bluuebunny/crossref_metadata_2025_split huggingface dataset:
Some Soil Characteristics Which Affect Root Penetration and Timber Site Quality of Douglas Fir in Western Washington
Authors: Schlots F. E. , Lloyd W. J. , Deardorff C. E. 
Published: July 2010

AbstractThis study was initiated to determine the relationships between soil properties and site quality for Douglas fir in Western Washington. The ultimate objective is to predict timber site quality and desirable management practices directly from soil survey maps.Forest production measurements and soil profile descriptions were obtained concurrently on 203 sites representing 14 soil types. Profile properties of five soil types are discussed in detail to show by comparison their relationship to rate of tree growth. The highest timber site quality was produced on sites with deep, friable soils of moderate to high fertility level. Progressively lower timber site quality was reflected on sites with increasing strong profile development or degree of horizonation. There is a close relationship between timber site quality and soil depth over claypan, fragipan, and hardpan horizons. Soils having similar profiles, though developed from different parent materials, have similar site qualities.The data collected provide a sound basis for assigning average site indices to the different soil types included in this study.Factors of slope, aspect, position and land form are more important in woodland regeneration, management practices, and logging operations. Most important to productive site quality is the combination of properties which determine soil type.
Forest Management Practices as Related to and Influenced by Forest Soil Differences in Western Washington
Authors: Lloyd W. J. , Schlots F. E. , Deardorff C. E. 
Published: July 2010

AbstractIn developing correlations between soil and site quality for Douglas fir, observations were made on other forest management factors which appeared to be related to the soil. Presence or absence of windfall was noted on each plot. Nearby cutover areas of the same soil were checked for abundance of regeneration and for encroachment of hardwoods. On soils with cemented or compacted subsoils, checks were made for occurrence of natural seedlings and for their proximity to old stumps as an indication of micro‐site differences in seedling receptivity. In addition to site quality, susceptibility or resistance to wind‐throw, susceptibility to hardwood brush encroachment, abundance of conifer regeneration, seasonal use limitations and other management factors are strongly influenced by the soil profile properties.Management should be varied to capitalize on the good or desirable factors and to eliminate or minimize the undesirable ones. Forest growth patterns are described for widely different soils, and specific forest management recommendations are given to illustrate the tailoring of management to fit individual soils.
The Potentialities for Decreasing Soil Moisture Evaporation Loss
Authors: Lemon E. R. 
Published: July 2010

AbstractThis paper has two objectives: (1) to make available to American workers the results of Russian work on soil moisture evaporation suppression; and (2) to lay a background for our present work along these lines; some of which is included.In the evaporation process, the loss of soil moisture can be divided into three stages. The first stage is that of rapid loss of water where capillary flow to the soil surface is sufficient to meet the evaporative demand of the above ground environment. The second stage in the evaporation process is one of rapid decline in rate of loss as the soil reservoir is depleted. In this case above‐ground conditions are no longer as important but intrinsic soil factors govern the rate of moisture flow to the soil surface. Capillary flow, vapor transfer, and the combination of the two in the capillary condensation evaporation process dominate the picture. The third stage of moisture loss is that of extremely slow rates and is governed by adsorptive forces of molecular distances at the soil liquid‐solid interface.Potentialities for suppressing this rate process lie in the first two stages of moisture loss.These potentialities group themselves into three categories: (a) Decreasing turbulent transfer of water vapor to the atmosphere by such procedures as, allowing stubble to stand, adding mulching material, increasing soil surface roughness. (b) Decreasing capillary continuity by tillage methods or chemical additives of the soil stabilizer type; and (c) Decreasing capillary flow and moisture holding capacity of the surface soil layers by chemical additives of the surfactant type.Each of these three catgories is discussed in turn. Recent work from this laboratory is cited, particularly that dealing with surfactants and mulches. Data presented in this regard demonstrate the influence of surfactants on capillary flow in clay‐water systems of the montmorillonitic and kaolinitic types. Net radiation data and temperature data obtained with mulched and bare field soils are presented, suggesting that the increased heat storage under a plant residue mulch may account for the surprising lack of evaporation suppression where mulching of this type has been practiced.
Water Velocity in Unsaturated Porous Materials
Authors: Gardner W. H. , Hsieh J. C. 
Published: July 2010

