bluuebunny/crossref_metadata_2025 huggingface dataset:
Limestone, Dolomite, and Calcium Silicate Slag for White Clover Pastures on Red and Yellow Soils
Authors: Jones U. S. , Edwards W. D.
Published: July 2010

An experiment has been conducted on five red and yellow podzolic soils since 1949 to study the effects of three kinds and four levels of lime on white clover seed and forage yields. The exchangeable calcium in the soil and soil pH as well as percentage of protein and calcium in the clover forage were used as measures of treatment effect. Other experiments were carried on to determine the availability of phosphorus in calcium silicate slag as measured by white clover forage yields. The design of the experiment was a split plot in which the whole plots were three kinds of lime, viz. calcium silicate, calcitic and dolomitic limestone, and the sub plots were rates of lime, viz. none, 1,000, 2,500, 4,000, and 6,000 pounds per acre. Lime applied at 1,000, 2,500, and 4,000 pounds per acre progressively increased clover forage and seed yields on Prentiss f.s.l., Bowie f.s.l., and Stough v.f.s.l. over a 3‐year period. On Loring and Richland silt loams, rates of lime up to 6,000 pounds per acre produced progressive increases in forage and seed production. Lime added at 1,000 to 4,000 pounds per acre produced an annual increase of protein in the clover forage from 36 to 190 pounds per acre. The calcium in the plant material was also increased by additional increments of lime. There was a progressive increase in soil pH and exchangeable calcium at all locations as the rates of lime increased. There was little difference among the three liming materials for increasing the pH and base content of the soil. Likewise, there was little difference among the three liming materials for increasing the forage and seed yields. Mean forage yields at all experimental sites showed a similar response to phosphorus contained in 4,000 pounds calcium silicate slag as to the phosphorus in 250 pounds of superphosphate applied with 4,000 pounds of calcitic limestone. The calcium silicate contained 1.3% P2O5.
Solubility of Phosphorus in Chemical Extractants as Indexes to Available Phosphorus in Ohio Soils
Authors: Thompson L. F. , Pratt P. F.
Published: July 2010

Eighteen samples of soils were subjected to greenhouse cropping with alfalfa and corn and to various extractant solutions for measurements of soluble P. The P removed from the soils by alfalfa and the “A” values calculated from the uptake by corn of radioactivity tagged superphosphate were used as a measure of plant‐available P. The accuracy of estimation of available P by the solubility data was obtained by comparing the P solubility in the various extractant solutions against the plant‐available P. The Bray No. 1 solution (0.03 N NH4F‐0.025 N HCl) and the 0.5 M NaHCO3 solution extracted amounts of P that were accurate estimates of plant‐available P. The Bray No. 2 solution (0.03 N NH4F‐0.1 N HCl), 0.002 N H2SO4, and citric acid extracted amounts of P that when plotted against the plant data gave a distinctly different relationship for young soils formed from high‐lime late Wisconsin till than for older soils formed from more acid parent materials.
Theory of Capillary Flow: I. Practical Implications
Authors: Miller E. E. , Miller R. D.
Published: July 2010

The authors describe elsewhere certain general consequences of assuming that the classical differential equations of surface tension and viscous flow govern the behavior of liquids within the microscopic pores and channels of an unsaturated porous medium. These consequences appear as macroscopic differential equations expressed in reduced variables and containing two time‐independent functionals of pressure which exhibit hysteresis and are characteristic of the medium. The present paper interprets these equations in practical terms.

Because of time independence, the term ▽ K appearing in L. A. Richard's analogous equation (1931) becomes . Accordingly it is possible to solve for the conductivity and capacity functionals from experimental flow system data, provided the accuracy is sufficient for evaluation of required derivatives of pressure.

The combination of reduced variables and time independence permits scale modeling of flow systems. In a small‐scale replica, the time scale is shortened, while “gravity” must be increased by means of a centrifuge. One possible application is to laboratory measurement of field capacity.

