bluuebunny/crossref_metadata_2025_split huggingface dataset:
Predicted Distribution of Organic Chemicals in Solution and Adsorbed as a Function of Position and Time for Various Chemical and Soil Properties
Authors: Oddson J. K. , Letey J. , Weeks L. V. 
Published: July 2010

AbstractEquations were developed to describe the mass transfer of organic chemicals through soil and evaluated for various soil conditions. Movement due to diffusion was assumed to be negligible. The model assumed the relationship ∂S/∂t = α(Kc − S) where S is the adsorbed concentration [mass per total volume], c is solution concentration [mass per total volume], t is time, and K and α are constants. The model also considered the effect of applying various amounts of chemical to the soil surface and allowed for a prior adsorbed concentration in the soil ahead of the wetting front. The following are conclusions drawn for the case when the soil is initially free of organic chemical.K influences the depth of maximum concentration of organic in solution but does not affect the value of that concentration. The organic chemical will move in solution as a wave through the soil. The lower K the more spread out the wave will be. The depth of movement of maximum concentration is equal to the depth of water penetration divided by K.The concentration of material adsorbed on the soil also moves down as a wave. The position of maximum adsorbed concentration is about the same as for the maximum concentration in solution. Increasing K causes an increase in concentration of adsorbed material.Application of greater amounts of organic chemicals to the soil surface has the effect of increasing the concentration of organic both in solution and adsorbed but does not influence the depth of movement greatly except at initial time periods.Increasing the value of α has the effect of making the wave of chemical moving through the soil narrower and increasing the concentration of the organic in solution as it moves through the profile as compared to a lower value of α.
The Effect of Calcium and Its Relation to Several Cations in Soybean Root Growth
Authors: Lund Zane F. 
Published: July 2010

AbstractShort‐term, split‐root experiments were conducted in a growth chamber with ‘Lee’ soybeans (Glycine max). The upper portion of the root medium was a limed, fertilized sandy loam surface soil; the lower portion was a nutrient solution. Calcium concentration of 0.25 ppm was sufficient to obtain maximum growth rates in a nutrient solution at pH 5.6. More than 2.5 ppm of Ca was required at a solution pH of 4.5, and 5 ppm of Ca was insufficient when the pH was 4.0. High concentrations of Mg [ratios of Ca/(Ca + Mg) of 0.1 or less] also reduced growth. Replacing half of the Mg with K at low ratios of Ca/total cations produced more rapid elongation than the Ca + Mg systems, but had no effect at the higher ratios. Aluminum in the nutrient solution reduced root growth when the ratio of activities of Al to Ca was greater than 0.02.
Measurement of Water Potential and Osmotic Potential in Soil with a Combined Thermocouple Psychrometer and Salinity Sensor
Authors: Ingvalson R. D. , Oster J. D. , Rawlins S. L. , Hoffman G. J. 
Published: July 2010

AbstractA combined thermocouple psychrometer and salinity sensor, which is embedded in a single ceramic body, is described. This design makes possible the measurement of the water and osmotic potentials of soil water at the same location in the soil. Errors produced by spatial variations in soil solution concentration, shown to be large, were eliminated by the instrument's ability to make both measurements on a single sample of soil solution. The instrument was tested in a soil‐plant‐water system, and the data obtained are reported. Desaturation of the ceramic at matric potentials more negative than −2 bars was shown to have a significant effect on conductance of the salinity sensor. Correction for this effect is discussed. Measurements showed that cotton plants extracted more water from the less saline zones in the soil. This had the effect of lowering the water potential to approximately the same value at two depths in the soil profile at the end of a drying cycle.
Transformation of Dibasic Calcium Phosphate Dihydrate and Octacalcium Phosphate in Slightly Acid and Alkaline Soils
Authors: Bell L. C. , Black C. A. 
Published: July 2010

AbstractChemical, petrographic, and X‐ray diffraction methods were used to investigate the transformation of CaHPO4·2H2O and Ca8H2(PO4)6·5H2O incubated in slightly acid and alkaline soils for 4, 16, and 44 weeks at 25 and 35C. At 25C, hydrolysis of CaHPO4·2H2O to Ca8H2(PO4)6·5H2O was confirmed after 4 weeks in soils having a pH value higher than about 7.9, and at 44 weeks the new phase was found in soils with pH values higher than 6.9. Transformation of CaHPO4·2H2O to Ca8H2(PO4)6·5H2O increased with increasing pH, temperature, and time of incubation but decreased in the presence of much magnesium. There was no evidence of conversion of added Ca8H2(PO4)6·5H2O to more basic phosphates.
Phosphate Forms in Particle Size Separates of Irish Soils in Relation to Drainage and Parent Materials
Authors: Hanley P. K. , Murphy M. D. 
Published: July 2010

