bluuebunny/crossref_metadata_2025_split huggingface dataset:
Salt‐Exchangeable and Titratable Acidity in Bentonite‐Sesquioxide Mixtures
Authors: Coleman N. T. , Thomas G. W. , LeRoux F. H. , Bredell G. 
Published: July 2010

AbstractsPrecipitation of ferric or aluminum “hydroxides” in bentonite suspensions resulted in the formation of claysesquioxide complexes with exchange and titratable acidity reminiscent of many acid soils high in iron and aluminum oxides. Tenth‐normal AlCl3‐treated samples containing different amounts of sesquioxide had exchange acidities between 0 and 0.42 me. per g. of bentonite, titratable but nondisplaceable acidities from 0.41 to 0.74 me. per g. The sum of exchange and titratable acidity was close to the cation‐exchange capacity of the clay. Substantial amounts of aluminum or ferric hydrous oxide existed as interlayers, aluminum ones being better ordered. Apparently ferric or aluminum hydrous oxides deposited on montmorillonite surfaces can exist there as R(OH)x, with x ≤ 3. At pH 8 to 9, there are 3 hydroxyls per trivalent ion, and the effective CEC is that of the clay. As pH is lowered, OH is removed or H is added to the sesquioxide coating, which becomes positively charged and interacts with exchange sites of the clay. At pH around 5, the effective exchange capacity is near zero. Addition of base to the acid system restores OH to the sesquioxide and recreates exchange capacity. The salt displacement and titration results in the bentonite‐sesquioxide systems parallel in many ways similar observations made with acid soils, suggesting that similar reactions occur in natural and synthetic systems.
Crop Responses to Some Micronutrients and Sodium on Sphagnum Peat Soil
Authors: MacKay D. C. , Chipman E. W. , Langille W. M. 
Published: July 2010

AbstractFive micronutrients and sodium were applied to a virgin sphagnum peat soil, having an initial pH of 3.5, in a 26 confounded factorial greenhouse experiment. To determine both immediate and ultimate deficiencies, a sequence of 11 crops were grown with spinach, lettuce and onions as the indicator crops. Yield data were supplemented by soil and crop analyses.The greatest effect resulted from molybdenum treatment which produced yield increases over no molybdenum of 67, 42 and 198% with the 8th, 10th and 11th crops, respectively. The onion crop was the most responsive.Copper had little effect on the first few crops, but with the 3rd application (on the 5th crop) serious toxicity resulted, and persisted until the 10th crop. A 63% yield increase from Cu was obtained with the final crop.A highly significant interaction of Mo x Cu was obtained with the last three crops. Although the overall effect of Cu was negative, not significant and positive on the three respective crops, the interaction was consistently positive.Repeated applications of manganese and zinc were toxic with yield depressions occurring on the 5th and persisting until the 11th crop.Sodium was neither beneficial nor detrimental for any crop. Boron had no detectable effect in these experiments, but analytical results indicated that impurities added in the lime or fertilizers were sufficient to prevent serious deficiency.
Linear Equations for the Simultaneous Flow of Matter and Energy in a Continuous Soil System
Authors: Taylor Sterling A. , Cary John W. 
Published: July 2010

AbstractSome transfer processes in soil are considered with respect to recent developments in the theory of thermodynamics of irreversible processes. The theory provides a general and systematic guide for setting up interrelated equations describing the transport of one or more components through soil. Darcy's law and the “diffusion equation” are shown to be components of this general development. Particular attention is given to the non‐isothermal flow of moisture and energy through soil. A general relation between the fluxes induced by the combined gradients of moisture content, temperature, and solutes is also suggested.
Microrelief Influences in a Saline Area of Glacial Lake Agassiz: I. On Salinity and Tree Growth
Authors: Sandoval Fred M. , Benz Leo C. , George E. J. , Mickelson R. H. 
Published: July 2010

