bluuebunny/crossref_metadata_2025_split huggingface dataset:
Urea‐Formaldehyde Fertilizer as a Source of Nitrogen for Cotton and Corn
Authors: Scarsbrook C. E. 
Published: July 2010

AbstractThree formulations of experimental 12‐12‐12 grade fertilizer, each containing a portion of the nitrogen as ureaformaldehyde, were compared with ammonium nitrate as sources of nitrogen for cotton and corn. The 12‐12‐12 used in 1955 contained 38% of the nitrogen as urea‐formaldehyde with an availability index of 20; in 1956 two formulations were used with urea‐formaldehyde percentages of 35 and 36 and availability indices of 49 and 57, respectively. Ammonium nitrate produced higher yields than equivalent rates of nitrogen from fertilizer containing urea‐formal‐dehyde. Nitrogen contents of corn leaf samples and of grain were higher where ammonium nitrate was the source of nitrogen. The residual value of nitrogen on oat forage following cotton was determined. Urea‐formaldehyde with an availability index of 49 had the greatest residual effect. However, the residual effect from ammonium nitrate was greater than from the index‐20 material.
A Study of Fragipans in Some Southern Indiana Soils
Authors: Anderson J. U. , White J. L. 
Published: July 2010

AbstractFragipans or “X” horizons have been recognized in highly weathered soils of southern Indiana for more than 30 years. They occur at depths of 2 to 4 feet, and are most common in imperfectly and moderately well‐drained soils.Profiles of three highly weathered soils of the residual area of southern Indiana were selected for study. A fourth profile which did not have a fragipan, but was formed from similar parent material was sampled for comparison. Detailed chemical and mineralogical studies were made on the nonfragipan profile and one of the fragipan profiles.Each of the soils with fragipans had a pH of 4.5 or less in the B horizon. The profile without a fragipan had a minimum pH of 5.6. Horizons of one fragipan profile were shown to contain iron oxide as a cementing agent. The clay of the fragipan was found to be lower in montmorillonite than the clay from comparable horizons of the profile without a fragipan. Only a small portion of this montmorillonite from the fragipan was capable of expansion without sample pretreatment.
Chemical Behavior of Monocalcium Phosphate Monohydrate in Soils
Authors: Lehr James R. , Brown Walter E. , Brown Earl H. 
Published: July 2010

AbstractTo gain an insight into the phenomena that are initiated when superphosphate is placed in soil, tablets containing monocalcium phosphate monohydrate were placed in several soils and observed directly. Petrographic examinations and supporting chemical studies gave information on chemical reactions associated with the dissolution process and on the transport of materials to and from the tablet—factors that bear upon the distribution and chemical combination of the phosphorus and thus upon agronomic response.The results suggest that capillary flow was a principal mechanism in the movement of phosphate solution away from the tablet. Vapor‐phase transport of water to the tablet apparently controlled the rate of dissolution. A significant part of the P remained at the tablet site as dicalcium phosphate, anhydrous or dihydrated. The dissolution process was affected by soil type, soil moisture content, humus content, microbiological activity, capillarity of soil and tablet, time, and temperature.
Determination of Sodium in Saline Solutions With a Glass Electrode
Authors: Bower C. A. 
Published: July 2010

AbstractAn experimental sodium alumino‐silicate glass electrode supplied by Beckman Instruments, Inc., was studied to determine its sensitivity to the cations commonly found in irrigation waters and in water extracts of soils. The electrode was found to be insensitive to Ca++ and Mg++ but sensitive to Na+, K+ and H+, giving theoretical relations between EMF's and cationic activities for the latter.A procedure for determining Na in waters and saturation extracts with the electrode is described. It involves dilution of the sample so that the total cation concentration does not exceed about 10 me. per liter, adjustment of the pH value to approximately 7, and precipitation of K as K tetraphenylboron. The Na concentrations of irrigation waters and saturation extracts of soils as determined by the electrode and by flame photometry agree closely.
Strontium and Calcium Contents of Crop Plants in Relation to Exchangeable Strontium and Calcium of the Soil
Authors: Menzel R. G. , Heald W. R. 
Published: July 2010

