bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Comparison of Different Methods for Measuring Soil Salinity
Authors: Nadler A. , Dasberg S. 
Published: July 2010

AbstractSoil salinity measurements with in situ salinity sensors, a four‐electrode salinity probe, a four‐electrode Wenner array, and a multi‐electrode probe were compared in an experimental plot irrigated with 3.1 mmho/cm CaCl2. Good agreement was obtained among expected salinity, soil extract (1:1) EC (electrical conductivity), and EC measurements with the salinity probe. The salinity probe requires good electrode‐soil contact and is therefore limited to the higher range of soil water contents. The Wenner array functions also at lower water contents, but interpretation of the results is influenced by soil layering. Salinity sensors gave the highest variance in the results.
Adsorption of Phosphate and Water‐extractable Soil Organic Material by Synthetic Aluminum Silicates and Acid Soils
Authors: Yuan T. L. 
Published: July 2010

AbstractThree synthetic Al silicates with different Si/Al ratios and soil samples from a Eutrandept, a Paleudult, and a Haplaquod, were separately treated with P and hot water‐extractable soil organic materials. The Al silicate with the lowest Si/Al ratio retained the most P but the least organic materials. The Paleudult which had a lower P adsorption capacity retained more organic matter than the Eutrandept. The Haplaquod had the lowest P and organic matter retention.Pretreatment of soils with organic material had varied effects on subsequent P adsorption. Pretreatment of soils with P reduced the adsorption of organic material, but at all organic matter levels the P adsorption was constant.The findings suggested that the sites for organic matter and P adsorption may differ, but certain sites seem to adsorb both P and organic matter.
Predicting Native Plant Copper, Iron, Manganese, and Zinc Levels Using DTPA and EDTA Soil Extractants, Northern Great Plains
Authors: Gough L. P. , McNeal J. M. , Severson R. C. 
Published: July 2010

AbstractThe utility of DTPA (0.005M, pH 7.3) and EDTA (0.01M, pH 7.0) extractants for measuring the availability of Cu, Fe, Mn, and Zn from uncultivated A‐ and C‐soil horizons to western wheatgrass (Agropyron smithii Rydb.), silver sagebrush (Artemisia cana Pursh), and above‐ground biomass was assessed at 21 geochemically diverse sites in the northern Great Plains. Positive relationships between the extractable or the total concentration of these elements in soils to concentrations in plants, as measured by multiple regression, were limited. A‐horizon DTPA‐extractable levels of Fe and Mn were significant positive independent variables in the prediction of Fe and Mn levels in wheatgrass. C‐horizon DTPA extractable levels of Mn and Zn were significant positive independent variables in the prediction of Mn and Zn sagebrush levels. Multiple regression techniques never gave significant relations between EDTA‐extractable element levels and plant element levels; however, strong relations were observed between soil pH and metal concentrations in plants. The relation between plant metal concentration and A‐horizon pH was always positive and apparently related to soil levels of metal carbonates. These data indicate that caution should be used in the formulation of regulations for plant available levels of these metals in Great Plains soils based solely on extractable levels.
Phosphorus Application Rate and Distribution in the Soil and Phosphorus Uptake by Corn
Authors: Anghinoni I. , Barber S. A. 
Published: July 2010