The reduced variables telescope into groups macroscopic flow systems that are equivalent except for scaling factors. Reducing the microscopic geometry by comparison to a characteristic pore size may prove useful in simplifying physical description of soils.
Profile Characteristics of Some Loess‐Derived Soils and Soil Aeration
Authors: Ruhe R. V. , Prill R. C. , Riecken F. F.
Published: July 2010

Inferences are made in evaluating soil drainage conditions from morphological characteristics of soils, such as mottles and deoxidized zones. These characteristics are not infallible criteria for indicating drainage conditions, and an evaluation of local and regional relationships often is necessary for a proper interpretation. An excellent example of the need for such an evaluation is afforded by a study of weathering zones in Wisconsin loess in southwestern Iowa. A repeated occurrence in regional distribution of two deoxidized zones, the upper one surmounted by an abundantly mottled zone, was observed in the Wisconsin loess. The present positions of these deoxidized zones are moderately well or well drained, indicating that they are not related genetically to the present environment but are relict from a preexisting environment of poorer drainage. Well‐drained soils occurring on the modern landscape frequently are mottled in the B and C horizons. This mottling in the profiles is interpreted as an incidental morphological characteristic and not related genetically to the profile development, but inherited from a pre‐existing environment of poorer drainage.
The Relation of Certain Loessial Soils of Northeastern Kansas to the Texture of the Underlying Loess
Authors: Hanna Robert M. , Bidwell O. W.
Published: July 2010

Particle size analyses were made on 10 profiles representing four soil series. The profiles were located on a traverse perpendicular to the Missouri River from the Missouri River bluffs in northwestern Doniphan County, Kansas, to a point in southwestern Brown County, 24 miles from the river. The first sampling site was located 2 miles from the Missouri River. Subsequent sites were located at approximately 2½‐mile intervals. The thickness of the loess, as measured at most sites, decreased from approximately 100 feet at the river bluffs to 6 feet at the tenth site. The textural composition and pH of each horizon were determined in the laboratory. The texture of the C, B, and A horizons was observed to become finer with increased distance from the river up to 16 miles from the bluff. Beyond that point there was little if any decrease in particle size with distance. The change in texture of the C horizon with distance from the river appears to be the dominant factor in the development of the four soil series, Monona, Marshall, Sharpsburg, Grundy, which have not been finally correlated in this area. This work further substantiates the belief that the Missouri River Valley flood plain was a source of some of the loessial deposits of northeastern Kansas.
Soil Moisture Regime in Some Forest and Non‐Forest Sites in Northern Wisconsin
Authors: Thames John L. , Stoeckeler Joseph H. , Tobiaski Robert
Published: July 2010

The soil moisture regime was studied in two paired sets of sites in northern Wisconsin.

In comparison of a forested and non‐forested Spencer silt loam there was less available soil moisture in the surface 1 to 2 feet of the forested site because of heavy depletion of soil moisture by the tree stand, as compared with the nearby site with a timothy hay crop. Bulk density of the soil in the hay land was 25% greater for the top foot and 32% greater for the top 2 feet than the forested site.

In a comparison of two paired forested sites both on sands and with permanent water table at 2.0 and 4.5 feet respectively, there was around 0.4 inch more water in the surface foot in the former, or around 4% on a weight basis in the top 2 feet during much of the growing season. Jack pine had almost the same site index on both sites, but in the case of aspen, the site index was 10 feet greater on the shallower water table area.
Theory and Measurement of Anisotropic Air Permeability in Soil
Authors: Maasland Marinus , Kirkham Don
Published: July 2010