AbstractConsiderable acreage of saline, imperfectly drained land in the northern Red River Valley of North Dakota has a gently undulating microrelief or nearly level topography. In slight to moderate saline lands the ridges are saline and the depressions relatively nonsaline. Salinity was studied in its relationship to microrelief under both shelterbelt and cultivated land use. Salinity in the ridge is composed primarily of magnesium and sodium sulfates. Exchangeable sodium is low and not a problem. Chemical compositions of shallow ground waters and saturation extracts of ambient soil are similar.Soil salinity of the first foot of soil was less in the shelterbelt than in the adjacent cultivated area. This reduction near the surface within the shelterbelt was accompanied by a salinity increase at the 42‐ to 60‐inch depth. The reduction was attributed to greater moisture absorptive qualities of the established grassed areas and increased water supply from snow accumulation in the belt. Russian olive shrubs did poorly and frequently failed to survive when planted in soil having more than 10 millimhos per cm. estimated electrical conductivity, but they experienced little detrimental effects with 3 millimhos per cm. or less. Salinity of shallow ground water was much higher under ridges than depressions which indicates very limited crossflow.
Physiological Changes in and Ozone Susceptibility of the Tomato Plant After Short Periods of Inadequate Oxygen Diffusion to the Roots
Authors: Stolzy L. H. , Taylor O. C. , Dugger W. M. , Mersereau J. D. 
Published: July 2010

AbstractThe degree to which tomato leaves were altered following short periods of reduced oxygen in the root zone was studied in relation to the following factors: apparent rate of photosynthesis, susceptibility to ozone, and carbohydrate concentration.Reduced rates of soil oxygen diffusion for 8 ½ hours brought about a 50% decerase in CO2 fixation by plants, while shorter periods (3 hours) had only a slight effect on apparent photosynthesis. However, the short period of anaerobic treatment over the soil surface, followed by normal soil aeration for 24 hours, reduced the susceptibility of the plant to ozone damage by as much as 50%. Carbohydrate analysis of leaf tissue for similarly treated plants showed a 50% reduction in sucrose and 33% reduction in starch. It is hypothesized that the anaerobic pretreatment brought about a change in the root membrane permeability or a shift in metabolism that promoted excretion of certain carbohydrates from the roots which in turn changed the concentration of carbohydrates in the leaves.
Reduction in Salt Content of Solution on Passing Through Thin Films Adjacent to Charged Surfaces
Authors: Kemper W. D. , Maasland D. E. L. 
Published: July 2010

AbstractAn equation was derived to measure the effect of salt and water diffusion on salt reduction of solutions forced through thin films of water by pressure differentials. Salt concentrations of solutions which had passed through thin films adjacent to charged particles were calculated from the equation and are plotted as a function of pressure differential, ionic mobility, film thicknesses, and cation valences. Experimental evidence showed that salt sieving increases as the pressure forcing solution through the clays increases. Salt sieving generally increases as the pores through which the water flows decrease in size, and is smaller when the soil is saturated with divalent rather than monovalent ions. These observations were in agreement with the theory.
Availability of P from Superphosphate to Spring Wheat as Affected by Growth Stage and Surface Soil Moisture
Authors: Boatwright G. O. , Ferguson Hayden , Brown Paul L. 
Published: July 2010

AbstractThe influence of periodic wetting of a dry surface soil on fertilizer P uptake at four growth stages was studied in the greenhouse using P32.Wheat plants did not absorb fertilizer P from a dry soil. At all stages of growth there was a lag in fertilizer Pu ptake after watering and the length of lag increased with age of plant after the flag leaf stage. Only small amounts of fertilizer P were found in plants grown on soil that had been wet less than 80 hours. This suggests that showers and weather conditions which do not allow the fertilizer zone to remain wet for 3 to 4 days contribute little to fertilizer P uptake by wheat. Most rapid rate of fertilizer P uptake occurred when fertilizer and water were added at the flag leaf and 30% headed stages of plant growth, but when added at the completely head stage little fertilizer P was absorbed.
The pH‐Percent Base Saturation Relationships of Soils
Authors: Clark J. S. , Hill R. G. 
Published: July 2010

AbstractThe curves obtained by plotting pH‐½p (Ca + Mg) against percent base saturation calculated from the ratio of exchangeable Ca + Mg to the sum of Ca + Mg + Al + H extracted from soils with 1.0N KCl had the characteristic shapes of clay titration curves. The experimental values for some montmorillonitic soils showed close agreement with the theoretical curve calculated for Al‐bentonite. The Podzolic and Glei soils fell along another curve with lime potential values higher than those for the montmorillonitic soils at the same % base saturation indicating that the exchange properties of the soils differed from those of bentonite. No close relation was observed when the cation‐exchange capacity (CEC) obtained with 0.9N Ca(OAc) 2 + 0.1N CaCl2 or with 1.0N CaCl2 was used to calculate percent base saturation.
Gamma Radiation Compared with Steam and Methyl Bromide as a Soil Sterilizing Agent
Authors: Eno Charles F. , Popenoe Hugh 
Published: July 2010

