bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluating the Use of Na+, Ca2+, and Divalent Cation Electrodes in Some Soil Extracting Solutions
Authors: El‐Swaify S. A. , Gazdar M. N. 
Published: July 2010

AbstractThe performances of sodium activity, calcium activity, and divalent cation activity electrodes were determined and compared with predicted theoretical responses in unbuffered systems and in buffered systems at concentrations of 0.2 m, 0.5 m, and 1.0 m. In support of previous findings on a less selective sodium electrode, results show that the Na‐electrode exhibits a response which is nearly Nernstian, allowing good estimates of Na+ ion activities in soil extracts. In contrast, the usefulness of the calcium and divalent‐electrodes in buffered systems (and subsequent usefulness for determining exchangeable ions) was found to be limited particularly at high levels of total salt concentration. Although better response was observed for these two electrodes in unbuffered systems, the determination of Ca2+ and Mg2+ in water‐soil extracts by their combined use is limited by the apparent reversibility of the calcium electrode to Mg2+ ions present in calcium‐magnesium salt mixtures.
Reactions of 144Ce in Solution and Suspensions of Soil Humie Acid and Bentonite
Authors: Brown R. E. , Franklin R. E. , Miller R. H. 
Published: July 2010

AbstractA study was made of the formation of radiocolloids by 144Ce and the adsorption of Ce by equilibrated suspensions of humic acid, bentonite clay, and a mixture of these two colloids saturated with either Ca or K and H. The availability of Ce in these suspensions was measured using excised roots. Ionic strength, Ce concentration, and pH were critical factors affecting the equilibrium between radiocolloidal and monomeric Ce. As ionic strength and Ce concentration decrease and as pH increases the equilibrium is shifted towards the radiocolloidal form of Ce. At pH 6.5 and ionic strength 10‐3 about 90% of the Ce in a solution is in the radiocolloidal form. A multiple regression equation was presented which showed the effects of pH, ionic strength, and Ce concentration on the formation of radiocolloidal Ce in salt solutions. Humic acid adsorbed much greater amounts of 144Ce and restricted uptake by barley and soybean roots more than did bentonite in the Ca‐H saturated system. However, humic acid and bentonite adsorbed similar amounts of 144Ce in the K‐H saturated systems. Mixing bentonite and humic acid produced a synergistic‐type effect in regard to Ce adsorption. It was proposed that the strong bonding of Ce by Ca‐humic acid and humic acid‐bentonite mixtures resulted from a more favorable orientation of the humic acid molecule for chelation of Ce.
Solubility of Calcium Carbonate Precipitated in Aqueous Solutions of Magnesium and Sulfate Salts
Authors: Doner H. E. , Pratt P. F. 
Published: July 2010

AbstractCalcium carbonates were precipitated in the presence of various salts at controlled CO2 partial pressures. Solubilities of the precipitates were compared with that of calcite and the precipitates were subjected to X‐ray diffraction for the detection of crystalline products and in some cases analyzed for coprecipitated Mg. In NaCl solutions, the solubility of the carbonate was that of calcite. In MgCl2 solutions, the solubility of the precipitate was higher than that of calcite, both calcite and aragonite were detected and Mg was coprecipitated in the solid phase. In solutions of Na2SO4, the solubility of the precipitate was higher than in the case of the MgCl2 solutions and both calcite and vaterite were detected. In solutions of MgSO4, the solubility of the precipitate was intermediate between that of the MgCl2 solutions and the Na2SO4 solutions. The solubility product of CaCO3 seemed to be related mainly to the nature of the solid phase.
Decomposition of 14C‐Labeled Cell Wall and Cytoplasmic Fractions from Hyaline and Melanic Fungi
Authors: Hurst H. M. , Wagner G. H. 
Published: July 2010

AbstractA hyaline fungus, Aspergillus niger, and an unnamed melanic fungus isolated from a soil sclerotium were grown on 14C glucose, fractionated into cell wall and cytoplasmic components, and the fractions analyzed for C, H, N, OCH3, and specific activity. The cell wall fraction from the melanic fungus was higher in C and OCH3 content than that from the hyaline organism. The fractions were incorporated into soil samples and 14CO2 evolved was determined during 6 months. The rate of decomposition for cell wall material of both organisms was initially lower than that for cytoplasmic material. The hyaline cell wall decomposed at a relatively steady rate for a prolonged period, and after 6 months 70% of the C in this fraction had been lost as CO2 compared with 62% of the C in the cytoplasmic fraction. Cell wall and cytoplasmic fractions of the melanic species were strongly pigmented and resistant to decomposition with 35% and 48% of the C in these respective fractions evolved as CO2. The decomposition of complete, non‐fractionated tissue of additional fungi was also studied. Hyaline organisms (Penicillium sp., Schizophyllum commune, Polystictus versicolor, Lenzites sp.) had a lower C content and underwent rapid decomposition in comparison with melanic organisms (Mycoleptodiscus terrestris, Cladosporium sp., Cenococcum graniforme, Mycelium radicis‐atrovirens, Macrophomina phaseoli).
Selenium Concentrations in Alfalfa from Several Sources Applied to a Low Selenium, Alkaline Soil
Authors: Carter D. L. , Brown M. J. , Robbins C. W. 
Published: July 2010

