bluuebunny/crossref_metadata_2025_split huggingface dataset:
Adsorption of Copper and Lead by Ap and B2 Horizons of Several Northeastern United States Soils
Authors: Harter Robert D. 
Published: July 2010

AbstractAdsorption of Cu and Pb by surface and subsurface samples of fifteen soils was ascertained. Soil adsorption maxima were derived from the reciprocal of the slope obtained by a least squares fit of “Langmuir” plots for each soil. The adsorption maxima were then regressed against various chemical and mineralogical properties of the soils in an attempt to deduce mechanisms of adsorption as well as to determine whether any commonly measured soil quantity could serve as a predictor of adsorption. The best predictor of adsorption by all samples was sum of bases, which explained 84 and 76% of the variation in Cu and Pb adsorption, respectively. In the subsurface horizons, the adsorption of both Cu and Pb was significantly related to vermiculite content (r2 = 0.78 and 0.85, respectively), but sum of bases was still a better prediction for these horizons alone (r2 = 0.83 and 0.92, respectively). Organic matter content had no significant relationship to adsorption by surface horizons.
Influence of Phosphate Fertilization on Zinc Adsorption by Tropical Soils
Authors: Saeed M. , Fox R. L. 
Published: July 2010

AbstractZinc adsorption isotherms were constructed for five soils from Hawaii which varied in mineralogy and history of phosphate fertilization. Equilibrating conditions were: 25°C, 0.01M CaCl2, soil solution ratio of 1:10, and 6 days. The amount of Zn added ranged from 0 to 600 µg/ml as ZnSO4 · 7H2O. Equilibrium was reached by 72 hours.Unfertilized soils which contained predominantly constant charge colloids absorbed more Zn than soils with variable charge colloids. Phosphorus fertilization increased Zn adsorption by soils that contained colloids predominantly of the variable charge type. The results support the hypothesis that phosphate additions to soils increase Zinc adsorption by increasing the negative charge on iron and aluminum oxide systems. For soils containing constant charge colloids, prior P applications decreased Zn sorption because the fertilizer contained Zn as an accessory element. Zinc sorption conformed to the Freundlich model at concentrations greater than 0.1 ppm Zn in solution.
Phosphorus Availability in a Calcareous Soil After High Loading Rates of Animal Manure
Authors: Meek B. D. , Graham L. E. , Donovan T. J. , Mayberry K. S. 
Published: July 2010

AbstractThe fixing of phosphorus (P) added to calcareous soils is rapid but can be reduced by applying organic sources. The objectives of this study were to measure in the field the residual NaHCO3‐extractable P resulting from manure applications at high rates and to contrast the NaHCO3‐extractable P levels for manure vs. inorganic P fertilizers.When inorganic P was applied at 490 kg/ha for each of 2 years the NaHCO3‐extractable P was increased from 16 to 31 ppm at the 0‐ to 30‐cm depth. The application of 98 kg/ha of P as triple superphosphate each of 2 years applied just before planting lettuce (September‐October) was as effective for increasing NaHCO3‐extractable P during the lettuce‐growing season (November 1976) as applying 490 kg/ha of P in May or June each of 2 years.High rates of P (5,344 kg/ha) applied from manure sources (treatment 720E) resulted in high levels of NaHCO3‐extractable P up to 377 ppm. Total application of more than 360 metric tons/ha of manure (2,672 kg P/ha) resulted in movement of P to the 30‐ to 60‐cm depth. The increased level of NaHCO3‐extractable P from a manure application (treatment 360B) was still evident in the 0‐ to 30‐cm depth 6 years after manure application had ceased.The application of 392 kg P/ha as triple superphosphate for each of 2 years increased the NaHCO3‐extractable P over the check by 11 ppm (November 1976). In contrast, the application of 334 kg P/ha from applied manure (treatment 180B) each of 2 years increased the NaHCO3‐extractable P over the check (after harvest in 1972) by 100 ppm.
Relationship of Ammonium Nitrogen Distribution to Mineralogy in a Hapludalf Soil
Authors: Sparks D. L. , Blevins R. L. , Bailey H. H. , Barnhisel R. I. 
Published: July 2010