AbstractRate of flow of moisture in unsaturated porous materials at constant temperature depends upon the gradient of the moisture potential, the size of the flow channel, and other factors relating to the fluid and porous medium but which may be held constant. Size of the flow channel likewise is continually changing. An experimental technique has been devised for direct measurement of the velocity of water movement in materials simulating soils. From these data, with the aid of moisture density measurements, rate of flow can be obtained. Velocity data obtained by this technique are being used to study the mechanics of flow under unsaturated conditions. Further information has been obtained on the nature of the f‐function in the equation, v = k f grad Φ, where v is velocity of flow, k is saturated permeability, and Φ is moisture potential.
Effect of Soil Hardness and Compaction on Corn Growth
Authors: Swanson C. L. W. , Jacobson H. G. M. 
Published: July 2010

AbstractA Proctor soil plasticity needle was modified so that the hardness of the soil surface in field plots could be measured. The instrument is simple in construction and penetration measurements can be made easily and quickly. Readings were taken before spring plowing, after the 2nd and 3rd cultivation, at first tassel, at the early milk stage, and at the dent stage of corn growth. Surface soil hardness through the growing season was in the order of 3 cultivations < 2,4‐D + 1 cultivation < noncultivated (2,4‐D only). Surface hardness was correlated with average corn yields for a 3‐year period. Data on the number of strokes (force) required to penetrate the soil at 0 to 2 and 4 to 6‐inch depths for taking core samples confirmed the penetrometer data. Corn yields varied inversely with the number of strokes. The area traversed by the rear tractor wheel in cultivation is more compact than the area between hills; the 0 to 2‐inch depth is less compact than the 4 to 6‐inch depth. Plots sidedressed with N generally showed less compaction than nonsidedressed plots. Production and uptake of NO3‐N was in the order of 3 cultivations < 2,4‐D + 1 cultivation < noncultivated being inversely correlated with soil hardness. Nitrates accumulated in the tractor wheel area. Apparently, sidedressings of N on soils with poor structure is no substitute for soils in good tilth for increasing corn yields. A soil conditioner chemical (VAMA) adversely affected soil structure, decreasing corn yields. It is suggested there are 5 horizontal and 2 vertical zones of soil hardness or compaction in some cultivated soils.
Fertilizer Evaluation: II. Estimation of Availability Coefficients
Authors: White R. F. , Kempthorne O. , Black C. A. , Webb J. R. 
Published: July 2010

AbstractResponse curves produced when plants are grown on soils treated with different rates of fertilizers are used as the basis for estimating the ratio of the availability coefficient of a nutrient in one fertilizer to that in another. A least squares method is described and illustrated for fitting each of three types of response curves. Concurrent linear response curves are illustrated by data on yield of phosphorus. Parallel linear response curves for log response against log rate of application are illustrated by data on content of radioactive phosphorus. Concurrent Mitscherlich curves with the same initial and limiting responses but different rates of increase are illustrated by data on yield of corn grain.
Some Factors Influencing the Utilization of Phosphorus from Crop Residues
Authors: Fuller W. H. , Nielsen D. R. , Miller R. W. 
Published: July 2010

