bluuebunny/crossref_metadata_2025_split huggingface dataset:
Moisture Storage and Use by Dryland Spring Wheat Cropping Systems
Authors: Haas H. J. , Willis W. O. 
Published: July 2010

AbstractSoil moisture data collected at Mandan, North Dakota from 1915 to 1954 were summarized to compare water storage and use from soil annually cropped to spring wheat and alternately fallowed and cropped to spring wheat. Consecutive 2‐year periods were used for the comparisons. The periods of study began with time of harvest.Water storage was similar for both systems from harvest to June 1 of the first year. Eighty‐four percent of the water stored during an entire fallow period had accumulated by July 1. Conservation of water over the second winter of fallow averaged only 0.02 inch. For the same period of time, the annually cropped soil conserved 1.67 inches. During an entire fallow period (about 21 months) only 4.36 inches of a possible 22.73 inches were stored. For the same period, an annually cropped soil stored 2.60 inches.Only 4 more inches of water was used by the annual cropping system in producing a wheat crop averaging 15 bushels per acre than was used during the same period by fallow where a crop had not been grown.
Numerical Method for Solving the Diffusion Equation: I. Horizontal Flow in Semi‐Infinite Media
Authors: Ashcroft Gaylen , Marsh Donald D. , Evans D. D. , Boersma Larry 
Published: July 2010

AbstractThe diffusion equation has been successfully used by several investigators to describe moisture movement in soil. Their success depends largely upon the Boltzmann transformation which can only be used for semi‐infinite, uniform regions.A numerical technique is developed for solving the implicit difference analogues of the diffusion equation. This method involves (1) devising suitable difference analogues for the differential equation, (2) developing a method for choosing diffusivity to convert the nonlinear difference analogues into linear equations, and (3) solving the system of linear equations.The numerical method can be applied to finite, nonuniform media. However, the study reported is limited to one‐dimensional, horizontal flow in a uniform, semi‐infinite medium so that the solutions obtained can be compared to solutions obtained by the Boltzmann transform technique. The results of the study indicate that the numerical methods and the Boltzmann transform techniques give very similar solutions and that solutions obtained by both methods are similar to experimental results.
Effect of Iron Removal and Dispersion Methods on Clay Mineral Identification by X‐Ray Diffraction
Authors: Harward M. E. , Theisen A. A. , Evans D. D. 
Published: July 2010

AbstractThe clay minerals identified in soil samples were found to be dependent on the pretreatment of samples for iron removal and dispersion. Treatments affected the characterization for chlorite, montmorillonite‐type minerals, vermiculite, and intergrade components. Increases in the degree of expansion upon solvation and in degree of collapse upon K‐saturation and heating were related to the severity of treatments used for dispersion. Iron removal treatments also increased the ease of expansion and collapse to 2:1 lattice clays. It was concluded that certain pretreatments tended to remove interlayered materials which were present in these samples.The degree to which clay mineral interpretation was affected by methods of pretreatment was not the same for all soils. Samples of the Astoria soil exhibited the greatest differences in diffraction patterns as a result of dispersion and Fe removal treatments while the Aiken was the least affected. The Willamette was found to be intermediate. The evidence suggested that the Astoria samples contained interlayer materials (intergrade components) which were poorly crystallized and thus more labile and subject to removal. On the other hand, the interlayer material in the Aiken seemed to be better crystallized and more toward the chlorite end of the spectrum.It has sometimes been assumed that the methods which permit the identification of the largest number of components with “clean‐sharp” peaks are the ones which should be used in sample preparation. It is suggested that the objective should be to obtain methods which permit the identification and reflect the properties of clay minerals as they existed in situ.
Comparing Measurements of the Effect of Residual Fertilizer Phosphorus in Some Iowa Soils
Authors: Smith Charles M. , Pesek John T. 
Published: July 2010