AbstractThe relative uptakes of Sr and Ca were determined for crops grown in the field and greenhouse. Exchangeable Sr and Ca contents were determined in 93 plow layer samples representing 51 soil types in 11 widely scattered states. The average ratio was 1.3, with a range of 0.2 to 4.0, Sr atoms per 1,000 Ca atoms. The ratio varied more according to area than according to type of parent rock, and was similar to the ratio in surface water supplies. The ratios of Sr and Ca in alfalfa or wheat grown in the field were nearly equal to those in the exchangeable cations of the soil. Ten species of cultivated plants grown on 4 soils in the greenhouse had Sr and Ca ratios averaging 0.7 times those of the exchangeable cations in the soils. Small, but statistically significant, differences in relative Sr and Ca uptakes were found with different crops and soils.
Phosphorus Solubility in Calcareous Soils: II. Effects of Exchangeable Phosphorus and Soil Texture on Phosphorus Solubility
Authors: Cole C. V. , Olsen S. R. 
Published: July 2010

AbstractP solubility expressed as the mean activity of dicalcium phosphate in equilibrium solutions increases regularly with the amounts of P adsorbed in the monolayer region on the surfaces of various materials likely to be present in calcareous soils. Values of the mean activity of dicalcium phosphate in equilibrium soil solutions increased as a direct function of the amount of phosphate added as concentrated superphosphate. Differences in P solubility behavior between soils of varying texture are explained by measurements of the surface area and the capacity of the soils for monolayer adsorption of P.
Some Growth Responses of Tomatoes to Soil Compaction
Authors: Flocker W. J. , Vomocil J. A. , Howard F. D. 
Published: July 2010

AbstractCompression of soil reduces the size and arrangement of soil air spaces. When this process is carried beyond certain limits it results in an overall inhibition of some of the physiological processes of plant growth.A greenhouse experiment was designed to determine some of the effects of reduced soil air spaces on growth of tomatoes. Three soils—Yolo fine sandy loam, Salinas clay loam, and Sacramento clay—were compressed hydraulically into 1‐gallon cans to air spaces varying from 42 to 2%. Percentage of germination, velocity of emergence, blossoming, rate of growth, and yield data were taken. Results showed that compacting soil to a certain density increased percentage of germination, but that compression beyond this point seriously reduced the percentage of germination. Compacting the soil increased the time required for seedlings to emerge. Blossoming was delayed as density increased for all three soils tested. Growth curves were plotted for some densities on the soils with the maximum rate of growth occurring at different plant ages, depending on soil air space. Reduced air space retarded growth in all three soils as measured by total height and the weekly change in height.The relationship between soil air space and total plant height was plotted. A curvilinear regression was found to be highly significant. Optimum air space for maximum height was calculated to be about 30%.
The Relation of Temperature and Phosphate Placement to Growth of Clover
Authors: Robinson R. R. , Sprague V. G. , Gross C. F. 
Published: July 2010

AbstractThe effect of placement of mono‐calcium phosphate on P availability to red clover seedlings was determined at 50°, 60°, 70°, and 80°F. in controlled temperature chambers. Band applications of phosphate, as compared with phosphate mixed with the soil, were much more effective at low temperatures than at higher temperatures. This is attributed to the effect of temperature on rate of P uptake by the plant. Where only small amounts of phosphate were mixed with the soil, the level of available phosphate was low and growth at low temperature was very poor. With increasing temperature, the rate of P uptake increased markedly and plant growth increased. It would appear that the more rapid uptake of P at higher temperature is associated with the temperature coefficient of absorption rather than with an increase in P concentration in the soil solution. Thus, as the temperature increases, plants apparently are able to absorb P more rapidly from soil solutions containing very small amounts of P. Band applications of phosphate greatly increase the concentration of phosphate in the root zone, and therefore the effects of temperature on rate of P uptake become less important.
Soil Organic Matter: I. Electrophoretic Separation of Acid‐Resistant Components
Authors: Johnston Harry H. 
Published: July 2010

