bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparisons of Human‐influenced and Natural Soils at the San Luis Archaeological Site, Florida
Authors: Collins M. E. , Shapiro Gary 
Published: July 2010

AbstractSoil‐human relationships of 10 archaeological test excavations were investigated at the San Luis Archaeological and Historic Site, Tallahassee. San Luis was a Spanish mission and Apalachee Indian village during the 17th century. The oldest dated archaeological soils are known to postdate 1520 (± 80) AD. A detailed topographic survey showed the locations of several 17th century features. Artifact distribution data indicated areas where soil development was affected by deposition of archaeological materials. Soil and archaeological observations were made at each excavation. Morphological features there (such as abrupt, smooth boundaries between layers; abrupt, laterally discontinuous layers; dark matrix colors extending to depths greater than expected; weakly‐developed soils as indicated by the lack of argillic or cambic horizons; and textures high in sand with mixings of clay in lower layers) were interpreted as the result of human activities. Several soil chemical and physical properties in the archaeological and buried soils differed. Total P contents were surprisingly low in the archaeological and buried soils, but extractable P amounts were high. Acidity values did not differ greatly in the archaeological and buried soils. Sand dominated the particlesize fraction in the archaeological soils. Clay contents increased as the buried soils were approached. Several of the soil properties studied in the archaeological and buried soils differed from the naturally occurring Orangeburg soil. Investigations at San Luis offered a rare opportunity in Florida to study anthrogentic soils.
Influence of Corn Residue on Compression and Compaction Behavior of Soils
Authors: Gupta S. C. , Schneider E.C. , Larson W.E. , Hadas A. 
Published: July 2010

AbstractCrop residues have low densities and are somewhat elastic in nature. The presence of these residues in the soil or at the soil surface might reduce the severity of soil compaction. The objective of this study was to investigate the compression and compaction behavior of soils in the presence of corn residue. Compression behavior of soil‐residue mixtures was studied in the laboratory using the uniaxial compression test. Treatments included three size fractions (0.25‐0.50, 1.00‐2.00, and 3.36‐5.66 mm) of corn residue, four amounts of residue addition, three soil water contents, and three soils (Webster clay loam, Sargent silt loam, and Zimmerman sand). Compression samples consisted of 60 g of wet soil mixed with 0.0, 0.5, 1.0, and 2.0 g of corn residue. The compression index of residue mixed Webster clay loam or Sargent silt loam was approximately the same for various amounts and sizes of corn residues. The compression index of Zimmerman sand increased slightly with an increase in the amount of corn residues. However, for a given amount of corn residue, there was no difference in the compression index of Zimmerman sand for various residue fractions. Bulk density at a reference stress (σk = 100 kPa) decreased slightly with an increase in the amount of corn residue addition. Assuming that the residues are uniformly mixed in the top 15 cm of soil or concentrated in the wheel track (one fourth of the surface area), calculations showed that corn residues available on the farm (6.7 t/ha assuming 100 bushel/acre corn yield) will have little influence on compression parameters and thus on compaction of soils. Influence of surface residues on field soil compaction was tested in an aboveground soil bin containing a top layer of Waukegan silt loam. Residue treatments included 0.0, 3.4, 6.7, and 10.1 t/ha of corn residues on the soil surface. Measurements included normal stress at 200‐mm depth under the center of a wheel track during the passage of a tractor, and soil sinkage and bulk density profile after the passage of a tractor. Differences in the maximum normal stress at 200‐mm depth were <80 kPa between bare and residue‐covered plots. This reduction in maximum normal stress is equivalent to a reduction in bulk density of 0.12 Mg m−3 due to the presence of corn residues. However, because of the soil variability, the bulk density profile showed no significant difference due to the presence of surface residues. In summary, both laboratory and field tests in this study showed minimal beneficial effects of using corn residues in reducing the compression and compaction of soils. This conclusion, however, assumes a maximum amount of 10.1 t/ha chopped corn residue that is approximately equal to a yield of 150 bushel/acre (assuming a grain to straw ratio of 1:1).
Relation Between Soil Properties and Effectiveness of Low‐cost Water‐harvesting Treatments
Authors: Emmerich W. E. , Frasier G. W. , Fink D. H. 
Published: July 2010