AbstractDistribution of fixed and exchangeable ammonium were examined in three soil profiles of the Shrouts series from the Knobs region of eastern Kentucky. Shrouts soils (fine, mixed, mesic, Typic Hapludalfs) have high base status; exhibit strong, prismatic structure; and are derived from calcareous, high magnesium, soft (weakly cemented) clay shale. Soil pH ranges from 6.3 in the Ap horizon to 7.9 in the C. Analyses, using the Silva and Bremner procedure, showed considerable fixed NH4+‐N in all horizons of each profile. Mean fixed NH4+‐N in the profiles was 365 ppm for the Ap, 463 ppm for the B21t, 433 ppm for the B22t, 469 ppm for the C, and 543 ppm for the Cr horizons. Exchangeable NH4+‐N also increased with depth, with values being about 1.2 to 1.5% of the fixed NH4+‐N values. X‐ray diffraction analyses of the clays and silts revealed predominantly mica in the 2–0.2 and <0.2 µm fractions, with some vermiculite present, and large quantities of mica in the silt fractions. High correlation (r = 0.92) was found between fixed NH4+‐N and exchangeable NH4+‐N. A correlation exists between fixed NH4+‐N and mica + vermiculite content with an r value of 0.68. The fixed NH4+‐N in the lower horizons is presumed to be indigeous, since no NH4+‐N has been added recently to the soil.
Titration Behavior of Aluminum Organic Matter
Authors: Bloom P. R. 
Published: July 2010

AbstractAn Aluminum (Al)‐substituted peat containing one equivalent of Al3+ per equivalent of carboxyl groups was titrated potentiometrically in a range of NaCl concentrations. The family of titration curves generated was similar to that obtained with many acid soils. Comparison of the data from the Al‐peat with soils having a similar pH (3.9) at the apparent zero point of charge showed that the contribution of Al organic matter to H+ and OH‐ adsorption during potentiometric titrations is likely very significant and that Al on organic matter likely influences the displacement of the apparent zero point of charge from the zero point of titration.
Soil Heat Transducers and Water Vapor Flow
Authors: Cary J. W. 
Published: July 2010

AbstractThe heat flow through a silt loam, silty clay, and loamy sand were measured in a calorimeter at 7 and 36°C under matrix potentials near −0.3 bars. The transient thermal conductivity probe, the heat flux transducer, and deVries's theoretical method all gave low values of the apparent thermal conductivity at 36°C. An empirical correction was proposed for deVries's method that improved its agreement with the observed conductivities. The thermal vapor diffusion coefficients for the three soils were then calculated from his equation and compared with experimental values from the calorimeter. It was also shown that the thermal water vapor flow can be estimated if one knows the soil's saturated thermal conductivity, quartz content, water content, bulk density and temperature distribution.
Zinc and Copper Solubility as a Function of pH in an Acid Soil
Authors: McBride M. B. , Blasiak J. J. 
Published: July 2010

AbstractStudies of the effect of pH and competing cations on Zn2+ and Cu2+ solubility in an acid mineral soil indicate the probable involvement of hydrous oxides of iron, aluminum, or manganese in the adsorption process. Adsorption on permanent charge sites of clays, or complexation with organic matter could not account for the apparent fixation of Zn2+ in a nonexchangeable form in the pH range of 5 to 7. Nucleation of Zn hydroxide on clay mineral surfaces may have produced the strongly pH‐dependent retention in the soil; however, Cu2+ showed more evidence of being controlled by organic complexation mechanisms. All soil solutions were undersaturated with respect to the least soluble hydroxides and carbonates of Cu2+ and Zn2+, at least at pH values below 7, indicating that simple precipitation was not involved in metal retention in the soil.
Purines and Pyrimidines in Soils and Humic Substances
Authors: Cortez J. , Schnitzer M. 
Published: July 2010

AbstractPurines and pyrimidines were determined by ion‐exclusion chromatography in soils and humic substances of widely differing origins. Concentrations of purines + pyrimidines ranged from 20.9 to 137.7 µg per g of dry soils, from 210.8 to 810.0 µg per g of dry, ash‐free humic acids, and from 294.3 to 1086.6 µg per g of dry, ash‐free fulvic acids. Quantitatively the distribution in soils was as follows: guanine > cytosine > adenine > thymine > uracil. Humic acids were richer in guanine and adenine but poorer in cytosine, thymine and uracil than were fulvic acids. Guanine + cytosine over adenine + thymine ratios for soils and humic substances averaged > 2 and methyl cytosine was not detected, suggesting a microbial DNA origin for the nucleic acid bases extracted. The proportion of total N in purines + pyrimidines was inversely proportional to the total N content. An average 3.3% of the total N in the inorganic soils but only 0.3% of the total N in the organic soils analyzed were found to occur in nucleic acid bases.
Phosphorus Toxicity as a Factor in Zinc‐Phosphorus Interactions in Plants
Authors: Loneragan J. F. , Grove T. S. , Robson A. D. , Snowball K. 
Published: July 2010

