bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Black Granular Mulch on Soil Temperature, Water Content, and Crusting
Authors: Qashu Hasan K. , Evans D. D. 
Published: July 2010

AbstractThe use of black granular coke material as a mulch and its influence on soil temperature, evaporation, and soil crusting were studied under laboratory conditions and in the field. Higher soil temperatures were measured under mulch as compared to the control. Thermal regimes in a sand tank differed with treatment as to mulch strip width and geometry for dry sand. Evaporation suppression from wet sand was proportional to the relative area covered by mulch.Application of mulch on ridges in the field resulted in the following: (i) increase in daytime soil temperatures in the top 30 cm of soil, (ii) higher water content in the top 3 cm of soil under the mulch as compared to the control, and (iii) a friable soil crust under mulch as compared with a massive rigid crust in the control.
Inorganic Nitrogen Transformations through the Oxidation and Reduction of Sulfur Compounds
Authors: Chao Tyng Tsair 
Published: July 2010

AbstractInorganic nitrogen transformations result from the chemical oxidation and reduction of sulfur compounds. In the reduction of nitrate by NaHS, Na2S2O4 in both acidic and basic solutions, nitrite was not obtained suggesting that it may not be one of the major intermediate products in such reductions. Hydroxylamine was one of the intermediate products in the reduction of nitrite in acidic solution. Ammonia was not produced appreciably in the reduction of nitrate and nitrite. Due to the interference of hydroxylamine with Nessler reagent, ammonium ion formed in the reduction of hydroxylamine by sulfur compounds could not be measured quantitatively. However, a larger amount of ammonium‐N in the reduction of hydroxylamine by H2SO3 was observed. Nitrite, hydroxylammonium, and ammonium ions were never found in the solution in large quantities presumably due to (i) the formation of H2N2O2 which is unstable with respect to the formation of N2O (1,2), (ii) the interaction between nitrite and hydroxylammonium ions in the formation of N2O (1,3), and (iii) the oxidation of hydroxylamine or hydrazine by sulfur compounds to form N2O and N2.
Exchangeable Soil Potassium as Influenced by Seasonal Cropping and Potassium Added in Crop Residues
Authors: Grimes Donald W. , Hanway John J. 
Published: July 2010

AbstractDetailed sampling of soils and crops from three long‐term field experiments permitted evaluation of the seasonal depletion of exchangeable soil K and the influence of K added as crop residue. Exchangeable soil K was markedly reduced during the growing season by a growing crop. For corn (Zea mays L.), the regression of the decrease (spring to fall) in exchangeable K (pp2m) on the initial (spring) level of exchangeable K was characterized by a quadratic relationship, Ŷ = −23.5 + 0.62X − 0.00072X2 (r2 = 0.78**). Increases in the exchangeable K from fall to spring were directly related to K additions in crop residues. Within a single crop rotation, the exchangeable K increased as a result of K additions from corn residues and declined when meadow was grown. When maintained in a field moist condition before the determination of exchangeable K, reduced levels of exchangeable K resulting from cropping were not restored by release of non‐exchangeable K. When the exchangeable K was reduced to a very low level, however, nonexchangeable forms of K were released to the exchangeable form to maintain a “minimal” level of exchangeable K.
Diameter Growth of Loblolly Pine Related to Available Soil Moisture and Rate of Soil Moisture Loss
Authors: Moehring D. M. , Ralston C. W. 
Published: July 2010

AbstractIn six sawtimber stands in northeastern Louisiana, loblolly pine (Pinus taeda L.) diameter growth was related to the amount of and weekly rate of change in available soil moisture from June through August. Regardless of the amount of moisture available during the summer, growth was curtailed when soil moisture loss was rapid. Consequently, the soil moisture content at which tree growth ceased was highly variable.
In Situ Measurement of Soil Salinity with a Sensor
Authors: Oster J. D. , Ingvalson R. D. 
Published: July 2010

