bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Influence of Low Temperature and Various Concentrations of Ammonium Nitrate on Nitrification in Acid Soils
Authors: Anderson O. E. , Boswell F. C. 
Published: July 2010

AbstractSeveral cultivated, acid soils were limed to pH 6.0 to 6.4, treated with 100 ppm. NH4‐N as NH4NO3, and incubated for 12 weeks at low and at near‐optimum temperatures for nitrification. In sandy soils, nitrate accumulation at 42°F. was either completely suppressed or delayed for several weeks. In a clay loam incubated at 37°F. nitrates accumulated at a very slow rate throughout the 12‐weeks but at 47°F., after a 6‐week delay period, the accumulation proceeded at a rapid rate. The great influence of differing soil characteristics on nitrification is shown by the fact that nitrate accumulation in the clay loam at 37°F, was about two‐thirds of that occuring in a loamy sand at 90°F. When the amount of added NH4NO3 was increased to 200 or 400 ppm. NH4‐N, nitrate accumulation, with one exception, failed to occur at 42°F. in sandy soils and was delayed in the clay loam. Even at 90°F., nitrate accumulation in the sandy soils, but not in the clay loam, was delayed and the rate reduced.
Ion Diffusion: II. Comparison of Apparent Self and Counter Diffusion Coefficients
Authors: Phillips R. E. , Brown D. A. 
Published: July 2010

AbstractThe experimental distributions of Rb86 diffusing in soil materials are obtained using a quick‐freeze method. The calculation of apparent diffusion coefficients of Rb from data obtained from these distributions is presented for the following geometries: (1) self diffusion and (2) counter diffusion of Rb diffusing from soil media initially saturated with Rb into the same soil media initially saturated with H+. The distribution of Rb86 counter diffusing from kaolinite clay, montmorillonite clay, Sharkey clay soil and Dundee silt loam soil pastes into H+ saturated kaolinite, montmorillonite, Sharkey and Dundee pastes can be characterized using self diffusion theory.The order of magnitude of apparent self diffusion coefficients is larger than those for counter diffusion in each of the four soil materials. The order of magnitude of the rate of Rb diffusion in the four soil materials is as follows: kaolinite clay > Dundee silt loam soil > Sharkey clay > montmorillonite clay. The values of the diffusion coefficients range from 3.9 × 10−7 cm.2 sec.−1 to 24.3 × 10−7 cm.2 sec.−1.Qualitative apparent counter diffusion coefficients of Rb diffusing from soil media initially saturated with Rb into strong acid exchange‐resin discs initially saturated with H+ are also presented for qualitative comparison purposes.
Effects of Soil Temperature and Oxygen on the Amounts of Macronutrients and Micronutrients in Citrus Seedlings (Citrus sinensis var. Bessie)
Authors: Labanauskas C. K. , Stolzy L. H. , Klotz L. J. , DeWolfe T. A. 
Published: July 2010

AbstractExperiments were conducted in a greenhouse during both fall and spring to study the influence of soil oxygen conditions and soil temperatures on the amounts of macro‐ and micronutrients in sweet orange seedlings (Citrus sinensis var. Bessie).The total amounts of 11 nutrients and Na were determined in the roots and tops of citrus seedlings. Slight soil temperature differences, close to the optimum (22.5C and 27.8C) did not affect the dry weight of plants and the amounts of nutrients in the plants. However, there was a greater percentage of total K, Cl, and B found in the tops of plants grown at the higher soil temperature than at the lower.The amounts of N, P, K, Ca, Mg, Zn, Cu, Mn, B, and Fe decreased in the citrus seedlings with decreasing soil oxygen supply to the roots. The chloride and Na content decreased in the roots and increased in the tops with decreasing soil‐oxygen supply to the roots of the seedlings.Citrus seedlings grown during the fall months produced more dry weight of plants, and contained, in general, larger amounts of nutrients per plant, except Na and Cl, than seedlings grown during the spring months.
Phosphorus Adsorption Maximum as Measured by the Langmuir Isotherm and Its Relationship to Phosphorus Availability
Authors: Woodruff J. R. , Kamprath E. J. 
Published: July 2010