AbstractThe accuracy of the chemical soil test (0.03N NH4F in 0.025N HCl) for predicting biological response to residual fertilizer P was determined for several Iowa soils. Significant correlations were obtained with various measurements in the field and greenhouse, including grain, total dry matter, yield of P and radioactively determined A values.Soil test P was the most highly correlated with greenhouse A values and the relationship was essentially linear over the range of levels of residual P. One regression line described this relationship for all neutral and acid soils tested but was different from that for a calcareous (pH 8.0) soil. The soil test predicted the A values equally well regardless of whether the fertilizer P had been applied 1, 2, or 3 years previously.
Heats of Desorption of Ammonia and Simple Organic Materials from Bentonite
Authors: Ellis Boyd G. , Mortland M. M. 
Published: July 2010

AbstractThe differential thermal analysis apparatus was used as a means of determining the heats of desorption of NH3, methylamine, and ethylamine from bentonite clay. A method was developed using nitrogen gas to prevent oxidation of the sample during analysis. The average heat of desorption of NH3 and methylamine for the temperature range of 200° to 450°C. was found to be 35.3 and 40.9 kcal. per mole, respectively. In each case the desorption was accompanied by loss of equal moles of water. It is postulated that the water loss arises from decomposition of Al(OH)3. The average heat of desorption of ethylamine for the same temperature range was 157 kcal. per mole; however, the simultaneous loss of large quantities of water accounted for most of the heat change.
High Frequency Titrimetry of Soils and Clays: Methodology, Theory, and Nature of the Ba‐Mg Exchange Reaction
Authors: Simonson Clifford H. , Axley John H. 
Published: July 2010

AbstractA highly sensitive method for studying cation‐exchange phenomena was developed. A high frequency titrimeter, sensitive to about 0.0002 me., was used along with a continuous‐delivery buret of precision ±0.0003 ml. Soil or clay samples of 0.5 to 2.0 g. (much less can be used) were first saturated with Na, then converted to Ba‐saturation, and finally titrated in semiaqueous media with standard sulfate solution.The apparent dissociation of Ba from exchange sites is indicated by comparisons with titration curves for strongly dissociated (BaCl2) and weakly dissociated (Ba‐(OAc)2) salts. For many soils and clays, four general stages or regions of the curve can be differentiated. These appear to represent loose bonding, moderate bonding, moderately strong bonding, and very strong bonding. The bonding characteristics of exchangeable Ba are further illustrated by curves of a few selected soils and reference clays. These curves also demonstrate: (1) similarities in clay‐mineral behavior between specific soil samples and reference clays; (2) differences between reference clays in the same group; and (3) differences between arable soils and those developed in hydromorphic environments.
Extractable Aluminum in Some Hawaiian Soils
Authors: Plucknett D. L. , Sherman G. D. 
Published: July 2010

AbstractExtractable Al was measured in 5 Hawaiian soils from Kauai at four 3‐month intervals. A relationship between extractable Al and rainfall was observed. Highest extractable Al was measured during high rainfall periods (winter) and lowest extractable Al was measured during low rainfall periods (summer). High extractable Al was also observed in the poorly drained Koolau soil. Low extractable Al during summer months could be the result of inactivation of Al on cation‐exchange sites due to dehydration. The method used for extractable Al in this study probably measured both “exchangeable” and “soluble” Al. Plant Al analysis indicated not all extractable Al measured was available to the plant. In subsoils treated with lime, extractable Al decreased with increased pH. Lower extractable Al due to P treatment was interpreted as inactivation of Al as the latter reacted with the phosphate.
Inability of the Kjeldahl Method to Fully Measure Indigenous Fixed Ammonium in Some Soils
Authors: Stewart B. A. , Porter L. K. 
Published: July 2010

AbstractIn the course of some N fractionation studies in soils, inconsistencies resulted between the summation of the N fractions and the total soil N. In some, but not all, soils the summation figure exceeded by 25% the Kjeldahl figure. This inconsistency was especially noted in one soil that contained as much as 55% of the total N as indigenous fixed ammonium. A question was thus raised about the accuracy of the Kjeldahl procedure to measure indigenous, clay‐fixed ammonium.When soils were treated with HF before Kjeldahl analyses, the difference between the summation figures and the modified Kjeldahl results was < 5%. These results leave little doubt that on soils which contained from 11 to 55% of the total N as fixed ammonium the HF pretreatment increased the total N recovered.
The Fate of Applied Phosphorus in Four Ohio Soils
Authors: Volk Veril V. , McLean E. O. 
Published: July 2010

