bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of Residual Effects of Phosphate Fertilization by Laboratory and Plant‐Response Methods
Authors: Eik K. , Webb J. R. , Black C. A. , Smith C. M. , Pesek J. T.
Published: July 2010

Samples of soil were collected in 1955 from three field experiments in which 0, 13.1, 26.2, 52.3, and 104.7 pounds of P per acre had been applied as superphosphate to one series of plots in 1953 and to a second series in 1954. In a greenhouse experiment conducted in 1957, sorghum was grown on quantities of these samples without further phosphate fertilization and on quantities of the samples from the control plots after treatment with superphosphate at rates equivalent to those applied in the field. Conditions in the greenhouse experiment were such that the yield of P in the test crop increased linearly with the quantity of P applied to each soil in each year. Samples of soil from all phosphate levels and years of application were analyzed in the laboratory for labile inorganic P by the 0.025N HCl, 0.03N NH4F method of Bray and Kurtz, the anion‐exchange resin method of Amer et al., and the NaHCO3 method of Olsen et al. The quantity of P extracted with each method increased linearly with the quantity of P applied to each soil in each year. The ratios of the slopes of the linear plots of yield of P obtained with the 1953 and 1954 applications to the 1957 applications were calculated for samples of soil from each of the three field experiments, and these were designated as availability‐coefficient ratios of residual and currently‐applied P. Corresponding slope ratios calculated from the quantities of labile P extracted were designated as extractability‐coefficient ratios of residual and currently‐applied P. The six availability‐coefficient ratios thus obtained from the two residual years in the three experiments were correlated with the corresponding extractability‐coefficient ratios, the best correlation (r = 0.98) being obtained with extractability‐coefficient ratios derived from the 0.025N HCl, 0.03N NH4F method, second best (r = 0.90) with the anion‐exchange resin method, and third best (r = 0.51) with the NaHCO3 method. These results show that appropriate laboratory tests provided an estimate of the relative residual value of fertilizer P that was largely independent of the nature of the soil.
Soil Sampling for Moisture Retention and Bulk Density Measurements
Authors: Aljibury F. K. , Evans D. D.
Published: July 2010

Four groups of soils were sampled at random and certain physical measurements were made on the samples to evaluate associated variances and sampling schemes. The measurements made were 0.1, 0.5, 1, 5, 10 and 15‐bar percentages along with bulk density. Locations were classified as to soil group strictly by soil map without field inspection. One of the objectives was to evaluate the utility of a soils map in estimating physical properties.

Although the soil groups studied are considered relatively uniform, there is considerable variation within each group. It was interesting to find that the variation within an 18‐acre tract is of the same order of magnitude as that between 18‐acre tracts. The variation among tracts was such that a mean for a soil group is a very rough estimate for a single tract within the soil group. In characterizing a soil group, it was calculated that 2 sites per 18‐acre tract were optimum. For characterizing a given 18‐acre tract, it would take up to 10 sites per tract to estimate the true mean within 20%, or 35 samples to estimate within 10%.
Gaseous Nitrogen Losses from Nitrogen Fertilized Soils Measured With Infrared and Mass Spectroscopy
Authors: Schwartzbeck R. A. , MacGregor J. M. , Schmidt E. L.
Published: July 2010

The evolution of nitrogen gases from four soils was studied by total soil nitrogen analysis, the mass spectrometer with N15‐labeled nitrogen carriers, and with infrared spectroscopy. The type and amount of nitrogen gas evolved was influenced by a number of factors. Soil type was important in that the Nicollet and Fargo soils resulted in the evolution of more N2 and N2O than did the Fayette and Laredo soils. Soil properties had little effect on the total N2 evolved from NH4NO3, but greater differences occurred from soils treated with HNO3. The type of nitrogen carrier influenced the nature of the gaseous nitrogen released. NH4NO3 treatment favored N2O evolution and HNO3 treatment favored N2. Only small amounts of N2 and N2O were evolved from soils treated with NH4Cl or urea. Nitrogen applied at 1080 pounds per acre always resulted in larger losess of N2O and N2 than that applied at 360 pounds per acre. However, in both the Nicollet and Fargo soils at water saturation, the percentage of applied nitrogen that was lost was about the same at both low and high rates of treatment. Substantial gaseous losses of applied fertilizer occurred mainly when water‐saturated conditions prevailed. Small losses did occur from soils at field moisture capacity. N2O evolution was influenced by the ammonium to nitrate ratio of the nitrogen treatment.
Fixation of Ammonia by Organic Soils
Authors: Burge W. D. , Broadbent F. E.
Published: July 2010

Ammonia fixation in organic soils of varying carbon content was found to be linearly correlated with percent carbon. In the presence of oxygen 1 molecule of ammonia was fixed per 29 atoms of carbon, and 1 for every 45 atoms of carbon in the absence of oxygen.