AbstractRed Bay loamy fine sand and Everglades muck were sterilized with gamma radiation, steam, and methyl bromide. Exchangeable NH4+; extractable N, P, and S; moisture equivalent; cation‐exchange capacity; and organic matter were measured. None of the sterilization treatments significantly altered cation‐exchange capacity. Steam significantly increased the amounts of N, P, and S extracted and the organic matter content values, compared to the check and the other two soil treatments; it also significantly decreased the moisture equivalent percentage. Gamma ray and methyl bromide sterilization generally increased the release of N, P, and S above the check. There was also a strong indication, based on the N data, that sterilization by gamma rays disrupted the soil organic materials more than methyl bromide. Finally, the intensity of all these factors is most closely associated with the organic matter content of the soil. Therefore, a sand, for example, would not be altered nearly as much as a loam or an organic soil.
The Temperature Dependence of Soil Water Vapor Pressure
Authors: Kijne Jacob W. , Taylor S. A. 
Published: July 2010

AbstractThe temperature dependence of soil water vapor presure was studied with a psychrometric vapor pressure technique in the range of 0.96 to 1.00 relative vapor pressures and below 0.96 with gravimetric and calorimetric heat of immersion techniques. For Millville silt loam at constant water content, the relative vapor pressure decreased with increasing temperature. Both differential and integral entropy values were calculated. The difference between the partial molar entropy of pure free water vapor and the partial molar entropy of adsorbed water led to the conclusion that soil water molecules are arranged, on the average, less randomly than water vapor molecules. At the same time, comparison with the entropy of vaporization of pure water suggested a more random arrangement of molecules in soil water than in free liquid water.
Relationship of Exchangeable Na Percentage at Different Soil pH Levels to Hydraulic Conductivity
Authors: Martin J. P. , Richards S. J. , Pratt P. F. 
Published: July 2010

AbstractThe relation of exchangeable Na percentage at different soil pH levels to the hydraulic conductivity of 6 soils with exchange capacities varying from 7.5 to 50.8 me. per 100 g. was studied. The same quantities of Na reduced hydraulic conductivity more in acid than in neutral or alkaline soils. This response was studied further by correlating hydraulic conductivity with Na percentage calculated relative to each of three quantities: (1) the cation‐exchange capacity (CEC) at pH 7, (2) the CEC at the pH of the soil sample, and (3) the sum of exchangeable Ca, Mg, K, and Na. Highly significant correlation coefficients relating hydraulic conductivity to Na percentage were obtained for all six soils when Na was expressed as a percentage of Ca + Mg + K + Na. Calculation of the Na percentage on the basis of the CEC at the pH of the soil and at pH 7 gave highly significant correlation coefficients in 4 and 2 soils, respectively.
Volatilization Losses of Nitrogen from Surface‐Applied Fertilizers, as Measured by Crop Response
Authors: Terman G. L. , Hunt C. M. 
Published: July 2010

AbstractYields and uptake of N by corn forage grown in pot experiments with N fertilizers mixed with and surface‐applied to moist soils a week prior to planting were determined. Losses of N were low with mixed placement. High losses of N, presumably as NH3, occurred from granular urea surface‐applied to Hartsells fine sandy loam limed to pH 6.2 and 7.5 and to Webster silty clay loam (pH 8.2). Losses were reduced by coating urea with S or by including phosphate in the granules as urea ammonium phosphate. Severe losses of N also occurred with surfaceapplied ammonium sulfate and diammonium phosphate, especially from the naturally calcareous Webster soil. Maximum recoveries from soils of pH 6.2 to 8.2 were obtained from monoammonium phosphate, ammonium nitrate, ammonium phosphate nitrate, and ammonium polyphosphate. Differences in losses of N as NH3 among N fertilizers can be explained largely in terms of urea hydrolysis or the reaction of certain acid radicals of ammonium salts with calcium compounds in soil.
Classification and Genesis of Some Solonetz (Sodic) Soils in Eastern Arkansas
Authors: Horn M. E. , Rutledge E. M. , Dean H. C. , Lawson M. 
Published: July 2010