AbstractKnowledge of the relationship between soil properties and treatment performance is important to obtain maximum benefit from low‐cost water‐harvesting treatments. Six low‐cost water‐harvesting treatments were field tested on small plots by determining runoff percentages and threshold values at eight sites for 164 weeks. Effectiveness of all treatments decreased over time, with the order of effectiveness being: waxes > silicones ≥ control (smoothed soil). Regression equations were developed to predict runoff percentages and threshold values based on soil properties. These equations can be used in determining which water‐harvesting treatment would be most appropriate for a specific soil. All soil properties evaluated influenced the effectiveness of the water‐harvesting treatments. Therefore, relationships between specific soil properties and the effectiveness of the treatments could not be established. A set of important soil properties were identified for each treatment in the regression equations, but more research is needed to determine the absolute importance of the individual soil properties in the effectiveness of the treatments.
Ammonium Retention in Sand Amended with Clinoptilolite
Authors: Ferguson G. A. , Pepper I. L. 
Published: July 2010

AbstractClinoptilolite zeolite has a rigid three‐dimensional lattice with 10−9 m sized tunnels, and an affinity for NH+4 on its internal exchange sites. These internal tunnels are too small for 10−6 m size microbes to access; hence, clinoptilolite has the potential to physically protect NH+4 from nitrification by microbes, and may reduce volatilization losses. The objective of this study was to evaluate NH+4 retention of sand amended with clinoptilolite. Retention of NH+4 on clinoptilolite amended sands incubated at 20% volumetric water content, was studied in the laboratory. Treatments were washed mortar sand amended with 0, 5, and 10% clinoptilolite by volume and 2.38 and 3.57 moles of NH+4 m−3 of soil. Retention was evaluated by monitoring NH+4 loss from the soil mix. Loss of NH+4 decreased with increasing clinoptilolite amendment. Losses also decreased when the amount of NH+4 initially applied was decreased. The effect of clinoptilolite in retaining NH+4 was more pronounced when the amount of NH+4 initially applied was increased. Clinoptilolite reduced NH+4 losses from the soil mix and would allow increased plant N fertilizer‐use efficiency. Thus clinoptilolite‐amended sands have potential as a growth medium for turfgrasses on golf greens, where N use efficiency is typically low.
A Quick Method to Extract Organic Phosphorus from Soils
Authors: Soltanpour P. N. , Fox R. L. , Jones R. C. 
Published: July 2010

AbstractThe objective of this study was to develop a quick method for extracting organic P from soils. Organic P was extracted from soils by a proposed quick method (0.3 M NaOH sonified for 3 min) and compared with other methods: (i) sequential extraction with 0.3 M NaOH, concentrated HC1, and 0.5 M NaOH (modified Mehta method), and (ii) extraction of ignited (540°C) and nonignited samples with 0.5 M H2SO4 (Saunders and Williams method). The study used four soils with different mineralogies belonging to the following great groups: Hydrandepts, Fluvaquents, Haplustolls, and Gibbsiorthoxs. The proposed quick method extracted, on the average, 89% as much organic P as the modified Mehta method from the soils studied. In six out of ten samples the Saunders‐Williams method yielded more organic P than the other two methods, probably due to an increase in solubility of Fe and Al phosphate minerals after heating. It is concluded that the proposed quick method can be used to extract organic P from soils. It gives results comparable to the more tedious method of Mehta and is probably more accurate than the Saunders and Williams method for highly weathered soils.
A Method for Application of Nitrogen‐15‐Labeled Anhydrous Ammonia to Small Plots
Authors: Sanchez C. A. , Blackmer A. M. 
Published: July 2010

AbstractA method is described that permits precise application of anhydrous ammonia in bands to plots of the size often used in 15N‐tracer studies. This method involves placing a stainless‐steel capillary tube in the soil where the ammonia is to be banded, attaching this tube to a cylinder of ammonia, and then pulling the tube through the soil with deposition of ammonia as an even band. The procedure has marked advantages over previously described methods because it can be used with mixtures of anhydrous ammonia and nitrificaton inhibitors and because the soil environment at the point of application is representative of the soil environment found when a conventional applicator is used.
Calculations of Error Variances with Standardized Variograms
Authors: Warrick A. W. , Myers D. E. 
Published: July 2010