AbstractThe phosphorus adsorption maximum as calculated by the Langmuir isotherm was determined for a number of soils with a wide range in chemical properties. Neutralization of exchangeable aluminum markedly reduced the P adsorption maximum. The growth of millet was related to the degree of saturation of the P adsorption maximum. The soils with a large P adsorption maximum did not require as high a P saturation as those with a low adsorption maximum. Maximum yields on the limed soils were obtained when the equilibrium solution concentrations of P were greater than 0.1 × 10‐4 moles/liter of P. A much higher concentration of P was needed on the soils with a high saturation of exchangeable aluminum to give maximum yields, however, the yields were lower than on the limed soils.
A Rapid Procedure for Securing Large, Undisturbed Soil Cores
Authors: Tackett J. L. , Burnett Earl , Fryrear D. W. 
Published: July 2010

AbstractA method is described for rapidly obtaining large, undisturbed soil cores ranging from 16 to 38 inches in diameter and to depths of up to 9 feet. Such cores, in some cases containing several thousand pounds of soil, may be used in‐place or moved to a controlled environment for a number of purposes; e.g., studies of transpiration, evapotranspiration, moisture flow, and others. In such cases, disturbed soil materials often are not satisfactory because of the influence of disturbing the soil on such properties as moisture transmission, moisture retention, and root distribution.
A Semimicro Technique for Studying the Oxygen Content of Gases
Authors: Sommerfeldt Theron G. , Knutson Kenneth W. 
Published: July 2010

AbstractA simple, compact, portable, and relatively durable instrument has been devised whereby the oxygen content of semimicro quantities of gases can be accurately and rapidly determined. A Beckman D‐2 oxygen analyzer is connected to a vacuum pump via a 3‐way valve in a way that the system can be evacuated. The evacuation process makes it possible to analyze a gas sample of less than 20 cc where 500‐ to 600‐cc were required by the unmodified analyzer. This unit was calibrated, using gases of known oxygen content. The results were very satisfactory and well within the limits of accuracy specified by the manufacturer.
Numerical Solution of the Nonlinear Diffusion Equation for Water Flow in a Horizontal Soil Column of Finite Length
Authors: Klute A. , Whisler F. D. , Scott E. J. 
Published: July 2010

AbstractThe nonlinear diffusivity form of the flow equation for water in soil was solved numerically subject to the conditions: θ(0, t) = θb, t > 0; θ(x, 0) = θs, 0 < x < L; ∂θ/∂x = 0, x = L, t > 0; and D(θ) = αeβθ. In these equations θ is the volume water content, D(θ) is the diffusivity function, α and β are constants, θb and θs are the constant values of boundary and initial water content, and L is the length of the column. The solution θ(x, t) and the flux and cumulative flow across the plane x = 0 were obtained for various values of the parameter β̄ = β(θs − θb). Both inflow and outflow cases were considered, and the effect of the parameters α and β on the flow behavior is discussed.
Characterization of Aluminum Interlayers in Soil Clays
Authors: Frink C. R. 
Published: July 2010

AbstractThe amounts of Al, Fe, Mg, K, and Si extracted by sodium citrate from 10 soil clays containing various amounts of chloritized vermiculite are related to changes in cation‐exchange capacity (CEC), intensity of the 14A spacing and sample weight loss. Those soils containing abundant interlayers underwent the largest changes in CEC, contained the most citrate‐soluble Al and lost the most weight. Although most of the change in CEC and intensity of the 14A spacing occurred in the first 2 hours, Al was steadily extracted from sources of similar solubility for at least 6 hours. Even though the increase in CEC was well correlated with the total Al extracted, it appears that Al interlayers exist as “atolls,” and that not all citrate‐soluble Al is contained in interlayer positions. No evidence for the presence of Fe interlayers was found; rather, Fe and Mg appear to exist as contaminants in citrate‐soluble Al compounds. A weathering sequence of illite‐vermiculite‐chloritized vermiculite‐gibbsite is proposed for these acid soils. Thus, abundant Al interlayers and low CEC are among the most prominent features of highly weathered acid soils.
Ionic Relationships in Clay Suspensions and Dialyzates: I. Rubidium‐86 as a Tracer for Potassium
Authors: Franklin R. E. , Snyder G. H. 
Published: July 2010

AbstractHighly significant linear correlations were found to exist between radiotracer quantities of Rb86 and the K concentrations of the dialyzate phases of clay‐water membrane equilibrium systems. The systems extended over a wide range of Ca/K saturation ratios, electrolyte concentrations, and pH values. The linear regression lines for bentonite, illite, kaolinite, and vermiculite systems had similar slopes. The actual amounts of K in the dialyzate phases were about 1.4 times the values indicated by the Rb tracer. Of the four clay minerals only the vermiculite presented problems because of specific fixation of K or Rb. Uptake of K42 by excised barley, corn, and soybean roots from bentonite systems was also significantly correlated with uptake of Rb86. It appeared that Rb86 could be used in tracer quantities to reflect relative changes in the K distribution in these systems.
Characterization of Taranakites and Ammonium Aluminum Phosphates
Authors: Frazier A. W. , Taylor A. W. 
Published: July 2010

