bluuebunny/crossref_metadata_2025_split huggingface dataset:
Soil Taxonomy and Regional Land Use Interpretations for Ohio
Authors: Olson K. R. , Wilding L. P. , Hall G. F. 
Published: July 2010

AbstractSoil Taxonomy provides for interpretations at each of the categorical levels; order, suborder, great group, subgroup, family and series, plus their phases. The potential for interpretations is best at the series level, but is feasible at higher categories. Categorically and cartographically generalized maps with percent compositions between 56 and 76% were prepared for Ohio. Once these maps were prepared it was possible to develop interpretations for each level of generalization by (i) assembling all the physical environmental data available for the area, (ii) applying the differentiae and covariant phenomena of soil taxonomic terms associated with the soil classification at the higher taxonomic levels, (iii) analyzing the existing land use and its associated limitations and suitabilities, and (iv) predicting the response of soil in similar taxonomic classes to alternative land uses. The taxonomic system does permit the separation of single factor criteria which in themselves are pertinent to interpretations and planning decisions. Two such soil properties that are reflected at high categorical levels include potential for saturated upper soil horizons (aquic suborders) and fragipans (fragi great groups) as diagnostic subsurface criteria.
Effects of Bicarbonate on Sodium Hazard of Irrigation Water: Alternative Formulation
Authors: Miyamoto S. 
Published: July 2010

AbstractThe conventional equation using the saturation index does not satisfactorily account for the effect of bicarbonate on sodicity. We, therefore, examined the existing method and presented an alternative formulation. The alternative formulation was based on direct numerical solutions of well‐known carbonate equilibrium reactions, and consisted of the solution of the second‐ or the third‐order polynomial approximation. The analytical results were then compared with published laboratory, lysimeter, and field data. The comparison indicates that the conventional equation using the saturation index overestimates the sodicity of irrigation water having a high ratio of Ca to HCO3 and underestimates otherwise. The method also generally overestimates the sodicity of drainage water. The proposed third‐power polynomial approximation yields a satisfactory prediction of the sodicity of irrigation water, of drainage water, and of surface soils. The second‐order approximation can also be used for predicting the sodicity of drainage water if the pH of the drainage water is known. The proposed methods are somewhat more complex than the conventional method, but can be conveniently utilized with a programmable calculator or a mini‐computer.
Mineralogical Characteristics and Transformations of a Vertical Rock‐Saprolite‐Soil Sequence in the North Carolina Piedmont: II. Feldspar Alteration Products‐Their Transformations Through the Profile
Authors: Calvert C. S. , Buol S. W. , Weed S. B. 
Published: July 2010

AbstractFeldspar minerals near the rock‐saprolite interface weathered directly to gibbsite, tubular halloysite, and amorphous aluminosilicate minerals. The gibbsite precipitated as aggregates of tiny plates deep in the profile. This mineral then resilicated into a tabular halloysite pseudomorphic after the gibbsite.There was very little evidence of amorphous materials throughout the profile but apparently amorphous spheres formed on the surface of feldspars and quartz in the weathering rock. These amorphous spheres seemed to radially crystallize into tube‐shaped minerals, presumably halloysite. Halloysite in the deep saprolite later recrystallized, via a randomly‐interstratified phase, to plate‐shaped kaolin minerals. Morphology of the 1:1 layer aluminosilicates did not provide evidence for degree of crystallinity as determined by X‐ray diffraction; poorly crystalline plate‐shaped and more highly crystalline tube‐shaped kaolin minerals were found in the same profile.
Inhibition by Xanthates of Nitrification and Urea Hydrolysis in Soil
Authors: Ashworth J. , Akerboom Helen M. , Crépin J. M. 
Published: July 2010

AbstractInhibition of urease activity and of nitrification by potassium xanthates was measured by adding them to soil amended with urea or (NH4)2SO4 and determining the urea remaining or nitrate produced after incubation at 23°C. The xanthates of unsubstituted alcohols of low molecular weight were the best inhibitors of urease and nitrification. The effectiveness of nitrification inhibition was not well correlated with the amounts of CS2 evolved from soil treated with xanthates in sealed Conway units.
The Magnesium Problem in Nitrate Determination by Steam Distillation
Authors: Clausen C. , Bock B. R. , Peterson G. A. , Olson R. A. 
Published: July 2010