AbstractTwo laboratory‐prepared ferric hydroxy bi‐selenites and CuSeO3 applied to Portneuf silt loam in the field provided slowly available Se to alfalfa, resulting in Se concentration adequate but nontoxic for livestock. These materials have potential as Se fertilizers at low application rates. The ferric hydroxy bi‐selenites offer little or no advantage over CuSeO3. Se from BaSeO4 alone, BaSeO4‐BaSO4 mixtures, and CuSeO4 was absorbed by alfalfa in concentrations toxic to livestock. A small fraction of applied elemental Se was available immediately after application, providing adequate Se to alfalfa for livestock. The remaining elemental Se was rather inert, and supplies only slightly more Se to alfalfa than did the untreated soil the year following application.
Soil Properties Affecting the Sorption of Atmospheric Ammonia
Authors: Hanawalt Ronald B. 
Published: July 2010

AbstractAt controlled atmospheric‐level ammonia concentrations, ammonia sorption from the atmosphere was weakly correlated with increasing cation exchange capacity and percent clay. Alteration of organic matter content and soil acidity produced only slight changes in sorption rates. These data indicate that lack of bonding sites per se does not limit the sorption rate. In air dry soil the major portion of the sorption occurs in the uppermost 0.5 cm. Sorption rates were closely related to increasing air permeability and moisture content. Since atmospheric ammonia concentration, air velocity across the soil surface, and temperature also strongly influence sorption rates, it is concluded that sorption of atmospheric ammonia by soils is primarily governed by those factors which effect the rate of supply of ammonia to the soil surface and the fraction of the ammonia molecules which are actually captured.
A Plinthaquult of the Aripo Savannas, North Trinidad: I. Properties of the Soil and Chemical Composition of the Natural Vegetation
Authors: Ahmad N. , Jones Robert L. 
Published: July 2010

AbstractAripo Fine Sand (Plinthaquult) occupies depressed topography in a region in North Trinidad where rainfall is over 250 cm annually; consequently, the area is submerged periodically in the wet season. The profile consists of a surface albic horizon of 25 cm consisting of bleached silt to fine sand with little organic matter; this is underlain by an argillic horizon with characteristic red and yellow mottling. On exposure, the mottled areas harden irreversibly to nodules. The profile is very strongly acid with very low base saturation. Exchangeable Al is correspondingly high. The albic layer has 0.4% free Fe2O3 in contrast to over 12 times more in the underlying mottled clay layers. Total P is lower than 80 ppm for the whole profile; only the ochreous exterior of mottles have higher P contents. Except in the bleached layer, Al‐P is almost absent and Ca‐P is absent throughout the profile. Forms of P associated with Fe make up the bulk of the total P in the soil. Truog's reagent extracted only 2 ppm P in the bleached layers and just traces in the clay enriched part of the profile.The flora of the area consists of short, coarse, tufted grasses, sedges, herbs, shrubs, and insectivorous and parasitic plants. Dominant plant species were analyzed for total and insoluble ash, N, P, K, Ca, Mg, S, Fe, and Al. Compared to levels of these nutrients present in rice (Oryza sativa L. var. Indica) and sweet potato (Impomoea batatas L. var. 049) grown under favorable conditions, all species of the vegetation had very low amounts of plant nutrients. The greatest difference occurred for P, K and S. All the species were high in Fe content but values fluctuated and only in the Gramineae was there any consistency. Many of the species, especially the Melastomaceae, were very high in Al. Soil and plant analysis indicated a soil of extremely low fertility status which was also reflected in the poorness of the vegetation.
A Method for Detecting and Estimating Hydrogen Sulfide in Flooded Soil
Authors: Ford H. W. , Calvert D. V. 
Published: July 2010