AbstractThe electrical conductivity (EC) of the soil solution was measured in situ in a soil‐plant system during three irrigation cycles. The salinity sensors used to make the measurements responded to changes in EC resulting from water uptake by the plant and salt movement in the soil profile by convection of salt in soil water. The accuracy of the measurements was estimated to be ± 0.5 mmho/cm throughout the irrigation cycles.
Relations Between Acidic Aluminum and Soil pH, Clay and Organic Matter
Authors: Pionke H. B. , Corey R. B. 
Published: July 2010

AbstractThe relationships of two measures of acidic Al contained in soil, namely KCl‐exchangeable Al and nonexchangeable acidic Al (pH 4.8N NH4OAc extractable Al minus KCl‐exchangeable Al) with soil pH, clay, and organic matter content were evaluated statistically. Exchangeable Al concentrations were observed to be primarily related to pH. The nonexchangeable acidic Al was found to be significantly correlated with pH, clay, and organic matter content at the 1% level. However, nonexchangeable acidic Al correlated best with the organic matter which would imply the existence of aluminum‐organic matter complexes in soil. A plot of nonexchangeable acidic Al with soil pH as determined in 1N KCl revealed an apparent maximum at a pH of approximately 4.1. These various interrelationships are combined into a proposed reaction scheme relating the various Al forms postulated to exist in soil.
Soil and Plant Silicon and Silicate Response by Sugar Cane
Authors: Fox R. L. , Silva J. A. , Younge O. R. , Plucknett D. L. , Sherman G. D. 
Published: July 2010

AbstractCalcium silicate slag increased sugar yields 12 tons/hectare in a field where phosphate extractable soil silicon and trichloroacetic acid (TCA) extractable silicon of sugar cane (Saccharum officinarum) leaf sheaths were about 20 ppm. Large amounts of P or lime did not alleviate leaf freckle whereas slag did so to a marked degree. Acid solutions of phosphate, sulfate, acetate, and water can be used successfully as extractants for soil silicon. The general order for extractable silicon from soils developed on basalt and alluvium was: Humic Ferruginous Latosol < Humic Latosol < Low Humic Latosol < Dark Magnesium clay. This is also the order of decreasing weathering for these soils as indicated by total soil silicon and occurrence of secondary minerals. Leaf sheath silicon (TCA extractable) was especially well correlated with log extractable soil silicon (r = 0.97 for water extraction). Irrigation waters may contain much silicon and contribute greatly to the supply of extractable soil silicon and to plant silicon.
The Lower Boundary of Selected Mollisols
Authors: Douglas C. L. , Fehrenbacher J. B. , Ray B. W. 
Published: July 2010

AbstractThicknesses of three Mollisols (Tama, Elburn, and Drummer series), developed from Wisconsinan‐age material in a toposequence in Central Illinois, were considerably greater (18 to 68 cm) when their lower boundaries were determined by the depth of rooting of native perennial big bluestem (Andropogon gerardi) than when determined by the lower limit of the solum. A combination of four criteria—structural development, significant clay accumulation, significant clay films, and the presence of completely unleached material—probably gave the best measure of solum thickness of these soils. However, evidence of some clay movement below the solums and the greater depth of rooting of native perennial grass, and also of such crops as corn (zea mays L.), suggests that material beneath the solum is important in the behavior, definition, and classification of many of these kinds of soils in the north‐central region of the U.S.
Phosphate Determination in Presence of Polyethylene Glycols
Authors: Segall E. , Mokady R. S. 
Published: July 2010

AbstractPolyethylene glycols, used in order to equilibrate aqueous solutions with unsaturated soils, interfere with colorimetric determinations of phosphate. The interference in the molybdovanadate method may be overcome by working in 25% 2‐butanone, and comparing with standards containing roughly the same concentration of the polymer as the samples.
Micromorphological Study of Soil Crusts
Authors: Evans D. D. , Buol S. W. 
Published: July 2010

AbstractSoil crusts were studied by preparing and examining thin sections taken normal to the soil surface. Several photomicrographs of the thin sections are presented which illustrate differences encountered among different soils and among different management practices of the same soil. Some crusts exhibited orientation of particles within the crust while others showed some orientation of the bulk soil mass in certain parts of the crust. A pronounced gradation of texture was evident in certain crusts. This work illustrates the visual evidence obtainable from the use of thin sections in soil crust studies.
Relationship of Total and Hot‐Water Soluble Boron, and Fixation of Added Boron, to Properties of Podzol Soils
Authors: Gupta Umesh C. 
Published: July 2010