AbstractSample error calculations are presented for five common variogram models: exponential, spherical, Gaussian (double exponential), Langmuir (Michaelis‐Menton) and linear. Numerical results for standardized variograms are presented in a 9 × 10 table useful for finding the maximum estimation (kriging) variance for a rectangular pattern valid for any spacing, slope, integral scale, etc., for zero nugget. Results are calculated based on the use of four or twenty‐five nearest neighbors.
A Rapid Centrifugation Method for Obtaining Soil Solution
Authors: Elkhatib E. A. , Hern J. L. , Staley T. E. 
Published: July 2010

AbstractA modified centrifugation technique for obtaining soil solutions was developed and compared to immiscible displacement technique using different immiscible liquids. Coefficients of variation and standard deviations for ionic composition of soil solutions obtained by the modified centrifugation method were consistently lower than those of immiscible liquids. Differences in the estimated concentrations and activities for Ca, Mg, K, and Al among the methods employed to obtain soil solutions were noticed. The largest disagreement between activity values occurred for Al species. Such discrepancies necessitate the use of the modified centrifugation technique to obtain soil solution especially when Al determination and speciation are critical. The modified centrifugation technique offers a reliable, rapid, contamination‐free, and inexpensive method for obtaining soil solution for chemical characterization. Practical aspects of the technique (relative centrifugal force, centrifugation time, and filtering materials) are discussed.
Effect of Phosphorus and Zinc Fertilization on the Solubility of Zn2+ in Two Alkaline Soils
Authors: Norvell W. A. , Dabkowska‐Naskret H. , Cary E. E. 
Published: July 2010

AbstractConcentrations of Zn2+ in equilibrium with two alkaline soils were calculated from the reactions of EDTA (ethylenediaminetetraacetic acid) chelates. The initial speciation of EDTA was varied to allow equilibrium with Zn2+ concentrations in the soil to be approached from above and below. Fertilizer Zn was added at 0 to 5 mg kg−1 as ZnSO4 and reacted thoroughly with the soil before additions of P or EDTA chelates. Phosphorus was added at 0 or 62 mg kg−1 as a mixture of KH2PO4 and K2HPO4. Concentrations of soluble Zn2+ in unfertilized soil were extremely low, approximately 5 × 10−10 M in the noncalcareous soil at pH 7.2 and 1 × 10−10 M in the calcareous soil at pH 7.6. These Zn2+ concentrations were raised 7‐ to 14‐fold by 5 mg kg−1 of added Zn, and the higher levels persisted for at least 11 weeks. Buffering of Zn2+ by the soils was substantial, ranging from about 15 to 45 (nmol g−1)/(nmol L−1). Additions of P caused small decreases in the concentrations of Zn2+ and other divalent cations in solution. Only in the Zn‐fertilized calcareous soil were the percent decreases in Zn2+ greater than those of the major divalent cations, Ca2+ and Mg2+. This effect of P in the calcareous soil is of special interest because of its apparent selectivity for Zn, but the effect was small as shown by reductions of only 12 to 19% in the [Zn2+]/[Ca2+ + Mg2+] concentration ratio.
Supercritical Gas Extraction of a Soil with Solvents of Increasing Polarities
Authors: Schnitzer M. , Preston C. M. 
Published: July 2010