AbstractParticle‐size separates of sand, silt, and clay from 24 representative Irish soils were analyzed for total, inorganic, and organic P (Mehta & Legg), and for forms of inorganic P (Chang & Jackson). In general, all forms of P were highest in the clay fraction and lowest in the sand. The inorganic P of the clays and silts was mainly iron‐P whereas calcium‐P was the dominant form in the sand fraction.The influence of parent material on the P content of the separates was examined, and it was found that soils of limestone origin had a higher content of calcium‐P in their separates than did those from the shale‐derived soils. The sands of the shale soils contained more total P than the same fraction in the limestone soils.Drainage also affected the distribution of P. In general, the clays and silts from the well‐drained soils were higher in total P, but total and organic P and the proportion of organic P to total P was higher in the sands of the poorly‐drained soils than in the sands of the well‐drained soils.A significant negative correlation (−0.61) was obtained between the percent clay in the soil and the total P content of its clay fraction.
Diffusion of Iron in Montmorillonite as Determined by X‐ray Emission
Authors: Ellis J. H. , Phillips R. E. , Barnhisel R. I. 
Published: July 2010

AbstractThe experimental distribution of Fe2+ and Fe3+ diffusing in thin, water‐saturated montmorillonite clay films (43.5% H2O on oven dry basis) were obtained using a miniature‐probe attachment for an x‐ray emission spectrometer; the montmorillonite clay was initially Ca‐saturated. The ionic concentrations were measured in either 0.5‐ or 1.0‐mm intervals from the origin of the diffusing salt giving detailed, experimental distributions of the diffusing ions. The method is sensitive to slight changes of iron concentration resulting in precise determination of experimental distributions. The method should work equally well for diffusion studies involving other ions with atomic numbers greater than Na.The diffusion coefficient of Fe3+ increased from 1.6 × 10‐7 cm2sec‐1 at a concentration of 0.1 meq Fe3+ per g clay to 4.35 × 10‐7 cm2sec‐1 at a concentration of 1.6 meq Fe3+ per g clay. Diffusion coefficients of Fe2+ were measured at concentrations up to 0.6 meq per g clay. These values were two to five times larger than for Fe3+.
Lime Requirements of Natal Oxisols Based on Exchangeable Aluminum
Authors: Reeve N. G. , Sumner M. E. 
Published: July 2010

AbstractThe exchangeable Al status of eight Natal Oxisols was found to be a suitable criterion for the measurement of lime requirement defined as the amount of lime necessary for maximum crop production. The principal function of lime in these soils was to eliminate Al toxicity; it had little or no effect on P availability. A “critical value” for exchangeable Al below which trudan (Sorghum sudanense) did not respond to lime application was found. On the average the amount of lime necessary for maximum growth and exchangeable Al control was approximately one‐sixth the amount required to raise the soil pH to 6.5.
Effect of Added Phosphate on the Inorganic Phosphorus Fractions of Soils Derived from Volcanic Ash
Authors: Appelt H. , Schalscha E. B. 
Published: July 2010

AbstractChanges in native and applied phosphate in volcanic‐ashderived soils of southern Chile were investigated. NH4Cl‐, NH4F‐, NaOH‐, and H2SO4‐extractable P were determined both before and after addition and incubation of these soils with 0, 90, 180, and 270 ppm of P. An anion exchange resin method for extracting P from the soil was also used to study relative P availability.Initially most of the added P was recovered in the NH4F‐extractable fraction. In the course of time a shift to the NaOH‐extractable fraction occurred. The H2SO4‐extractable fraction did not change with rate of P application or time of equilibration. The anion exchange resin was able initially to extract large amounts of the added P, but the quantities extracted diminished markedly with increased time of incubation. The changes that occurred followed a pattern peculiar to each soil.
Soil Organic Matter Content and Composition as Related to Ley Clipping Management and Fertilization
Authors: Tan K. H. , Edwards J. H. , Beaty E. R. , McCreery R. A. 
Published: July 2010

