bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ion Exchange Equilibria Involving Aluminum in a Kaolinitic Ultisol
Authors: Pleysier J. L. , Juo A. S. R. , Herbillon A. J. 
Published: July 2010

AbstractCation exchange equilibria in an acid Ultisol profile involving K‐Al, Ca‐Al, K‐Ca, Na‐K, and Na‐Ca exchanges were studied. Selectivity coefficients, surface activity coefficients and free energy changes were computed using the thermodynamic formulations.In exchange equilibria involving Al, the magnitude of selectivity coefficients Kc, was affected by pH, surface composition, and hydrolysis of Al. In equilibria not involving Al, good reversibility for K‐Ca, Na‐K and Na‐Ca exchanges was obtained. Potassium was selectively adsorbed in all horizons of the profile. The over‐all selectively sequence follows the order of K>Al>Ca≈Na.
Infrared Spectra of Sewage Sludge Fractions: Evidence for an Amide Metal Binding Site
Authors: Boyd S. A. , Sommers L. E. , Nelson D. W. 
Published: July 2010

AbstractInfrared studies were conducted to qualitatively characterize sewage sludge light (organic) and heavy (inorganic) fractions obtained using a heavy liquid separation technique. Infrared spectra of sludge organic fractions revealed the presence of proteinaceous and polysaccharide‐like materials. Infrared absorptions characteristic of carboxyl groups and aromatic compounds were not observed in the spectra of sludge light fractions. The position of the amide‐I band in the infrared spectra of the sludge light fractions was used to obtain direct evidence of metal binding sites involving amide N and possibly amide O. A discrete shift in the position of the amide‐I band was initiated by extracting indigenous metal cations from the sludge organic fraction. This shift was reversed by saturating the extracted sludge organic fraction with Cu2+. Absorption bands of quartz and calcite dominated the infrared spectra of sludge inorganic fractions.
Characterization of Zinc Adsorption in Some Soils of India
Authors: Shukla U. C. , Mittal S. B. 
Published: July 2010

AbstractLaboratory studies were conducted to characterize Zn adsorption in some soils varying in texture using a wide range of equilibrating Zn concentrations. The fit of adsorption data was tested both in Freundlich and Langmuir isotherms. The Langmuir isotherm was resolved into two linear portions. Binding energy coefficients (K) were higher and adsorption maxima (b) were lower in part I than part II of the curves for both soils. b values were higher and K values were lower for loam than sand. The Freundlich isotherm was also resolved into three distinct portions having different K and n values. The adsorption pattern at different concentrations indicated differential bonding energies for adsorbed Zn, and occurrence of precipitation reactions along with adsorption in these soils, even before saturation of cation exchange capacity (CEC). The results showed the limitations in describing Zn adsorption through Langmuir or Freundlich adsorption isotherms in such soils of pH ⩾ 8 at 6 ppm Zn concentrations due to precipitation. Zinc adsorption exceeded CEC at equilibrating Zn concentration of 10−2M. The soil texture did not affect the nature of adsorption curves but more Zn was adsorbed by loam than sand showing the effect of the number of adsorption sites.
Relationship of Antibiotic Resistance to Effectiveness in Rhizobium trifolii Populations
Authors: Hagedorn C. 
Published: July 2010

AbstractFifty Rhizobium trifolii isolates were divided into five categories of symbiotic effectiveness and examined for resistance to 15 antibiotics. The cultures were resistant to high concentrations of 11 of the antibiotics but were relatively sensitive to chloramphenicol, streptomycin, tetracycline, and vancomycin. Resistance to any particular group of antibiotics was not associated with any one of the different categories of effectiveness but rather was equally dispersed between all categories. Eighteen isolates which differed in effectiveness were used to develop subcultures resistant to 3× or 4× the average minimum inhibitory concentration (MIC) of the parent strains for each of the antibiotics. Reduction in effectiveness was found in 12.5% of the resistance strains, was not associated with any particular antibiotic, and was randomly distributed throughout the five effectiveness categories. Increased effectiveness occurred with only three subcultures (2.5% of the tests). Cross‐resistance patterns were generally restricted to those antibiotics which expressed similar modes of activity and the development of cross‐resistance occurred in 5.7% of the possible resistance combinations. Results presented in this study do not agree with other reports in which antibiotics were divided into groups based on their association with effectiveness.
Effect of Soil Nutrient Status and pH on Nitrogen‐Fixing Algae in Flooded Soils
Authors: Wilson J. T. , Alexander M. 
Published: July 2010