AbstractA large proportion of phosphorus of crop residues was found to be readily available to succeeding crops. Some of the factors that influence the rate of release of phosporus from plant residues added to soils for use by succeeding plants were studied. They were: (a) maturity of the crop residue, (b) phosphorus content of the residue, (c) rate of application of the residues, (d) time of contact of the crop residue with the soil, (e) kind of crop residue, and (f) plant part involved. The study was conducted under greenhouse conditions in large glazed pots that held 1 kg. or more of soil.The influence of the above factors on the utilization of phosphorus by several test crops is less pronounced in soils well supplied with available phosphorus than in soils low in available phosphorus. The rate of availability of the phosphorus of the crop residues to the test crops, ryegrass and tomato, was inversely related to the stage of growth of the residues. For example, green manures cut prior to blooming supplied plants with about as much phosphorus as did liquid H3PO4 fertilizer. The phosphorus of straw, on the other hand, was absorbed by plants to a lesser extent than that of the liquid H3PO4. The phosphorus of residues high in total phosphorus was more readily available to plants than was that of residues low in phosphorus. The threshold phosphorus content of the crop residue above which the phosphorus of the residue was not wholly immobilized by microorganisms for use in decomposition was found to be about 0.2%. Phosphorus from root residues was less readily available than that from top residues only if the residues came from fully mature plants.
The Relationship of Water Soluble and Exchangeable Potassium to Yield and Potassium Uptake by Ladino Clover
Authors: Hood J. T. , Brady N. C. , Lathwell D. J. 
Published: July 2010

AbstractAn attempt was made to evaluate in a relative way the K in the soil solution as a measure of the immediately available potassium in the soil. When the K content of Ladino clover was below the critical level, the water soluble potassium, a measure of the K in the soil solution, was better correlated with yield than was exchangeable K. The water soluble potassium also gave a better correlation with the potassium absorbed by plants in a short period of time. A percolation procedure which consisted of leaching a soil with a large volume of a low electrolyte extractant was a better measure of the K supplying power of a soil than the initial exchangeable level of potassium.
The Measurement of Soil Moisture Diffusivity
Authors: Bruce R. R. , Klute A. 
Published: July 2010

AbstractThe solution of the differential equation describing the flow of moisture in unsaturated porous media is difficult because of the dependence of the permeability on moisture content. In the case of horizontal flow this equation can be written in a form similar to the non‐linear diffusion equation. The diffusivity in this equation is dependent upon the moisture content of the medium. Boltzmann has developed a treatment of the non‐linear diffusion equation which allows one to calculate the diffusivity‐moisture content function from a moisture content distribution curve. This treatment assumes that the moisture content is a function of a variable dependent on distance and the square root of the time.Columns of sand at a constant moisture content throughout their length were prepared. Water was applied at one end of the columns and allowed to move into them for a measured period of time. The distribution of moisture content in the columns was then determined and calculations of the diffusivity‐moisture content function were made. Data from one column gave moisture diffusivity values representing the entire moisture range of that column. The results indicate that there may be a maximum in the diffusivity‐moisture content function at a moisture content less than saturation.
The Effect of pH, Sulfate and Phosphate Concentrations on the Adsorption of Sulfate by Soils
Authors: Kamprath E. J. , Nelson W. L. , Fitts J. W. 
Published: July 2010

AbstractSome of the factors affecting sulfate adsorption were studied using Cecil, White Store, and Nipe soils and H‐Al‐bentonite. The soils which contained a relatively large amount of 1:1 type clay minerals adsorbed more sulfate than the soils containing predominantly 2:1 type clay minerals. The amount of sulfate adsorbed decreased as the pH of the soil suspension increased from 4 to 6. The amount of sulfate adsorbed was found to be directly related to the concentration of sulfate in solution. For all of the soils studied, increasing the phosphate concentration in the solution reduced the amount of sulfate adsorbed by the soil. The data indicate that less sulfate ion is adsorbed by the clay particle in the presence of phosphate ion.
Crop Response to Different Soil Fertility Levels in a 5 by 5 by 5 by 2 Factorial Experiment: I. Corn
Authors: Hutton C. E. , Robertson W. K. , Hanson W. D. 
Published: July 2010