AbstractTwo acid‐resistant fractions were isolated from three soils, a Sims clay loam, a Houston Black clay, and a Xenia silt loam. The fractions were separated by paper electrophoresis and analyzed for functional groups by infrared spectra. One component was a dark‐colored nonfluorescent material and the other a yellow fluorescent water‐soluble material. Chemical analysis of the darker humic acid obtained from the Xenia silt loam gave the following results: C, 52.48%; O, 38.38%; H, 4.65%; N, 1.98%. This material was found to contain 6.7% methoxy groups. Infrared spectra of the two fractions showed them having a different structure, but both materials were throught to contain hydroxyl and carbonyl groups. The N content of the dark‐colored fraction separated by electrophoresis was 1.98% for the Xenia and Sims soils and 1.79% for the Houston soil. Because of the similarity of these materials in infrared spectra and N content, it is believed that these acids are of fundamental importance in the structure of soil organic matter.
Evaluation of Two Methods of Measuring Available Soil Copper and the Effects of Soil pH and Extractable Aluminum on Copper Uptake by Plants
Authors: Blevins R. L. , Massey H. F. 
Published: July 2010

AbstractThe relationship between Cu uptake by millet grown in the greenhouse on 34 Kentucky soils and the available Cu in the soil as determined by the versenate procedure of Cheng and Bray and an adaptation of the dithizone procedure for Zn of Shaw and Dean was studied. The pH of the soil and the Al extracted by 0.1N CaCl2 were also correlated with Cu uptake.Highly significant correlations between both methods for available Cu and Cu uptake by the millet plants were obtained, but the relatively low values of the correlation coefficients indicate that neither procedure adequately measures available soil Cu. There was no correlation between soil pH and Cu uptake. Al extracted by 0.1N CaCl2 was inversely correlated with Cu uptake. The uptake of Cu by wheat plants was decreased by Al concentrations of 0.4 to 1.0 ppm. in short term solution‐culture experiments. An Al concentration of 0.1 ppm. appeared to increase the uptake of Cu.
Diffusivity of Soil Water During Sorption as Affected by Temperature
Authors: Gardner W. R. 
Published: July 2010

AbstractThe sorption diffusivity at saturation and at the air‐dry water content has been measured for five soils of different textures as a function of temperature. Near saturation, the viscosity effect is predominant. At low water contents, the effect of temperature upon the suction becomes important and in some cases exceeds the viscosity effect. The hysteresis effect is often as large or larger than the temperature effect. For many purposes it may be acceptable to assume the diffusivity and capillary conductivity to be independent of temperature, at least at normal laboratory and field temperatures.
Drain Depth and Spacing Effects on Water Removal from a Gray‐Brown Podzolic Soil
Authors: Goins Truman , Taylor George S. 
Published: July 2010

AbstractThe effect of two depths and two spacings of drains on tile flow rates and drawdown in a glaciated Ohio soil were evaluated. Drain depths were 2 and 3 feet, and the spacings were 30 and 60 feet.Flow rates were linearly related to the water table (WT) level at the midpoint between drain lines. Tile flow was more closely related to the position of the WT in the profile than to the height of the WT above the drain, indicating the strong influence of the conductivity profile in drainage. The highest flow rates were obtained from drains at the 2‐foot depth; while spacing had no significant influence on maximum flow rates. Drains at the 2‐foot depth lowered the WT faster in the upper 18 inches of soil than did those at the 3‐foot depth; and drains spaced 30 feet apart were more effective in lowering the WT than those spaced 60 feet. The relative performance of the drains at 2‐ and 3‐foot depths was a result of decreased soil hydraulic conductivity with depth.Estimates of soil hydraulic conductivity based on drain flow and WT levels showed that the auger hole and the O'Neal methods underestimated the conductivity by factors no smaller than 4 and 2, respectively.
Equilibrium of Soil Grains at the Threshold of Movement by Wind
Authors: Chepil W. S. 
Published: July 2010