AbstractThe development of indigenous N2‐fixing algae in 10 of 12 flooded soils, as measured by acetylene‐reduction activity, was stimulated by the addition of phosphate. In P‐supplemented flooded soils, these algae generally developed readily at pH 7.3 or greater but poorly at pH 6.5 or less. Iron additions stimulated the activity of inoculated blue‐green algae in a phosphate‐amended flooded soil of pH 7.9 but not in a soil with a pH of 5.5. Indigenous algae in an acid soil (pH 4.8) were stimulated by CO2. Nitrogen fixation and development of indigenous blue‐green algae were correlated with pH and the levels of extractable K and of Ca and Mg in these soils, but not with the concentrations of organic matter, inorganic N, or extractable phosphate and Fe.
Soil‐Geomorphic Relationships in Postglacial Alluvium in New York
Authors: Scully R. W. , Arnold R. W. 
Published: July 2010

AbstractIn south‐central New York alluvial soils of the three postglacial geomorphic units were correlative between two sites on different size rivers. Noncumulative Inceptisols dominate the higher postglacial terrace. Cumulative soils, with buried A horizons, that are fluventic subgroups of Inceptisols have developed in overbank silts episodically deposited during the past 3,500 years on the lower terrace (high bottom). Significantly less developed soils, but sometimes taxonomically identical, have developed in the oldest portion of the flood plain (low bottom). Weakly structured soils dominate the younger alluvial fills of the flood plain whose sandy lateral accretion deposits are less than 880 ± 130 years B.P. old. The weakly structured soils have remnants of textural stratification and lack color evidence of alteration and are presumably Fluvents.
pH‐Dependent Zinc Adsorption by Soils
Authors: Bar‐Yosef B. 
Published: July 2010

AbstractThere is a need for a simple equation relating the adsorption of Zn to its solution concentration and pH. Such an equation was derived using the competitive Langmuir adsorption isotherm. Experimental results obtained for five different soils in batch experiments were compared with results computed for each soil according to fitted parameters. Three criteria for the adequacy of the equation were tested: an acid titration curve in the absence of Zn, Zn adsorption as a function of its solution concentration at a given pH, and Zn solution concentration at a fixed total amount of Zn as a function of pH. Close agreement between calculated and experimental results was obtained for the analyzed soils in all tests.
Reclamation of Saline‐Sodic Soils by Leaching
Authors: Jury W. A. , Jarrell W. M. , Devitt D. 
Published: July 2010

AbstractSeven lysimeters containing sandy loam or clay loam soils were reclaimed by ponded or unsaturated leaching following a saline irrigation experiment of 2.5 years duration. Initial soil electrical conductivity was as high as ECe = 25 mmho/cm with associated exchangeable sodium percentages (ESP) up to 60%. Substantial quantities of solid gypsum and lime were present in the soil profile from precipitation reactions during the crop irrigation stage.Drainage volumes were expressed in pore volume units to scale out differences between water retention and leaching rates. Plots of scaled chloride concentrations (Cl/Cl initial) vs. pore volumes were similar for all lysimeters, with essentially all chloride removed by 1.5 pore volumes. Total salt removal was well described by a single curve (C/Cinft)(PV) = 0.8 for all treatments. Standard cation exchange equilibrium equations were used in a chromatographic displacement model to produce an algebraic equation to describe exchangeable Na reductions as a function of leaching pore volumes. This model, along with a model for calculating exchangeable Mg reductions, was in good agreement with measured changes for all treatments.No special amendments were required to maintain high permeability during leaching, even when distilled water was used, because of redissolution of previously precipitated Ca salts.
Effect of Montmorillonite and Trace Elements on the Growth of Penicillium frequentans: II. Nitrate Nitrogen Source
Authors: McCormick R. W. , Wolf D. C. 
Published: July 2010

