bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of Rainfall Energy on Soil Loss and Infiltration Rates: I. Effect over a Range of Texture
Authors: Moldenhauer W. C. , Long D. C. 
Published: July 2010

AbstractSoil and water losses were determined from sieved air‐dry samples of five Iowa soils varying in texture using a laboratory rain simulator with a 3‐m. drop fall, a 4.85 to 5.00 mm. drop diameter, and an intensity ranging from 3.43 to 6.78 cm. per hour. The soil samples were contained in a pan 15.2 cm. deep, 30.5 cm. wide and 45.7 cm. long and tilted to a 9% slope. Runs were 90 minutes in length. The infiltration rate was the most important factor influencing total soil loss. Relative total soil losses for 90 minutes of run at high intensity were silty clay > silty clay loam > silt > loam > fine sand. At the low intensity, the positions of silty clay and silty clay loam and of silt and loam were reversed. Total soil loss varied with intensity, but infiltration was essentially constant over the entire range except on the fine sand. With equal water loss the order of erodibility was find sand > silty clay > silty clay loam > silt > loam. Total kinetic energy required to initiate runoff was constant over a range of time and intensity.
Measurement of Sediment Density by Attenuation of Transmitted Gamma Rays
Authors: McHenry J. Roger , Dendy Farris E. 
Published: July 2010

AbstractThe measurement of density by observing the attenuation of transmitted gamma rays was adapted to the measurement of sediment density. A dual probe, utilizing transmission techniques, was evaluated for use in measuring the density of sediments collected from runoff of plots or small watersheds. The equipment consists of a 7‐mc. cesium137 source placed in one access tube and a probe containing a NaI scintillation crystal, photomultiplier tube, and preamplifier in the second tube. The high‐voltage power supply and scaler ratemeter for readout are supplied in a portable unit powered by silver‐cadmium recharge‐able dry cells. Cesium137 gamma radiation is measured by employing electronic discrimination to eliminate all phostons of energies below about 0.65 Mev. Sediment densities were measured in silt boxes installed on a small watershed at the North Mississippi Branch Experiment Station, Holly Springs, Mississippi, following laboratory calibration tests. The dual probe employed measured densities of sediments to within 0.01 absolute density units. The vertical resolution of the apparatus is less than I inch so that density measurements of thin layers and of materials at interfaces can be made. In one field test sediment weights, of the order of 8,500 pounds, computed for a silt box on the basis of dual probe density determinations varied less than 1% from a gravimetric determination. Changes in sediment density with time, with additional increments of sediment, and with storms were effectively measured.
Precipitation of Phosphate by Iron Oxide and Aluminum Hydroxide from Solutions Containing Calcium and Potassium
Authors: Taylor A. W. , Gurney E. L. 
Published: July 2010

AbstractWhen acidic calcium phosphate solutions such as those formed by the dissolution of fertilizers react with aluminum hydroxide in the presence of little potassium, all the potassium is precipitated as taranakite, K3Al5H6(PO4)8·18H2O; most of the rest of the phosphate is precipitated as aluminum and calcium aluminum phosphates. In the presence of considerable potassium, the precipitation of phosphate is governed by the initial composition of the solution; as much as 25% of the phosphate is precipitated as dicalcium phosphate and most of the rest is precipitated as taranakite. Iron oxide reacts much more slowly with phosphate than aluminum hydroxide and has much less effect on the precipitation of phosphate.
The Effect of Periodate Oxidation on the Strength of Soil Crumbs: I. Qualitative Studies
Authors: Clapp C. E. , Emerson W. W. 
Published: July 2010

