bluuebunny/crossref_metadata_2025_split huggingface dataset:
Water Movement and Freezing Pressures
Authors: Hoekstra Pieter 
Published: July 2010

AbstractPressures develop when cylindrical columns of saturated soils are frozen unidirectionally under conditions of constant volume with an open water supply at the warm side. The value and behavior of these pressures depend on soil type.If water migration can take place in the frozen soil and ice lenses grow behind the freezing front the value of the pressure depends on the temperature at the ice lens. This process occurs in clayey soils, and the pressure is theoretically limited by the phase transition ice 1 — water. Values of 100 atm have been measured experimentally.In soils where water migration in the frozen soil does not occur and ice lenses form at the freezing front, the pressure reaches a constant value, which may vary between 0.2 atm for a sand soil and 3 atm for a silt soil.Thermodynamic models proposed to explain these phenomena are discussed.
The Stability of Different Forms of Selenium Applied to Low‐Selenium Soils
Authors: Cary Earle E. , Allaway W. H. 
Published: July 2010

AbstractIn some acid‐to‐neutral soils, water‐soluble selenite salts react rapidly with the solid phase to form a relatively insoluble adsorption complex. The Se in this complex is less available to alfalfa (Medicago sativa L. ‘Dupuit’) than the Se added to the same soil as Fe(OH)3‐HSeO3. In other soils, or in some acid soils limed to neutrality, the availability of Se to alfalfa from NaHSeO3 and from Fe(OH)3‐HSeO3 is essentially the same. The availability of Se from Seo added to the same soils is less than from either NaHSeO3 or Fe(OH)3‐HSeO3 sources. Oxidation of Seo is initially rapid in these soils, and does not seem to be pH dependent, but the rate of oxidation varies in different soils. Soluble selenite may be the most practical form of Se to add to low‐Se soils in order to produce crops containing sufficient Se to meet animal requirements.
Poorly Drained Soils with Permafrost in Interior Alaska
Authors: Allan R. J. , Brown Jerry , Rieger Samuel 
Published: July 2010

AbstractPhysical, chemical, and mineralogical properties are presented for five soils with permafrost in interior Alaska. The soils are shallowly thawed, with permafrost usually at 60 cm or less, and with a thick accumulation of organic matter, usually about 25 cm deep, over a gleyed mineral soil. They are classified as Histic Pergelic Cryaquepts in the comprehensive soil classification system adopted by the US Department of Agriculture. Histic Pergelic Cryaquepts are the most extensive soils developed over permafrost in Alaska. In three of the five profiles, particle‐size analyses reveal a slight increase (2–4%) in clay content of the thawed mineral soil over that of the permafrost. The coarsest horizon in all five profiles contains only 48% sand. The dominant texture is silt loam. In one of the profiles, base saturation increases (52–90%) with depth in the thawed mineral soil, then remains fairly constant in the permafrost. Percent Zr (0.02%) remains constant in the coarse silt fraction of all horizons of all five profiles both above and in the permafrost. The dominant clay minerals in the thawed horizons were vermiculite and kaolinite.
Growth and Foliar Nutrition of White Pine Seedlings as Influenced by Simultaneous Changes in Moisture and Nutrient Supply
Authors: Schomaker Charles E. 
Published: July 2010

AbstractA greenhouse study was used to investigate the effects of varying moisture supply and nutrient solution concentration concurrently on the growth and foliar nutrient concentration of white pine (Pinus strobus L.) seedlings. Seedlings were treated with four nutrient solution concentrations over four different periods of time between irrigations in all possible combinations. Mean seedling weight decreased with reduced nutrient solution concentration and with increasing time between irrigations. The interaction between nutrient solution concentration and irrigation schedule was highly significant in regard to effect on seedling weight.Mean N, K, and P concentrations in the needles showed significant increases with an increase in moisture stress. Irrigation treatment had no significant effect on foliar Ca or Mg concentrations. Of the micronutrients only B and Mn were affected by irrigation treatments. In general foliar concentrations of the macronutrients were negatively correlated with the micro‐nutrients.
The Utilization of Applied Zinc as Affected by pH and Pyrophosphate Content of Ammonium Phosphates
Authors: Hossner L. R. , Blanchar R. W. 
Published: July 2010