AbstractA 60‐ml sorption cell utilizing 0.5 mil PVC membranes permeable to H2S is described. NaOH is used as the sorbing solution. The cell is capable of detecting H2S in soil zones containing < 0.1 ppm in groundwater over short and prolonged periods of anaerobic flooding under conditions of a fluctuating water table.
Evaluation of Atomic Absorption Methods for Determinations of Aluminum, Iron, and Silicon in Clay and Soil Extracts
Authors: Yuan T. L. , Breland H. L. 
Published: July 2010

AbstractAtomic absorption methods for Al, Fe, and Si determinations were evaluated in clay and soil extracts obtained with 1N NH4OAc (pH 4.8), 0.1N HCl, 0.2M (NH4)2C2O4 (pH 3.0), 0.5N NaOH, and buffered Na2S2O4. The evaluation was made either by correlating the results with those of chemical methods or by calculating the percentage recovery of added Al, Fe, or Si from the extracts. Highly significant correlations and regressions were obtained between the atomic absorption and colorimetric methods for NH4OAc‐ and HCl‐extractable Al and Fe in soils, dithionite‐extractable Fe in clays, NaOH‐extractable Al in soils and clays, and NaOH‐extractable Si in clays. Recoveries of added Al, Fe, and Si from oxalate, dithionite, and dilute alkali media were successful except that the recovery of Fe in soil extracts exceeded 110% in most cases. The presence of a natural humic acid “Leonardite” did not affect the atomic absorption analyses of Al and Si. However, the Fe results were high as was found in soil extracts, indicating organic matter interference in the determination of Fe by this technique. Removal of humic acid by precipitation reduced the Fe but not Al recovery. The coefficients of variation for 10 determinations were below 3% for all three elements with the exceptions of Si at concentrations below 15 ppm and Fe below 2 ppm. Some difficulties were encountered with the oxalate and dithionite as extractants.
Exchangeable Potassium and its Selectivity by Soils as Quantity‐Intensity Parameters for Soil Potassium
Authors: Rezk A. I. , Amer Fathi 
Published: July 2010

AbstractSignificance of K selectivity by soils, as revealed by the Gapon exchange selectivity coefficient, in improving exchangeable K as an availability index was tested on 12 UAR alluvial and desert soils under the high intensity cropping of a Neubauer experiment. Supply of K to plants decreased as selectivity increased and the selectivity coefficient, k, was used to correct exchangeable K, K̄, for differences in selectivity among soils. The ratio K̄/k, proved superior to exchangeable K alone for assessing K supply and accounted for as much as 95.3% of the variation in K uptake by barley plant during 24 days of growth. At variance with exchangeable K and the selectivity coefficient, their ratio K̄/k was found independent of the method of extraction and may prove to be a characteristic soil property defining the quantity‐intensity aspects of soil K supply. For soil testing purposes, the product of potassium‐adsorption ratio and cation‐exchange capacity may offer a simple substitute for the K̄/k ratio in soils having Ca and Mg as the dominant exchangeable cations.
Soil Structure Evaluation With Audiofrequency Vibrations
Authors: Rickman Ron W. 
Published: July 2010

AbstractYoung's moduli for soils measured with a vibrational technique varied with soil aggregate size, water content, texture, sensor‐to‐sample contact, and column handling. The magnitude of a Young's modulus varied from 107 dynes/cm2 (147 psi) for nearly saturated columns to over 109 dynes/cm2 for an airdried, Na‐saturated silt. The accuracy of the moduli measurements is in the order of 15% to 20%. The measured values compare favorably with others previously reported in the literature for undisturbed and reworked soil samples. The range of measured soil moduli, the repeatability of the measurements, the lack of restriction on sample size and the nondestructive nature of the technique indicate that this procedure may provide a useful measure for soil structure evaluation.
An Alkaline Oxidation Method for Determination of Total Sulfur in Soils
Authors: Tabatabai M. A. , Bremner J. M. 
Published: July 2010

AbstractA rapid and precise method of determining total sulfur in soils is described. The soil sample is heated with alkaline sodium hypobromite solution to oxidize soil sulfur compounds to sulfate, and the sulfate thus formed is reduced to hydrogen sulfide by a modified Johnson‐Nishita procedure and determined colorimetrically as methylene blue. The method gives quantitative results with pure organic and inorganic sulfur compounds, including amino acids, sulfonic acids, organic sulfates, sulfoxides, thioureas, sulfates, sulfites, sulfides, and elemental sulfur. It gives quantitative recovery of organic and inorganic sulfur added to soils and soil extracts, and its results with soils agree closely with those obtained by other methods proposed for total sulfur analysis of soils.
Effect of EDTA on the Self‐Diffusion of Zinc in Aqueous Solution and in Soil
Authors: Elgawhary S. M. , Lindsay W. L. , Kemper W. D. 
Published: July 2010