AbstractFour years' data are reported for a 5‐level NPK factorial experiment with 2 levels of dolomitic limestone. The experiment was conducted on Red Bay fine sandy loam in western Florida. Phosphorus showed the greatest yield response at the beginning of the experiment, but the amount of phosphorus required to give a maximum yield decreased as the experiment progressed. Nitrogen showed an excellent yield response in years when rainfall distribution was good. Potassium gave a positive response each year, with the degree of response increasing as the experiment progressed. The increase in the potash requirement was due to the depletion of soil potash on treatments which received small annual potash applications. Dolomitic limestone gave significant increases each year; these were greater at the 3‐ton‐per‐acre rate than at lower rates.These data were fitted to general parabolic response surfaces, and equations were determined by multiple curvilinear regression techniques to describe each years results. The units of N, P2O5, and K2O required to give a maximum yield and a maximum net return per acre were determined for each year reported.
The Effect of Time and Rate of Fertilizer Application on the Yield, Composition, and Longevity of Alfalfa
Authors: Nelson W. W. , MacGregor J. M. 
Published: July 2010

AbstractAn experiment was conducted on Port Byron silt loam (aeolian) at the Rosemount Experiment Station in eastern Minnesota to determine the effect of time and rate of fertilizer application on the yield, composition, and longevity of alfalfa. Six tons of lime per acre were applied late in 1949 and alfalfa was seeded early in the following spring. Commencing in 1951, three cuttings were made annually.The total alfalfa yield without fertilizer for the 3 years (1951–53) was 9.69 tons per acre. Highly significant yield increases were obtained only where potash was included in the fertilizer. The highest 3‐year total yield of 13.52 tons per acre was obtained by applying 1,000 pounds of 0‐20‐20 per acre in the spring before the alfalfa was seeded and later top‐dressed with 200 pounds of 5‐20‐20 per acre for the second and the third crop years. When nitrogen was omitted from the top dressing, the 3‐year yield was 13.44 tons.Fall and spring fertilization was equally effective on the eight fertilizer treatments compared.Crude protein, phosphorus, and potassium were generally highest in the second cutting of alfalfa and lowest in the first cutting. Crude protein content of the alfalfa varied from 19.1% to 24.8%, phosphorus from 0.20% to 0.39%, and potassium from 1.09% to 2.17%–the mineral content being affected by fertilizer treatment.In the fourth year, the stand on most of the treatments was still very good.
Experiments in Soil Genesis—The Role of Leaching
Authors: Thorp James , Strong Laurence E. , Gamble Erling 
Published: July 2010

AbstractAs a part of our study of the processes contributing to the formation of soils from glacial deposits we have examined the chemical and physical changes produced by organic acids and water‐soluble materials found in leaves. Our laboratory procedure used columns of Miami B2 soil through which various solutions were passed intermittently. These solutions flowed through the columns and were then collected at intervals and analyzed. Appreciable quantities of calcium, magnesium, iron, and manganese were mobilized in this way. In addition we found detectable amounts of fine silicate clays moving in suspension. Evidence for redeposition of iron compounds within the soil columns was found as well as the formation of “colloidal” films holding the originally discrete soil particles together. Colored bands which appeared in the columns were suggestive of soil horizons found in the field, particularly among the Podzolic soils.
Soil‐Vegetation Survey Information in Range Management Planning and Administration
Authors: Burcham L. T. , Storie R. Earl 
Published: July 2010

AbstractSince 1947 the State of California has been conducting a soil‐vegetation survey—an inventory of the vegetative cover and underlying soils of the wild land areas of the state. This soil‐vegetation survey is a particularly remunerative source of much information on the physical factors that affect the business of ranching. Practical applications of this information are discussed herein; a review of specific cases illustrates the value of these surveys in range management planning and administration. These cases also demonstrate that soil‐vegetation surveys are a practical tool for both the rancher, and the range technician in public service or private enterprise. They are an extremely effective means of conveying information, and have a great potential for developing interest in, and an incentive for, better range management.
The Nature of Reductant‐Soluble Phosphorus in Soils and Soil Concretions
Authors: Bauwin George R. , Tyner Edward H. 
Published: July 2010