Treatment of these organic soils with ammonia usually resulted in decreased capacity to retain barium and cupric ions, but the amount of ammonia fixed bore no quantitative relation to the decrease in cation retention.

Blocking hydroxyl groups in soil organic matter by treating with dimethyl sulfate decreased the capacity of the organic matter to fix ammonia, indicating that these groups are involved in the fixation reaction. Aldehyde groupings are apparently not involved. Formation of amides through the action of anhydrous ammonia on carboxylic esters may play a minor role in ammonia fixation.

A tracer experiment showed that fixed ammonia is slowly made available to plants.
Phosphorus Changes in Great Plains Soils as Influenced by Cropping and Manure Applications
Authors: Haas H. J. , Grunes D. L. , Reichman G. A.
Published: July 2010

Soil samples from 15 dryland experiment stations in the U. S. Great Plains and 21 farms in North Dakota were analyzed to determine the effect of cropping and manure on total, inorganic, organic, and NaHCO3‐soluble P content. In general, total P in the surface 6 inches of soil increased from south to north. Total P in soils from the experiment stations was reduced an average of 8% by cropping without manure, but was increased an average of 14% above virgin sod where manure had been applied.

Inorganic P was not influenced by cropping to a rotation without manure, but organic P was reduced an average of 35% as compared to virgin sod. Manure applied in the rotation increased inorganic P considerably, but had no effect on reducing the loss of organic P.

Cropping without manure increased NaHCO3‐soluble P in the soil at the majority of the stations, with the greatest increase occurring in the south. When manure was applied in the rotation, NaHCO3‐soluble P averaged nearly five times that of virgin sod.

A highly significant positive correlation existed between NaHCO3‐soluble P and total P of virgin soils from the southern stations, but a significant correlation did not exist for the northern stations.
Morphological and Chemical Properties of Important Depressional Soils of Lowlands in the Western Coal Field Region, Kentucky
Authors: Cox Frank R. , Hutcheson T. B.
Published: July 2010

Morphological and certain chemical properties of Alligator, Sharkey, Patton and Dekoven series found in the Western Coal Field region of Kentucky were determined and compared with available data from other areas. These series occur in depressional areas along the tributaries of the Ohio River and are derived from mixed sediments of sandstone, shale, loess, limestone and glacial till origin. The data obtained for the Alligator, Sharkey and Patton profiles sampled in Kentucky differ very little from similar data for these series sampled and studied in other states. Consequently, their classification appears to be justified. No data on the Dekoven series from other states were available for comparison.
Movement of Water as Effected by Free Energy and Pressure Gradients: I. Application of Classic Equations for Viscous and Diffusive Movements to the Liquid Phase in Finely Porous Media
Authors: Kemper W. D.
Published: July 2010

The macroscopically observed laws of viscous and diffusive flows were extrapolated to flow of water in thin films in porous media. Correction factors were developed to account for the effects of the diffuse layer of adsorbed cations and greater viscosity of water near particle surfaces. Equations for the two types of flow are combined to give a relationship from which molar free energy gradients can be evaluated in comparison with pressure gradients, as to their abilities to move water.
Movement of Water as Effected by Free Energy and Pressure Gradients: II. Experimental Analysis of Porous Systems in Which Free Energy and Pressure Gradients Act in Opposite Directions
Authors: Kemper W. D.
Published: July 2010

Osmotic pressures across compacted clays were measured. These pressures were compared with pressures calculated from theory developed in the first paper of this series. Tortuosities and effective thicknesses of films in which water flows, which are necessary for these calculations, were calculated from hydraulic conductivity and salt diffusion data. The measured and calculated values of osmotic pressure were in fair agreement and probable reasons were given for the discrepancies observed. The qualitative agreement supports the assumptions and theory developed in paper I of this series.
Pressure Distribution During Steady Flow in Unsaturated Sands
Authors: Scott V. H. , Corey A. T.
Published: July 2010

A differential equation is derived which describes the pressure distribution during steady flow in a porous material occupied by two immiscible fluids such as air and water. It is assumed that Darcy's equation applies simultaneously to the wetting and the nonwetting phase. Each phase is assumed to be continuous, and therefore, any isolated portions of either phase must be regarded as part of the porous matrix. The equation may be applied to fluids flowing in any direction with respect to each other or in any direction with respect to the earth's gravitational field. In order to solve the equation, it is necessary to know the relationship between the pressure discontinuity across interfaces between the phases and the conductivity of the flowing phase or phases. The nature of this function and a method of obtaining it are discussed briefly.