AbstractLaboratory preparations of pure ammonium ortho‐ and pyrophosphates were blended to give mixtures containing 0, 20, 40, 60, 80, and 100% of the total P as pyrophosphate at pH values of 3.6, 4.0, 5.0, 6.0, 7.0, and 8.0. Each ammonium phosphate mixture was blended with ZnSO4 · H2O to yield a product containing 2 or 8% Zn, formed into a pellet, and reacted with soil solution. Residues were recovered and analyzed for chemical and mineralogical composition.The quantity and species of Zn precipitating in the residues were markedly influenced by the pyrophosphate content and pH of ammonium phosphate mixtures. At pH 3.6 and 4.0, the quantity of Zn in the residue was increased with increasing pyrophosphate content. At pH 5.0 all of the Zn precipitated when the P was 100% orthophosphate but as the pyrophosphate level was increased to 60% more Zn moved out of the pellet. The Zn content of the residues decreased as pH increased (6.0, 7.0, and 8.0) and was lowest when the mixture contained 40, 60, and 80% pyrophosphate, respectively.Two zinc ammonium orthophosphates, ZnNH4H3(PO4)2 · H2O and ZnNH4PO4, were identified in the residues. Zinc ammonium pyrophosphates identified were Zn(NH4)2H4(P2O7)2 · 2H2O, Zn3(NH4)2(P2O7)2 · 2H2O, and Zn(NH4)2P2O7 · H2O.Ammonium phosphate mixtures with pH values of 3.6, 6.0, and 8.0 containing 2% Zn as 65ZnSO4 · H2O were spot‐placed in pots and evaluated in growth chamber experiments. Plant uptake of Zn was proportional to the quantity of Zn which moved from the placement site.
Hydrolysis and Sorption of Ortho‐, Pryo‐, Tripoly‐, and Trimetaphosphate in 32 Midwestern Soils
Authors: Blanchar R. W. , Hossner L. R. 
Published: July 2010

AbstractHydrolysis and sorption reactions of orthophosphate (OP), pyrophosphate (PP), tripolyphosphate (TPP), and trimetaphosphate (TMP) were studied in 32 Corn Belt soils. TMP hydrolyzed to TPP in 1 day in all but two soils. TPP hydrolyzed to PP and OP within 7 days in 30 of 32 soils, and 15 to 80% of the PP formed in the soil remained after 14 days. The sodium salts of OP and PP were compared as P sources for corn and found to be equal. It was concluded that under our conditions (25C), the rate of TMP, TPP, and PP hydrolysis was rapid enough so it would not limit the availability of P to plants.TMP added to soil remained water soluble. The sorption of TPP and PP by soil was more than OP.
Soil‐Water Hysteresis Measured in a Sandy Loam and Compared with the Hysteretic Domain Model
Authors: Topp G. C. 
Published: July 2010

AbstractA uniformly packed column of sandy loam soil was subjected to a controlled series of wetting and drying changes. Soil water contents were obtained from gamma ray attenuation information while simultaneous tensiometer pressures at five locations along the column were measured by a pressure transducer. In addition, the flows of the water solution to and from the column were read in burettes. The data from the tensiometers demonstrated a high degree of uniformity throughout the soil. Analysis of the primary scanning curves of the water content versus pressure head showed that the independent domain theory of hysteresis is an inadequate model for both wetting and drying curves. A refinement to the theory could not be tested with these data. Following consolidation during the initial drying phase there was no measurable hysteresis in the water content‐hydraulic conductivity relationship.
Resolving Time, Mass Absorption Coefficient and Water Content with Gamma‐Ray Attenuation
Authors: Fritton D. D. 
Published: July 2010

AbstractA method is described that was used to experimentally determine an intensity correction for gamma‐ray attenuation. The correction is determined by using the minute nonlinearity of a semi‐log plot of gamma‐ray intensity versus the thickness or the product of thickness and density of a material. The experimentally determined correction is expressed in terms of resolving time and varied with both material and counting rate. A correction of 5.0 µsec/count was determined experimentally as the best resolving time to correct the observed counting rates for water content determination. Part of the 5.0 µsec/count correction was evidently due to causes other than resolving time. Mass absorption coefficients of water and soil were 0.08105 and 0.07309 cm2/g, respectively, with no correction and were 0.0871 and 0.0773 cm2/g with a 5.0 µsec/count correction. The difference between gravimetric water content and gamma‐ray water content dropped from 3.02% to 0.60% when this correction was used.
An Organic Carbon‐Organic Matter Conversion Equation for Pennsylvania Surface Soils
Authors: Ranney R. W. 
Published: July 2010