AbstractIn preliminary studies on the relative abundance of the various phosphorus fractions in the different mechanical separates of soils, a number of iron‐manganese concretions were observed even in the very fine sand fractions. Phosphorus forms insoluble compounds with iron and manganese. It was postulated that the nonextractable phosphorus present in soils might be occluded in the iron coatings of weathered colloidal silicates or in micro‐concretions. The objective of this investigation was to determine: (1) if solution of the nonextractable phosphorus could be achieved with suitable iron reduction procedures; (2) the effect of grinding on the solubility of nonextractable phosphorus; (3) the mineralogical nature of nonextractable phosphorus as revealed by X‐ray analysis.The Jeffries and Deb iron reduction procedures were combined with the Bray and Kurtz phosphorus fractionation procedures in attempts to extract the total soil phosphorus. Solution of the total soil phosphorus was achieved only when the secondary iron compounds were reduced by the Deb sodium acetate‐sodium tartrate buffered sodium hydrosulfite procedure. This established the positional nonextractability of the insoluble phosphorus fraction. The phosphorus brought into solution by the buffered Deb procedure was termed reductant‐soluble phosphorus in lieu of the term “nonextractable phosphorus” previously used to describe the insoluble phosphorus fraction.Soils and concretions were ball‐milled to increase their specific surfaces. In all cases, prolonged ball milling reduced the phosphorus extracted by the Bray and Kurtz phosphorus fractionation procedures. Increasing the fluoride concentration of the extracting solutions enhanced the solubility of the phosphorus present in the ball‐milled products. However, it was not possible to solubilize the total soil phosphorus. In view of the similarities in extraction behavior of ball‐milled soils and soil concretions, it was concluded that the reductant‐soluble phosphorus present in concretions and soils was similarly retained.Powder diffraction patterns of soil concretions revealed the presence of goethite and silica, but no phosphate minerals. It was concluded that reductant‐soluble phosphorus probably exists as chemisorbed phosphorus dispersed at random in the matrix making up soil concretions and the iron coatings of the clay separates.
Quantitative Determination of Clay Mineral Mixtures by X‐Ray Diffraction
Authors: Jarvis N. Lynn , Dragsdorf R. Dean , Ellis Roscoe 
Published: July 2010

AbstractThe quantitative determination of clay minerals by X‐ray diffraction procedures was investigated using MgO as an internal standard. The determination of intensity constants for the 001 diffraction lines of samples of illitic, kaolinitic, and montmorillonitic types of clay was made with reference to the 1.48 Å MgO diffraction line. These constants were calculated using the integrated intensity of the specified diffraction lines, the known weights of clay and MgO in each sample, and the calculated value for the intensity of the MgO line. For kaolinitic and illitic types of clay the constants were evaluated with less than 2% average deviation, whereas for the montmorillonitic types the average deviations varied from 2 to 5%, depending upon the clay sample used. The values of the constants vary quite markedly from one species of clay mineral to another within each general clay type and, therefore, constants must be determined for each of the various clay species when they occur in a sample to be investigated.From the intensity constants for the 001 diffraction lines of each clay specie present in a mixture and the integrated intensity of the respective lines, the percentage composition of known synthetic mixtures of two and three components was determined with an average deviation of 1.87% from the actual composition. It was found that clay constituents appearing in quantities less than 10% by weight gave considerably larger deviations, and in the case of such small quantities of illitic types, the diffraction line often could not be differentiated from the background radiation.
A Study of the Influence of Moisture and Compaction on Soil Oxidation‐Reduction Potentials
Authors: Copeland Otis L. 
Published: July 2010

AbstractThe effects of 2 moisture levels and 2 degrees of compaction on the oxidation‐reduction potentials of 17 soils were investigated during an incubation period of 8 weeks. Soils receiving the optimum moisture‐no compaction treatment maintained the highest potentials throughout the incubation period, while the saturated‐high compaction series developed the lowest potentials. Apparently the Hagerstown soil used in this study possesses a high degree of poise against reducing conditions. This is shown by the failure of drastic treatments involving compaction and saturation to lower the potentials by large values. The positive poising capacity is attributed to large quantities of hydrated iron oxides present within the soil, coupled with the paucity of active organic matter.