Experiments were conducted using a hydrocarbon liquid as the wetting fluid, air as the nonwetting fluid, and long columns of sand as porous media. Several cases were investigated, and results of two are presented: (1) downward flow through a uniform sand, and (2) downward flow through a sand into another sand of finer texture. Good agreement between experimental data and theory was obtained for all cases.
Alfalfa Yield and Composition After Different Times and Rates of Lime and Phosphorus Application
Authors: Singh R. N. , Seatz Lloyd F.
Published: July 2010

Lime and phosphorus applications were made to a Hartsells loam soil with a pH of 4.7 and an extremely low available phosphorus supply. Lime rates of 0, 1, 2, and 4 tons per acre and P2O5 rates of 0, 40, 80, and 120 pounds per acre were applied 3 months before planting and at planting in the four possible time‐of‐application combinations. Two crops of alfalfa were harvested and yield and P content were determined.

Highly significant yield increases to both lime and phosphorus applications were found. The highest yield was obtained when the highest rates of lime and phosphorus were both applied at the time of planting. Phosphorus applications to the unlimed soil were not as effective, even though the soil was limed 3 months after the phosphorus was applied, as when the phosphorus was applied to the limed soil. These results indicate that the rate of equilibrium of phosphorus compound formation in soils at different pH levels may occur very slowly.
Genetic Soil Relationships in a Saline Glacio‐Lacustrine Area
Authors: Sandoval Fred M. , Shoesmith Lloyd
Published: July 2010

A genetic approach supported by laboratory studies was used as a technique in diagnosing a saline soil problem in North Dakota. Depths to 12 feet were studied. Soils of most of the area (saline phases of Bearden and Glyndon series) have silt loam or silty clay loam surfaces, and are derived from thick lacustrine sediments. Magnesium usually was the dominant cation, followed by sodium. Most common horizon sequence in lacustrine areas was: A1, Aca, Cca, C, Cg, and G. A lesser acreage of shallow lake‐washed or reworked materials over firm calcareous clay loam glacial till assumed importance because of higher elevation physiography and a closer chemical relationship to saline waters under artesian pressure from the underlying Dakota Sandstone geologic formation. Where till was closer to the surface the horizon sequence was: A1, Aca, Cca, C, Cg, D or Dg, and G, with frequent absence of C layers depending upon depth to till.

Chemical differences between lacustrine and till areas are attributed to genetic differences, i.e., the fine‐textured lacustrine sediments themselves appear high in Mgbearing materials. These saline, hydromorphic, imperfectly drained soils were classed as calcareous solonchaks.
The Effect of Phosphorus Fertilization on the Zinc Nutrition of Several Irrigated Crops
Authors: Burleson C. A. , Dacus A. D. , Gerard C. J.
Published: July 2010

In field experiments, P‐induced Zn deficiencies were observed in field corn in 1958 and in sweet corn, tomatoes and field corn in 1959.

In greenhouse experiments with Red Kidney beans (Phaseolus vulgaris), severe P‐induced Zn deficiencies occurred with P fertilization. Zinc absorption was increased by Zn fertilization and decreased by P fertilization. Phosphorus uptake was increased with P fertilization and decreased by Zn fertilization. When both Zn and P were applied, the uptake of both Zn and P were reduced.
The Influence of Soil Temperature on the Growth and Mineral Composition of Corn, Bromegrass and Potatoes
Authors: Nielsen K. F. , Halstead R. L. , MacLean A. J. , Bourget S. J. , Holmes R. M.
Published: July 2010

When grown with different nutrient treatments in temperature‐controlled soil in the greenhouse, yields of corn and bromegrass tops increased with increments in temperature from 41° to 80° F., but yields of potato tops and tubers showed a less consistent relationship with temperature. Yields of corn and bromegrass roots also increased with temperature except for a decline in bromegrass roots when temperature was increased from 67° to 80° F. Tuber yields were usually higher at soil temperatures above 41° F., but the optimum temperature varied with nutrient treatment.

The nutrient composition of the crops showed few consistent trends in relation to soil temperature. The P content of bromegrass and potato tops, however, increased with rising temperatures when the plants were grown without added P. Uptake of N, P, Ca, Mg and K by the crops usually increased with increasing temperature to at least 67° F. The uptake of P by the plants without addition of the nutrient, relative to the uptake obtained with addition, increased almost invariably with each increment in temperature. Water‐use efficiency usually increased where N, P and K were added together and often decreased as soil temperatures increased.
Soil Survey Refinements Needed for Accurate Classification of Black Oak Site Quality in Southeastern Ohio
Authors: Carmean Willard H.
Published: July 2010

Soil‐site studies of black oak in southeastern Ohio show that site index varies widely within upland soil types as they are now defined. In fact, the variation is so great that soil types alone cannot be used to estimate site accurately for any specific local area. Furthermore, average site indexes for most upland soil types in south‐eastern Ohio are strikingly similar and it is evident that these soil types do not define either the very good or the very poor sites. At best, average site indexes for soil types alone can indicate only slightly different degrees of medium site quality.