AbstractSoil organic matter content' and composition, with particular attention to C/Porg and C/N relationship, were investigated under clipping and fertility treatments applied to Pensacola bahiagrass (Paspalum notatum, Flugge) grown on a Eustis loamy sand.The results indicated that soil organic matter accumulation was influenced by the interaction of nitrogen fertilization and clipping management. Nitrogen fertilization alone had some effect, whereas clipping only had no influence on the organic C content of the surface soil. The C/N ratio decreased with depth in the profile with weekly clipping, but remained relatively constant from the surface to 30–40 cm depth with monthly clipping intervals.The C/Porg ratio in the surface soil increased with increasing N‐fertilization as well as by monthly and 6‐weeks clippings. The effect of interaction of N‐fertilization and clipping frequency on the C/Porg ratio was greater than the influence of clipping frequency or N‐fertilization alone. The C/Porg ratio of the subsoil was unaffected by either.
Some Folists on Whiteface Mountain, New York
Authors: Witty J. E. , Arnold R. W. 
Published: July 2010

AbstractRelatively shallow, nonsaturated organic soils on Whiteface Mountain in New York have been characterized and classified. These Folists consist of strongly acid O1 and O2 horizons of litter accumulations in varying stages of decomposition overlying bedrock or carpeting fragmental materials at depths commonly ranging from 10 to 75 cm. These soils occur mainly above 760‐m elevation and are relatively pure units on narrow ridge crests and on steep mountain slopes. On less steep slopes these Folists are intimately associated with Spodosols. The main families observed are: dysic Typic Borofolists; dysic, micro‐Typic Borofolists; dysic Lithic Borofolists; dysic, shallow Lithic Borofolists; and dysic, micro Lithic Borofolists. Borofolists are cold Folists with mean annual soil temperature < 8C; the Lithic subgroups have a lithic contact within 1 m of the surface; and the Typic subgroups are underlain by fragmental materials. The shallow family indicates a lithic contact between 18 and 50 cm, whereas the micro family has a solum less than 18 cm thick. All families observed are dysic having a pH < 4.5 measured in neutral salt solution.
Use of Sample Data and Seventh Approximation Criteria in Delineating Areas of Similar Soils
Authors: Mausel P. W. , Runge E. C. A. , Carmer S. G. 
Published: July 2010

AbstractSoil series data, from the Soil and Water Conservation Needs Inventory 2% sample for a nine county study area in east‐central Illinois, were transformed into Seventh Approximation nomenclature at the order, suborder, great group, and subgroup categories. The dominant and second most dominant classes of soil within each sample area, with an indication of the degree of dominance, were plotted on outline maps. Stream locations were placed on the maps before soil boundaries were drawn. Soil regions were delineated by placing boundaries midway between sample areas of a different classification.Analysis of the maps indicates that the resulting subgroup map shows characteristics of soil distribution generally comparable to currently used county soil association maps. The development of this method is not intended to replace traditional methods of map construction in pedologically advanced areas. However, it may be a useful method for constructing accurate soil maps at various selected levels of generalization in areas of the world where soil distribution patterns are unknown or incompletely understood.
Accuracy in the Identification of Subgroups Delineated by a Sample‐Based Soil Association Map
Authors: Mausel P. W. , Runge E. C. A. , Carmer S. G. 
Published: July 2010

AbstractA procedure to develop Seventh Approximation primary and secondary subgroup soil maps was applied to sample data for Christian county, Ill. A measure of accuracy of the resulting subgroup soil association map was determined by comparison with the modern detailed Christian county soil survey. The two most dominant subgroups of soils in two‐thirds of the county were identified correctly using a sample‐based soil association map. One of the two most dominant subgroups of soils was identified correctly in most of the remainder of the county. The virtual absence of areas where the two dominant subgroups of soils were incorrectly identified is further evidence that the Seventh Approximation maps based on sample data can be used in those areas of the world needing modern soil information.
A Prediction Equation for Vegetation Effects on Water Yield from Watersheds in Arid Areas
Authors: Grover B. L. , Campbell C. B. , Campbell M. D. 
Published: July 2010

AbstractA water yield prediction equation based on plant type, water use profiles, and historic precipitation records is presented. The equation can be set at any desired probability value. Yields predicted for sites occupied by deep‐rooted brush species average 14 cm less per year than those for sites occupied by a grass‐forb complex. This pattern holds for central Utah watersheds higher than 2,330 m above mean sea level in 4 out of 5 years.
Annual Variation in Foliage of Fertilized and/or Irrigated Red Pine Plantations
Authors: Leaf Albert L. , Berglund John V. , Leonard Raymond E. 
Published: July 2010