AbstractSelf‐diffusion coefficients for Zn and ZnEDTA (zinc ethylenediaminetetraacetic acid) were determined in aqueous solution and in soil. Those in solution were estimated from diffusion measurements in agar‐agar gel and were found to be 8.8 × 10‐6 cm2 sec‐1 for Zn and 6.8 × 10‐6 cm2 sec‐1 for ZnEDTA. The apparent diffusion coefficient of Zn in soil increased from 0.36 × 10‐9 cm2 sec‐1 to 3.0 × 10‐9 cm2 sec‐1 with addition of 1.53 × 10‐8 mole of EDTA/g soil and to 9.0 × 10‐9 cm2 sec‐1 with addition of 1.53 × 10‐8 mole of ZnEDTA/g soil. The true diffusion coefficient Dp of Zn in soil was fairly constant at different levels of EDTA, averaging 1.81 × 10‐7 cm2 sec‐1.Addition of EDTA to soils increased the diffusion of Zn; this increase was explained by the transformation of the solid phase soil Zn into soluble ZnEDTA complexes, thereby increasing the concentration gradient of total diffusible Zn. Chelating agents were shown to play an important role in overcoming the rate‐limiting steps of solution and diffusion which are largely responsible for the movement of micronutrient cations in soils.
Surface Soil Properties of Black Walnut Sites in Relationship to Wood Color
Authors: Maeglin Robert R. , Nelson Neil D. 
Published: July 2010

AbstractVarious soils that supported black walnut (Juglans nigra L.) growth in Indiana and Missouri were analyzed for surface pH, organic matter, available P, exchangeable K, Ca, Mg, total N, silt plus clay content, cation‐exchange capacity (CEC), and depth to mottling or to impervious layer. Quantitative color values (luminance, dominant wavelength, purity) of heartwood of walnut trees grown on these soils were determined by reflectance spectroscopy. The soil properties analyzed were moderate to high for most soils studied. A few soils were found low in available P, silt plus clay content, and organic matter. Regression analyses indicated that variations in soil fertility were correlated with difference in wood color between individual sample trees. The range of observed site quality was rather limited, however, poorer sites showed a tendency toward darker, redder heartwood (lower luminance, higher dominant wavelength). Available P, exchangeable K, Ca, Mg, total N, and pH were found to be most important in relation to color variation.
Further Characterization of Iron Uptake in Two Genotypes of Corn
Authors: Brown J. C. , Ambler J. E. 
Published: July 2010

AbstractTwo genotypes of corn, (Zea mays L.) homozygous yellow stripe ys1/ys1 (Fe‐inefficient) and Pa 54 (Fe‐efficient), were grown in nutrient solution with two levels of CaCO3 using two plant populations. The nutrient solution and plant population were varied to evaluate and compare the two genotypes relative to modifications in their growth medium favorable to Fe transport. Plant factors recognized as favoring Fe transport were (i) ability of roots to lower the pH of their growth medium, (ii) efflux of material by the root that reduces Fe3+ to Fe2+, (iii) increase of citrate in root sap, and (iv) decrease of P in root sap. The Fe‐efficient Pa 54 corn was more efficient than the yellow stripe ys1 in all of the above factors and transported more Fe to leaves than ys1. Once the iron requirement of the plant had been satisfied, the activity of the factors favoring Fe transport diminished and less Fe was taken up by the plant.
Growth and Manganese Uptake by Potatoes as Related to Liming and Acidity of Fertilizer Bands
Authors: White R. P. , Doll E. C. , Melton J. R. 
Published: July 2010