AbstractVarious methods of extraction and oxidation of soil organic matter were used in combination with a sodium saturation technique to assess the binding strength of wet soil crumbs. The procedure consisted of equilibrating a few 3‐ to 5‐mm crumbs with 0.05m NaCl, treating the crumbs with chemical reagents to remove the effective stabilizing components, and then observing the degree of slaking and dispersion of the crumbs when the sodium ion concentration is reduced. For crumbs from predominantly montmorillonitic or illitic soils, the dispersion solution was either 0.01m NaCl buffered with p‐nitrophenol at pH 7 or 0.025m Na2B4O7 at pH 10. For kaolinitic soils a more severe dispersion technique was required.The stability of crumbs formed under long‐term grass was reduced greatly by oxidation of the organic matter with 0.05m NaIO4 followed by extraction with Na2B4O7. Complete dispersion in Na2B4O7 or NaCl/Na p‐nitrophenol was obtained when a preliminary extraction with neutral Na4P2O7 was followed by periodate oxidation. The stability of corresponding cultivated crumbs was destroyed completely without pyrophosphate extraction in a shorter period of oxidation. Surface crumbs from wooded sites on the same soils showed extreme resistance to all treatment combinations. It appears that there are two types of polymeric organic material binding the grassland crumbs together, one extractable by pyrophosphate and the other oxidizable by periodate.Samples from Houston Black clay behaved anomalously until the CaCO3 was removed by dilute HCl treatment in the cold. The latter process in itself caused no loss in strength of the crumbs.
The Effect of Periodate Oxidation on the Strength of Soil Crumbs: II. Quantitative Studies
Authors: Clapp C. E. , Emerson W. W. 
Published: July 2010

AbstractThe rate of consumption of sodium periodate by Fargo clay loam surface grassland crumbs was measured at different periodate concentrations, and the degree of subsequent slaking and dispersion of the crumbs in 0.01m NaCl/Na p‐nitrophenol was observed. Prior leaching of the crumbs with 0.05m NaCl was essential before crumb stability was reduced appreciably 0.250 mmoles of periodate per gram of soil.Release of the effective inorganic and organic binding agents by NaCl, Na4P2O7, and NaIO4 treatments was studied quantitatively. The effect of periodate oxidation alone was demonstrated when no measurable release of organic matter occurred with preliminary leaching by 0.05m NaCl. The amount of periodate consumed by the grassland crumbs was more than could be accounted for by primary oxidation of the carbohydrate present.The loss in strength for the grassland crumbs, after systematic removal of the binding agents, was measured quantitatively by means of a plummer balance. The effect of prior leaching with 1m NaCl followed by 0.05m NaCl also was investigated. After the combined treatments, dispersion was still incomplete for the Fargo crumbs, indicating some residual bonding. The dispersion of Houston Black clay crumbs was complete, however, when 0.1m Na4P2O7 was substituted for 1m NaCl. The organic material released by either NaCl or Na4P2O7 stabilized the claysized fraction of the soil only. The periodate‐oxidizable substances stabilized both the silt‐ and clay‐sized fractions.
Aluminum in Soils: VII. Interrelationships of Organic Matter, Liming, and Extractable Aluminum with “Permanent Charge” (KCl) and pH‐Dependent Cation‐Exchange Capacity of Surface Soils
Authors: McLean E. O. , Reicosky D. C. , Lakshmanan C. 
Published: July 2010

AbstractSeven Ohio surface soils which had been incubated with little or no lime and with sufficient quantities to nearly neutralize them were analyzed for “permanent charge” or KCl‐ and pH‐dependent cation‐exchange capacity (CEC). The low‐ and high‐lime soils were also analyzed for both of these components of CEC after organic matter was destroyed with hydrogen peroxide. CEC was also determined by extraction with 1n NH4OAc‐pH 7.Changes in both the KCl‐CEC and pH‐dependent CEC caused by liming and by destruction of organic matter appeared to be the result of activation or inactivation of exchange sites of the organic matter initially occupied by Al. Only in the case of one soil (Venango, A2 horizon) did hydroxy‐Al appear to be equal to organic matter in effect on pH‐dependent CEC.
Gradient Elution of Soil Phosphorus
Authors: Avnimelech Y. , Hagin J. 
Published: July 2010

AbstractSoil phosphorus was fractionated by the means of gradient elution technique used in chromatography. This method involves a nonequilibrium extraction of the soil P, whereas conventional methods are based on equilibrium extraction. Non‐equilibrium extraction is needed in order to describe the fate of the applied P before it reaches equilibrium with the entire soil system.Soil samples were leached with a solution of linearily increasing acidity. Thus soil P was fractionated according to its solubility in acid. Upon leaching a soil sample, fertilized with superphosphate, two steps in P fixation could be demonstrated. The first step was a rapid one, decreasing the water solubility of the P, yet keeping it soluble in mildly acidic solutions. In the second slower step, P solubility in acidic solutions was decreased.
Decomposition and Binding Action of Polysaccharides from Azotobacter Indicus (Beijerinckia) and Other Bacteria in Soil
Authors: Martin J. P. , Ervin J. O. , Shepherd R. A. 
Published: July 2010