AbstractThe addition of montmorillonite to culture media has been shown to stimulate growth and metabolic activity of several soil fungi. The objective of this study was to determine if the growth stimulation of a common soil fungus, Penicillium frequentans, was due to montmorillonite supplying required trace elements when glucose and NaNO3 were used as the C‐energy and N sources, respectively.The trace element treatments were (i) no trace elements, (ii) trace element solution 1, and (iii) trace element solution 2 which contained a 0.1M phosphate buffer plus trace elements. Either montmorillonite, at a concentration of approximately 500 mg/100 ml, or distilled water (controls) was added in dialysis tubing to the trace element solutions.Without trace elements, the addition of clay increased biomass from 571 to 861 mg/100 ml, an increase of 51%. Biomass production in the controls of both trace element solutions was not significantly different than that produced in the no trace element solution with montmorillonite added. With the addition of clay to trace element solution 1, a 14% increase in biomass from 829 to 944 mg/100 ml was obtained. There was no significant increase in biomass in trace element solution 2, with the addition of clay. The montmorillonite maintained the pH of the medium at least 1.5 units greater than the controls in the no trace element and trace element 1 treatments. With trace element solution 2, a 0.5 pH unit increase after 6 days of growth resulted due to the montmorillonite. When clay was present in the medium, the Cu, Fe, and Mn content of the fungus was increased. As a result of fungal growth, the Zn and Cu contents of the montmorillonite were decreased from 51 to 28 and 37 to 28 µg/g, respectively.A large portion of the stimulation in fungal growth due to montmorillonite was apparently due to the ability of the fungus to obtain trace elements from the clay. There was however, an increase in growth in trace element solution 1 which could not be attributed to trace elements when NO3‐N was used as a N source.
Dissolution of Sulfur‐Coated Urea in Soil: I. Wax‐Sealed Sulfur‐Coated Urea
Authors: Hashimoto Isao , Mullins R. C. 
Published: July 2010

AbstractThe release of urea from three wax‐sealed, sulfur‐coated urea (SCU) samples was tested in a laboratory soil system. These samples were of nearly matched 7‐day dissolution values but had different amounts of total coatings. Soil‐SCU mixtures were incubated for varying times up to 18 weeks at different temperatures, pH (liming), and microbial (sucrose) levels. The release of urea from all samples increased markedly with increasing temperature but only slightly with increasing pH or microbial levels. Their time‐release patterns were different in spite of their similar 7‐day dissolution test values.
Manganese Toxicity in Flax Growing on Certain Calcareous Soils Low in Available Iron
Authors: Moraghan J. T. 
Published: July 2010

AbstractManganese toxicity and high levels of plant Mn are normally found in plants growing on acid soils with high levels of watersoluble or salt‐extractable Mn. However flax (Linum usitatissimum L.) accumulates excessive Mn and develops Mn‐toxicity symptoms, which are eliminated by application of FeEDDHA, when grown on some calcareous soils. Flax was grown in the greenhouse on seven soils, varying in pH and extractable Mn and Fe, in the presence and absence of 2 ppm FeEDDHA‐Fe. Plants on three of the soils, which were calcareous and had the highest pH values, developed Mn‐toxicity symptoms and accumulated approximately 500 ppm Mn in above‐soil parts in the absence of the chelate and less than 50 ppm Mn when the chelate was applied. Plant‐Mn concentration was poorly related to Mn extracted from soils with DTPA (0.005M diethylenetriamine pentaacetic acid, 0.005M CaCl2, 0.01M triethanolamine, pH=7.3), 0.01M CaCl2, 1N NH4OAc (pH=7), or 1N NH4OAc + 0.2% hydroquinone (pH=7), but was significantly inversely related to DTPA‐extractable Fe. It is hypothesized that plant‐Fe status influenced the ability of flax roots to utilize soil Mn, possibly through changes in pH or redox potential at or adjacent to roots.The influence of P fertilizer, Ca(H2PO4)2, on Mn toxicity in one of the three problem soils, with 3.5 ppm NaHCO3‐extractable P, was also studied. Addition of P greatly increased yields, due presumably to a P response, but also increased plant‐Mn concentration. Manganese‐toxicity symptoms were observed both in the presence and absence of the added P.
Greenhouse Evaluation of Nitrogen Fertilizers for Rice
Authors: Craswell E. T. , Vlek P. L. G. 
Published: July 2010