AbstractThe effects of liming and of the acidity of fertilizer bands on the growth and manganese uptake by Norland and Sebago potatoes (Solanum tuberosum L.) were determined on an acid sandy soil in a greenhouse experiment. Four levels of two sources of lime were established and four additional unlimed treatments consisted of: a) no supplements to the fertilizer band, or the addition b) of Al, c) of Mn, or d) of both Al and Mn in the fertilizer band. On all treatments, the equivalent of 1,000 pp2m of a 5‐20‐20 fertilizer was banded. Changes in soil pH and the pH in the fertilizer bands during the growing period were determined by direct contact pH measurements made through access tubes.Symptoms of Mn toxicity (chlorosis and black specks on the stems and undersides of the leaves followed by death of the lower leaves) were observed on those plants grown on the unlimed soils, and on those containing very high levels of Mn. When the soil was limed to pH 6.5 or above, Mn levels in the plants were markedly decreased and the toxicity symptoms disappeared. Additions of Al to the fertilizer band markedly lowered band pH but had little effect on plant Mn content. Additions of Mn to the band did not affect band pH, and increased plant Mn only slightly. The Norland variety was less tolerant of high Mn levels than was the Sebago variety. The uptake of Mn by the potato plants in this experiment was related to soil pH rather than to the acidity of the fertilizer band.
Distribution of Macro‐ and Micronutrients in Soil Profiles Developed on Lithosequences and under Biosequences in Northern Greece
Authors: Apostolakis Costas G. , Douka Catherine E. 
Published: July 2010

AbstractThe status and the distribution of the macro‐ and certain of the micronutrients in selected soil profiles developed on different parent materials such as granite, quartz diorite, dacite, and marble and under varying cover such as spruce (Picea excelsa L.), scotch pine (Pinus silvestris L.), beech (Fagus silvatica L.), and grasses were investigated.The results presented in a series of graphic illustrations indicate a distinct tendency for an accumulation of the nutrient supply in the uppermost horizons of the studied profiles.The nutrient level is influenced by the initial capital of the elements and the alteration to which it has been subjected during soil development processes.Interactions between the biotic and the edaphic parameters affect the distribution of the nutrients within the profiles.
Variations in Tension Lysimeter Leachate Volumes
Authors: Cochran P. H. , Marion Giles M. , Leaf Albert L. 
Published: July 2010

AbstractLeachate volumes collected with tension plate lysimeters placed in a glacial outwash soil and maintained at a fixed tension varied from 1.9–629.9% of the total water applied through rainfall and/or irrigation. The amounts of K passing through plates at depths of 152 cm ranged from 0.02–86.1% of that applied at the surface. These differences were attributed to several factors including (i) nonuniform application of water, (ii) large differences in soil moisture retention and flow properties for individual strata, and (iii) irregularity of soil strata arrangement at different locations within the study area. Lateral flow to plate surfaces can result in large overestimates of the nutrient flux at a given soil depth.
Sulfur Uptake by Corn as Influenced by Ammonium and Nitrate Nitrogen
Authors: Rehm G. W. , Caldwell A. C. 
Published: July 2010

AbstractThe effect of NH4 and NO3 ions on S uptake by corn (Zea mays L.) from a starter fertilizer was studied with the use of 15N and 35S. When both the N and S were applied as a starter, the uptake of fertilizer S was significantly increased when NH4 instead of NO3 was used as the N source. This effect was observed in young plants through 4 weeks of age. More N was absorbed by the corn plant when NH4 rather than NO3 was supplied as the N source. The N source, however, had no significant effect on the total S, SO4‐S or total N content of the tissue and the corn yield.
Manganese Movement from Fertilizer Granules in Various Soils
Authors: Mortvedt J. J. , Giordano P. M. 
Published: July 2010

AbstractMovement of Mn in acid Hartsells fsl (pH 5.1) from fertilizer granules containing 2% Mn as 54Mn‐labeled MnSO4 was in the order: KCl = NH4NO3 [AN] > soil (no carrier) = concentrated superphosphate [CSP] = NH4H2PO4 [MAP] ≫ (NH4)2HPO4 [DAP] = (NH4)3HP2O7 [TPP] = ammonium polyphosphate [APP]. In limed Hartsells soil (pH 7.6) Mn movement was less from granules of all fertilizers, but the order remained the same.Movement of Mn applied in soil or MAP granules was greater in Spencer sil (pH 4.7) than in five other soils with higher pH levels. Application of Mn with MAP resulted in decreased Mn movement in all soils except Houghton muck. Little or no movement of Mn occurred when MnSO4 was applied with TPP to any of these soils. Reduced movement may have been due to formation of reaction products of low solubility which reduced the concentration gradient of soluble Mn in the soil near the granule site.Percentage recoveries of applied Mn from the soil immediately adjacent to the granule sites by H2O, neutral 1N NH4OAc, and neutral 1N NH4OAc containing 0.2% hydroquinone showed little difference for Mn applied alone or with granular AN, KCl, CSP, or MAP. However, the recoveries of Mn applied with DAP, APP, and TPP were lower, indicating lower solubility of Mn applied with these fertilizers. Recoveries of applied Mn also were less in soils with higher pH levels.