AbstractMedium‐textured Solonetz soils, comprising an estimated 600,000 acres in Arkansas, are extensively developed in loess and backwater alluvial deposits of eastern Arkansas. Three general groups are recognized: (1) Soils of less than about 10 inches depth to a sodic horizon, (2) soils with acid upper horizons and moderate depth (about 24 inches) to a sodic horizon, and (3) soils with sodic horizons and acid sola. Laboratory analyses of Lafe and Foley soil profiles indicate that their sodic horizons contain high percentages of exchangeable Na (15 to 40% or more) and Mg (40 to 50% or more) with electrical conductivities ranging up to 5 mmho. per cm. These horizons are commonly characterized by prismatic or columnar structure. It appears that these soils are undergoing leaching and that soils of high exchangeable Na and solonetz morphology are probably the result of prior high Na content.
The Effect of Fatty Alcohol and a Nonionic Surfactant on Soil Moisture Evaporation in a Controlled Environment
Authors: Law J. P. 
Published: July 2010

AbstractEvaporation studies have been conducted in a controlled environment chamber. Three variables were introduced: Treatment rate, relative humidity, and wind velocity. Air temperature was held constant at 100°F. Two evaporation media were employed: washed masonry sand, and Amarillo fine sandy loam soil.The fatty alcohol used in the study was a commercial mixture of hexa‐ and octadecanol, which was uniformly mixed with the top 3‐inch layer of soil. The rates of application were: 100, 200, and 400 pounds per acre with the masonry sand, and 200 and 800 pounds per acre with the sandy loam soil. A third treatment with the soil consisted of irrigating the column with a 0.1% solution of a nonionic surface active chemical. The control in each case consisted of untreated sand or soil. All columns were irrigated and drained to approximately field capacity at the start of each drying cycle. Evaporative loss was measured by weighing.Fatty alcohol effectively reduced evaporation from the sand surface up to a maximum of 87% at 400 pounds per acre, at 20% relative humidity, and 2 miles per hour wind velocity. The greatest reduction with soil was 24% at 800 pounds per acre, at 20% relative humidity, and 2 miles per hour wind velocity. The nonionic surfactant reduced evaporation from the soil surface up to a maximum of 52% at 60% relative humidity and 8 miles per hour wind velocity.Increased relative humidity reduced evaporation rates in all cases. The higher wind velocity accelerated the evaporation process, causing the earlier formation of a dry diffusion barrier at the surface.The mechanism by which the fatty alcohol suppressed evaporation from the masonry sand appeared to be essentially the same as that which acts to reduce evaporation from an open water surface. With the soil, the mechanism appeared to be that of reducing capillary flow of moisture to the soil surface. The treated soil formed a dry layer at the surface sooner than the control.The action of the nonionic surfactant in reducing evaporation was probably due to decreased surface tension at the solid‐liquid interface, thereby reducing capillary flow to the surface layer of the soil, and causing the formation of a dry diffusion barrier.
Water Movement and Loss Under Frozen Soil Conditions
Authors: Ferguson Hayden , Brown Paul L. , Dickey David D. 
Published: July 2010

AbstractSoil water and temperature distributions in a silty clay loam soil were studied in the field under freezing winter conditions. Appreciable upward water movement to a frozen zone occurred in plots in which the unfrozen subsoil water was held at tensions of less than about 2 atm. and water held at tensions of less than 5 atm. moved toward the frozen zone. It appears that the upward water movement to the frozen zone conributed to overwinter water losses since soil water losses of 0.36 and 0.50 inches were measured from those plots in which there was appreciable upward water movement. Plots containing 7.9, 6.2, 4.2, and 1.4 inches of available water before freezing occurred conserved −0.36, −0.50, 0.0, and 0.81 inches, respectively, of the 4 inches of precipitation that occurred during the winter.
Effect of Small Amounts of Gypsum in Soils on the Solutes in Effluents
Authors: Dutt Gordon R. 
Published: July 2010