AbstractThis study examined the hypothesis that accumulation of P to toxic levels in plant tissues may explain reported effects of high P in increasing the Zn requirement of plant tissues. It also examined the contribution of other mechanisms to the complex interaction of Zn and P fertilizers on plant growth.Three levels of Zn and P fertilizers were applied to a siliceous and a ferruginous sand with low and high capacities to react with P, respectively. Application of P fertilizer induced or enhanced symptoms resembling Zn deficiency in subterranean clover (Trifolium subterraneum L.) in three distinct ways:1) On the ferruginous sand but not on the siliceous sand, it induced Zn‐deficiency by depressing Zn absorption.2) Where P limited growth, additional P depressed Zn concentrations and induced Zn deficiency in plants by promoting growth thus diluting available Zn supplies.3) Where P did not limit growth, additional P increased P concentrations to toxic levels producing necrotic symptoms in old leaves and depressing growth.Where plant tops had high Zn concentrations (> 40µg/g), P toxicity produced nectrotic symptoms in the absence of any of the characteristic symptoms of Zn deficiency. Where plant tops had low Zn concentrations (< 16µg/g), the necrotic symptoms developed in addition to the characteristic Zn‐deficiency symptoms of bronzing and chlorosis of old leaves and “little leaf” of young leaves thus strongly enhancing the apparent severity of Zn deficiency. Zn deficiency strongly enhanced P toxicity at the middle and high levels of P application apparently by limiting plant growth and concentrating the available P in plant tissues.The enhancement of P toxicity by Zn deficiency explains reports that high P increases Zn requirements of plant tissues. It will occur more easily in plants grown in sand and water culture than in plants grown on soils with some capacity to react with P.
Fate of Tagged Fertilizer Nitrogen Applied to Winter Wheat
Authors: Olson R. V. , Murphy L. S. , Moser H. C. , Swallow C. W. 
Published: July 2010

AbstractA field experiment using ammonium sulfate tagged with 7.65 A% 15N was conducted to assess how rates and times fertilizer is applied influence the fate of N applied to winter wheat (Triticum aestivum L.). Bottomless metal boxes were pressed 142 cm into the soil to confine the tagged fertilizer. Treatments, replicated four times, consisted of two rates (50 and 100 kg N/ha) and two application times (fall and spring). Fertilizer N used by the crop and that remaining in the upper 180‐cm of the soil after harvest were measured. Amounts of ammonium‐N and nitrate‐N from the fertilizer in the 0 to 10‐cm layer also were determined.The N balance indicated 9.7 – 10.3 kg N/ha were unaccounted for at the 50‐kg N rate and 19.7 · 23.4 kg, at the 100‐kg rate. Losses did not differ significantly between application times. With 100 kg/ha the crop removed significantly more fertilizer N, and significantly less remained in the soil with spring than with fall applications. The crop used similar amounts of total N in each case, but with the spring applications more fertilizer N but less soil N was taken up. Fertilizer applications caused no priming effect on mineralization of indigenous soil N. Most of the fertilizer remaining in the soil was in the 0 to 10‐cm layer, with no evidence of N moving deeper than 50 cm, so losses were from gaseous loss rather than leaching.Most of the fertilizer N in the 0 to 10‐cm layer of soil after harvest was immobilized, with only 9.6 – 11.5% remaining in inorganic forms. Immobilization was the principal reason for differences in spring and fall applications and for limited leaching. The percentages of NH4+‐N and NO3‐‐N, which originated from the fertilizer were 4 – 8 times the percentages of total N from the fertilizer, so more fertilizer N was in inorganic forms than was the case with indigenous soil N. Since there was a direct relationship between amounts of NO3‐‐N in the surface soil from fertilizer and amounts of N unaccounted for, it was concluded that gaseous losses resulted from denitrification processes.
The Role of Mycorrhizae in the Interactions of Phosphorus with Zinc, Copper, and Other Elements
Authors: Lambert D. H. , Baker D. E. , Cole H. 
Published: July 2010