AbstractSteam distillation of NH3 is commonly used to quantify the amount of mineral N in soil and plant materials. A problem with NO3‐ recovery by this method was encountered in an NH3 volatilization study. When NH4NO3 solutions were collected in acid and analyzed for NH4+‐N and NO3‐‐N, incomplete recovery of NO3‐ occurred. As the volume or normality of H2SO4 added to the distilling solution increased, more of the MgO used to raise the pH of the distilling solution was solubilized, which caused NO3‐ recovery in the first 25ml of distillate to decrease. Only 80% NO3‐‐N recovery was obtained with 20 ppm of Mg2+ in the distilling solution. Soils with 3 meq exchangeable Mg2+/100 g depressed NO3‐‐N recovery by 15% using the standard distillation procedure. An interaction between Mg2+ and Devarda's alloy evidently inhibits NO3‐ reduction.
Evaluation of Phosphorus Fixation Capacity of Tropical Savannah Soils of Western Nigeria
Authors: Ayodele Olufemi , Agboola Akinola A. 
Published: July 2010

AbstractIt is generally believed that tropical soils fix most Phosphorus (P) applied as fertilizers into forms not available to plants. To study fixation characteristics of savannah soils of western Nigeria, 22 surface soil samples varying in cropping histories, physical and chemical properties, and derived from igneous and metamorphic rocks were evaluated for capacities to fix soluble‐P with time.The fractional recovery (FR) which is the proportion of added P extracted by Bray's P1 (0.03N NH4F + 0.025N HCl) decreased with time following a pattern of rapid decline during the first few days of incubation and a slower decline thereafter. The decrease suggests an exponential relationship, and fits into the equationFR = ‐K ln t + C.The equations were used in calculating probable residual values of applied‐P at times within or outside the range of the experimental period.The high FR and residual values indicate that these soils fix little P in contrast to earlier‐held views about the P‐fixation capacity of tropical soils. The FR was significantly correlated with organic matter, clay, citrate‐dithionite‐extractable oxides of Fe and Al while there was no correlation with soil pH.
Trace Metal Complexation by Fulvic Acid Extracted from Sewage Sludge: I. Determination of Stability Constants and Linear Correlation Analysis
Authors: Sposito Garrison , Holtzclaw K. M. , LeVesque‐Madore C. S. 
Published: July 2010

AbstractThe complexes formed between either Cd2+ or Pb2+ and fulvic acid extracted from sewage sludge mixtures were investigated by potentiometric titration of K/H fulvate with either Cd(ClO4)2 or Pb(ClO4)2 at pH 5.0 and 25°C, in an ionic medium of 0.1M KClO4. Formation functions were calculated from the titration data and analyzed by the Scatchard plot method. The results were similar to those obtained previously for sludge‐fulvic acid complexes of Ca2+ and Cu2+, in that two classes of complexes were found for both Cd2+ and Pb2+. The common logarithms of the measured conditional stability constants for the two types of complexes with sludge‐derived fulvic acid were hypothesized to be linearly correlated with the Misono softness parameter, which is a quantitative measure of the tendency to covalent bonding on the part of a metal cation. The resulting linear correlation equations had r2‐values ≥ 0.99 and, therefore, were used to predict conditional stability constants for complexes of sludge‐derived fulvic acid with Mg2+, Mn2+, Fe2+, Ni2+, and Zn2+, which cannot be investigated by the method of potentiometric titration.
Calcium Phosphate Precipitation: Identification of Kinetic Parameters in Aqueous Limestone Suspensions
Authors: Brown J. L. 
Published: July 2010

AbstractPhosphate disappearance from aqueous calcitic limestone suspensions was described using an equation for interface‐, controlled crystal growth following addition of hydroxyapatite seed crystals. Phosphate removal from solution exhibited second order dependence on the phosphate concentration. Hydroxyapatite seed crystals were more important than limestone in governing phosphate removal. Limestone functioned primarily to buffer the activities of (Ca2+) and (OH‐). At pH 8.5, an increase of 0.1‐millimolar (mM) NaF caused a fivefold increase in the rate constant. Twenty successive reactions of limestone with phosphate caused a fourfold increase in the phosphate removal rate. A portion of freshly precipitated calcium phosphate probably served as seed for development of new crystals. Participation of both (F‐) and hydroxyapatite crystals suggests a mixture of fluorapatite and hydroxyapatite, or an apatite precursor formed in the experiments.
Residual Effects of Phosphorus Applications on a High Phosphorus Adsorbing Oxisol of Central Brazil
Authors: Yost R. S. , Kamprath E. J. , Naderman G. C. , Lobato E. 
Published: July 2010