AbstractLow temperature ashing was used to determine the organic matter content of soils by weight loss. This technique utilizes oxygen excited by radiofrequency energy to effect oxidation at relatively low temperatures. Ashing at 375C was used for samples high in organic matter. Corrections were applied for weight loss of inorganic constituents and for incomplete oxidation of organic matter. The following regression equation was developed to convert organic carbon percent to organic matter percent in Pennsylvania surface soils:Percent organic matter = 0.35 + 1.80 × percent organic carbon.
Effect of Picloram, Diuron, Ametryne, and Prometryne on Nitrification in Some Tropical Soils
Authors: Dubey H. D. 
Published: July 2010

AbstractEffect of 4‐amino‐3,5,6‐trichloropicolinic acid (picloram), 3‐(3,4‐dichlorophenyl)‐1,1‐dimethylurea (diuron), 2‐ethylamino‐4‐isopropylamino‐6‐methylthio‐s‐triazine (ametryne), and 2,4‐bis(isopropylamino)‐6‐methylthio‐s‐triazine (prometryne) at rates from 2 to 100 ppm on nitrification of 100 ppm applied NH4‐N was studied in several soils of Puerto Rico incubated at 24C for 8 weeks.The effect was greatly dependent on the nitrifying capacity of the soils. Inhibition of nitrification by herbicides was less in soils of high nitrifying capacity than in soils of low nitrifying capacity. Picloram at 2 ppm caused a weak inhibition and at 20 to 100 ppm complete inhibition except in the soil of high nitrifying capacity. Diuron inhibited nitrification at 20 ppm and above in soils of low to intermediate nitrifying capacity. It did not affect nitrification in the soil of high nitrifying capacity even at 100 ppm. Ametryne and prometryne at 100 ppm inhibited Nitrobacter bacteria, but not NH4‐ oxidizers resulting in high NO2‐ accumulation. At certain times 60 to 100% of the applied NH4‐H appeared as NO2‐ when prometryne and ametryne were applied at 100 ppm, respectively. Nitrite accumulated, however, only at soil pH of 6.8 and above.
Leaf Composition and Yield Response of Corn in Relation to Quantity‐Intensity Parameters for Potassium
Authors: Koch J. T. , Orchard E. R. , Sumner M. E. 
Published: July 2010

AbstractData obtained by the quantity‐intensity (Q/I) technique were tested against field experimental results to assess the value of the Q/I approach for characterising the potassium (K) status of soils. Q/I data describe K status by relating the energy level or intensity (I) of K in the labile pool to the amount (Q) present.It was shown that in a leached ferrallitic soil (Oxisol), the pool of labile K is a good index of the amount available to corn (Zea mays L.). It is superior as a criterion to both the equilibrium activity ratio and exchangeable K.Potassium content of the leaf is related to the pool of labile K free to participate in the mechanisms by which K is supplied to roots. Critical values for K in the labile pool at the beginning of the growing season are proposed, below which K deficiency is likely to reduce corn yield.
Calcium Deficiency and Ammonia Toxicity as Separate Causal Factors of (NH4)2HPO4‐Injury to Seedlings
Authors: Bennett A. C. , Adams Fred 
Published: July 2010

AbstractShort term experiments were conducted in a growth chamber with seedlings of sudangrass (Sorghum sudanensis) and cotton (Gossypium hirsutum L.) on a Lucedale sandy loam surface soil treated with different rates of MgO, CaO, (NH4)2HPO4, K2HPO4, and Ca(H2PO4)2. Sudangrass seed was planted in treated soils and the seedlings were allowed to grow for 14 days, during which time they were observed for symptoms of Ca deficiency or NH3 toxicity. Cotton seed was planted in a layer of untreated soil that was underlain by treated soil in glass‐front boxes for direct observation of root growth. The depth to which each primary root of cotton extended into the treated soil was measured periodically for 3 days after the root entered the treated soil. Results were related to ionic composition of soil solutions in situ. Calcium deficiency symptoms and reduced growth occurred on all soils with aCa/Σacation i ratios in soil solutions of 0.15 or less. Ammonia toxicity symptoms on foliage were caused by only one treatment although toxic concentrations of NH3(aq) were present in three other soil solutions. These solutions were also deficient in Ca. When conditions conducive to Ca deficiency and NH3 toxicity existed in the same soil solution, Ca deficiency symptoms dominated except at the highest NH3(aq) concentration.
Graphic Presentation of a Mathematical Solution for Interacting Diffuse Layers
Authors: Kemper W. D. , Quirk J. P. 
Published: July 2010