AbstractNear‐terminal, current‐year autumnal foliage from 160 trees in 2 by 2 m spaced, 40‐year‐old red pine plantations (Pinus resinosa Ait.) growing on sandy outwash soil was sampled for 6 consecutive years and analyzed for length and dry weight, and concentrations and contents of ash, N, P, K, Ca, and Mg. The sample trees are from the dominant canopy on a 0.8‐ha area of known K deficiency, subdivided into four paired treatment plots of 40 sample trees per treatment: control, irrigation, fertilization, and combination treatments. The paper describes spatial and temporal variation and treatment response in foliage characteristics. The results indicate that the bases of expression of nutrient elements and climatic conditions affect the nutrient status diagnosis for long‐term management considerations.
Influence of Manganese and pH on Chemical Composition, Bronzing of Leaves, and Yield of Carrots Grown on Acid Sphagnum Peat Soil
Authors: Gupta Umesh C. , Chipman E. W. , MacKay D. C. 
Published: July 2010

AbstractGreenhouse experiments were conducted on the direct effects and interactions of pH and Mn on the growth and the Mn and Fe contents of carrots (Daucus Carota L., sativa D.C.) grown on an acid sphagnum peat soil. The highest content of Mn in carrot tops occurred at pH values of 4.4 to 5.0 and the lowest at pH 6.2 and 6.4. However, the Mn content was lower at pH values of 4.0 and 4.1 than at pH 4.4 to 5.0. There was a significant interaction of pH and Mn on the Mn content of tissues. At low pH, high rates of applied Mn increased the Mn content of tissue several times more than it did at high pH. Bronzecolored symptoms on carrot leaves appeared when the Mn content of tops was more than 2,600 ppm. Such symptoms were associated with lower yields of carrots, when Mn content of tops ranged from about 7,100 to 9,600 ppm. This reduction in yield was also related with low pH. The Mn content of roots varied from 133 to 236 ppm. The Fe content of tops was lower at pH 4.1 than at higher pH values.
Magnesium Fertilization of Potatoes as Related to Liming and Potassium
Authors: Hossner L. R. , Doll E. C. 
Published: July 2010

AbstractThe effects of lime and soil K levels on yield and levels of Ca, Mg, and K in petioles of potatoes (Solanum tuberosum, var. Sebago) fertilized with Mg were determined in field experiments on Karlin loamy sand. Yield response to Mg fertilizer was related to both level of exchangeable soil Mg and to soil Mg/K ratio. Above 0.3 meq/100 g of soil Mg, yields were not affected by either level of soil Mg or Mg/K ratio, and below 0.3 meq Mg, yields decreased markedly when the soil Mg/K ratio fell below 0.8 (equivalent basis). Yields were increased by liming when soil pH was 5.0, but these differences were not statistically significant. Soil test levels after cropping indicated that considerable amounts of Ca, K, and Mg probably leached below the plow layer.Yields decreased when Mg in petioles was less than 0.15% after 6 weeks. Increasing the level of K in petioles decreased the level of Mg. In Mg‐deficient plants, Mg in petioles decreased as the season progressed, while Mg increased in nondeficient plants.
Effects of Stemflow Water on a Miami Soil Under a Beech Tree: I. Morphological and Physical Properties
Authors: Gersper P. L. , Holowaychuk N. 
Published: July 2010

AbstractThe effects of the stemflow portion of the biohydrologic soil forming factor on the morphological and physical properties of a Miami soil under a beech tree were determined. Effects were assessed by comparing properties of soil profiles located at different distances from the tree stem. Differences were tested by analysis of variance and Duncan's Multiple Range Test.The most obvious effects of stemflow water on morphological properties of this soil was to have caused a thickening of the A2 horizon, considerable low‐chroma mottling in the B horizon, and an increase in the number of subdivisions of the B horizon. Effects of stemflow water on physical properties of this soil were just as pronounced. Bulk density of the A1 horizon was lowered considerably. Clay content of the A horizon was increased while the content of the B2 horizon was decreased. Correspondingly, the silt content of the A horizon was decreased while the content of the B2 horizon was increased.
Pyrophosphate Hydrolysis of Ammonium, Calcium, and Calcium Ammonium Pyrophosphates in Selected Texas Soils
Authors: Hossner L. R. , Melton J. R. 
Published: July 2010