AbstractHigh crop yields on P‐deficient Oxisols are not possible without application of relatively high amounts of fertilizer P. Correction of P deficiency can be accomplished by an initial broadcast application of a high rate of P or by lower rates of P applied as a band treatment or combination broadcast and band treatment. The residual effect of such P applications is influenced by the rate and method of application. A field study was established on a Haplustox in the Cerrado of Contral Brazil to evaluate the residual value of applied P as measured by corn yields and soil P analyses.Comparisons were made of the residual‐P effectiveness where a total of 140, 280, and 560 kg P/ha were applied initially as one broadcast application or, in equal increments as banded applications, to the previous four crops.With a total application of 140 and 280 kg P/ha, the residual P from the banded applications gave greater corn yields and P uptake than the initial broadcast applications. At the 560 kg P/ha rate, where yields were nearly maximum, there were no differences in yield due to the application method.Soil test P levels indicated a considerable residual effect from the higher rates of broadcast P. Fractionation of soil P indicated a conversion with time of more soluble forms of P to less soluble forms. Estimates of P requirements from P. sorption curves suggested a residual efficiency of 40–60% of the previously broadcast fertilizer P. Although clayey Oxisols have a high P requirement for maximum yields, there is a considerable residual effect of fertilizer P which needs to be included in estimates of the efficiency of P fertilization.
Effects of Litter Alteration on Carbon Dioxide Evolution from a South Carolina Pine Forest Floor
Authors: Reinke J. J. , Adriano D. C. , McLeod K. W. 
Published: July 2010

AbstractA field study in the upper Coastal Plain of South Carolina was conducted to evaluate the impacts of several litter manipulations on carbon dioxide evolution from a longleaf pine (Pinus palustris Mill.) forest floor. These manipulations, which included prescribed burning, removal of the L‐layer material (red straw), and total litter (O1 and O2 horizons) removal, were compared with undisturbed control treatment using a static alkali absorption technique for CO2 measurement.Though slight reductions were noted, the burning and removal of the L‐layer material had less effect on the evolution of CO2 from the forest floor than total litter removal. Total litter removal, however, significantly reduced the average rate of CO2 evolution by approximately 22% (p ≤ 0.05). The amount of CO2 evolved was sensitive to rainfall and air temperature, showing declines in periods of drought and cool temperature. However, on an annual basis, the air temperature was much more important than rainfall in estimating the CO2 evolution. The burning treatment increased the pH and nitrogen concentrations of the litter and the soil pH at the 0 to 5‐cm depth. The calculated net annual respiration (CO2‐C production), exclusive of root metabolism, was approximately equivalent to 95% of the C input from litterfall deposited on the ground during this period, indicating that perhaps the accumulation of litter has reached a steady state condition.
Influence of Spartina Alterniflora on Nitrogen Loss from Marsh Soil
Authors: Buresh R. J. , DeLaune R. D. , Patrick W. H. 
Published: July 2010

AbstractThe influence of Spartina alterniflora, a common salt marsh macrophyte, on loss of NH4+‐N from a Louisiana salt marsh soil was examined in the greenhouse. Labelled NH4+‐N, equivalent to approximately 100 µg N/g soil, was added in 10 installments over 18 weeks to undrained soil cores with and without stands of S. alterniflora. In the presence of S. alterniflora, 93% and 94% of the added N was recovered from constantly flooded and alternately flooded and dried soil, respectively. In the absence of S. alterniflora, loss of added NH4+‐N was greater; only about 56% of the added N was recovered from constantly flooded soil. Actively growing S. alterniflora apparently assimilated the inorganic soil N before it could be lost in gaseous form via nitrification‐denitrification reactions.
Automated Aluminum Analysis with the Aluminon Method
Authors: Bertsch P. M. , Alley M. M. , Ellmore T. L. 
Published: July 2010