AbstractThe scaled electrical potential, Y = zεψ/kT, is presented as a function of the effective surface charge density, the external solution concentration, valence of the cation and distance between clay platelets for symmetric electrolytes. Swelling pressures and ion concentrations near the platelets may be calculated from these values of Y using some of the simple equations published by other authors and reproduced herein.
Elution of Potassium in Soil
Authors: Avnimelech Y. , Shaham Vera , Feder Adina 
Published: July 2010

AbstractDisplacement of potassium in soil by a solution of calcium sulphate is considered. The basic assumptions are the existence of a state of microscopic equilibrium and neglecting dispersion. A model is developed and computed.The computed curves reveal the existence of two potassium peaks moving during the first stages of the leaching, one peak in the solution front and the main peak behind it. The first peak disappears at advanced stages of the migration. The experimental curves showed the main peak at the predicted locations, and indicated the existence of the first peak, which was flatter than the computed ones.The relative velocity of the displaced ion (Rf) is discussed and computed. This value can be easily obtained for different soils and solutions and is an important parameter for a number of practical problems. The computed and experimental values for the relative velocity of the eluted potassium were in good agreement.
Comparison of Some Methods for Determination of Total Sulfur in Soils
Authors: Tabatabai M. A. , Bremner J. M. 
Published: July 2010

AbstractA comparison of five methods of determining total sulfur in soils showed that the acid oxidation method of Arkley and the alkaline oxidation method of Tabatabai and Bremner gave almost identical results and were more precise than other methods studied. The results obtained by use of X‐ray fluorescence spectrography for determination of total sulfur in soils were, on average, slightly higher than those obtained by the Arkley or Tabatabai‐Bremner method, and they indicated that this technique can be used satisfactorily for routine sulfur analysis of mineral soils. Attempts to adapt the Leco Sulfur Analyzer for rapid and precise determination of total sulfur in soils were unsuccessful, but they suggested that this automated instrument might prove useful for sulfur analysis in some types of soil investigations. The data obtained indicate that several methods proposed for total sulfur analysis of soils give satisfactory results.
Degradation of Gamma‐BHC in Rice Soils
Authors: Yoshida T. , Castro T. F. 
Published: July 2010

AbstractThe biodegradation of the organochlorine insecticide, γ‐BHC (γ‐isomer of 1,2,3,4,5,6‐hexachlorocyclohexane) was evaluated for four Philippine rice soils: Casiguran sandy loam, Luisiana clay, Maahas clay and Pila clay loam. Rapid degradation of the insecticide was observed under flooded soil conditions. The rate of degradation for γ‐BHC was highest in Casiguran sandy loam; none of the parent insecticide remained in the soil after 1 month of incubation at 30C. Organic matter levels were related directly to rate of decomposition. Molecular oxygen, nitrate, and manganic oxide retarded the rate of γ‐BHC degradation. Increased temperature increased the rate of γ‐BHC degradation, and it appears that γ‐BHC residues are unlikely to be a problem in the tropical rice‐growing areas.
The Plant Availability of Potassium in Fly Ash
Authors: Martens D. C. , Schnappinger M. G. , Zelazny L. W. 
Published: July 2010

AbstractThe availability of K in fly ash obtained from nine coal burning power generating plants was evaluated by greenhouse and laboratory procedures. The total K content of the samples of fly ash ranged from 0.65 to 3.14%. Eight of the samples were bituminous coal ashes, and one was lignite coal ash. The samples of bituminous coal fly ash neutralized less than 0.25 meq H3O+/g, whereas the sample of lignite coal fly ash neutralized 3.05 meq H3O+/g. Application of three samples of the bituminous coal fly ash and the sample of lignite coal fly ash increased K uptake by corn plants (Zea mays L.) grown on Davidson clay loam. Potassium uptake was higher from application of 158 mg K as KCl to 2,100 g of the soil than from application of a higher rate of K as the four samples of fly ash. Equivalent K uptake by corn plants occurred from application of 79 mg K as KCl and 207 mg K as the lignite fly ash. However, yield was lower where the ash was applied. Tissue analyses indicated that B toxicity limited yield on the latter treatment. Application of certain of the fly ash samples increased Mg uptake by corn plants. This increase in Mg uptake probably caused a decrease in K uptake by plants grown in the fly ash‐soil mixtures.
Comparison of Iron and Aluminum Hydroxy Interlayers in Montmorillonite and Vermiculite: II. Dissolution
Authors: Carstea D. D. , Harward M. E. , Knox E. G. 
Published: July 2010