AbstractOptical, X‐ray diffraction, infrared absorption, and differential thermal analysis data are presented for the salts K3Al5H6 (PO4)8·18H2O, (NH4)3Al5H6(PO4)3·18H2O, (NH4)2AlH(PO4)2·4H2O, NH4AlPO4OH·2H2O, and NH4AlPO4OH·3H2O. Where the particle size is too small for determination of optical characteristics, a combination of X‐ray diffraction and infrared absorption methods is the most satisfactory means of identification of these compounds. Differential thermal analysis is unsuitable for the ammonium salts.
The Significance of the Rate of Organic Matter Decomposition on the Aggregation of Soil
Authors: Meredith H. L. , Kohnke H. 
Published: July 2010

AbstractLaboratory studies of different types and amounts of organic materials added to a moist soil resulted in maximum release of CO2 after about 48 hours and in maximum stability of soil aggregates after about 2 weeks incubation. The experiments indicated that a fairly rapid and sustained rate of decomposition of organic residues is a necessity in the stabilization of soil aggregates. Corn stover was more effective than corn cobs—when ground to similar fineness. The benzene‐alcohol and the alkali soluble extracts from a soil that had been incubated with ground corn stalks greatly increased the aggregate stability when added to an otherwise untreated soil. The benzenealcohol soluble fraction likely reduced the rate of wetting of soil aggregates. As a consequence the dispersion effect of water was less pronounced. Water‐soluble extracts had little influence on stabilizing soil aggregates.
Variation of Soil Morphological Properties Within Miami, Celina, and Crosby Mapping Units in West‐Central Ohio
Authors: Wilding L. P. , Jones R. B. , Schafer George M. 
Published: July 2010

AbstractVariation of soil morphological properties within mapping units of Miami, Celina, and Crosby soils in Ohio has been statistically summarized. Ten randomly selected profiles within each of 24 mapping delineations of these soils were sampled for this characterization. The most variable properties were horizon thickness, depth of leaching of carbonates, loess thickness, depth to mottling, pH, and class (size) of soil structure. Clay content, grade (strength) of soil structure, and soil color were least variable. The number of observations required to estimate the population mean of the above parameters within certain limits using a .95 confidence interval was computed. These soils were correctly classified with regard to great group at 96% of the 240 observations, to subgroup at 85%, to soil series at 42%, and to soil type at 39%. Parent material was mapped accurately 88% of the time; erosion, 94%; pH, 70%; solum thickness, 63%; and drainage class, 65%. Since all delineations contained 30% or more inclusions of other soils, these mapping units would be considered complex or undifferentiated units based on the present concept of a mapping unit. It is proposed that the concept of the mapping unit be modified to emphasize the dominant soil of the area rather than implying 85% mapping accuracy of a specified soil.
The Genesis of Certain Calcareous Floodplain Soils of Virginia
Authors: Mathews H. L. , Prescott G. W. , Obenshain S. S. 
Published: July 2010

AbstractA study was made to determine the origin of the calcareous material found in certain floodplain soils of the limestone valleys of Virginia. The CaCO3 in these soils was derived from the highly fractured and faulted limestone underlying the area. Groundwater, high in dissolved CO2, percolated through the crushed limestone, dissolving an appreciable amount of Ca and Mg carbonate. This water issued at the surface in the form of large springs and lost some of the dissolved CO2 which resulted in a saturated solution with respect to calcium. The CaCO3 depositing alga Oocardium stratum Näg was found below the point of saturation in the streams and was thought to be of major importance in the deposition of CaCO3. In a 200‐foot section of stream channel beginning 450 feet below a spring having a rate of flow of 104 gallons/min, approximately 2.85 tons of CaCO3 were deposited annually as tufa. Algal‐deposited tufa is torn from stream channels during heavy rains and redeposited downstream by flood waters. Calcareous material occurs several miles from the source area and is a constituent of the flood plain soils along the creeks and rivers of the area.
Salt Entry into Plants
Authors: Hendricks Sterling B. 
Published: July 2010

