizons, depth of solum, and position and degree of development of the lime zone are related directly to the original deposition of the soil‐forming materials. These properties are presented as proper criteria for Sierozem soils.
The Partial Specific Volume of Water in Bentonite Suspensions
Authors: Low Philip F. , Anderson Duwayne M. 
Published: July 2010

AbstractAn equation was derived relating the partial specific volume of water in a clay suspension to the clay concentration and the suspension density. By means of this equation and the observed suspension densities at different clay concentrations, the partial specific volume of water was determined to be the same as that of pure water in Li‐, Na‐, and K‐clay suspensions at concentrations up to 0.14 g. of clay per cc. (13% clay).From the above results it was possible to calculate the densities of Li‐, Na‐, and K‐clay. The respective densities were 2.71, 2.80, and 2.75.
Storage of Soil Samples and Its Effect upon the Subsequent Accumulation of Nitrate Nitrogen during Controlled Incubation
Authors: Harpstead M. I. , Brage B. L. 
Published: July 2010

AbstractTen South Dakota soils were investigated to determine the effect of prolonged storage under air‐dry conditions on the accumulation of nitrate nitrogen during subsequent laboratory incubation. Each soil was sieved and spread out in a drying cabinet where there was forced air circulation at room temperature. While the soils were still moist, as they occurred in the field, a sample of each soil was leached free of nitrate and incubated in a humid chamber for 14 days. Nitrate nitrogen which accumulated during the incubation period was determined. Similar incubations were made after soils had been stored at room temperature for 3, 6, 9, 18, 24, 34, and 50 weeks.Results showed the nitrification rate of freshly‐collected soil was high compared to that after air‐drying and 3 weeks of storage prior to incubation. Subsequent incubations showed a progressive increase in the nitrification level. The precision of results among replicates improved with the length of storage. Prior to 18 weeks of storage the amount of nitrate nitrogen accumulated during incubations was not correlated with oat yield responses to nitrogen fertilization. Incubations made after 18 weeks of storage, however, yielded results which correlated with the response of oats to nitrogen fertilization.
Influence of Base Saturation and Calcium Levels on Yield and Mineral Content of Alfalfa
Authors: Dawson M. D. 
Published: July 2010

AbstractA greenhouse investigation was carried out on four pedologically contrasting soils. The soils were limed to different base saturation levels. Yield and mineral composition were determined for the alfalfa grown on these soils.Soil pH readings at the same base saturation levels varied considerably on the different soils. The pattern of alfalfa response to lime also varied. On the Brown Latosol optimum growth was obtained at 40% base saturation while the other three soils gave optimum growth at either 80 or 100% base saturation. The yield response was attributed to either the direct or indirect effects of lime. Concurrently a split‐root experiment was conducted to study the effects of additional calcium supplied to an isolated section of alfalfa roots at each base saturation level. Additional calcium supplied to isolated root sections independent of the soil increased alfalfa yield significantly on two soils. The addition of calcium to the roots also decreased the manganese content of the foliage.
Distribution and Nitrification of Anhydrous Ammonia in a Nicollet Sandy Clay Loam
Authors: McIntosh T. H. , Frederick L. R. 
Published: July 2010

AbstractA roughly cylindrical distribution of NH3 centered at the knife openings was found when anhydrous ammonia was applied with a field applicator at a depth of 4 inches, by sampling an 8‐ by 8‐ by 2‐inch cross section perpendicular to the applicator row. NH4‐N, NO3‐N and pH were determined on each 1‐inch square subsample. NH4‐N decreased from a maximum concentration of 1,300 to 2,000 ppm. (pH 9.5) at the center to less than 200 ppm. (pH 8) in the area about 1½ inches away from the center of the retention zone. After 2 weeks, the maximum concentration of NH4‐N was about 800 ppm. (pH 8.8) in the center decreasing to less than 100 ppm. (pH 7.0) in the area about 2½ inches away from the center of the retention zone.Nitrification initially proceeded more rapidly in the outside 2 inches of the retention zone where the concentration of NH4‐N was less than 400 ppm. Later in the original ammonia retention zone, nitrification appeared to be limited by low pH and nitrate concentration; at the end of 4 weeks the pH had decreased to a value of 5.0 to 5.5 and NO3‐N had increased until 200 to 300 ppm. were present. Ammonia applied in November just prior to freezing showed little nitrification by March. Rapid nitrification began in mid‐April when soil temperatures rose above 40° F. Approximately 8 weeks were required to completely nitrify the ammonia.
Ammonia‐Salt Systems as Nitrogenous Fertilizers
Authors: Zimmerman M. F. , Smith F. W. , Leonard G. W. 
Published: July 2010