AbstractAs part of a research program to improve the efficiency of N fertilizers for lowland rice (Oryza sativa, L. var. IR38) in developing countries, a number of modified urea products have been evaluated in a greenhouse experiment. Fertilizers were applied to rice grown in two soils subjected to continuous or intermittent flooding. The results demonstrate the advantages of split application, deep placement, and controlled release in increasing fertilizer efficiency. However, the major finding was that a combination of deep placement and controlled release results in a substantial increase in fertilizer N recovery by the plant. This combination, in the form of sulfur‐coated supergranules of urea, gave a mean apparent recovery of fertilizer N by rice of approximately 84% compared with only 28% for urea applied in a single dose at transplanting.By using 15N‐labelling, losses of applied N were measured for selected treatments. Extensive losses (∼30% for Decatur soil, ∼50% for Crowley soil) were measured for urea applied at transplanting. Much less (∼6% and 14–24%, respectively) was lost of ammonium sulfate applied similarly. Point application of the urea as a supergranule at the 8‐cm depth reduced losses to < 4%. The intermittent flooding did not promote losses. Losses of broadcast fertilizers were greater from the Crowley soil (pH 6.2) than from the Decatur soil (pH 5.0).
Productivity of Quaking Aspen (Populus tremuloides Michx.) as Related to Soil Mapping Units in Northern Minnesota
Authors: Esu Ivara E. , Grigal D. F. 
Published: July 2010

AbstractRelationships of quaking aspen (Populus tremuloides Michx.) site index and stand basal area to conventional soil mapping units and soil mapping units regrouped into great group units in northern Minnesota were examined. Soil survey data from three counties mapped at different scales were used; Carlton County at 1:20,000, Itasca County at 1:24,000, and Crow Wing County at 1:31,680. The vegetation data were collected from 0.4 ha, 10‐point cluster forest survey plots. Plots marked on aerial photographs were matched with soil mapping units. Site index for quaking aspen, and for a number of other species, was poorly related to soil mapping units. Stand basal area, however, was related both to mapping units within counties and to the overall great group units. The relationship between forest productivity and soil mapping units needs further evaluation; decisions are necessary regarding the indices appropriate for measurement, and whether the measurement should be of actual or potential productivity.
The Effect of Trickler Line Spacing on Yield of Tomatoes (Lycopersicum esculentum Mill.)
Authors: Tsipori Y. , Shimshi D. 
Published: July 2010

AbstractTomatoes (Lycopersicum esculentum Mill. cv. VF 198) growing in rows spaced 80 cm apart, were irrigated with trickler lines spaced every 1, 2, 3, 4, and 5 plant rows. The seasonal amount of irrigation, on a par hectare basis was 600 mm for all the five treatments, so that with wider line spacing, more water was discharged through each line. The lowest yield (70 tons ha−1) was produced by the one‐row spacing, and the highest yield (118 tons ha−1) — by the four‐row spacing. The yield of the rows adjacent to the trickler line increased with line discharge to an extent that overcompensated for the lower yield of the outlying rows. The amount of irrigation applied was lower than potential evapotranspiration, and it is concluded that under these conditions, the higher uniformity of application associated with closer line spacing is a worse irrigation strategy than applying the same amount of irrigation to a portion of the area, thereby enhancing its production at the expense of the drier portion; the probable reason for the low yields under close spacing is the relatively high loss of soil water through surface evaporation, and the shallow soil volume through which transpirational flux occurs.
A Mathematical Treatment of the Initial Stages of Drying of a Soil Column
Authors: Zachmann David W. , Gardner H. R. , DuChateau Paul C. 
Published: July 2010

AbstractA nonlinear diffusion equation governing the initial stages of drying of a soil column is numerically integrated using a method designed to adjust the time step to compensate for steep moisture content gradients. A balance of mass check is used to determine when the simulation becomes invalid. Resulting tables of relative moisture depletion are given for various soils and drying rates. In view of the improved technique of numerical integration and the attention to the balance of mass check, it is felt that the numerical results obtained are more reliable than previously available results.
Fixation and Loss of Nitrogen During Transformations of Nitrite in Soils
Authors: Smith C. J. , Chalk P. M. 
Published: July 2010