AbstractThe surface horizon of the Bainsville soil, an Aquoll, was extracted by supercritical gas (SCG) extraction with solvents of increasing polarities. These included n‐pentane, ethanol, and mixtures of ethanol and acetone with water. Each extract was analyzed by chemical and 13C nuclear magnetic resonance (NMR) methods. Proportions of alkanes, alkanoic acids, and carbohydrates in the extracts decreased as the polarity of the solvent increased. Conversely, proportions of aromatics increased with increasing polarity of the solvent. The presence of carbohydrates and amino acids in the SCG extracts, as indicated by 13C NMR, was confirmed by chemical methods. As the polarity of the solvent increased, concentrations of hexoses increased while those of pentoses, except for arabinose, decreased. Similarly, concentrations of basic amino acids increased under these conditions. Hydrolyzates of SCG extracts contained high concentrations of NH3. A mixture of acetone and water (40:60 v/v%) was found to be the most efficient supercritical gas extractant under the experimental conditions employed. Carbon‐13 NMR spectra of the SCG extracts were exceptionally well‐defined with sharp and distinct peaks revealing fine chemical structure. The distortion‐less enhancement by polarization transfer (DEPT) NMR technique was used to determine C multiplicity and to further enhance resolution. The combination of supercritical gas extraction with 13C NMR provides soil scientists with a powerful tool for generating important information on the chemical composition and structure of soil organic matter.
Effect of Zinc Deficiency on the Accumulation of Boron and Other Mineral Nutrients in Barley
Authors: Graham Robin D. , Welch Ross M. , Grunes David L. , Cary Earle E. , Norvell Wendell A. 
Published: July 2010

AbstractThe hypothesis that Zn deficiency enhances the accumulation of B in barley (Hordeum vulgare L.) was tested in plants grown in nutrient solutions containing varying concentrations of B. Mean daily B uptake rates in 3‐week‐old seedlings supplied no Zn (−Zn treatment) were from 2 to 2.5 times higher as in plants supplied 2 µM Zn (+ Zn treatment). These effects were observed after only 7 d growth without added Zn. During this time, Zn in grain reserves and contaminant‐Zn were still adequate to maintain all plants with an internal tissue Zn concentration well above the critical tissue concentration (about 15 mg kg−1 Zn on a dry weight basis), and no yield response to Zn supplementation occurred. The effects of Zn on B uptake, therefore, support the concept that Zn performs a protective role at the external surfaces of, or in, root‐cell membranes. When the concentration of B in the nutrient solution was extremely high (e.g., 3000 µM), this protective effect of Zn disappeared and plants in all treatments developed B toxicity symptoms and accumulated high B concentrations. Other nutrients were also accumulated under Zn deprivation—namely, P, NO3, S, Ca, Mg, K, and Cu, but not Fe. Higher concentrations of P in the nutrient solution resulted in higher uptake rates of all ions, especially in the ‐Zn plants. A similar but smaller effect of added P on ion uptake occurred in +Zn plants.
Soil Series Differentiae Selected by Discriminant Analysis Based on Ranks
Authors: Edmonds W. J. , Lentner M. 
Published: July 2010

AbstractSoils derived from parent materials weathered from sedimentary rocks of different chronostratigraphic units have been correlated as members of the Berks and Weikert series in Virginia. These correlations assume similar lithostratigraphic units. In an attempt to discriminate soils derived from four groups of parent materials weathered from rocks of different chronostratigraphic units, 34 properties were evaluated as differentiae by similarity of distributions among the parent materials and by contributions to discriminant functions. Selected properties had nonnormal distributions for one or more parent materials. Therefore, α‐levels associated with the ANOVA F‐test would not be maintained for these data. For this reason, the distribution‐free Kruskal‐Wallis test provides a more appropriate basis for comparison. In addition, Hotelling's T2 test assumes multivariate normality. Therefore, ranks were used to calculate the discriminant functions. The discriminant functions indicate that distinct groups are formed by soils derived from the Chilhowee group and from the Rome‐Waynesboro formation. Soils derived from the Chilhowee group contain lower amounts of available plant nutrients while soils derived from the Rome‐Waynesboro formation contain more feldspar in the sand and silt fractions. Soils derived from rocks of the Brallier, Chemung, Millboro, Martinsburg, and Athens formations are not discriminated by any combination of the 34 soil properties. Differentiae selected by discriminant analysis explain differences in soil responses to use and management observed by field soil scientists. Therefore, we conclude that classes produced by discriminant analysis provide more accurate predictions of soil responses than classes produced by a priori‐selected properties and limits in a hierarchical system. The simultaneous consideration of several properties approximates responses of soils as integrated systems.
Compaction Characteristics of a Soil Cropped to Corn and Bromegrass
Authors: Angers D. A. , Kay B. D. , Groenevelt P. H. 
Published: July 2010