AbstractFour acid soils were selected on the basis of the level of available P and the magnitude of P fixing capacity (ability to retain soluble P against Bray P1 extracting solution). Water‐soluble P labeled with P32 was applied at the rate of 3.4, 29.2, and 106 pp2m. parts of soil with and without additions of lime. The availability of the soil P to oats in the greenhouse was computed by the methods of Fried and Dean (also Larsen and Sokolov) and of Murdock and Engelbert. Fractionation of the phosphate compounds formed in the soil was also made by the method of Chang and Jackson.Both the initial level of available P and the P fixing capacity were found to be important in determining the amount of plant response to applied P. A value indexes of available P generally increased with rate of application of P and lime. The application of soluble P to soils high in P fixing capacity decreased the availability (Bray P1 extractability) of the native P, while the added P tended to increase the availability of the native P in the low fixing soils. Almost all of the applied P was recovered in the Al and Fe phosphate components. There was a tendency for recovery of more than half of the applied P as FePO4 in the soils of high P fixing capacity and more than half as AlPO4 in those of low fixing capacity.
Residual Effects of Phosphorus Fertilizer in an Irrigated Rotation in the Southwest
Authors: Leamer Ross W. 
Published: July 2010

AbstractResponse to phosphorus fertilizer on a phosphorus‐deficient Reddish‐Brown soil was measured through 8 years. Yields, percent P in plant, and NaHCO3‐extractable soil P were followed through 2 cycles of alfalfa and 2 intervening crops of sorghum. Increased yields were obtained until P equal to the application was removed in harvested crops. Alfalfa yields were closely correlated with both percent P in hay and NaHCO3‐extractable soil P during the first 4 years. High yields were maintained in the second cycle of the rotation, but percent P in hay and NaHCO3‐extractable soil P were at levels associated with low yields during the first cycle. Sorghum following alfalfa was not affected by N fertilizer. Second‐year sorghum benefited from N only where there was ample P.
The Effect of Nitrogen Fertilization on the Concentration and Weight of Nitrogen, Phosphorus, and Potassium in Douglas‐Fir Trees
Authors: Heilman Paul E. , Gessel S. P. 
Published: July 2010

AbstractAnalyses were made of composite samples of needles, live branches, dead branches, bark and wood of 70 Douglas‐fir trees taken from five areas and ranging in age from 30 to 50 years. The fertilized trees were from plots that had been fertilized at rates of 200, 300, 500 and 660 pounds of elemental nitrogen per acre.The data show increased concentration of nitrogen and decreased concentration of phosphorus and potassium in the foliage, as a result of nitrogen fertilization. The nitrogen concentration of other components was also increased, but the concentration of phosphorus and potassium in these tissues did not demonstrate dilution effects that were observed in the needles. The nitrogen:phosphorus ratio in the foliage showed promise for use in diagnosis of nitrogen deficiency of Douglas‐fir by foliar analysis.The data on total weight of nutrients in the trees on an area basis show that almost twice as much nitrogen, greater quantities of potassium and approximately equal amounts of phosphorus were contained in the vegetation on certain fertilized plots as were contained in the unfertilized vegetation. Needles showed the greatest increase in nitrogen, with branches and bark showing lesser increases, and wood no increase.
Measurements of Capillary Conductivity for a Taiwan Latosol and Alluvial Soils
Authors: Shyr‐yaung Lin , Tsen‐tuo Chen 
Published: July 2010

AbstractThe capillary conductivities of natural cores and sieved samples of Taiwan latosol have been determined and compared with those of alluvial soils. Calculations were made from pressure plate outflow data at 0.06‐ to 0.10‐, 0.10‐ to 0.20‐, 0.20‐ to 0.33‐, and 0.33‐ to 0.50‐atm. ranges by the methods of Gardner, and of Miller‐Elrick which was extended for non‐negligible plate impedance. In the case of non‐negligible plate impedance, the Gardner method met limitation, and the Miller‐Elrich method was preferable. At low moisture tension, the capillary conductivity of the clayey latosol was similar to that of sandy soils. It seems that no generalization is yet possible about the influence of soil texture upon capillary conductivity.
Some Principles of Chelation Chemistry
Authors: Lehman D. S. 
Published: July 2010