Three fundamental theorems on the movement of air through anisotropic soil are stated. New and simple proofs for two of the theorems are given; proof for one is referred to in the literature. On the basis of these theorems, formulas are derived for converting, to horizontal and vertical permeabilities, air flow measurements, previously reported in the literature, on soil clods. It is shown that the reported values of anisotropic permeabilities are apparent values, and that these apparent values depart considerably, in certain cases, from the correct values. As an extreme example, the reported ratio of the apparent horizontal to apparent vertical permeability for clod samples of Clarion soil, is 2.09, whereas the corrected ratio is 13.0. One particularly interesting general result of the theory is that an apparent value of the vertical permeability is, in fact, the geometric mean of the vertical and horizontal permeabilities of the sample. It is finally shown that the arithmetric mean of the apparent vertical and apparent horizontal permeability does not deviate greatly from the arithmetic mean of the true horizontal and true vertical permeability, the deviation being, for the Clarion sample, only 24%.
Current Status of Research in Soil Compaction
Authors: Raney W. A. , Edminster T. W. , Allaway W. H.
Published: July 2010

Discussion of this problem requires separation and careful definition of the kinds of soil conditions ordinarily considered under the general term soil compaction. Implement traffic, tillage operations, and livestock trampling may cause the formation of soil horizons of high bulk density and low porosity in soils which ordinarily have good physical properties. In planning research and extending research results, it is very important to distinguish these compacted layers from the conditions found in soils with genetically developed pan horizons. Examples of different kinds of both genetically‐developed and traffic‐induced pans are offered.

Literature concerning the cause and nature of traffic‐induced pans and their effects on crop production is reviewed and analyzed. The extent of such pans in the Eastern and Southern states is considered. Current research dealing with prevention of compaction and the amelioration of compacted soils is reviewed and aspects of the problem requiring additional research are pointed out.
Mineral Content of a Latosolic Brown Forest Soil and a Humic Ferruginous Latosol of Hawaii
Authors: Tamura T. , Jackson M. L. , Sherman G. D.
Published: July 2010

Mineralogical analysis for two soils representing the Latosolic Brown Forest and Humic Ferruginous Latosol groups were made using X‐ray, thermal, and chemical techniques. In the A horizon of the Latosolic Brown Forest soil goethite (28%) was the predominant mineral; in the B horizon gibbsite (42%) predominated. Other minerals included hematite (15–25%), magnetite (0–10%), quartz (5–10%), and layer silicates (15–20%) in the A and B horizons, respectively. In the A2 horizon of the Humic Ferruginous Latosol from the island of Maui hematite (48%) was dominant; in the B horizon gibbsite (31%), hematite (25%) and amorphous alumino silicate (22%) were present in nearly equal quantities. In the C horizon of Humic Ferruginous Latosol the gibbsite content (48%) was substantially higher than the iron oxides (14%). The A22, B and C horizons of another Humic Ferruginous Latosol from the island of Kauai were also examined. The A22 horizon was predominately hematite (45%) with appreciable anatase (15%) and ilmenite (15%). The B horizon contained both hematite (30%) and goethite (30%) as the dominant minerals; the C horizon contained kaolinite (35%) as the major mineral constituent.
A Survey of the Nutrient Composition of Leaf Samples from North Carolina Peach Orchards
Authors: McClung A. C. , Lott W. L.
Published: July 2010

A group of 153 leaf samples was collected from North Carolina peach orchards over the period 1950–52 using sampling techniques which were standardized in respect to date of sampling and leaf age and position. The samples were analyzed spectrographically for phosphorus, potassium, calcium, magnesium, boron, copper, manganese, iron, and aluminum. Zinc and nitrogen were determined by chemical methods. The data are discussed from the standpoint of discerning broad general trends in the nutrient status of trees in a particular area and of using this information as a basis on which to establish or expand soil fertility investigations.

Levels of phosphorus, potassium, and manganese were found to be well above the deficiency ranges for peaches as reported from this and other areas. Clear‐cut foliar symptoms of deficiencies of magnesium and zinc were noted in some orchards, and leaf analyses indicate near deficiency in other orchards. Leaf levels of iron, boron, and copper were low as compared with results from surveys in other areas. Foliar symptoms of iron deficiency and symptoms possibly due to boron deficiency were noted in some orchards. Symptoms of copper deficiency were not observed here, nor have they been described for peaches elsewhere. Leaf levels of copper were in many orchards lower than the levels of adequacy reported for other crops. The results of this survey suggest that further study is warranted concerning deficiencies of magnesium, zinc, iron, boron, and copper in North Carolina peach orchards.
Fertilizer Placement for Small Grains in Relation to Crop Stand and Nutrient Efficiency in Nebraska
Authors: Olson R. A. , Dreier A. F.
Published: July 2010