AbstractTotal and hot‐water soluble B content of soils ranged from 45 to 124 and 0.38 to 4.67 ppm, respectively. The largest quantities of hot‐water soluble B were recorded in Acadia silty clay loam, Caribou silt loam, and Interval loam to silt loam soil series. Water‐soluble B was comparatively low in soils derived from Permo‐carboniferous rocks.In general the B content was lowest in coarse‐ and highest in fine‐textured soils. Percent of total B in the hot‐water soluble form varied from 0.44 to 4.69, with the highest percentage occurring in the fine‐textured soils and lowest in the coarse‐textured soils.Hot‐water soluble B content was higher in “well‐managed” soils than in “neglected” soils. The quantities of such B were positively correlated (significant at p = 0.01) with organic matter and with total B.Higher amounts of B were fixed by soils after incubation periods of 8 and 12 weeks than after 2 and 4 weeks. A higher percentage of B was fixed in the O'Leary sandy clay loam than in the Dunstaffnage sandy loam soil with all incubation periods. Varying the moisture content of soil from 50 to 100% of the field capacity did not affect the B fixed over a 12‐week period.
Supply of Ca, Sr, Mn, and Zn to Plant Roots Growing in Soil
Authors: Halstead E. H. , Barber S. A. , Warncke D. D. , Bole J. B. 
Published: July 2010

AbstractThe influence of four soils and two transpiration rates on the amounts of Ca, Sr, Mn, and Zn supplied to the root by root interception, mass‐flow and diffusion and on the uptake of these ions by four plant species was investigated in a growth chamber experiment. The relation between the calculated supply to the root by root‐interception plus mass‐flow and the uptake of Ca and Sr was different for each species but was not affected by soil or transpiration rate. The relation between supply of Mn and Zn and uptake was not affected by plant species. The relation of the uptake of Mn was highly correlated with supply by root interception plus mass‐flow over a very wide range of values. The correlation observed between Zn uptake and the supply by root interception plus mass‐flow was lower than for Ca, Sr, or Mn because considerable quantities of Zn also reached the root by diffusion.Three methods of calculating the quantity of root interception were evaluated by determining the relative degree of correlation between the calculated supply and uptake by the plant. The method which estimates the maximum possible root interception gave the highest correlation. The use of a parameter based on root area was very poorly correlated with uptake.
The Effect of Phosphorus Source on the Movement and Uptake of Band Applied Manganese
Authors: Hossner L. R. , Richards G. E. 
Published: July 2010

AbstractPlant uptake of band‐applied Mn from a Selma silt loam soil (pH 7.0) was enhanced by blending MnSO4·H2O with each of four P sources in growth chamber tests. The relative value of ammonium polyphosphate (APP), monoammonium phosphate (MAP), diammonium phosphate (DAP), and monocalcium phosphate (MCP) in increasing Mn uptake by soybeans (Glycine max ‘Hawkeye’) was MAP = APP≫MCP = DAP. There was a highly significant correlation between the plant concentration of Mn and P. Plant uptake of Mn was greatest when the pH of the P source was between 2 and 4. The amount of Mn which was absorbed per increment of P varied with the P source. In this experiment APP = MAP > MCP > DAP.Manganese movement and recovery (measured as exchangeable plus easily reducible) as influenced by P source decreased in the order: APP > MAP > MCP≫DAP. Manganese movement from phosphate mixtures was not detected when the soil pH was greater than 5.8.
Water and Salt Transfer in Soil Resulting from Thermal Gradients
Authors: Weeks L. V. , Richards S. J. , Letey J. 
Published: July 2010