AbstractThe decomposition rate and binding effect in soil of a polysaccharide synthesized by A. indicus (Beijerinckia) were compared with those of other bacterial polysaccharides, including one from Chromobacterium violaceum and with other type organic materials. In acid and neutral soils an average of 19% of the A. indicus polysaccharide decomposed in 8 weeks. This compared with averages of 38%, 39%, 51%, 67%, and 84% decomposition for almond shells, C. violaceum polysaccharide, corn stalks, Azotobacter chroococcum polysaccharide, and glucose, respectively. Of these and additional organic materials tested, only peat moss was more resistant to decomposition than the A. indicus polysaccharide. All the bacterial polysaccharides were highly effective in binding soil particles into water stable aggregates. After 30 days of incubation A. indicus polysaccharide reduced numbers or had little effect on bacteria and fungi developing on soil dilution plates. Growth of fungi from soil dilutions on media containing no carbohydrate was as good or better than on the same medium containing poly‐saccharide from A. indicus or C. violaceum. Polysaccharides from A. indicus, C. violaceum, and B. subtilis reduced germination and/or growth of soil bacteria on agar media.
The Carbonyl Group in a Soil Organic Matter Preparation
Authors: Schnitzer M. , Skinner S. I. M. 
Published: July 2010

AbstractThe 2,4‐dinitrophenylhydrazone, phenylhydrazone, semicarbazone, and oxime of organic matter extracted from a Podzol Bh horizon were prepared. The four derivatives were analyzed by ultimate analysis, infrared, ultraviolet, and visible spectroscopy, and by X‐ray diffraction analysis.The formation of derivatives was checked by increases in nitrogen content over that in the original organic matter. In the case of the 2,4‐dinitrophenylhydrazone a spectrophotometric method, specific for the derivative, was also used. The number of ketonic C=O groups per mole of original organic matter as determined by analysis of the 2,4‐dinitrophenylhydrazone was 2.1, of the phenylhydrazone 2.5, of the semicarbazone 2.0, and of the oxime 2.2. The presence of C=N bonds, symptomatic of derivative formation, was indicated in the infrared spectra. Evidence for the formation of the derivatives was also provided in some of the ultraviolet spectra and in one visible spectrum. X‐ray diffraction analysis of the original organic matter and of the derivatives indicated that these materials were amorphous.On the basis of reductive acetylation, followed by infrared analysis of the product, and from reductometric titrations it was concluded that this organic matter did not contain measurable amounts of quinone groups and that the groups that had reacted with the reagents were ketonic carbonyl groups.
Nitrogen Carriers: I. Soil Effects
Authors: Wolcott A. R. , Foth H. D. , Davis J. F. , Shickluna J. C. 
Published: July 2010

AbstractReplicated field plots on moderately acid sandy loam soils were sampled after 3 to 7 years' annually repeated applications of eight nitrogen sources at rates of 40 to 300 lb N/acre. Soil pH, exchangeable K, Ca and Mg, and lime requirement to pH 6.5 were measured. Acidifying effects to a depth of 15 inches were of the order: (NH4)2SO4 > NH4Cl > NH4NO3 ≊ NH3 ≊ urea > ureaform. Residual basicity from Ca(NO3)2 and NaNO3 was approximately equal to the acidifying potential of climate and management.Observed declines in exchangeable bases were ⅓ to ½ the calculated equivalent acidity of acidifying carriers; increases in lime requirement were 1.5 to 6 times greater than calculated. Major increases in lime requirement occurred below the pH range 5.0 to 5.5 and were ascribed to retention of protons in the form of ionic complexes with Al and Fe. Uniquely greater residual acidity from (NH4)2SO4 may have been due to greater exchange affinity and base displacement by hydroxy‐Al‐SO4 complexes as compared with complexes with monovalent anions (Cl‐, NO3‐).It is proposed that a fundamental objective of liming practice is to maintain soil pH well above the range where pathways of proton transfer are dominated by mobile sesquioxide buffer systems.
Effect of Temperature on the Occurrence of Phosphorus‐Induced Zinc Deficiency
Authors: Martin W. E. , McLean J. G. , Quick James 
Published: July 2010