Site index was found to be related to depth of surface soil, subsoil texture, subsoil stone content, aspect, slope position, and slope steepness. These factors can be used to modify existing soil series and soil type descriptions, to describe new soil types and phases, or to superimpose upon present soil classifications to attain better accuracy in site prediction. Greater precision in mapping forest site quality in southeastern Ohio should result.
Titration of H‐Al Bentonite With Tetra‐Alkyl Ammonium Bases
Authors: Spain J. M. , White Joe L.
Published: July 2010

It was postulated that tetra‐alkyl ammonium hydroxides would be useful in the titration of acid clay systems because of their base strength and the stability of complexes formed between the tetra‐alkyl ammonium cations and clay minerals. Conductometric titrations of H‐Al bentonite were performed using tetramethyl‐ and tetraethanol‐ammonium hydroxides; the resulting titration curves were very similar to those obtained with strong inorganic bases.

An improved titration procedure was devised in which a vacuum tube a.c. volt meter was used to determine the null point. Separate small aliquots of clay suspension were titrated with different increments of base equivalent to successive points on a titration curve. This technique permitted an examination of the magnitude and rate of resistance change after the addition of any given increment of base. For lithium hydroxide and tetramethyl ammonium hydroxide, 2 to 3 hours were required for the resistance of the suspensions to become essentially constant. It is concluded that conventional titrations, even with strong inorganic bases, may be subject to considerable error.

An explanation of the time dependency of the conductometric titration of H‐Al bentonite systems was offered in terms of differences in diffusion rates of cations in the system. A postulated mechanism for the conversion of an H‐bentonite into an H‐Al bentonite was presented.
The Effect of Rates of Application of Ammonium Sulfate on Gaseous Losses of Nitrogen from Soils
Authors: Carter J. N. , Allison F. E.
Published: July 2010

Additions of (NH4)2SO4 to a sandy loam at concentrations corresponding to those that might be found in band applications resulted in losses of 0 to 30% of the added nitrogen in forms other than ammonia. In these studies of limed and unlimed soils, where the pH values were in the range of 4.7 to 6.9, the losses increased with increase in ammonium sulfate additions and were greater on limed than on unlimed soil.

Losses of ammonia by volatilization from the soils during incubation periods of 6 to 10 weeks were negligible. Losses of ammonia during air‐drying of these soils following incubation and prior to analysis were also negligible in the absence of lime, but were as high as 15% on soils limed to pH 6.7 and receiving the largest amount of (NH4)2SO4. Gaseous losses of nitrogen from two silt loams were much smaller than from the sandy loam.
Photomicrographic Study of Soil Aggregates and Microorganisms As Influenced by Stubble Mulching and Plowing
Authors: Turelle J. W. , McCalla T. M.
Published: July 2010

A photomicrographic study was made of the soil at the surface of stubble‐mulched and plowed soil plots on July 7, August 28, and October 22, 1959. These soils had been subjected to stubble mulching or plowing for a 20‐year period. The plots were in corn in 1959 following wheat in 1958. The surface of the stubble‐mulched soil had larger soil aggregates and voids than plowed soil. Contact slides placed in the plots showed more microorganisms on stubble‐mulched than on plowed soil.

Water‐stable aggregates from each type of tillage were also embedded in plastic compounds. These aggregates were sliced in sections 30 and 0.2µ thick and photomicrographed with light and electron microscopes, respectively. A major problem was the impregnation of soil aggregates for sectioning. The cross‐sections of aggregates from stubble‐mulched plots seem to be less compact and more porous than from plowed plots in both the 30 and 0.2µ sections of soil aggregrates.
Modal Analysis of Soils
Authors: Anderson Duwayne M. , Binnie R. R.
Published: July 2010

The statistical elements of petrographic modal analysis are reviewed. The application of this procedure to soils and unconsolidated sediments is discussed and justified. Application of this method to obtain more complete quantitative estimates of mineralogical composition and pore space of soils should facilitate progress under the present system of soil classification and promote the use of objective criteria in new classification schemes.
Inefficiency of Fertilizer Use Resulting from Nonuniform Spatial Distribution: I. Theory
Authors: Jensen Don , Pesek John
Published: July 2010

Nonuniform physical distribution of a fertilizer nutrient was expressed as a function of space coordinates and substituted into an equation which characterizes yield response to that nutrient. The resulting differential equation was then integrated over the area fertilized to give a new yield potential function which is valid under any specified nonuniformity restriction. In particular, a periodic cosine function with amplitude “a” was selected to represent the spatial distribution function for a single fertilizer nutrient, while a quadratic equation of the form Y = b0 + b1X + b11X2was used to express the relationship between yield and the nutrient. The new yield potential equation
urn:x-wiley:03615995:saj2sssaj196203615995002600020022x:equation:saj2sssaj196203615995002600020022x-math-0001 was derived from these particular functional forms. Yield loss associated with the cosine distribution pattern then was obtained as the difference between the ideal and the restricted production equations.