AbstractRate equations developed from the theory of thermodynamics of irreversible processes were used to analyze water transfer induced by thermal gradients along a sealed cylindrical horizontal column of Pachappa soil. Functional relations to calculate values of coefficients in the flow equations were determined from experimental data which were obtained during steady‐state flow conditions. The relations were used to compute values of coefficients in order to calculate flow rates past selected positions along the column at various times during transient flow periods. Suction head (h) values were maintained in a range that could be measured with tensiometers which were located at three positions along the column. Liquid water transfer toward the warm end was assumed to be due to an induced suction head gradient. This transfer was confirmed by sectioning the column at the end of the experiment and measuring the concentrations of Na+ and Cl‐ and the EC of saturation extracts prepared from the sections.
Platinum Microelectrode Poisoning Factors
Authors: Rickman Ron W. , Letey J. , Aubertin G. M. , Stolzy L. H. 
Published: July 2010

AbstractThe oxide coating that occurs on platinum electrodes would be expected to influence oxygen diffusion rate (ODR) measurements on the basis of electro‐chemistry literature. However, no consistent influence of condition of electrode oxidation on ODR measurement in clay suspension was found by the authors. The current density on electrodes in clay suspensions was suspected of being below that density where the oxide would exhibit an influence on current.A deposit of salts, principally calcium bicarbonate, and clay particles, principally biotite, on electrodes left in place in a loamy sand reduced measured ODR's by an average of more than 50% after 2 months compared to ODR's from reinserted electrodes in the same soil. The deposits did not form to such an extent on electrodes in a clay and ODR measurements from in‐place electrodes remained comparable to those from reinserted ones throughout the 2‐month period.A nitric acid pretreatment procedure provided an electrode cleaning technique without any abrasion and brought electrodes to an oxidized condition after prolonged use or disuse.
Sand and Cotton Bur Mulches, Bermudagrass Sod, and Bare Soil Effects on: I. Evaporation Suppression
Authors: Wiegand C. L. , Heilman M. D. , Swanson W. A. 
Published: July 2010

AbstractMoisture, water table, and temperature changes were recorded for 3 years under four surface cover conditions used for salinity reclamation under the rainfall conditions (58 cm/yr during the study) in the Lower Rio Grande Valley of Texas. Surface cover conditions were (i) 1.5‐cm‐thick mortar sand mulch; (ii) 44,800 kg/ha cotton bur mulch (Gossypium hirsutum); (iii) coastal bermudagrass sod (Cynodon dactylon L.); and (iv) bare fallow.Relative profile moisture depletion among treatments and soil moisture suctions measured in the surface 50 cm of the soil show that even shallow soil depths remained moist during long, rainless periods under the sand and cotton bur mulches. The amount of water in the surface 61 cm of soil for 37 measurement dates averaged 1.32 cm more under the burs, 1.38 cm more under the sand much, and 2.85 cm less under the grass sod, respectively, than under the bare soil condition. Monthly means of daily maximum and minimum soil temperatures measured at the 10‐cm depth were both in the order sand mulch > bare soil > bur mulch > bermudagrass sod, but the higher soil temperatures under the sand mulch did not obviate its effectiveness in evaporation suppression. Since soil moisture suctions were low under the mulches, even moderate rainfall amounts rewet the soil to field capacity and should have effected leaching.
Effect of Plant Weathering of Soil Clays on Plant Availability of Native and Added Potassium and on Clay Mineral Structure
Authors: Conyers E. S. , McLean E. O. 
Published: July 2010

AbstractPlants were grown for 4 weeks in suspensions of Brookston and Clermont soil clays for the purpose of removing K. At weekly intervals, samples of the plant‐weathered clays were removed for determination of K uptake by soybean plants (Glycine max) and for X‐ray analysis. Labeled K was added and equilibrated with the clay samples. Specific activity of 42K adsorbed by cation‐exchange resin confined in cellulose tubing was lower than that added to the clay and decreased relatively more with time of weathering. This indicated that K was released from the clays diluting the 42K added, but that fixation of 42K (and 39K) added eventually became relatively greater than K released.Plant uptake of K during the weekly 1‐hour uptake periods was determined from 42K uptake and specific activity of 42K adsorbed by the resin at weekly intervals. Amounts of K uptake initially decreased with time or did so ultimately as more K was removed from the clays. X‐ray diffractograms revealed that plant weathering altered the basal spacings of the clays. Weathering effects noted were partial degradation of illite and apparent reduction in amount of kaolinite in both soil clays, and reduction in amount of vermiculite in the Clermont.
Plant Uptake and Residual Value of Six Tagged Nitrogen Fertilizers
Authors: Broadbent F. E. , Nakashima T. 
Published: July 2010