AbstractThis paper, based on wind tunnel studies, presents an analysis of the nature and magnitude of forces on soil grains at the threshold of their movement by wind. Forces of drag, lift, and gravity were analyzed in relation to each other.The equilibrium between these forces and the soil grains was found to be influenced by the diameter, shape, and immersed density of the grains, the angle of repose ø′ of the grains with respect to the mean drag level of the fluid, the closeness of packing η of top grains on the sediment bed, and the impulses of fluid turbulence TD and TL associated with drag and lift, respectively. All those factors were measured and related with actual and theoretical forces involved.New approaches to measurement of η, ø′, TD and TL are presented. Analyses indicate that the magnitude of pressure impulses of both TD and TL is statistically distributed according to the somewhat skewed normal error law. The ratio of mean pressure to standard deviation σ was constant for any size of grains or fluid velocity and could be expressed by equation σ = cP̄ in which P̄ is the mean pressure of lift or drag and c is a constant which was found to have a mean value of 0.49.
Nature of the Reactions of Monocalcium Phosphate Monohydrate in Soils: IV. Repeated Reactions With Metastable Triple‐Point Solution
Authors: Lindsay W. L. , Stephenson H. F. 
Published: July 2010

AbstractA series of soil samples was reacted repeatedly, first with solution saturated with respect to Ca(H2PO4)2 · H2O and CaHPO4 · 2H2O (MTPS), and later with water, in an attempt to simulate the changing chemical environment of soil surrounding a superphosphate granule.The reaction of MTPS with soil was accompanied by increase in pH and precipitation of Fe, Al, and Ca phosphates from solution. Soil repeatedly contacted by MTPS gradually became more acidic and showed continued dissolution of Fe and Al. Subsequent additions of water to the soil residues remaining after reaction with MTPS increased the pH and caused further precipitation of phosphate from solution. Many filtrates obtained during these reactions yielded precipitates upon standing. The following crystalline compounds were identified from these precipitates: CaHPO4 · 2H2O, H6K3Al5(PO4)8 · 18H2O, H8K(Al,Fe)3(PO4)6 · 6H2O, and CaHPO4. The indications are that these compounds may form as initial phosphate reaction products of superphosphate fertilizers in soils. Tentative conclusions are presented regarding the nature of the reactions of Ca(H2PO4)2 · H2O in soils.
Organic Matter Decomposition and Plant Nutrient Release from Incorporations of Soybean Hay and Wheat Straw in a Holston Sandy Loam in Outdoor Lysimeters
Authors: Shaw W. M. , Robinson Brooks 
Published: July 2010

AbstractAn acid Holston sandy loam, unlimed and limed to 60 and 100% base saturation, without organic matter and with soybean hay and wheat straw was placed in 1/20,000‐acre outdoor lysimeters which were exposed to weather and kept free of vegetation for a period of 3 years. Soil samples were taken at the end of each year and analyzed for organic matter and total N content. The leachates were analyzed for the annual outgo of Ca, Mg, K, S, N, and soluble organic matter.A 2% soybean hay incorporation in a Holston sandy loam after a 3‐year exposure to weather and leaching has resulted in a net gain to the soil in percentages of the additives: 20% of organic carbon, 40 to 60% of N, and about 70% of the mineral nutrients. The soybean hay treatment resulted in a 10% increase in cation‐exchange capacity of the soil.A shallow incorporation of the soybean hay (4 inches) resulted in a 50% greater retention, and a smaller (1/3) loss by volatilization of the nutrient N as compared to full‐depth incorporation.
Solubility of Dicalcium Phosphate Dihydrate in Aqueous Systems
Authors: Moreno Edgard C. , Brown Walter E. , Osborn Glen 
Published: July 2010

AbstractThe metastable solubility isotherm for dicalcium phosphate dihydrate, CaHPO4·2H2O, (DCPD), in the pH range 3.5 to 7.5 was established by (a) leaching solutions of dilute phosphoric acid through columns of DCPD, and (b) by shaking suspensions of DCPD in dilute phosphoric acid solutions.In other experiments, equilibrium was approached both from undersaturated and supersaturated conditions. In both cases the final solution compositions were represented by points on the isotherm obtained by the methods mentioned above, and dissolution or precipitation occurred with a Ca/P ratio equal to one.The solubility product constant of DCPD was found to be 2.77 × 10‐7 for all concentrations tested when appropriate corrections were made in the calculation of ionic activities.
Stability of Dicalcium Phosphate Dihydrate in Aqueous Solutions and Solubility of Octocalcium Phosphate
Authors: Moreno Edgard C. , Brown Walter E. , Osborn Glen 
Published: July 2010