Time and method of fertilizer nutrient application have been found to markedly influence stand and growth of small grains in Nebraska. Severe stand reductions and yield losses have been noted as a result of moderate rates of N as well as K applied with the seed. These losses do not occur every year, nor are they uniform across the state in the years when noted. On the other hand, efficiency of applied P usually has been much greater when applied with the seed than by other methods.

Investigations in the field and constant temperature laboratory suggest a low moisture level at which the most serious damage of fertilizer salts to germination occurs, but full germination is not assured at any soil moisture level without a surface increment to leach fertilizer away from the seed. Emergence loss from N adjacent to the seed at low moisture level is in direct proportion to the time interval before rain or irrigation raises the level. In general, N materials are more detrimental per unit weight than K, and the latter more than P. Damage to germination under critical soil moisture is apparent at 10 lbs. N/acre, increasing to the point of stand elimination with 160 lbs. N/acre. Among N carriers, CaCN2 and NH4OH are most deleterious to germination followed by CO(NH2)2 > NaNO3 > KNO3 > (NH4)2SO4 > NH4NO3. Straight carriers of phosphate cause little damage, but ammonium phosphates of 1:1:0 ratio are harmful when placed with the seed under conditions of limited moisture; the damage is less with pelleted than finely ground material. Fertilizer and seed need not be in immediate contact for germination inhibition, as evidenced by appreciable migration of N and P to the imbibing seed.

Soil microorganisms are in part responsible for fertilizer injury to germinating seed, occasioned by their greater tolerance of low moisture supply and high salt concentration. Seed treatment at the lower moisture levels alleviates but does not eliminate the fertilizer detriment.

Phosphorus placement with the seed of small grains is desirable in the drier regions so long as the N concurrently added with the seed does not exceed 10 or 15 lbs./acre. Supplementary N is essential to maximum P fertilizer utilization, but much of it should be applied separate from the seed.
Efficiency of Various Nitrogen Sources for Pasture Grasses in Large Lysimeters of Lakeland Fine Sand
Authors: Volk Gaylord M.
Published: July 2010

A 3‐year study of the efficiency of various amounts and sources of nitrogen for Pensacola Bahiagrass, Pangolagrass, coastal Bermudagrass, and carpetgrass was made in 12 lysimeters approximately 22 square feet in area and 4 feet deep filled with Lakeland fine sand. There was no consistent difference in yield or nitrogen content of forage when three 20‐pound applications of nitrogen were derived from urea, NH4NO3 or NaNO3, nor between urea and NH4NO3 when applied at 60 pounds of nitrogen per month for 6 or 8 months.

Leaching loss of nitrogen generally was low even for the high nitrogen applications, except in the case of carpetgrass. Percentage recovery of nitrogen in the forage ranged from 50% to 80% depending on the amount applied and the vigor of the grass. Leaching losses were not a major factor in accounting for the lack of recovery of nitrogen in the forage.

The pH of the 0 to 10 inch surface soil was lower, and that of the 10 to 18 inch subsoil higher at the end of the study than it had been at the time the lysimeters were filled. The pH of the entire 0 to 18 inch depth was consistently lower where NH4NO3 had been used as compared to urea.

The use of evapotranspiration values and soil moisture reserves calculated for the conditions of the lysimeters indicated that reduced leaching due to interruption of the moisture profile by the lysimeter bottom probably would not exceed 2 to 2.5 inches of leachate per growing season, and would not introduce a major error in the estimation of the efficiency of the nitrogen materials.
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

This 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

In 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

This 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

Rate 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

A 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

Response 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

A 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

An 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

The 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

Some 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

Four 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

An 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

As 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

Since 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

In 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

The 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

The 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.
Soil Aggregation in Relation to Various Soil Constituents
Authors: Chesters G. , Attoe O. J. , Allen O. N.
Published: July 2010

The relative importance of diverse factors affecting aggregation in four Wisconsin soil types was studied by multiple regression analyses. Single and combined effects of pH and contents of organic matter, microbial gum, clay, and free iron oxide were considered.