AbstractAn automated method of aluminum analysis by the aluminon (ammonium salt of aurin tricarboxylic acid) procedure is described. The method employs ascorbic acid for removal of Fe(III) interference and eliminates, with proper sample pretreatment, the need for a protective colloid. The calibration curve has a correlation coefficient > 0.99 and a standard deviation around the regression line of ± 0.07 absorbance units up to 1.2‐ppm Al in solution. Standard autoanalyzer components are utilized in the system and computer interfacing is possible.
Properties of the Sorptivity for Exponential Diffusivity and Application to the Measurement of the Soil Water Diffusivity
Authors: Braddock R. D. , Parlange J. Y. , Lisle I. G. 
Published: July 2010

AbstractFor certain diffusivities, first integral techniques can be used to decouple the soil‐water diffusion equation, in similarity form, into a set of first‐order equations. Such a decoupling is possible where the diffusivity depends on the water concentration, as either a power law or as an exponential function. Here we show that the exponential case is related to the power law case, but with some resulting complications.For this class of diffusivities, the solutions form a special class, and we generate some of their properties. In particular, the sorptivity can be represented by a simple relation to a universal function of the water content. This function is tabulated and compared with results obtained by another method, i.e., optimization. The results are applied to the measurement of soil‐water diffusivity.
Sodium‐Calcium Exchange in Nile Delta Soils: Single Values for Vanselow and Gaines‐Thomas Selectivity Coefficients
Authors: Sheta Tarek H. , Gobran George R. , Dufey Joseph E. , Laudelout Henri 
Published: July 2010

AbstractNa‐Ca exchange measurements were carried out on 11 representative soils from the Nile Delta. Experiments were conducted over a wide range of exchanger compositions. Due to their common alluvial origin, all soils showed identical exchange properties.The experimental data appeared to be well described either by a single Vanselow selectivity coefficient or by a single Gaines‐Thomas coefficient. The Gapon coefficient, as originally defined, increased linearly with the exchangeable calcium fraction (or decreased with ESP). After examining the sensitivity of those coefficients to experimental errors, as a function of the exchanger composition, values of 5.97 and 2.30 mol/liter were calculated for the Gaines‐Thomas and Vanselow coefficients, respectively. These correspond to a Gapon coefficient as redefined by Sposito equal to 48 (mol/m3)½.
Leaching of Fertilizer Ions in a Ultisol from the High Rainfall Tropics: Leaching Through Undisturbed Soil Columns
Authors: Pleysier J. L. , Juo A. S. R. 
Published: July 2010

AbstractDownward movement of applied Ca3+, Mg2+, K+, and NO3‐ in a coarse‐textured, kaolinitic Ultisol profile was studied in the laboratory using undisturbed soil columns. The soil columns were leached with an amount of water equivalent to the annual rainfall of the sampling site (2,420 mm) through a rainfall simulator over a period of 72 days. Added nitrate in the forms of Ca, Mg, or K salts leached readily through the profile. Nitrate leached mainly with Al3+ ions. Cations leached differentially, depending upon the exchange selectivity of the soil and upon the surface loading of the cation in question. The leachability of the cations under the experimental conditions follows the order K < Al ≈ Ca ≈ Mg < Na.The vertical distribution of added Ca in the leached profile may be predicted by Walter's formulation of ion exchange chromatography.The limed soil columns retained more Ca in the surface layer than the columns treated with Ca(NO3)2 when an equal amount of Ca was applied.
Grazing of Blue‐Green Algae (Cyanobacteria) in Flooded Soils by Cypris sp. (Ostracoda)
Authors: Grant Ian F. , Alexander Martin 
Published: July 2010

AbstractGrazing by the microcrustacean, Cypris, on five species of 14C‐labelled N2‐fixing blue‐green algae (cyanobacteria) in flooded soils indicated diet preferences among the algae. Animal size and floodwater temperature markedly affected feeding rates, but pH had little effect from pH 5.0 to 10.0. Control of feeding was achieved with low concentrations of lindane. Cell size of the blue‐green algae was not apparently responsible for diet selection, but cell age was significant with two species. It is suggested that nitrogen fixation by blue‐green algae in paddy fields may be increased by using inocula of algae not suitable for active grazing or by suppressing grazing by means of insecticides.
Long‐Term Recovery of Fertilizer Nitrogen Applied to a Native Mixed Prairie
Authors: Power J. F. 
Published: July 2010