AbstractThe manner of salt entry into roots is discussed. Reasons are given for considering the plasmalemma of the epidermal cells as being the rate‐limiting barrier. The dependence of uptake on aeration is considered to arise from production of adenosine triphosphate (ATP) by oxidative phosphorylation in the mitochondria. Passage of the salt at the cellular membrane, however, is considered to depend on utilization of ATP. Partial processes involve H+ exchange for cations and OH‐ exchange for anions. The eventual charge balance within the root depends on production of carboxylic acids (initially oxaloacetic) by fixation of carbon dioxide. In salt accumulation, if transport from the roots is limited, an eventual equilibrium is reached with equal efflux and influx rates. Recent work indicating that the function of K+ in plants as chiefly one of determining protein configuration is cited.
Chloride Diffusion in Clay‐Water Systems
Authors: van Schaik J. C. , Kemper W. D. 
Published: July 2010

AbstractSelf‐diffusion coefficients of chloride were determined in sodium‐and calcium‐saturated bentonite in steady and transient state systems. In steady state systems a decrease in diffusive flow with lower salt concentrations in the equilibrium solutions can be attributed to anion exclusion in clay‐water systems. In transient state systems the influence of the free electrolyte concentration on the porous system diffusion coefficient of chloride is practically negligible. An observed reduction by about 50% in the apparent diffusion coefficient of anions in these systems was attributed to heterogeneity of the negative adsorption due to a wide range of pore sizes.
Morphology and Genesis of Six “Red Hill” Soils in the Oregon Coast Range
Authors: Parsons R. B. , Balster C. A. 
Published: July 2010

AbstractThe distribution and development of six soils in the Oregon Coast Range are related to geomorphic surfaces and slope gradients on a basalt highland. The soils exhibit one or more textural discontinuities as evidenced primarily by stone lines and stone contents which decrease with profile depth.Several soils having high base saturation and contents of Ca and Mg are related to landslides and saddles where base‐enriched groundwater moving through basalt saprolite may temporarily accumulate.
Formation of Gibbsite from Aging Hydroxy‐Aluminum Solutions
Authors: Hsu Pa Ho 
Published: July 2010

AbstractHydroxy‐aluminum solutions of NaOH/AlCl3 molar ratio = 0.3 to 2.7 and concentration of Al = 0.02m were prepared and aged for 2 years. The solutions of NaOH/AlCl3 = 1.5 and below remained unchanged during the entire period of study. Those solutions of NaOH/AlCl2 molar ratio = 1.8 to 2.7 were stable for about 6 months to 1 year, then the solutions gradually became turbid, and eventually gibbsite formed in association with a decrease in pH. When a solution of NaOH/AlCl3 = 2.7 was either diluted ten‐fold with water or dialyzed to remove the Na+ and Cl‐, the same reaction took place in 2 weeks. When NaCl was added at a concentration of 0.12m, the solution became only slightly turbid at the end of 1 year. At 0.6 and 1.2m NaCl, amorphous Al precipitates formed immediately after preparation and remained amorphous even after 2 years.It is proposed that the formation of gibbsite from aging hydroxy‐aluminum solutions follows the same mechanism as the rapid precipitation of bayerite at NaOH/AlCl3 = 3 in an alkaline medium, the latter being discussed previously by Hsu and Bates in 1964. The difference between these two processes is the source of OH‐ for the completion of neutralization. The OH‐ added as NaOH is taken up by hydroxy‐aluminum polymers almost instantaneously, whereas the spontaneous hydrolysis of these polymers is slow, particularly in the presence of high salt concentration.
Potentiometric Titration of Acid Montmorillonite
Authors: Sawhney B. L. , Frink C. R. 
Published: July 2010

AbstractTwo buffer ranges representing the titration of H and Al ions are generally observed in the potentiometric and conductometric titration curves of acid montmorillonite. Recently, a third buffer range has been reported by two groups of investigators. The weak acid neutralized in the third range has not been fully characterized, however, and hence was investigated further.Aging of acid montmorillonite prepared by passing the lay through a resin column increased both the second and third buffer ranges while it decreased the first range. In addition, the ratio of the third to the second buffer range increased continuously. Titration curves of acid clay prepared by treatment with different concentrations of HCl contained different amounts of the third range: the higher the concentration of acid, the greater was the third range. The acidic component titrated in this range was held very strongly by the clay and could not be extracted with 1n HCl or 1n NaCl.These observations led to the conclusion that the weak acid titrated in the third buffer range of acid montmorillonite is a complex alumino‐silicate resulting from the decomposition of the clay by acid action.
Decomposition of the Iron, Aluminum, Zinc, and Copper Salts or Complexes of Some Microbial and Plant Polysaccharides in Soil
Authors: Martin J. P. , Ervin J. O. , Shepherd R. A. 
Published: July 2010