A corresponding derivation was made for the case of n variable factors of production under the assumption of a quadratic response equation and distinct cosine laws for physical distribution of each variable. Yield losses were expressed in the form
urn:x-wiley:03615995:saj2sssaj196203615995002600020022x:equation:saj2sssaj196203615995002600020022x-math-0003 where bij is the coefficient for interaction of the i'th and j'th factors, and ai and aj are respective amplitudes of the cosine distribution funcations of the i'th and j'th nutrients.
Nitrification as Affected by Temperature and Moisture Content of Mulched Soils
Authors: Parker D. T. , Larson W. E.
Published: July 2010

In the temperature range of 16° to 20°C., a 2°C. differential in soil temperature had a measurable effect on the rate of conversion of NH4‐N to NO3‐N. However, as soil temperature increased to the range of 25° to 30°C. or as the supply of NH4‐N became limiting, differences in NO3‐N production resulting from small differences in soil temperature were not observed. In field soil, very early in the season when soil temperature was in the range of 16° to 20°C., mulched soil was 1° to 2°C. cooler than bare soil. During this period greater accumulation of NO3‐N could occur in bare than in mulched soil as a result of the temperature difference.

As measured in the laboratory, NO3‐N production was retarded at soil moisture tensions below 50 cm. of water. At still higher moisture levels, considerable mineral N was lost from the soil. Measurements in the field showed that the soil moisture content of mulched soil exceeded that of bare soil. For short periods of time the moisture level of mulched soil was high enough to cause retarded nitrification and loss of N.
Sorption of Anhydrous Ammonia by Dry Clay Systems
Authors: Brown James M. , Bartholomew W. V.
Published: July 2010

NH3 sorption and/or retention over the pressure range of 0 to 100 ml. of mercury by dry bentonite, halloysite, and synthetic gibbsite was investigated using a manometric technique employing equilibrium measurements in a special sorption apparatus. Chemisorbed NH3 is believed to be that which has gained a proton and undergone exchange reactions with the exchangeable cations and that which has reacted with the weakly dissociated hydroxyl groups of the lattice edges. The differential influence of saturating cations is believed to be due, at least in part, to the differences in degrees of hydration of these ions. Possible mechanisms of sorption are proposed.

There were no differences in amounts of NH3 sorbed and chemisorbed by Ca‐bentonite adjusted to pH 8, 9, and 10. This lack of influence is explained on the basis of the pH range involved and the mechanisms of sorption. The failure of synthetic gibbsite, Al(OH)3, to chemisorb NH3 is explained by the basic nature of the mineral.
Characteristics of Some Brown Grumusols of Arizona
Authors: Johnson W. M. , Cady J. G. , James M. S.
Published: July 2010

Extensive areas of well‐drained brown Grumusols developed from weathered ultrabasic volcanic rocks exist in north‐central and eastern Arizona. They are on nearly level to rolling topography under grass; precipitation ranges from < 10 to > 20 inches annually. They have clay profiles of nearly uniform brown color; moderately low organic matter content; very high base status; dominance of montmorillonite in the clay fractions; and evidence of much internal soil movement, namely: numerous slickensides, very gradual decrease of organic matter with depth, and diffuse or gradual and wavy horizon boundaries. Mineralogical studies indicate that in these soils the course of weathering of the rock and the nature of the weathering products are determined early and remain constant; montmorillonite is the dominant clay mineral in all horizons including the weathered material adjacent to the fresh rock. Comparisons are given with associated dark gray, poorly‐drained Grumusols and with dark brown soils having textural B horizons that formed under timber‐grass vegetation.
The Interaction of the Simultaneous Diffusions of Heat and Water Vapor
Authors: Cary J. W. , Taylor S. A.
Published: July 2010

The theory of thermodynamics of irreversible processes and the Onsager reciprocal relation were tested for the case of thermally induced water vapor diffusion through air and through moist soil in the temperature range of 15° to 45°C. The general rate equations for heat and mass flow were transformed into simple relations giving the flux as a function of temperature.

The simultaneous steady state rates of heat and vapor flow through air and moist soil were measured. A portion of these data was used to solve for the specific phenomenological coefficients, and the remainder was used to test the rate equations. It appeared that the rate equations so derived, were applicable over the range of soil conditions tested. Furthermore, the interaction coefficients between heat and vapor flow and between vapor and heat flow were found to be nearly identical, which was in agreement with Onsager's theory.
Seedling Emergence of Wheat, Grain Sorghum, and Guar as Affected by Rigidity and Thickness of Surface Crusts
Authors: Taylor Howard M.
Published: July 2010

A nonporous wax surface crust technique was devised to study seedling emergence of wheat, grain sorghum, and guar. Emergence through crusts with wax penetration numbers ranging from 15 to 80 was evaluated using crust thicknesses of ¼, ½, and 1 inch.