AbstractPrevious research on perennial grassland soils has generally shown that a large part of any fertilizer nitrogen (N) added is immobilized in grass roots or in soil organic matter. Few studies have measured the amount of such immobilized N that eventually becomes mobilized and taken up by plant growth in subsequent years. In this experiment, up to 540‐kg fertilizer N/ha was applied to native mixed prairie in North Dakota during a 1‐ to 6‐year period, and residual effects of these treatments on grass production were followed until no further plant growth response was measured. When a total of 270‐ or 540‐kg N/ha had been applied, plant growth responses were measured for up to 9 years after fertilization ceased. As fertilizer N rate decreased, length of residual effects likewise decreased. Part of the residual response may have resulted from increased density of cool‐season grasses where higher N rates were applied. Growth responses after fertilization ceased were often greater when fertilizers were applied over a 6‐year period, rather than applying an equal quantity of fertilizer N all in 1 year. For the 540‐kg N/ha treatment, as much as 12% of the fertilizer N applied was recovered in top growth after fertilization ceased. Assuming that all increased inorganic N in the soil resulting from fertilization was used by plants during the residual period, and that the remaining fertilizer N taken up by top growth after fertilization ceased came from mobilization of fertilizer N present in grass roots in 1968, then an estimate can be made of availability of fertilizer N in roots. Maximum value for such an estimate was 44‐kg N/ha, leaving 60‐ to 160‐kg fertilizer N/ha permanently immobilized as this root material decomposed. Thus, when 270‐ or 540‐kg fertilizer N/ha was applied, typically about 30% was permanently immobilized by absorption into root material during the period of fertilization, 35% was removed in top growth, and 35% was either immobilized permanently in soil organic matter or lost by gaseous means.
Comparisons of Arithmetic Average Soil pH Values with the pH Values of Composite Samples
Authors: Baker A. S. , Kuo S. , Chae Y. M. 
Published: July 2010

AbstractClose agreement was found between arithmetic mean pH values of limed samples and the pH values of composited samples. Agreement was consistently and considerably poorer when pH values were converted to H‐ion activities [(H+)] before averaging. Results are explained by the greater linearity between soil pH and base saturation (BS) in the acid range of mineral soils than between (H+) and BS. Linearity can be assessed by comparing average pH values with those of composited samples.
Release of NH4+ in Soils by Oven Drying
Authors: Frye W. W. , Hutcheson T. B. 
Published: July 2010

AbstractThere is often a pronounced increase in exchangeable NH4+ content when soils are dried, particularly when oven‐dried. The origin of the NH4+ is unknown. The objectives of this study were (i) to determine the effects of oven drying on the release of NH4+ in soils with different properties, and (ii) to evaluate possible sources that may account for the release. Samples form the Congaree, Davidson, Huntington, and Maury soils were oven‐dried at 110°C for 24 hours and analyzed for 2N KCl‐extractable NH4+ (exchangeable NH4+) and NO‐3. Values for moist samples of soils were subtracted from values for oven‐dried soils to determine the amounts of NH4+ released by drying. The amounts ranged from 5 to 20 ppm N, with the greatest amounts released from the top 30 or 45 cm of the Davidson and Maury soils. Generally, the amount of NH4+ released by oven drying decreased with depth in the soils. Monochloracetic acid (CH2ClCOOH) extracted more NH4+ than did KCl from oven‐dried surface samples of the Congaree and Davidson soils, but there was little or no difference in the amounts of NH4+ extracted by the two solutions from moist samples of Ap horizons or from samples below the Ap horizons, whether moist or oven‐dry. These results suggest an organic source of NH4+ in the Ap horizons. The relatively large amount released from deep in subsoils suggests the presence of an inorganic source also. We conclude that NH4+ is released from both organic and inorganic compounds during oven drying. Nonexchangeable NH4+ in interlayers of clay minerals usually increased with oven drying. We therefore conclude that nonexchangeable NH4+ is not a source of released NH4+. In fact, some of the NH4+ released by oven drying appears to be simultaneously fixed as nonexchangeable NH4+ in certain cases. The organic source of NH4+ is probably several constituents of rather highly decomposed soil organic matter. The inorganic source is thought to be NH4+‐phosphate complexes, perhaps taranakite‐like compounds. Further research is needed to identify specific sources.