AbstractColumns of soil initially containing exchangeable Ca2+ and 0.0, 0.5, 1.0, and 2.0% CaSO4·2H2O by weight were leached with a solution containing 50 me. NaCl and 50 me. MgCl2 per liter. The effluents from these columns were collected and analyzed for Ca2+, Mg2+ and Na+. The breakthrough curves for Na+ were not affected significantly by the presence of gypsum; however, the curves for Mg2+ were dependent on the amount of CaSO4·2H2O present in the system. When small amounts of gypsum were present, Mg2+ concentration in the effluent increased and then leveled off at some concentration below that of the solution entering the column. The length of the plateau and the concentration at which it occurs are functions of the amount of gypsum present in the system. When the gypsum was leached from the system, the Mg2+ concentration increased to a value approaching the concentration of the solution entering the soil.A general method for calculating the ionic composition of the effluent from initial conditions was developed. It was found that theoretical values calculated by this computer method approximated those found experimentally.
Cyclic Variations and the Pedon
Authors: Arnold R. W. 
Published: July 2010

AbstractThe applicability of utilizing a half‐cycle width as a pedon limit for soils having cyclic horizon variations is analysed using a sine curve as a model. The low probabilities of success associated with the half‐cycle limit, even when accepting ranges less than the total observed vertical variation, indicates a practical width limit of approximately 0.8 cycle.A method for determining the width of a pedon necessary to include an acceptable range of horizon variability is given. Included in the method is a visual technique for estimating some pragmatic limits of variations of horizon thicknesses. This method of determining pedon widths is illustrated using a hypothetical soil cross section.Some implications of determining pedon size for soils having cyclic horizons are intermittent or cyclic and recur at linear intervals of about 1.3 to 4.3 m. the pedon should include 80 to 90% of the vartical horizon variability and have lateral dimensions of approximately 0.8 of a cycle.
Mechanisms for Hydrogen to Aluminum Transformations in Clays
Authors: Miller Raymond J. 
Published: July 2010

AbstractThe rates of Al release from montmorillonite and kaolinite clays by acid‐dissolution techniques were determined. For kaolinite the release of Al obeyed pseudo zero order kinetics and form ontmorillonite the release of Al obeyed pseudo first order kinetics. The kinetic studies indicate a difference in mechanism of H attack on these two clays. A diffusion controlled edge attack is proposed in the case of kaolinite and an all surface attack is proposed for montmorillonite. Kinetic studies using different size fractions of the two clays support the proposed mechanisms.
Effect of Lime and Potassium Additions on Soil Potassium Reactions and Plant Response
Authors: Powell A. J. , Hutcheson T. B. 
Published: July 2010

AbstractLime and/or wetting‐drying cycles following its application to soils of micaceous mineralogy resulted in lower exchangeable K levels, as measured by N NH4OAc extraction, which were closely correlated with K levels before liming. K level changes were not related to initial pH levels over a range from pH 4.7 to 6.2. Liming effects on exchangeable K levels were not reflected by crop response or uptake of K. Release of nonexchangeable K was enhanced and fixation of applied K was prevented by lime applications. It is suggested Ca2+ ions may prop open edges of clay mineral packets, thus preventing entrapment of K+ ions and releasing previously “trapped” or lattice K.
Ion Gradients and Nitrification Associated with Decomposition of a Plant Material Layer in Soil
Authors: Smith J. H. , Burns G. R. 
Published: July 2010

AbstractChanges in the pH and in concentrations of ammonia, NO2‐, NO3‐, and K+ with distance from layers of decomposing leguminous plant material in Red Bay sandy loam soil were measured after 16 days' incubation. High concentrations of ammonia (2.7 meq/100 g) and of K+ (1.4 meq/100 g) were found near the plant material layer. Nitrification was inhibited and NO2‐ was found in this zone. Farther away, NO3‐ accumulated. A change in pH from 8.9, near the layer, to 5.6, about 4 cm away, was observed. Treatment with CaCO3 decreased the pH range and increased nitrification. When the decomposing plant material layer was separated from the soil on one side by an air space, NH3 diffused across the air space. This resulted in segregation of some of the NH3 from the cations and other potentially toxic substances and lowered the overall toxicity to nitrification. Besides the toxicity observed, the availability of plant nutrients as well as growth of microorganisms and plant roots could be drastically affected by pH and cation concentration changes found near layers of decomposing plant material.