Seedling emergence of wheat, grain sorghum, and guar was affected by hardness and by thickness of crusts. A curvilinear relationship existed between seedling emergence and crust hardness. No emergence occurred in any of the 3 plant species when the wax penetration number was 27.0 or less. There was no difference between species in this critical wax penetration number. As crust thickness increased, higher wax penetration, i.e., softer waxes, were required before any seedling emergence occurred.
Inhibition of Germination and Seedling Development by Crop Residues
Authors: Guenzi W. D. , McCalla T. M.
Published: July 2010

Wheat and oat straw, soybean and sweetclover hay, corn and sorghum stalks, bromegrass and sweetclover stems were extracted with hot and cold water, using 1 part of residue to 15 parts of water. One‐half of the water extract of each residue was autoclaved for 1 hour at 20 pounds steam pressure. In addition, wheat straw was extracted with ethanol and the extract was separated into strong and weak acids, neutral, basic, and water‐soluble compounds. The ethanol‐soluble compounds were tested for their effect on wheat, whereas the hot and cold water extracts of residues were tested for their effect on germination and growth of wheat, sorghum, and corn seeds.

All the residues contained water‐soluble substances that inhibited the germination and growth of sorghum, corn, and wheat. The cold water extracted more toxic materials than did the hot water. Autoclaving increased the toxic effect of the water extract of residues on root growth. The toxic effect on germination and shoot growth was decreased for most residues by autoclaving of aqueous extract. Ethanol‐soluble substances of wheat straw inhibited the germination and growth of wheat seeds. The ethanol extract of wheat straw, separated into strong acid, water‐soluble, neutral, weak acid, and basic compounds, showed decreasing toxicity in the order listed.
Microbiological Processes Associated with the Use of Chitin for Biological Control
Authors: Mitchell R. , Alexander M.
Published: July 2010

In an investigation of the mechanism of action of chitin in the biological control of Fusarium solani f. phaseoli in soil, statistically significant control of a root rot caused by the fungus was noted when the aminopolysaccharide was added to soil up to 2 weeks prior to planting. No significant suppression by the microflora responding to the amendment was observed in longer periods of preincubation. Saprophytic soil fungi were also inhibited during the first 2 weeks after chitin incorporation. Actinomycetes, chitinase‐producing microorganisms, and chitinase activity were markedly stimulated during that period of time, but the population of bacteria was not altered appreciably. It is suggested that mycolytic activity and toxin production may be implicated in the selective influence of chitin in suppressing certain soil fungi. Acetate effectively controlled disease, but it appears that the mechanisms of action of chitin and acetate are distinct.
Decomposition in the Field of Buried and Surface‐Applied Cornstalk Residue
Authors: Parker D. T.
Published: July 2010

The decomposition of cornstalk residue placed on the surface of soil or buried in soil in the field was followed during a corn crop‐growing season by removing from the soil at various times subsamples of decomposing residue contained in glass‐cloth bags. Decomposition during the season (20 weeks) amounted to 50% of the surface residue and 65% of the buried residue. Half of this decomposition occurred in 8 weeks and in 5 weeks for surface and for buried residue, respectively.

There was little change in the total N content of surface residue throughout the season. Nitrogen was not immobilized. However, the C/N ratio declined from 57 to approximately 30.

A maximum of 12 pounds of N per 3 tons of residue per acre was immobilized by buried residue. This occurred after 3 weeks incubation. Thereafter, total N content of the residue declined. A net loss of N occurred after 5 weeks with no N fertilization and after 15 weeks' with N fertilization. The C/N ratio declined from 57 to 22. The decline in C/N ratio, both with surface and with buried residue, was caused by loss of carbon from the residue rather than an increase in total N.

Early season growth of corn plants was retarded by surface residue, but the retardation was not a consequence of N immobilization. A slight retardation of growth with buried residue might, in part, have been caused by immobilization of N.
The Effect of Wetting Agents on Infiltration
Authors: Pelishek R. E. , Osborn J. , Letey J.
Published: July 2010

Laboratory studies conducted on the effect of wetting agents on infiltration rates indicated that (1) a wetting agent can increase infiltration rates into hydrophobic soils but have either no effect or adverse effects on soils which are not particularly hydrophobic; (2) the wetting agents used in the study produced a beneficial residual effect; and (3) the wetting agent is not completely leached from thatch.
Effect of Partial Surface Covers on Evaporation from Soil
Authors: Willis W. O.
Published: July 2010

Evaporation rates from small columns subjected to convected energy under laboratory conditions were found to be dependent on both percent of surface covered by plastic film and on size of continuous area exposed. Partial covers appear to be most effective when the soil is wettest. When the energy available for evaporation is supplied by convection, the most efficient covering pattern for evaporation control will probably be one which provides as large a continuous cover as practical, as well as one with the least exposure of soil surface.
The Use of Ferrosul, a Steel Industry Byproduct, as a Soil Amendment
Authors: Stroehlein J. L. , Berger K. C.
Published: July 2010

The disposal of spent pickle liquor (largely spent sulfuric acid and sulfate of iron) has long been a problem of the steel industry. Ferrosul, a neutralized and precipitated pickling material, was applied to field plots at rates of 200,000 and 400,000 pounds per acre. Corn was grown with and without starter phosphorus fertilizer treatments to determine if phosphorus was fixed by the iron in Ferrosul. The ferrosul and phosphorus treatments had little effect on corn grain yield when compared to check plots.