AbstractEvaluation of the effect of P addition and distribution in soil on P uptake by corn (Zea mays L.) plants, requires knowledge of the relation of soil P level to corn root growth rate and morphology. This research was conducted to obtain these relationships so that they could be used with root P influx and soil supply characteristics to calculate P uptake. Corn was grown for 12 and 18 days on two soils, each with five levels of P application, in pots in a controlled climate chamber. Root growth and P uptake were measured. Except for the lowest rate, increased rate of P mixed uniformly with the soil decreased average root length per pot even though shoot growth increased. Placing a common rate of P per pot in part of the soil volume increased root growth in the P‐treated soil volume as compared to root growth in the untreated soil. The difference was expressed by the relation y = x0.68, where y was the fraction of total plant root length in x, the fraction of the total soil volume that was P treated. Separate calculation of P uptake from each soil volume showed low P uptake from the untreated soil compared to that from the treated soil. Predicted P uptake per not calculated with a mathematical simulation model was correlated (r = 0.81 and 0.78 for the two soils) with observed P uptake. Information on effect of P on corn root growth and on P influx can be used in mathematical models to investigate relative P uptake from alternate P application practices.
Soil‐Geomorphic Relationships in the Western Margin of the Willamette Valley, Oregon
Authors: Glasmann J. R. , Brown R. B. , Kling G. F. 
Published: July 2010

AbstractGeomorphology and soils were studied in a 285‐ha agricultural watershed lying between the 63‐and 135‐m elevations in the western Willamette Valley. Previously named geomorphic surfaces, strata, and soils are recognized, and the Brateng surface is introduced and defined.The Irish Bend Member of the silty Willamette Formation is found only below the 80‐m elevation. The Greenback Member mantles the Irish Bend silts and higher portions of the landscape, thinning out at 122 m. A paleosol, developed from soft sedimentary rock of the Spencer Formation, lies beneath the Irish Bend and Greenback silts. Above the 80‐m elevation, the paleosol is part of the solum.The concept of the late Pleistocene Bethel geomorphic surface, with which the Irish Bend silts are associated, is expanded to include low‐relief ridge spurs merging upslope with the Brateng surface. The Brateng surface, between 80 and 122 m, is mantled by late‐Pleistocene Greenback silts and thus is late Pleistocene in age. The mid‐Pleistocene Dolph surface is found above the 122‐m elevation.Soils beneath the newly defined Brateng surface are mainly in the fine and fine‐silty Ultic Haploxeralfs and fine Aquic Xerochrepts. Soil mapping in the Brateng landscape is complicated by marked soil variability, a function of variations in thickness of surface silts, in degree of expression of the buried paleosol, and in texture of the underlying bedrock.
Fertilizer Fate in a 13‐year‐old Slash Pine Plantation
Authors: Shoulders Eugene , Tiarks Allan E. 
Published: July 2010

AbstractSurface application of 403 kg N, 95 kg P, and 64 kg K per ha to a 13‐year‐old slash pine (Pinus elliottii Englem. var. elliottii) plantation on Caddo loam soil increased total volume growth during the next 6 years by 8.3 m3/(ha·year). Trees responded rapidly to the fertilizer; measurable differences in diameter growth developed by mid‐May. Fertilization markedly increased the amount of N, P, and K accumulated in current‐year needles during the first year after treatment. Fertilized trees continued to accumulate more P in current foliage for at least 8 years. Ratios of Rb/K in foliage indicated that K from the fertilizer comprised 27% of K accumulated in current‐year needles of fertilized trees during the fifth and sixth growing seasons, and 20% accumulated in the eigth. Ten months after treatment, added K had apparently disappeared from the top 13 cm of soil, but about half the added P remained available there. After 8 years, fertilized soil contained 40 ppm available P in the 0.9 cm layer; unfertilized soil contained only 2 ppm. In 8 years, fertilized plots accumulated 9.2 metric tons/ha more litter than did control plots. Litter had 50 kg/ha more N, 11.3 kg/ha more P, and 5.1 kg/ha more K than did litter on unfertilized plots. Disking to incorporate the fertilizer into the soil gave no advantage.
Comparison of Modified Urea Fertilizers and Estimation of Their Availability Coefficient Using Quadratic Models
Authors: Tejeda Hernan R. , Hong Chong W. , Vlek Paul L. G. 
Published: July 2010