AbstractThree ammonium‐tagged fertilizers, two nitrate‐tagged fertilizers, and N‐tagged urea were added to three soils in green house pots. Plant uptake of surface‐applied fertilizer N was measured by growing four crops over a period of 314 days. In another experiment, tagged ammonium sulfate, ammonium nitrate, and aqueous ammonia, were compared using band application. With surface application, uptake of fertilizer N in plant tops varied from 35 to 71%, with nitrate sources showing the higher values. Residual N in soil ranged from 18 to 41%, and its availability decreased with successive crops. All ammonium sources suffered some loss with surface application, especially aqueous ammonia, but losses were negligible with band application.Availability of soil N was influenced to some extent by the nature of the fertilizer applied. From 5 to 13% of the soil N was utilized by four crops.
Molybdenum in Plant Tissues: Analysis by an X‐Ray Spectrographic Volume Dilution Technique
Authors: Theisen A. A. , Pinkerton A. 
Published: July 2010

AbstractA volume dilution method, previously shown to give good good results for the X‐ray spectrographic determination of Mn, Fe, and Zn in plant materials, is shown to be suitable for the analysis of Mo in ashed plant tissues. Agreement with chemical determination is good for 10 out of 11 plant tissue samples.
An Improved Membrane System for Oxygen Probes
Authors: Enoch H. , Falkenflug V. 
Published: July 2010

AbstractA probe, designed to measure partial oxygen pressure in a three‐phase system such as soil‐water‐air, is described. The probe is almost equally sensitive in the gaseous or liquid phase of the system. In place of the usual single membrane, the oxygen probe is fitted with two separated membranes and a spacer which form a gas‐filled diffusion chamber. The variable diffusion impedance of the environment is hereby reduced to insignificance by increasing the contact area between the environment and that part of the membrane through which the oxygen diffusion takes place. The probe can be used for continuous or discontinuous measurements.
Self‐Diffusion of Sodium Ions in Frozen Wyoming Bentonite‐Water Paste
Authors: Murrmann R. P. , Hoekstra P. , Bialkowski R. C. 
Published: July 2010

AbstractSelf‐diffusion of sodium ions in frozen Na‐Wyoming bentonite paste was studied at different subzero temperatures using a radioactive tracer technique. The value of the apparent self‐diffusion coefficient decreased rapidly from 8.8 × 10‐7 cm2 sec‐1 at −0.6C to 4.3 × 10‐7 cm2 sec‐1 at −3.0C but then decreased slowly to 1.7 × 10‐7 cm2 sec‐1 at −15.0C. Thus, the rate of ion diffusion in the frozen bentonite paste was relatively high even at low temperatures. The reduction in ion mobility with decreasing temperature was primarily a consequence of a concurrent decrease in film thickness of the unfrozen water.
Effects of Adding Charcoal During Dilute Acid Extraction of Manganese from Soils
Authors: Gilliam J. W. , Cox F. R. , Reid P. H. 
Published: July 2010

AbstractAddition of charcoal during extraction of soil with dilute HCl + H2SO4 increased the amounts of manganese and iron extracted but had little or no effect on the copper, zinc, and aluminum extracted concurrently. Experiments indicated that the increase in extractable manganese due to the presence of charcoal was not a consequence of an increase in efficiency of extraction of reduced manganese already present but resulted from a reaction in which forms of manganese of low solubility were reduced and made soluble and in which CO2 and CO were evolved. The amounts of manganese extracted from soils by dilute HCl + H2SO4 in the presence of charcoal and by dilute HCl + H2SO4 containing hydroquinone were highly correlated. The effect due to charcoal increased with the acidity of the extracting solution, the time of extraction, and the amount of charcoal added.