AbstractThe hydrolysis of dicalcium phosphate dihydrate, CaHPO4·2H2O, in dilute phosphoric acid solutions and in water was investigated at 25° C. in the absence of CO2. Octocalcium phosphate, Ca4H(PO4)3·3H2O, was found to precipitate when the pH of the solution was higher than 6.38. The extent of the hydrolysis was larger the higher the initial pH of the solution. The solution composition followed the metastable solubility isotherm for dicalcium phosphate dihydrate until a singular point between octocalcium phosphate and dicalcium phosphate dihydrate was reached. At this point the solution had a pH of 6.38 and Ca and P concentrations of 1.36 × 10‐3M and 2.21 × 10‐3M, respectively. The solubility product of octocalcium phosphate was calculated to be (Ca)4(H)(PO4)3 = 1.25 × 10‐47.Relative rates of solution and precipitation of both dicalcium and octocalcium phosphates are discussed. No formation of anhydrous dicalcium phosphate or hydroxyapative was detected in equilibrations for as long as 90 days, even though both of these compounds are more stable than dicalcium phosphate dihydrate under the experimental conditions.
Behavior of Free Amino Acids in Soil
Authors: Schmidt E. L. , Putnam H. D. , Paul E. A. 
Published: July 2010

AbstractThe behavior of a mixture of amino acids in a soil environment was studied. Extractions were made with 80% ethanol. The extract was concentrated and then was analyzed for amino acids by gradient elution chromatography. After 1 hour of soil contact in the cold, at least some of each amino acid could be recovered, but the extraction was not efficient. Replicate soil flasks to which amino acids had been added were incubated at 28° C. under conditions that allowed for both CO2 and amino acid analysis of the same flask. After 24 hours, substantial degradation had occurred but at least trace amounts of each of the added amino acids except threonine could still be detected. Beta alanine appeared on the 24‐hour chromatogram although it was not among the amino acids added initially. Results of both chromatographic analysis and CO2 collection suggested that nearly all of the added amino acids were degraded by the end of 96 hours. Separate studies using microbiological assay failed to confirm the persistence of threonine in soil as reported in the literature. The possibility that the beta alanine found in the soil environment was formed from aspartic acid decarboxylation was explored, but large additions of aspartic acid to soil did not result in substantial increases in beta alanine.
Ponderosa Pine Productivity in Relation to Soil and Landform in Western Montana
Authors: Cox G. S. , McConnell R. C. , Matthew L. M. 
Published: July 2010

AbstractForest soil productivity for growth of ponderosa pine (Pinus ponderosa Dougl.) in Montana west of the Continental Divide was studied. Data were obtained on 255 plots located in medium‐ to well‐stocked stands on 28 soil series and 9 landform types. Mean site indices for the soils studied ranged from 54 to 99 feet at 100 years.Effective depth of soil in which tree roots might develop was the principal factor influencing tree growth. Four depth factors limited development of roots: depth to gravel or loose sand, depth to a slowly permeable layer, depth to bedrock, and depth to lime. Areas receiving supplementary moisture from seepage or high water tables were good sites for tree growth regardless of the type of soil involved.
Soil Capillary Conductivity: Comparison of Measured and Calculated Values
Authors: Nielsen D. R. , Kirkham Don , Perrier E. R. 
Published: July 2010

AbstractCapillary conductivities were measured for two loess soils and two glacial till soils at four depths and at five values of water suction, up to and including 100 cm. of suction. For the same soils, curves of moisture content vs. suction were obtained and, from the latter data, capillary conductivities were calculated by the Childs and Collis‐George method and by the Marshall method. The values obtained by the Marshall method were all considerably higher than the measured values. Those obtained by the former method—a method which utilizes a matching constant to fit the experimental data at one point—agreed satisfactorily for the loess soils, but not for the glacial soils. Suctions as small as 25 cm. of water reduced capillary conductivities by as much as 10‐4 for the glacial soils. The reduction was not as marked for the loess soils. The theories tested had been developed for nonshrinking materials such as sieved sand and slate dust. The present results show that the use of one of the theories may be extended to agricultural soils, and that the other theory could also be so extended, if a matching constant were used.