AbstractThe stabilities of hydroxy‐Al and ‐Fe interlayers in montmorillonite and vermiculite were evaluated by subjecting the systems to HCl treatment and to sequential treatments which included boiling 2% Na2CO3, buffered sodium citrate‐dithionite, a second citrate‐dithionite treatment, and boiling NaOH.The stability of hydroxy interlayers was dependent on kind of mineral matrix, whether the interlayer was Fe or Al, and the conditions of acidity under which they were initially formed. Hydroxy‐Al interlayers formed under acid conditions were more stable than those formed under alkaline conditions in both montmorillonite and vermiculite systems. Iron interlayers formed under neutral and alkaline conditions in montmorillonite and vermiculite were more stable than those formed in acid media. The hydroxy‐Al and ‐Fe interlayers in montmorillonite exhibited a higher stability than their counterparts in vermiculite.A residual 14A line after K‐saturation and heating to 550C was observed in some samples which received the dithionitecitrate and NaOH treatments. This occurred to a greater extent in vermiculite and particularly with Fe‐hydroxy systems. The data suggested a resolution of a mixed system into collapsible and noncollapsible components.In montmorillonite, the hydroxyl‐Al interlayer, formed in alkaline conditions, showed the highest stability to the HCl treatment, whereas that formed in acid medium was the least stable. In vermiculite, the stability of hydroxy‐Al interlayer to the HCl treatment decreased from acid to alkaline media.Iron interlayers in montmorillonite formed in all media exhibited high stabilities to the HCl treatments. In vermiculite, the HCl treatments removed more interlayers from acid media than from alkaline media.Some of the dissolution treatments tested in this study are often used as pretreatments for removal of coatings and cementing agents prior to separation or analysis of clay fractions. These reagents will remove hydroxy interlayers and result in changes of properties of clays from soils and sediments. This must be recognized for proper interpretation of data for clay mineral identification and characterization.
Soil Temperature and Water Content Changes During Drying as Influenced by Cracks: A Laboratory Experiment
Authors: Selim H. M. , Kirkham Don 
Published: July 2010

AbstractA container consisting of three identical compartments each 30 cm long, 30 cm deep, and 10 cm wide, was used to study the influence of artificial soil shrinkage cracks on heat and water content redistribution in three soil materials subjected to wind or radiative drying of 1.18 and 2.54 cm of water per 24 hours evaporation potential, respectively. Three crack widths were used, 0, 0.64, and 1.91 cm. Moisture content and temperature distributions were measured with time up to 12 days. The cracks decreased water content as much as 5 to 10% by volume. Evaporation through crack walls caused lateral movement of water for a distance of 4 to 5 cm from the wall of a 0.64‐cm crack after 12 days of radiative drying. These distances were greater up to 14 cm (for the sand). Under wind, distances of lateral movement of water were about 5 cm, for all drying times. For all three soils with cracks, after 4 days of wind drying, soil temperature was cooler (1 to 2C lower) than for the soils with no cracks. Under radiation all three soils were warmer (5 to 10C higher) than soils with no cracks, after 4 days. In general, shrinkage cracks increased evaporation from bare soil 12–16% with cracks 0.64 cm wide and about 30% with cracks 1.91 cm wide as compared to evaporation from soils with no cracks.
Accumulation of Mercury Vapor in Soils Laboratories
Authors: Fisher H. D. , Cary J. W. 
Published: July 2010

AbstractThe rate of accumulation of mercury vapor in a closed room was determined as a function of surface area of the exposed mercury, ambient temperature, and air flow. The rate of mercury vapor accumulation was much higher than suspected by many soil scientists. For example, in a 3‐ by 3‐ by 2‐m constant temperature room, 250 cm2 of mercury surface produced toxic levels of mercury vapor within 13 minutes. Water or oil covering the surface of the mercury was a highly effective means of suppressing vaporization. The standard decontamination treatment with sulfur proved effective, but only after complete amalgamation occurred.