AbstractThere are various factors which contribute to the stability of a metal chelate. The number of rings formed by one molecule of chelating agent with the metal ion, the size of the rings, and the nature of the donor atoms are of prime importance. Also to be considered are the effects of resonance stabilization and steric relationships. Thermodynamic data shows that a favorable increase in entropy often makes a significant contribution to the stability of a chelate. In addition the environment, for example, the pH, plays an important role in chelation reactions.
Miscible Displacement in Saturated and Unsaturated Sandstone
Authors: Corey John C. , Nielsen D. R. , Biggar J. W. 
Published: July 2010

AbstractA description of soil water movement is more complete if the nature of the pore structure is known. Miscible displacement techniques were used to investigate the nature of the pore structure of a sandstone. The mixing of a 75‐ml. slug of tritiated CaCl2 solution during displacement through 5 lengths of sandstone was measured. Different velocities and different degrees of water saturation were involved. Limited mixing by molecular diffusion for the various experimental conditions clearly revealed the lack of interconnection between major pore sequences. This pore structure differs markedly from that of soils or other unconsolidated porous materials.
Multilayer Adsorption of Water by Kaolinite
Authors: Jurinak J. J. 
Published: July 2010

AbstractThe Frenkel‐Halsey‐Hill isotherm equation for multilayer adsorption was applied to water adsorption by various monoionic kaolinites at 10.0°C. The FHH Equation described water adsorption over a wide P/P0 range in all systems. Li‐kaolinite showed no evidence of ion hydration or capillary condensation up to P/Po = 0.972 and was used to calculate free water adsorption in terms of statistical layers, n. The calculated multilayer adsorption isotherm for water was identical for Li‐, Ca‐, Ba‐, and Al‐kaolinites. The same isotherm also described water adsorption by Na‐kaolinites up to P/Po = 0.9 where ion hydration was initiated. A definite effect on the parameters of the FHH equation was found as the nature of the substrate surface was varied when water is used as the adsorbate.
Immobilization and Mineralization of Nitrogen in Several Organic Fractions of Soil
Authors: Stewart B. A. , Porter L. K. , Johnson D. D. 
Published: July 2010

AbstractStraw and N fertilizers were incubated in soil and changes in content of some organic N fractions were measured. Ammonia and nitrate N, as well as the N in several organic fractions, were determined to detect changes in the organic fractions which could be related to increases or decreases in the inorganic N.Most of the N immobilized during incubation with soil and straw was found in the nondistillable acid‐soluble N fraction of the hydrolysate. Although the nondistillable acid‐soluble N fraction constituted only about one‐half of the total organic N, studies using N15 showed that about about three times as much fertilizer N went into this fraction during immobilization as went into the distillable acid‐soluble and acid‐insoluble N fractions combined.
Oxygen‐18 as a Tracer in Soil Aeration Studies
Authors: Jensen C. R. , Kirkham Don 
Published: July 2010

AbstractThis paper describes a procedure for use of O18 in soil aeration tracer studies. Atmolysis, isotopic exchange, and respiratory fractionation produce only small errors when using O16O18 as a tracer for O2 diffusing in soil under steady state conditions. A special train for producing equal, continuous streams of O18‐enriched and unenriched air was developed. Analyses of experimental samples of oxygen were performed with a mass spectrometer. A split canopy experiment is described in which the effects of different surface conditions on the soil oxygen supply may be compared; in this case, the presence and absence of corn seedlings were compared. Results are expressed in terms of the mixing ratio of air from the two halves of the canopy. Improvements and possibilities of the method are discussed.
Effect of Exchangeable Potassium Level and Drying upon Availability of Potassium to Plants
Authors: Dowdy R. H. , Hutcheson T. B. 
Published: July 2010