AbstractA procedure to compare N fertilizers based on comparing complete response curves simultaneously represented by a quadratic multifertilizer response model (MRM) is discussed. A modified version of the MRM, called fertilizer testing model (FTM), is used to test differences among response curves. The FTM describes the response curve to a fertilizer selected as a standard as well as the additional effect of test fertilizers over the response to the standard. In case of different response curves, an approximate test to decide whether the curves have equal limiting yield is introduced. Finally, a procedure to estimate the availability coefficient from quadratic response curves having equal limiting yield is derived.These procedures were employed to analyze six field experiments conducted over a period of 3 years in Korea using three varieties of rice (Oryza sativa L. ‘Tongil,’ ‘Jinheung,’ and ‘Milyang 23’) and three fertilizers (urea and two sulfur‐coated ureas, or SCU) applied at four or five levels of N. Two out of six experiments showed a significant effect from SCU‐A (25% release/7 days) beyond that of split‐applied urea, whereas SCU‐B (14% release/7 days) showed significant additional effects in three out of five experiments. However, in four of these six experiments, the limiting yield of the response curves of SCU was significantly higher than that of urea, precluding a valid estimation of the availability coefficient. Possibly, the proper combination of N dose and timed release of N from SCU in these experiments translated into grain yields unmatched by split applications of urea.
Dissolution of North Carolina Phosphate Rock in Acid Colombian Soils as Related to Soil Properties
Authors: Chien S. H. , Leon L. A. , Tejeda H. R. 
Published: July 2010

AbstractInformation on the dissolution of phosphate rock in soils as related to soil properties is needed in order to understand the solubility behavior of the phosphate rock in soils as related to crop response. This study was conducted to determine the relationships between the dissolution rate of North Carolina phosphate rock and selected chemical properties of 16 acid Colombian soils. A modified Elovich equation, Ct =Co − (1/β) ln (αβ) − (1/β) ln t, was used to describe the dissolution of phosphate rock in the soils. In the equation, Ct is the P concentration in water extract at time t, Co is the maximum P concentration in the water extract when t→0, α and β are constants. Of the various soil properties studied, the best correlations of reactive Al were a simple linear relationship with β and a log‐log relationship with α. Results from tests with two other acid soils from Colombia showed these relationships allow prediction of the dissolution rate of the phosphate rock in other soils from a single measurement of reactive Al content.Phosphorus sorption capacities of the 16 soils were correlated with amounts of reactive Al or active Al but not with amounts of free Fe2O3 and exchangeable Al in the soils. Amounts of water‐extractable P in the soils treated with concentrated superphosphate (CSP) or the phosphate rock decreased as P sorption capacity increased; however, the relative amounts of water‐extractable P of the phosphate rock with respect to CSP increased as P sorption capacity increased. This suggests that the relative agronomic effectiveness of phosphate rock compared with CSP would be highest on the strongly P‐fixing soils.
Description of Soils Having Disturbed or Discontinuous Horizons
Authors: Fisher R. F. , Miller R. J. 
Published: July 2010

AbstractThe highly disturbed and discontinuous horizons of many podzolic soils make them difficult to describe, classify, and identify in the field. A method of differentiating such soils was used on three map units in Southern Ontario. The method required some modification because it failed to use discontinuity as a variable. The use of a disturbance index and a discontinuity index in describing soil series and map units with highly disturbed and/or discontinuous horizons is suggested.
Importance of Prereducing Selenium(VI) to Selenium(IV) and Decomposing Organic Matter in Soil Extracts Prior to Determination of Selenium Using Hydride Generation
Authors: Workman S. M. , Soltanpour P. N. 
Published: July 2010

AbstractHydride generation techniques using NaBH4 are widely used for the determination of Se in aqueous solutions. In soil extracts, Se(IV) is the only form of Se reduced to SeH2 by NaBH4. Se(VI) must be prereduced to Se(IV) to be measured. Organic constituents of soil extracts also appear to inhibit hydride production. A pretreatment procedure overcoming these problems is presented, and a simple hydride generator is described.
Chloride Movement in Undisturbed Soil Columns
Authors: Tyler D. D. , Thomas G. W. 
Published: July 2010