AbstractZinc, Copper, iron, and Aluminum salts or complexes of a series of bacterial and plant polysaccharides containing from 6 to 83% uronic acid units were prepared. The rate of decomposition of the metal‐polysaccharide complexes or salts and the original polysaccharide preparations was determined in Greenfield sandy loam. Some or all of the metals exerted marked effects on decomposition rate and percentage decomposition at 8 weeks of the majority of polysaccharides tested. Specific effects of the metals depended on the polysaccharide. Zinc and Al exerted very little influence on decomposition of Azotobacter chroococcum polysaccharide for example, while Cu and Fe reduced decomposition by about 50%. A much smaller percentage of Zn, on the other hand, reduced decomposition of Karaya gum from 67% to 0 in one test and to 3% in a repeat trial. The Cu‐salt of Azotobacter indicus polysaccharide was highly resistant to decomposition. After 8 weeks, 3% had decomposed compared to 29, 32, 16, and 16% for the original polysaccharide and the Al, Zn, and Fe complexes, respectively. With the exception of the Al combined with the Arthrobacter viscosus polysaccharide, all of the metals sharply reduced decomposition of A. viscosus polysaccharide and alginic acid but exerted very little effect on polysaccharides from Chromobacterium violaceum and a Bacterium sp. When added directly to the soil in concentrations equivalent to that in the metal‐A. chroococcum polysaccharide complexes (75% uronic acid), the metals exerted no effect on decomposition of Bacillus subtilis fructosan.
Examination of the Change in Soil Moisture Diffusivity During Outflow
Authors: Kunze R. J. , Peters D. B. 
Published: July 2010

AbstractExperimental outflow curves were matched with theoretical curves by assuming a change in diffusivity proportional to a ratio of theoretical and experimental time values. The noted change of the diffusivity is not a function of the change in moisture content, but presumably the result of a complicated drainage sequence of soil pores.
Depth of Barrier and Water Table Fall in a Tile Drainage Model
Authors: Asseed Mohamed , Kirkham Don 
Published: July 2010

AbstractA laboratory model having a transparent photographable front and containing glass beads has been used for determining, under idealized conditions, the influence of a barrier on tile drainage, in regard to both rate of fall of the water table and tile discharge. Photographs of the modeled water table and the measured discharge as it varies with time are raw experimental data, and charts of dimensionless drainage parameters have been derived therefrom. The results show that changes in depth of a shallow porous medium markedly influence drainage. A critical depth occurs when the barrier is at a depth equal to one fifth of the drain spacing; then the barrier has negligible influence on rate of fall of the water table and on drain discharge. When steady rainfall (in the form of drops of glycerol) was applied, the water table arch at equilibrium was more curved for the higher rates of rainfall. Graphs of rainfall‐intensity versus water table height were straight lines both for a position over the tiles and midway between tiles. The data reported here differ from other published data in that here a number of steady state rainfall conditions were used to establish initial conditions. Data were compared with theoretical work, and a good agreement was obtained.
A Soil Beidellite
Authors: Ross G. J. , Mortland M. M. 
Published: July 2010

AbstractX‐ray diffraction analysis of the < 2 µ fraction of the main horizons of a Deer Park sand, a Podzol soil in northern Michigan, shows that montmorillonite is the dominant layer silicate in the A2 horizon of this soil. This montmorillonite appears to have weathered from illite and mica and chlorite interstratified with vermiculite and montmorillonite which are present in the underlying horizons. Chemical and X‐ray data indicate that the montmorillonite in the fine fraction (< 0.2 µ) of the A2 horizon contains some randomly interstratified mica. The Greene‐Kelly test, X‐ray powder diffraction, differential thermal, infrared, and chemical data show that the expanding component of this fine fraction is a beidellite of formula [Al1.62Fe0.18Mg0.28][Al0.45Si2.55]O10[OH]2 with exchange capacity = 0.49 M+ per half unit cell. This beidellite has a high layer charge, most of which arises from tetrahedral substitution, and shows a strong tendency to fix potassium.