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

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

Data on six soil types in North and West Florida for 2 years were used to evaluate subsoiling and deep placement of fertilizer. Lime, fertilizer, fertilizer plus lime, and fertilizer plus lime plus minor elements placed in the subsoil were compared with subsoiling alone and surface fertilization at low and high rates. Corn yields, root distribution and the chemical composition of ear leaves were used to measure responses.

Where organic hardpans existed, as on the Leon fine sand, Ona fine sand, and combinations of these soil types with related soils, yield increases were obtained for subsoiling alone and fertilizer, lime and/or minor elements placed in the subsoil. Responses to fertilizer were related to the chemical composition of the soil profile and rainfall distribution. Better responses were obtained when moisture stress periods occurred during the first part of the season. The Norfolk loamy fine sand, Ruston fine sandy loam and Red Bay fine sandy loam soils contained compact clay zones or plow soles beneath the surface. When drought periods were of short duration, subsoiling and deep placed fertilizer improved corn yields above the check. When the drought period was of 25 days' duration the advantage of having a deeper root system and a larger corn plant was lost.

On the Klej fine sand where there was nothing in the profile to impede roots, fertilizer on the surface was as good as. deep placement and subsoiling alone was of no benefit.

The residual effects of the subsoiling treatments were generally small. There was some indication that it would be necessary to subsoil annually even though additional fertilizer in the subsoil may not be needed.
Chelating Ability of Soil Organic Matter
Authors: Himes Frank L. , Barber Stanley A.
Published: July 2010

It was discovered that organic matter reacted with divalent metal ions in a manner similar to chelation reactions. Radioactive zinc was used to facilitate the adsorption measurements. Multiple regression was used to develop a prediction equation to determine the amount of zinc adsorbed as influenced by zinc added, pH, and ionic strength of the solution.

Removal of organic matter by oxidation with hydrogen peroxide destroyed the ability of the soil to chelate zinc. Removal of hydrous silicates did not influence the retention of zinc by the soil.

The organic matter was fractionated into the humic and fulvic fractions. Both fractions reacted with zinc in a manner similar to the untreated soil. Methylation of the organic matter was used to determine the functional groups involved in the chelation reaction. Carboxyl groups did not appear to be important.

The stability constant for the zinc soil complex was investigated by two independent methods. For a Maumee sandy loam soil at pH 7 and 2N KCl it was found to be 5.6.
Adsorption of Hydrolyzed Polyacrylonitrile on Kaolinite: I. Effect of Exchange Cation and Anion
Authors: Mortensen J. L.
Published: July 2010

The rate and extent of adsorption of hydrolzed polyacrylonitrile (HPAN) on kaolinite was determined, using HPAN labelled with C14. Continuous mixing in the presence of univalent exchange ions gave steady state adsorption within 4 hours. Langmuir type adsorption isotherms resulted. Saturation adsorption was 2.6 me. HPAN per 100 g. H‐Cl‐kaolinite.

The exchange cation affected the extent of adsorption of HPAN in approximately the same order as such cations reduce the zeta potential of kaolinite, i.e., Th4+ > Ca2+ > Ba2+ > H+ > NH4+ > K+ > Na+. An anomalous increase in adsorption in the presence of polyvalent exchange cations suggested adsorption at the site of base exchange salt formation. Anions of sodium salts sorbed on kaolinite increased adsorption of HPAN in the order F‐ > OH‐ > H2PO4‐ > Cl‐ > CH3COO‐ > NO3‐ > HPAN.

HPAN was apparently adsorbed as a monolayer on a single set of sites which are most likely “positive spots” on the edge of the kaolinite crystal or which arise from adsorbed or colloidal sesquioxide impurities.