AbstractChloride movement was studied in soil columns taken from three Kentucky alluvial soils—Karnak, Huntington, and Bruno. The soils ranged from silty clay loam to sandy loam in texture and from well structured to unstructured. Columns were taken by driving a 15‐cm diameter heating duct into the soil to a depth of 30 cm and then digging out around the column to remove it. These columns were mounted on blocks of candle wax and leached under 1.5 cm of Hg tension. A 25‐ml “slug” of KCl was applied to each column and followed by deionized water at a rate just slow enough to prevent ponding on the soil surface. The maximum effluent concentration of Cl appeared far ahead of 1 pore volume in both Huntington and Karnak soils, which have well‐defined structure, and at 1 pore volume in the Bruno sl which is not structured. The results emphasize the channeling of water in soils with well‐defined structure.
The Importance of Cr Horizons in Soil Classification and Interpretations
Authors: Lietzke D. A. , Weber R. S. 
Published: July 2010

AbstractParalithic boundaries and underlying Cr horizons have been observed in numerous soils on an extensive variety of sedimentary rocks both flat lying and steeply dipping in the Appalachian region of Virginia and in every type of igenous and metamorphic rock that is common to the Southeastern United States Piedmont and Blue Ridge geological provinces. In addition, the very dense basal till that underlies soils formed in glacial materials also appears to qualify for a Cr horizon. Cr horizons profoundly affect water movement and root penetration. The depth to Cr horizon and its thickness in a soil is especially important in interpreting soil properties for septic tank drainfields where water movement is crucial. A paralithic boundary (the top of the Cr horizon) is usually difficult to detect with barrel auger observations. Paralithic boundaries may be located by the presence of root mats, clay plugged zones, or other evidence of reduced permeability in soils with and without argillic horizons. The Cr horizon lying just below the paralithic boundary does not have any evidence of soil fauna activity that produced pores and tunnels. Soil pits are much more useful in observing and evaluating these particular soil features. Soil scientists can learn to locate a paralithic boundary with barrel augers by changes in moisture content, increased shearing resistance, and increased coarse fragments content. A Cr horizon at < 1.8‐m depth in a soil has an important place in Soil Taxonomy since its presence determines the depth at which base status is evaluated for placement at the order or great group levels.A Cr horizon should be diagnostic at the subgroup level when it occurs at depths of 50 to 100 cm, at the series level when it occurs between depths of 100 and 125 cm, and at the phase level when it occurs between depths of 125 and 180 cm.
The Quantitative Assay of Minerals for Fe2+ and Fe3+ Using 1,10‐Phenanthroline: I. Sources of Variability
Authors: Stucki J. W. , Anderson W. L. 
Published: July 2010

AbstractFactors affecting the reliability of results using 1,10‐phenanthroline (phen) in the quantitative assay of minerals for Fe2+ and total Fe were studied. The greatest source of variability was the photochemical reduction of ferric‐phen species during Fe2+ analyses. It is believed that oxo‐bridged dinuclear complexes of Fe2+ and phen are formed in the mineral digests, which then are susceptible to photochemical reduction by wavelengths < 400–500 nm. The rate of photoreduction of a solution obtained by digesting oxidized nontronite was sufficient to increase the predicted Fe2+ content of the clay from about 0 to 2.45% by simply leaving the sample for 1 hour in normal fluorescent light in the laboratory; and for partially reduced nontronite, from 3.25 to 4.68%. The rates of increase for the two clays were 0.0024 and 0.0014 absorbance units/min, respectively. Interferences due to this phenomenon were eliminated when samples were kept in the dark or under subdued red light. Other factors that adversely influence the accuracy and precision of the standard curve included (i) the amount of 48% HF used to digest the sample; (ii) addition of chemical reducing agents such as hydroxylamine hydrochloride and hydroquinone; (iii) the order in which phen is added relative to other reagents; (iv) pH; and (v) the length of time allowed for color development if phen is added only to the final dilution.
Hydraulic Properties of Fullerton Cherty Silt Loam
Authors: Luxmoore R. J. , Grizzard T. , Patterson M. R. 
Published: July 2010