AbstractWhen alkaline‐hydrolyzing N fertilizers are band‐applied to soils, the biological oxidation of NO2‐ is inhibited and NO2‐ may accumulate. Nitrite can react chemically with soil organic matter and become fixed, and at the same time nitrogenous gases can be evolved. The aim of the work described here was to study mechanisms of gaseous‐N formation using 15NO2‐ as a tracer, and to define the relationship between fixation and loss of N.Fixation of Na15NO2 in five soils varying in pH and organic C content ranged from 0.6 to 36% of applied NO2‐, while the 15N not recovered varied from 6 to 53%. A significant positive correlation was found between 15N fixed and 15N not recovered in the five soils, sampled after 1, 2, and 3 days of incubation.The 15N enrichment of NO + NO2 evolved from three γ‐irradiated soils treated with Na15NO2 was only slightly less than the atom % 15N of added NO2‐, and the rate of evolution increased as the pH of the soils decreased. These data suggest that NO + NO2 was derived from the self‐decomposition of HNO2. Approximately equal amounts of indigenous soil N and added NO2‐‐N reacted to form N2, indicating that a Van Slyke‐type reaction may have been partly responsible. Differences in the atom % 15N2 between soils suggested that more than one loss mechanism was operating, and that their relative importance may have been determined by soil pH. Nitrogen‐15 balance data showed that another nitrogenous gas, in addition to N2O, was evolved.
Soils of Marshes in the Apalachicola, Florida Estuary
Authors: Coultas C. L. 
Published: July 2010

AbstractThe marshes of the Apalachicola, Florida estuary were traversed and the principal soils were described, sampled, and characterized. Cladium jamaicense (sawgrass) was the predominant plant of this ecosystem, but Juncus roemerianus (needlerush) was also common. Sulfihemists predominated in the delta of the Apalachicola River. In the eastern portion of the estuary, Sulfaquents and Fluvaquents were common. Sulfihemists were not saline, but some Sulfaquents and Fluvaquents were saline‐alkaline. Montmorillonite was the predominant clay‐sized mineral and mica was common in the sand fraction.
The Effect of Profile Modification of a Fragiudalf on Water Extraction and Growth by Grain Sorghum
Authors: Bradford J. M. , Blanchar R. W. 
Published: July 2010

AbstractThe dense and slowly permeable layer in fragipan soils restricts the downward movement of water and plant roots. Thoroughly mixing a Hobson soil profile (Typic Fragiudalfs) and incorporating lime and sawdust into the profile increased sorghum grain yields and water storage. Over a 3‐year period, sorghum grain yields were increased by 50% due to the mixing process alone and by 150% when lime and sawdust were added prior to mixing. The water storage in the early growing season was greater in sawdust‐incorporated modified soil plots, and greater amounts of water were utilized by the plants during the growing season. The natural fragipan profile contained the greatest amount of water in late summer, but the water in or below the fragipan was not accessible to the plant because of restriction on rooting.
Cation Exchange Capacity of Acid Forest Humus Layers
Authors: Kalisz P. J. , Stone E. L. 
Published: July 2010

AbstractCation exchange capacities (CEC's) of acid forest humus layers and mineral soils were measured at the pH of air‐dried samples (CEC [field pH]) using a neutral salt procedure. The values obtained were ¼ to ½ those measured by NH4OAc at pH 7 (CEC [pH 7]). Organic matter was the chief source of exchange capacity at all localities studied. CEC (field pH) of mors from the Adirondack Mt. area (pH ≤4.1) and mulls from central New York (pH 4.9–5.4) averaged 52 and 123 meq/100 g OM (organic matter), respectively, as compared with 183 and 236 meq/100 g when determined at pH 7. Base saturation calculated from the lower CEC measured at field pH may range from 15 to 30% for H layers below pH 4, and from 81 to 94% for mull layers at pH 5.4. At one location where the pH of a mor layer varied naturally from 3.2 to 5.6, CEC (field pH) was linearly correlated with pH; CEC increased about 30 meq/100 g OM per pH unit. CEC (field pH) was unrelated to total N over the range 1.6–2.6% N, ash‐free. Estimates of total forest floor CEC (field pH) for seven Adirondack and New England localities with mor layers ranged from 10 to 165 keq/ha.