AbstractSuccessive croppings of Sudangrass showed that K uptake by plants was greater from soil samples that released K upon drying than from comparable continuously moist samples. For soils originally low in exchangeable K, more K was released from continuously moist samples than from similar samples which had been air‐dried prior to cropping. This was considered a response to increased stress by the plants upon the K equilibrium, because of less readily available K in the continuously moist samples.Potassium uptake data, reductions in exchangeable K levels, and K‐release patterns strongly suggested that added K fixed by drying was available for plant use. Crop yields were the same for both moist and air‐dried soil samples at high levels of exchangeable K; but, yield data did reflect K released by drying samples initially low in exchangeable K.
Ammonium Influences on Rubidium Absorption and Distribution by Tobacco Seedlings
Authors: Skogley E. O. , McCants C. B. 
Published: July 2010

AbstractMechanisms whereby NH4 influences the accumulation of cations in tobacco were investigated using short‐term solution studies with Rb86. Measurements on the influence of seedling size and absence of tops on the accumulation of Rb in roots indicated that the size of the plant was positively correlated with Rb accumulation only to the extent of 0.7. During a 6‐hour period roots had the major influence on Rb accumulation, the absence of tops making little or no difference. During this absorption period it was found that NH4 had the same influence as K on the absorption of Rb, while after 24 to 48 hours NH4, relative to K, had an additional depressive influence on Rb accumulation, especially in the tops of seedlings. The possible involvement of NH4 influences on transpiration rate and associated passive ion transport was investigated. No NH4 influence on transpiration was found during periods extending to 70 hours. Salt treatments subsequent to Rb86 treatments indicated that the distribution of Rb was dependent more on conditions during its absorption than on those imposed later. Results from these and other studies are used to develop a mechanism for Rb absorption and distribution by tobacco seedlings which accounts for the observed influences of NH4 on Rb accumulation through an effect on absorption competition and metabolic ion transport.
Yield and Nutrient Composition of Tomatoes in Relation to Soil Temperature, Moisture, and Phosphorus Levels
Authors: Cannell Glen H. , Bingham F. T. , Lingle J. C. , Garber M. J. 
Published: July 2010

AbstractTomato plant growth was determined for 4 soil temperatures in combination with 2 soil moisture conditions and 3 phosphorus levels. There was a curvilinear relationship between yield and temperature. The highest yields were at 68°F., low soil suction, and high phosphorus. Yields increased with decreasing soil suction and with increasing phosphorus. Chemical leaf analysis, with exception of Mg, showed Ca, K, P, N, Cu, Fe, Mn, and Zn to vary significantly with temperature changes. Ca, Mg, K, N, Mn, and Zn were increased with decreasing soil moisture. Ca, Mg, K, P, N, and Mn tended to decrease with higher rates of phosphorus.
The Management of Soil Salinity in Lysimeters
Authors: Williamson R. E. 
Published: July 2010

AbstractSoil salinity quickly became a problem in sheltered lysimeters used for studies of the drainage requirements of crops in North Carolina. Water tables were maintained by subsurface watering at depths of 6 to 40 inches below the soil surface in 3‐foot‐square lysimeters, with some sheltered from rainfall and others exposed to rainfall. All were exposed alike to other atmospheric conditions. Very high levels of P, K, and Ca were established in the soil by mixing 0‐20‐0, muriate of potash, and lime with the soil placed into each tank.Soybean plants exhibited chlorosis and stunted growth in the lysimeters with subsurface watering only. These symptoms were serious approximately 1 month after the establishment of water tables only 6 inches beneath the surface, but were less pronounced with the deeper water tables. They were not observed where rain fell on the soil.At any water table depth, the plant growth and yield were best on the lysimeters that were leached with rainfall. Plant growth increased with depth to water table to a depth of 24 inches, both with and without rain on the soil.After soybean harvest in 1959, the electrical conductivity of the saturation extract from the soil in the top 6 inches of all lysimeters was 4 to 5 millimhos where subsurface watering only was used, and 0.4 millimho where rain fell on the soil.Lower fertilizer applications and leaching with small amounts of water kept the soil salinity in the upper 6‐inches at a low level in subsequent years. Crops of soybeans, cabbage, corn, grain sorghum, and string beans were produced successfully both in the lysimeters sheltered from rain and in those exposed to rain.