Corn and alfalfa were grown in the greenhouse on Plainfield sand and Miami silt loam soils treated with 1, 10, 20, and 40% Ferrosul on the weight basis, as well as an untreated check. It was found that corn yields were best on the 1% treatment with the Plainfield sand as a result of a sulfur deficiency of the check. Corn yields were decreased at the 40% level with both soils. Alfalfa yields were generally best with the Ferrosul treatments. The highest total yield of eight harvests was with the 20 and 40% treatments with the Miami and Plainfield soils, respectively. Phosphorus fixation was not found to be a problem when additions of phosphorus fertilizer were made.

It is concluded that large amounts of Ferrosul can be applied to agricultural land without detrimental effects on crops and soils.
Chemical and Mineralogical Characterization and Comparison of Hagerstown and Maury Soil Series
Authors: Hutcheson T. B.
Published: July 2010

Maury and Hagerstown soil series have largely been differentiated in central Kentucky on the basis of phosphate level as determined by chemical quick test in the field. Slight color differences have been noted, but considerable overlap of this criterion exists. Consequently, field differentiation of these two series without chemical testing is most difficult. Chemical and mineralogical data obtained for three Maury and two Hagerstown profiles point up the similarity between the two series as well as illustrate about as much range in many properties within the individual series as between them. These data suggest that as the soils occur in central Kentucky, differentiation at the series level is not justified.
The Loss of Strontium90 from Small Cultivated Watersheds
Authors: Frere Maurice H. , Roberts Howard
Published: July 2010

Soil samples were taken from the plow layer of eight small watersheds and analyzed for strontium90. Two watersheds in permanent pasture, with no recorded loss soil, contained about 90 mc. per square mile, which is slightly higher than an estimated total deposit at the time of sampling.

The plow layer of six watersheds under cultivation was sampled by compositing soil cores taken on contours of each watershed. The Sr90 concentration of these samples was from one‐third to two‐thirds of that in the permanent pastures.

The loss of Sr90 appeared to be influenced by length of slope and cropping history. No areas of Sr90 accumulation were found within these watersheds.
Role of Chelating Agents on the Availability of Nutrients to Plants
Authors: Wallace Arthur
Published: July 2010

The presence of natural chelating agents is one of several possible explanations of how plants are able to obtain Fe which ordinarily in soil is very insoluble. The role of such chelating agents in plant nutrition is mostly an unexplored field. Synthetic chelating agents are proving useful in supplying Fe and to a lesser extent Zn and Mn to plants under conditions in which plants are subject to deficiencies of those metals. The chelating agents keep the metals soluble in the soil and are taken up by the plants with the metals. The two components may be separated in the roots but both can be transported to leaves. Chelating agents without metals often compete with roots and soil for metals and are generally not a good method of correcting micronutrient deficiencies. There are other interactions of soils, chelating agents, and micronutrients. Plant species differ greatly in their responses to chelated metals and some fail to respond.
Root‐Soil Boundary Zones as Seen in the Electron Microscope
Authors: Jenny Hans , Grossenbacher Karl
Published: July 2010

Plants were grown in bentonite clay and in permutite sand. After a suitable period, all void spaces were filled with liquid resin monomer which hardened to a stone‐like mass. Thin sections, a few hundred Angstrom units thick, were cut and observed in the electron microscope. The root is surounded by mucigel which fills the space between cell wall and mineral soil particles. Often it contains colonies of microbes. Contact between mucigel and clay surface is intimate. Colloid chemical interpretations are presented.
Ion‐Exchange Reactions of Cesium
Authors: Coleman N. T. , Craig Doris , Lewis R. J.
Published: July 2010

Column leaching experiments with 0.001N CsCl with 1N KCl or CaCl2 showed Cs sorption by a number of clays to be much larger from Ca than from K solutions. The sorption affinity of Cs relative to the complementary ion corresponded with that found by others for the Cs‐K ion pair, but in Cs‐Ca systems the Cs was sorbed to a larger extent than would have been expected from the results of experiments where Cs‐Ca ratios in the equilibrium solution were not so small.