Abstract“Divers' solution” (an NH4NO3‐NH3 system); similar systems of NaI‐NH3, NH4I‐NH3, NaSCN‐NH3, NH4SCN‐NH3, NH4Br‐NH3; and three solid nitrogenous fertilizers (NH4NO3, CO(NH2)2, and urea‐form) were compared in the greenhouse as sources of nitrogen for wheat and millet plants.The systems of NaSCN‐NH3, NH4SCN‐NH3, NH4I‐NH3, and NaI‐NH3 were very toxic for the first crop of plants. Lethal effects of NaSCN‐NH3 and NH4SCN‐NH3 disappeared in about 5 months. Both systems, NH4I‐NH3 and NaI‐NH3, were toxic for a longer period. Applications of NH4Br‐NH3 caused considerable wilting at first but no lethal effects occurred.The greatest nitrogen percentage in wheat plants occurred from use of NH4Br‐NH3 but the greatest total accumulation in plants resulted from use of NH4NO3‐NH3. Urea‐form was ineffective as a source of nitrogen for the first crop. Solid ammonium nitrate and urea were of about the same effectiveness.Herbicidal possibilities for some of the systems were suggested.
A Unifying Numerical Solution for Two‐Dimensional Steady Flow Problems in Porous Media With an Electrical Resistance Network
Authors: Bouwer Herman , Little W. C. 
Published: July 2010

AbstractNumerical solutions of two‐dimensional steady flow systems that are partially or completely unsaturated involve satisfying the tension vs. conductivity relations of the media in addition to some approximative expression of the Laplace equation for nonhomogeneous conductivity. Where tensions and conductivities are initially unknown, assumed conductivity values are used in the first relaxation procedure after which the correct values are determined by a process of repeated relaxation analyses with conductivity to tension adjustments after each relaxation. Relatively rapid solutions can be obtained by use of an electrical resistance network for relaxing the system.A numerical procedure is developed for expressing the equivalent conductivity of the medium between any two adjacent points of the network in terms of the conductivities or tensions at the two points. This procedure is independent of the nature of the relation between tension and conductivity and utilizes experimentally determined values in the form of graphs or tables.The equivalent conductivity between adjacent points of the network differs from the arithmetic mean of the conductivities at the points, especially when the conductivity values are relatively far apart. The arithmetic mean appears to be an accurate measure of the equivalent conductivity only in event of horizontal flow with a linear relation between tension and conductivity.Examples of completed analyses include a solution of flow in tile‐drained soil with the saturated and unsaturated zone united into one system and a solution of unsaturated subirrigation flow from perforated underground tubing in the presence of a deep water table. The shape of the water table in the drainage example was immaterial to the solution of the problem, but it could be evaluated after the analysis as the atmospheric‐pressure contour. The streamlines above the water table deviated from the vertical direction causing the flow rate across the water table to be nonuniform.
Effect of Gamma Radiation on Growth and Metabolism of Microorganisms in an Organic Soil
Authors: Stotzky G. , Mortensen J. L. 
Published: July 2010

AbstractSamples of Rifle peat were irradiated with gamma rays from a Co60 source at doses of 2, 8, 32, 64, 128, and 250 kiloroentgens (kr.). The irradiated samples were incubated for 54 days, and periodic determinations were made on the rate of CO2 evolution, P and N mineralization, pH changes, and development of bacterial and fungal populations.The radiation doses employed had no significant effect on development of the bacterial population, pH, mineralization of P, and evolution of CO2. Growth of the fungal population and ammonia utilization was increasingly inhibited by doses of 8 to 250 kr.Gross changes in the metabolism of the soil microflora did not take place. Higher dose levels than those used in this study apparently are required for the sterilization of organic soils.