AbstractGreenhouse studies with tomato plants as indicators have been carried out to study the influence of temperature upon occurrence of phosphorus‐induced zinc deficiency. The soils used were from areas in commercial potato fields where “fern leaf” and chlorosis due to Zn deficiency has been observed. The soils were found to be concurrently deficient in both P and Zn. Field soil treatments with Zn caused a marked improvement in growth.The effects of several rates of P, with and without Zn, upon tomato plant growth have been studied at 50, 60, 70 and 80F. Results on soil with moderately low (0.9 ppm) dithizone extractable Zn show P to induce Zn deficiency symptoms at 50 and 60F but not at 70 and 80F, although some growth differences attributable to Zn occurred at the higher temperatures. On soil from an acutely Zn deficient area (0.1 ppm Zn), P‐induced Zn deficiency was observed at all temperatures.Phosphorus applications were observed to reduce Zn concentration in the tissue while Zn applications tended to reduce P concentration. Stunted plants showing acute Zn deficiency symptoms had about the same Zn and P concentrations on the dry weight basis as did normal appearing plants grown at higher soil temperatures with the same P treatments.
Radial‐Flow Cell—Further Tests
Authors: Miklich F. J. , Richards L. A. 
Published: July 2010

AbstractAdditional information has been obtained on the use of the radial‐flow cell for measuring capillary conductivity and soil‐water diffusivity. The equations used for describing unsaturated flow and the assumptions made in applying the equations to the transient outflow that occurs from the radial cell were described in a previous paper along with procedures for handling samples. Experience with both the linear‐outflow method and the radial‐outflow method indicates that the mathematical expressions developed to date do not accurately describe the transient outflow process. The reasons for the discrepancies are not fully understood.
Change of Phosphate Potentials of Calcareous Soils on Adding Phosphorus
Authors: Withee L. V. , Ellis Roscoe 
Published: July 2010

AbstractIn two calcareous soils studied the phosphate potentials (0.5 pCa + pH2PO4) and lime potentials (pH − 0.5 pCa) indicated that the forms of mineral phosphates that determine the amount of phosphorus in solution were basic calcium phosphates similar in solubility to octocalcium phosphate, Ca4H(PO4)3·3H2O. Phosphorus as H3PO4 added to the soils at the rate of 200 ppm P saturated them with respect to octocalcium phosphate, and 500 ppm P saturated them with respect to dicalcium phosphate. Wetting and drying the soils for 5, 10, or 20 cycles after adding phosphorus increased the phosphate potentials. No tendency for calcium phosphates to convert to hydroxyapatite was observed after 20 wetting and drying cycles. Repeated extraction of soil samples—some in their original condition and some to which phosphorus was added—with 0.01m CaCl2 solution increased their phosphate potentials. The dominant form of calcium phosphate in the soil to which phosphorus had been added changed with extraction from dicalcium phosphate to a form or mixture of forms intermediate between dicalcium and octocalcium phosphate.
Nitric Oxide Adsorption by Clay Minerals
Authors: Mortland M. M. 
Published: July 2010

AbstractNitric oxide was found to be chemically adsorbed on mont‐morillonite and nontronite when the exchange complex was saturated with certain transition metal ions. Infrared data showed a number of reactions depending on the nature of the saturating ion including: (i) coordination of NO as the mono or dinitrosyl complex; (ii) formation of N2O; (iii) formation of (NO)+. The NO molecule was able to penetrate the interlamellar regions of Co‐montmorillonite or Co‐nontronite. On all other systems, apparently only surface adsorption occurred. When air was admitted, all surface‐adsorbed NO was immediately oxidized, but interlamellar NO decreased at a rate apparently dependent upon the diffusion of NO to the clay mineral surface. A produce of oxidation was found to be coordinated nitrite.
Gibbsite, Bayerite, and Nordstrandite Formation as Affected by Anions, pH, and Mineral Surfaces
Authors: Barnhisel R. I. , Rich C. I. 
Published: July 2010

AbstractX‐ray diffraction, differential thermal, and chemical analysis indicate that the pH, presence of anions or salt, and mineral surfaces have important roles in the formation of crystalline Al(OH)3 polymorphs from Al‐interlayers and/or hydroxy‐Al polymers.Hydroxy‐Al was introduced into kaolinite, quartz, and montmorillonite systems by slowly adding appropriate amounts of AlC3 and NaOH (or OH‐resin) into rapidly stirred suspensions. Systems having various OH/Al molar ratios were prepared, and they were aged 0, 1, 3, and 6 months.The pH or OH/Al molar ratio had the greatest influence on controlling the relative amounts of gibbsite and bayerite that crystallized in the various systems. Gibbsite crystallized better in acid environments, nordstrandite in slightly acid to neutral, and bayerite in basic environments. Nordstrandite also crystallized under acid conditions in systems having relatively low amounts of Na+ and Cl‐ ions.Mineral surfaces and/or interlayer water structures, in addition to anions or salt, control the degree of crystallinity of the various Al(OH)3 polymorphs.
Importance of Carbon Dioxide in Uptake of Calcium by Plants Receiving Only a Nitrate Source of Nitrogen
Authors: Bartlett R. J. 
Published: July 2010