AbstractThis study was initiated in order to determine if the compaction characteristics of soils are modified by cropping history. Uniaxial compression tests were made on cores of aggregated soil. The tensile strength of individual aggregates was also measured. Four different cropping histories ranging from 15 yr of continuous corn (Zea mays L.), C15, to 15 yr of continuous bromegrass (Bromus inermis Leyss.), B15, were investigated. The bulk density of soil cores under standard compaction conditions (100 kPa load and 50% water saturation) did not vary with cropping history. However, interaggregate porosity under standard compaction conditions was 18% larger in B15 than in C15, and the aggregate strength, which was positively correlated with interaggregate porosity, was 50% larger. The compression index was 12% larger in B15 than C15 and was positively correlated with interaggregate porosity under standard compaction conditions. This suggests that the loss of porosity on compaction was strongly influenced by collapse of interaggregate pores. Soils with a recent history of bromegrass had a greater proportion of interaggregate pores and this benefit persisted across a range of pressures that would normally be encountered in the field (<500 kPa). Changes in the compression index, tensile strength and interaggregate porosity appeared to occur rapidly when cropping practices changed.
Effect of Subsoiling and Irrigation Regime on Dry Bean Production in the Pacific Northwest
Authors: Miller D. E. 
Published: July 2010

AbstractZones of high strength are common in irrigated soils. Root penetration may be reduced if soil strength exceeds 1 to 3 MPa, resulting in a decreased supply of water and nutrients to the plant. On sandy soil this may allow plant water stress to develop between irrigations. Bean plants (Phaseolus vulgaris L.) are particularly sensitive to high soil strengths. A study was conducted on two soils to determine the effect of subsoiling on soil strength, bean root development, and plant reaction to different irrigation regimes. On a rigid uncemented matrix sandy soil, subsoiling reduced soil strength from >3 to <1 MPa, promoted deep rooting, and increased foliage. Without subsoiling, plants frequently suffered water stress between irrigations applied at 4‐d intervals. This resulted in blossom drop and delayed maturity by about 2 weeks. The deeper rooting associated with subsoiling reduced water stress and bean plants grew and matured normally. On a loam soil subsoiling also reduced strength to about 1 MPa or less and increased rooting depth and foliage density compared to normal tillage. With the dense foliage, 65 to 80% of the bean plants were infected with Sclerotinia white mold and dry bean yields were low. Because of the Sclerotinia injury, results were inconclusive.
Late Season Changes in Fascicle Nutrient Content, Weight, and Phosphorus Uptake by Slash Pine
Authors: Comerford N. B. , Mollitor A. V. , McFee W. 
Published: July 2010

AbstractThe autumn to winter season in Georgia's and Florida's lower coastal plain is marked by a mild climate and warm soil temperatures. While height growth of pine ceases in late August, climate conditions sustain root growth and needle weight gain. The purpose of this study was to (i) investigate the changes in the needle weight and N, P, K content of slash pine (Pinus elliottii Englm. var. elliottii) crowns that occur between September and January, and (ii) to investigate whether there is measurable uptake of P when applied as fertilizer late in the growing season. In the 12 locations studied, needle weight and total needle content of N and P increased during the fall and winter months. Increases in N and P total needle content ranged from 12 to 95 and 6 to 92%, respectively. Potassium content generally decreased throughout the crown or increased in the bottom portion of the crown only. Measurable uptake of P occurred during this period. Trees fertilized in late September had 49 to 57% more P in their needles by November than those that were unfertilized. This suggests that, in the southern coastal plain, plant uptake of fertilizer or native nutrients should be considered an important process throughout, at least, the autumn season.
A Simple Device for Sectioning Saturated Soil Cores Under Laboratory Conditions
Authors: Jugsujinda Aroon , Khind C. S. , Patrick W. H. , Lindau C. W. 
Published: July 2010

AbstractThe laboratory technique described for obtaining thin horizontal sections of prepared saturated soil cores is very simple, quick, and employs a one‐piece assembly. It can be used effectively for monitoring various chemical, electrochemical, and physical parameters of soils incubated under flooded conditions. An average coefficient of variation in sample weights of 4.79% was obtained with this technique for sectioning of the cores prepared in the laboratory, which compares well with results obtained using other more complex apparati.