AbstractMycorrhizae increase the uptake of Zn and Cu by many plants, but mycorrhizal activity is suppressed by P fertilization. Soybean (Glycine max Mer.) and two lines of corn (Zea mays L.) were used to determine if this mechanism is a major cause of P‐induced Zn and Cu deficiencies. Shoot dry weights and concentrations or total uptake of P, Zn, Cu, Fe, Mn, K, Ca and Mg were determined for mycorrhizal and nonmycorrhizal plants given 0, 25, 75, or 200 ppm P. Phosphorus fertilization significantly reduced Zn and Cu concentrations in mycorrhizal soybeans, but concentrations in nonmycorrhizal treatments were not affected. Concentrations of Zn and Cu in mycorrhizal and nonmycorrhizal corn were reduced by P fertilization, but the reduction for mycorrhizal plants was significantly greater than the decrease for nonmycorrhizal plants. Reductions in Zn and Cu concentrations in nonmycorrhizal corn were the result of a dilution effect and could be attributed to increased plant size rather than increased P fertility per se. The concentrations of the other analyzed elements were all affected by P level and/or mycorrhizal condition. In general, mycorrhizal and non‐mycorrhizal dry weights and element concentrations converged as soil P was increased. Patterns of response to P and mycorrhizae differed slightly between corn lines, and such differences were marked for certain elements when corn was compared with soybean.
The Nature and Forms of Sulfur in Organic Matter Fractions of Soils Selected Along an Environmental Gradient
Authors: Bettany J. R. , Stewart J. W. B. , Saggar S. 
Published: July 2010

AbstractThe role of S in humus formation and transformation was hypothesized on the basis of C/N/S ratio and percent HI‐reducible S determinations on organic fractions obtained from soil Ap horizons by a 0.1M NaOH − 0.1M Na4P2O7 (pH 13.0) extraction‐separation technique. Differences in C/N/S ratios of the conventional humic acid (HA‐A) fractions were greater (from 113:10.6:1 to 270:23.3:1) than those of the total soil organic matter (61:6.5:1 to 112:9.7:1) in soils along an environmental gradient delineated by semiarid Chernozemic Brown to sumhumid Luvisolic Gray soils. This fraction (HA‐A) is thought to represent the end product of the humification process. Differences in C/N/S ratios of conventional fulvic acid (FA‐A), clay associated humic acid (HA‐B) and <2 µm humin were smaller than for HA‐A along the gradient. On the basis of C/N/S ratios and the average percentage of HI‐reducible S in each fraction, e.g. HA‐A, 26%; HA‐B, 44%; FA‐A, 82%; and <2 µm humin, 52%; it was postulated that FA‐A, HA‐B, and <2 µm humin contained the majority of potentially labile S.
Nutrient Losses from a Forest Soil as Affected by Nitrapyrin Applied with Granular Urea
Authors: Bengtson George W. 
Published: July 2010

AbstractNitrapyrin (2‐Chloro‐6‐(trichloromethyl)pyridine) effects on nitrate production in a forest soil (Bladen fsl) of the Lower Coastal Plain of Florida were evaluated in a pot study. Nitrapyrin (as N‐Serve® 24) was applied to the soil with two rates (25 and 100 ppm) of N as granular urea; for each N rate a range of nitrapyrin concentrations (0, 0.5, 1.0, 2.0, and 4.0% of the urea‐N) was evaluated. Postfertilization leaching of N and of other nutrients and growth and nutrient uptake by seeded slash pine (Pinus elliottii var. elliottii Engelm.) were observed in unlimed (pH 5.2) and limed (pH 6.5) soil.Nitrapyrin effects were most apparent in limed soil and at the higher N and nitrapyrin rates. In general nitrapyrin concentrations below 2.0% of the urea‐N and below approximately 4.0 kg of nitrapyrin/ha were ineffective. Effectiveness increased up to the highest concentration (4.0%) and the highest rate (8.0 kg/ha). Leaching data indicate that the duration of the nitrapyrin inhibition of nitrification was from 5 to more than 10 weeks. Nitrapyrin to 8.0 kg/ha did not affect germination of slash pine seed.Seedling N uptake and growth were reduced in proportion to nitrate‐N leaching losses. Quantities of K, Ca, and Mg in leachates were also correlated with leached nitrate‐N, but tissue analyses indicated that growth deficits associated with leaching were due primarily to N deficiency. In limed soil heavily fertilized with urea‐N, results also suggest some benefits to pine seedling growth and N utilization associated with inhibition of nitrification apart from those attributable to reduced leaching losses of nitrate.
A Hysteresis Model Based on an Explicit Domain‐Dependence Function
Authors: Mualem Y. , Miller E. E. 
Published: July 2010