AbstractFive soils of varying chemical and mineralogical composition were treated with several pyrophosphates, and the rate of pyrophosphate hydrolysis determined. Pyrophosphate hydrolysis was a function of the pyrophosphate compound, soil type, and CaCO3 treatment.Except for Ca2P2O7, hydrolysis rate could not be predicted by the relative solubility of the pyrophosphate compound. For example, in the three acid soils, hydrolysis rates were: CaH2P2O7 = Ca3(NH4)2(P2O7)2 · 6H2O = (NH4)3HP2O7 · H2O >> Ca2P2O7. However, for the two basic soils, hydrolysis rates were: CaH2P2O7 > Ca3(NH4)2(P2O7)2 · 6H2O > (NH4)3 HP2O7 · H2O > > Ca2P2O7. Pyrophosphates were hydrolyzed more rapidly in acid soils than in basic soils.Application of 2% CaCO3 reduced hydrolysis rates of the acid soils. The same application of CaCO3 to the basic soils either slightly increased or had little effect on the hydrolysis rates.
The Solubility of Mixed Magnesium‐Aluminum Hydroxide in Various Aqueous Solutions
Authors: Hunsaker V. E. , Pratt P. F. 
Published: July 2010

AbstractThe object of this study was to investigate the release of Mg to water and various aqueous solutions by synthetic crystalline Mg‐Al hydroxide and the same material freshly precipitated on hydroxy Al‐montmorillonite. Washing in centrifuge tubes and leaching columns was used to determine the amount of Mg released by 50‐mg samples of the synthetic mineral in water, in solutions of NaCl, and in solutions of NH4NO3 and NH4OAc at pH 6.0 and 9.0. Mixed Mg‐Al hydroxide, precipitated on hydroxy Al‐coated montmorillonite, was also leached with similar solutions. NH4OAc buffered at pH 6.0 released nearly 25% of the Mg present in crystalline mixed hydroxide, while NH4NO3 at pH 5.7 and NaCl at pH 6.3 released 11.5% and 4.2$, respectively. The dissociation of the mixed Mg‐Al hydroxide, either well crystallized or freshly precipitated, is strongly dependent on the pH of the solution and, therefore, the weakly acidic NH4 solutions were very effective in releasing Mg. The mineral is partially soluble in water and only slightly more soluble in NaCl.
Lime Response as Related to Percent Al Saturation, Solution Al, and Organic Matter Content
Authors: Evans Clyde E. , Kamprath E. J. 
Published: July 2010

AbstractConcentration of soil solution Al in mineral soils was related to the percent Al saturation of the effective CEC. In organic soils, however, the concentration of Al in the soil solution was more related to the amount of exchangeable Al than to percent Al saturation. Soils with increasing organic matter content had a lower content of soil solution Al at a given pH.Liming increased the growth of corn on mineral soils when the Al saturation was greater than 70%. On all soils except one, corn responded to liming when the concentration of soil solution Al was greater than 0.40 meq/liter. Soybeans responded to liming on mineral soils when the Al saturation was greater than 30%. On all soils soybeans responded to liming when the concentration of soil solution Al was greater than 0.20 meq/liter.
Release of Nitrogen by Burning Light Forest Fuels
Authors: DeBell D. S. , Ralston C. W. 
Published: July 2010

AbstractSmokes produced by burning pine litter, green needles, and fuels of lower nitrogen content were drawn through dilute acid solutions which were then nesslerized in the presence and absence of titanous sulfate. Kjeldahl analyses of fuels and residues indicated that 62% of the nitrogen contained in pine litter and leaf materials was released by burning. No ammonia was detected in combustion gases. Only minor amounts (0.3% and less) of the nitrogen released by burning were detected by nesslerization (+TiSO4) of dilute acid solutions. We concluded that only small amounts (0.30 − 0.48 kg/ha‐1 for typical loblolly stands) of nitrogen released by forest fires could be returned to the soil via precipitation and be made available for tree growth. Most nitrogen in organic matter presumably is volatilized as nitrogen gas.
Two Dimensional Heat Transfer in Porous Media with Steady‐State Water Flow
Authors: Erh K. T. , Nielsen D. R. , Biggar J. W. 
Published: July 2010

AbstractTheoretical and experimental temperature distributions were examined for laboratory columns of Hanford sandy loam, Panoche clay loam, and Aiken clay saturated with water flowing at a constant rate. The temperature of the water entering the columns was kept below or above the ambient temperature for several values of soil water velocity. Temperature distributions were predicted as a function of flow velocity, radial size, apparent thermal conductivity, and the wall heat transfer coefficient of the cylindrical container for the soil. Values of the apparent axial and radial thermal conductivity depend upon the flow velocity at values less than 0.3 cm min‐1 with only one exception. The value of the axial thermal conductivity was 1.1 greater than that of the radial thermal conductivity for all soils and flow velocities. Increasing the soil column radius had the same effect on the temperature distribution as increasing the water velocity.