While all except a very small proportion of the sorbed Cs was displaced on leaching with 1N KCl, some 36 times as much remained after leaching with equal volumes of 1N CaCl2.

Vermiculite sorbed very large amounts of Cs (about 1/3 of exchange capacity) from 0.001N CsCl‐1N CaCl2. The sorbed Cs was largely “fixed” against exchange with 1N CaCl2. This suggests that Cs contained in interlayer spaces of vermiculite results in interplanar distances which will admit K but not Ca.
Chemical Distribution of Added Nitrogen in Soils
Authors: Cheng H. H. , Kurtz L. T.
Published: July 2010

The distribution of added nitrogen (N) among the various components of soil N was determined, using isotopic tracing techniques. Three lysimeter soils, previously fertilized with N15‐enriched N, were studied. Methods of fractionating soil N were modified to permit estimation of the isotopic ratio as well as the N content of the different fractions. Soil N was fractionated into: exchangeable NH4+ plus NO3‐, fixed NH4+, N in acid hydrolyzate, and acid‐insoluble humin N. The N in acid hydrolyzate was further separated into the alkali‐labile N and the alkali‐stable N. The alkali‐labile N consisted of hydrolyzed NH4+ and amino sugar N. The alkali‐stable N was divided into soluble N, which included the amino acid N, and acid‐soluble but alkali‐insoluble humin N. Validity of the classification was discussed. Usefulness of N15 data was also evaluated. Estimation of the distribution of added N showed that over 90% of added N in soils was found in the hydrolytic products of soil organic matter, mainly as amino acid N, amino sugar N, and other soluble N.
Urea Hydrolysis and Subsequent Loss of Ammonia
Authors: Chin Wei‐tsung , Kroontje Wybe
Published: July 2010

The biochemical hydrolysis of urea is rapid and can be related to soil microbial activities. The reaction rate of the chemical hydrolysis of urea is very slow and insignificant in comparison with the biochemical hydrolysis. Ureanitrogen loss through ammonia volatilization proceeds rapidly and may immediately follow urea hydrolysis. Urea hydrolysis and ammonia volatilization from ammonium carbonate are first order reactions.
The Effect of Soil Surface Conditions on Evaporation of Soil Water
Authors: Benoit G. R. , Kirkham D.
Published: July 2010

A laboratory study investigating the comparative effectiveness of a dust, a ground corncob and a gravel mulch in inhibiting the evaporation of soil water from prepared 15‐inch long soil cores 3 inches in diameter under various conditions of radiation (0, 200, or 450 ft‐c.) and air movement (0.5 and 7.5 feet per second) showed the gravel mulch to be more effective than either a dust or a ground corncob mulch. The dust mulch proved to be the least effective. For example, the rate of loss from the mulched cores under conditions of 450 ft‐c. of radiation and air movement of 7.5 feet per second was 0.089, 0.146, and 0.170 g. per hour for the gravel, the corncob and the dust mulch, respectively. It was also observed that the rate of evaporation from the cores increased with both radiation and air movement levels. By the end of 600 hours unmulched cores had lost 1.25 to 5 times as much water as had mulched cores.

A concurrent study of the soil moisture distribution that develops with depth as evaporation of soil water proceeds was conducted. The study indicated that the soil moisture distribution in the mulched cores and for the 6‐ to 15‐inch depth of unmulched cores remained essentially constant with depth.
Soil Moisture Interface Effects upon Readings of Neutron Moisture Probes
Authors: Lawless G. Paul , MacGillivray Norman A. , Nixon Paul R.
Published: July 2010

Measurements of soil moisture by the neutron scattering method are inaccurate when made in the presence of abrupt moisture changes. The effects of air‐soil interfaces and of wet‐dry soil interfaces were investigated using neutron probes of four different designs. Three of the probes were used to study the effects of wet soil layers within dry soil masses.

Readings taken at shallow depths were found to have the greatest errors. These errors were always negative. Absolute error and depth within the soil to which this effect occurs were related to soil moisture content. Some means of correcting such errors should be used. Errors in determining moisture content of soil zones containing wet‐dry interfaces or wet layers were not as serious, and could be neglected in many practical applications. This was especially true when depth reading increments of 6 inches or less were used. These errors were usually negative. Neutron probes tend to underestimate soil moisture content at interfaces or in stratified profiles.

Probe depth reading increments of 1, 3, and 6 inches all gave about the same accuracy of moisture determination. Twelve‐inch reading increments gave errors of as much as 6 times greater than those of the smaller increments.

The influence of probe geometry upon neutron meter readings is also discussed. When compared on a basis of equivalent source strength, in uniform soils, the probe with end placement of the source was found to be considerably more efficient than the probes with center placement of the source.
Hydrolysis and Exchange Reactions of the Aluminum Ion in Hectorite and Montmorillonite Suspensions
Authors: Frink C. R. , Peech Michael
Published: July 2010

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

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

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

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