AbstractCalcium deficiency was induced in maize seedlings (Zea mays L.) growing with roots in contact with limestone gravel or CaCO3 in suspension. This was done by supplying N in the nitrate form and by extreme aeration to prevent CO2 accumulation. The probable cause of the deficiency was the tendency of nitrate nutrition to maintain the pH of the alkaline medium, preventing solubilization of CaCO3.When CO2 was allowed to build up in the suspension or limestone gravel culture, pH was lowered during growth, Ca became more soluble and deficiency of Ca in plants receiving nitrate nitrogen was corrected.Substitution of ammonium for nitrate in CaCO3 suspension similarly corrected Ca deficiency. This resulted as ammonium uptake lowered pH and solubilized Ca.Though unappreciated in this role because of their universal presence in the soil, both CO2 and ammonium N may be important in increasing the availability of Ca.
Assessing Wind Erosion Forces: Directions and Relative Magnitudes
Authors: Skidmore E. L. 
Published: July 2010

AbstractWind erosion force vectors were computed from data of frequency of occurrence of directions by windspeed groups based on wind erosion being proportional to windspeed cubed times the duration of the wind. The vectors were obtained by evaluating Σ Ū13 f1 for each of the 16 principal directions where Ū13 is the cubed mean windspeed within the ith speed group and f1 is percentage of total observations that occur in the speed group and direction under consideration.The wind erosion force vectors were used to compute monthly magnitudes of the total wind erosion forces and direction where the ratio of the wind erosion forces parallel and perpendicular to that direction is a maximum. The computed direction indicates proper orientation of a wind barrier for maximum barrier protection. The magnitude of the ratio gives the preponderance of wind erosion forces in the direction of maximum wind erosion forces. The magnitude of the total wind erosion forces indicates the potential need for protection against the erosion forces.
A Wind Erosion Equation
Authors: Woodruff N. P. , Siddoway F. H. 
Published: July 2010

AbstractThe amount of erosion, E, expressed in tons per acre per annum, that will occur from a given agricultural field can be expressed in terms of equivalent variables as: E = f(I′, K′, C′, L′, V) where I′ is a soil erodibility index, K′ is a soil ridge rougness factor, C′ is a climatic factor, L′ is field length along the prevailing wind erosion direction, and V is equivalent quantity of vegetative cover. The 5 equivalent variables are obtained by grouping some and converting others of the 11 primary variables now known to govern wind erodibility. Relations among variables are extremely complex. Charts and tables have been developed to permit graphical solutions of the equation. The equation is designed to serve the twofold purpose of providing a tool to (i) determine the potential erosion from a particular field, and (ii) determine what field conditions of soil cloddiness, roughness, vegetative cover, sheltering by barriers, or width and orientation of field are necessary to reduce potential erosion to a tolerable amount. Examples of these applications of the equation are presented. Weaknesses in the equation and areas needing further research are discussed.
Zonal Salinization of the Root System in Relation to Plant Growth
Authors: Lunin J. , Gallatin M. H. 
Published: July 2010

AbstractCorn and tomatoes were grown in the greenhouses in boxes containing three horizontal soil zones with a layer of coarse quartz sand to separate the zones. Either fresh or saline waters were supplied to each soil zone through porous ceramic tubes to maintain a fairly uniform water suction in each zone. Introduction of saline water into a given zone caused the uptake of water by the plant from that zone to decrease as soil salinity increased to a critical value, at which point water uptake ceased. The amount of water taken up by the plant from the nonsaline zones increased so that the total amount of water taken up by the plants was slightly less where one‐third of the soil was salinized as compared with the nonsalinized treatment. Water uptake further decreased where two‐thirds of the root system was salinized. Plant growth was unaffected when one–third of the root system was salinized, and yields were only slightly decreased when two‐thirds of the root system was salinized. Excessive salinization of the surface soil did not affect water uptake. Water uptake by tomatoes was more affected by zonal salinization than was corn.