AbstractA quantitative model of hysteresis is proposed, assuming the pore‐water blockage against air entry to be a direct function of the volume of pore domains located in the completely‐filled region of the state diagram. The relative volume of the porewater domains θo, evaluated from the history of the capillary head ψ assuming the domains are independent, is employed in a dependency correction function P*d(θo). For calibration, this model requires only the main loop of hysteresis and one drying scanning curve. The merit of this “Model IIIexpl” compared with Model III (Y. Mualem, 1974b, Y. Mualem and G. Dagan, 1975) is that any hysteretic process of wetting and drying is expressed analytically in explicit form. This property simplifies the computational procedure and saves computer time in practical application.The overall agreement between predicted and measured hysteretic behavior is acceptable. However, the study reveals that in the range of the air entry value the model does not reproduce the main drying curve accurately if it diverges considerably from the drying scanning curve. This deficiency may reflect the less physical ground for Model IIIexpl compared to the implicit Model III.
Statistical Considerations for Evaluating Micronutrient Tests
Authors: Keisling T. C. , Mullinix Ben 
Published: July 2010

AbstractFor the purposes of making recommendations, micronutrient soil or tissue tests are basically classification procedures. The empirical test variable usually groups samples into three areas, i.e. a group containing mostly samples with no micronutrient problems, a second group containing mostly samples with the micronutrient problems, and a third group containing samples both with and without micronutrient problems. The third group described above can be thought of as occurring at a “transition zone” where the correct status of a sample is unidentifiable by the micronutrient test. Statistical methods using an interaction Chi‐Square are presented for identifying the boundaries of the “transition zone.”It is proposed that a micronutrient test be evaluated in terms of the proportion of successful recommendations. A successful recommendation results when the proper status of a sample is identified by the test. Under the assumption of random sampling from a stable population, the above evaluation scheme follows a binomial distribution. The computation of variances and confidence intervals is shown and discussed for the proportion of successful recommendations. A statistically valid method for comparing different empirical tests, such as extracting solutions, is shown and contrasted to previously used methods.
Ferruginous Beidellites in Turkish Soils
Authors: Özkan A. I. , Ross G. J. 
Published: July 2010

AbstractSmectites were found to be dominant in the clay fraction of five calcareous soils of different great soil groups from various areas of Turkey. Characterization by X‐ray, thermal, infrared, and chemical analyses of these smectites in a Terra Rossa, Vertisol, Rendzina, and Volcanic Ash profile showed that they resemble each other and are ferruginous beidellites having the average formula
urn:x-wiley:03615995:saj2sssaj197903615995004300060039x:equation:saj2sssaj197903615995004300060039x-math-0001The smectites also have relatively high Mg content and are similar to the beidellites in some African and Indian soils formed under alkaline weathering conditions. Soil solution analysis indicates that the smectites in the Turkish soils are stable. The smectites in these soils appear to be mainly inherited since they already are the dominant layer silicate in the parent material. The results of this and other investigations show that ferruginous smectites are of widespread occurrence and may be found in alkaline soils formed not only on ironrich but also on iron‐poor material.
Comparison of Field and Laboratory Determined Hydraulic Conductivity Values
Authors: Dane J. H. 
Published: July 2010

AbstractSeveral new methods of determining hydraulic conductivity (K)‐volumetric water content (θ) relations have been developed recently. Emphasis is on simplification of procedures that determine K(θ) relations in the field. This paper compares four different procedures by which K(θ) relations were determined for several horizons of a Troup loamy sand (Grossarenic Paleudults). The first procedure consisted of in situ measurements of water content and pressure head profiles following irrigation. All measurements were obtained with the soil surface covered to prevent evaporation. The data were used to calculate K(θ) values. The second procedure consisted of a model that used water retention curves and saturated K values determined on undisturbed core samples. The third method was a variation of the second in that water retention data were used as measured in situ. The fourth method used in situ measured water content data only. For the coarse textured soil used in this investigation the latter method was modified in that two empirical equations were needed instead of one to represent one K(θ) relation. All four methods resulted in K(θ) relations that were in fairly good agreement.