AbstractSoil hydraulic properties at eight depths in a Fullerton cherty silt loam (a clayey, kaolinitic, thermic Typic Paleudult) profile were derived from measurements of water content with a calibrated neutron probe and of matric potential with tensiometers during drainage of a flooded 2‐ by 2‐ by 3‐m deep soil plot. Soil cores taken from the field plot were used for laboratory determinations of the retention properties. The field retention data were generally unsatisfactory, indicating significant differences in the response times and spatial resolution of the tensiometers and neutron probe. The tensiometers did not provide reliable hydraulic gradient data during drainage. Hydraulic conductivity was calculated by the instantaneous profile method and by three simple field methods, assuming a unit hydraulic gradient in all methods. There were greater differences in hydraulic characteristics between two profiles 1 m apart than there were between the alternative methods of calculation. Maximum hydraulic conductivity calculated by the instantaneous profile method for the well‐aggregated B horizons had values up to 58 and 177 cm per day at two positions in the soil plot.
Physical and Chemical Characteristics of Pre‐mine Soils and Post‐mine Soil Mixtures in Illinois
Authors: Snarski R. R. , Fehrenbacher J. B. , Jansen I. J. 
Published: July 2010

AbstractThe chemical, physical, and mineralogical properties of Sable and Darmstadt soils were studied to determine the value of solum and subsolum material as mediums for plant growth. Sable silty clay loam from western Illinois has nearly ideal physical and chemical properties for plant growth, while the more weathered Darmstadt silt loam from southern Illinois has unfavorable chemical and physical properties that limit plant growth.The suitability of various soils and subsurface overburden mixtures were determined by measuring and defining the chemical and physical properties that have a potential for enhancing or limiting plant growth. The B2 horizon material from the Darmstadt soil has the least favorable properties. The top 3‐m mix (topsoil included) and 3‐m mix (topsoil not included) have similar properties and appear to be the most favorable materials for use in constructing a post‐mine soil. The range of chemical and physical properties in the Sable mixtures are not as great as in the Darmstadt mixtures. The top 3‐m mix, 6‐m mix (exclusive of the A horizon), and calcareous loess mix from the Sable soil all have similar chemical and physical properties.Incorporation of the A horizon into the 3 m below the A horizon of both Sable and Darmstadt soils only slightly enhances the chemical and physical properties of the mixtures.Comparison of tested and calculated soil values indicate that most chemical and textural properties of a solum and subsolum mixture can be predicted prior to mining. The pH of a mixture can also be predicted by using an equilibration technique.
Tillage Effects on Wheat and Sunflower Grown in Rotation
Authors: Unger Paul W. 
Published: July 2010

AbstractMethods of fallowing commonly used in the Southern Great Plains are relatively ineffective for increasing soil water contents, and subsequent crop yields on a total area basis are less with fallow than with continuous cropping. Consequently, improved cropping practices are needed that increase soil water storage during fallow or that decrease the total time devoted to fallow in a cropping sequence. The objective of this study was to determine the effects of disk, sweep, limited‐, and no‐tillage on soil water storage and yields of dryland sunflower (Helianthus annuus L.) and irrigated wheat (Triticum aestivum L.) when grown in rotation. The tillage treatments were applied during the 10‐month fallow period between harvest of irrigated wheat and planting of dryland sunflower. Wheat was planted immediately after sunflower harvest. Average gains in soil water content during fallow ranged from 3.8 cm with disk tillage to 7.2 cm with no‐tillage. These differences were statistically significant, but subsequent sunflower seed yields, which averaged 1.26, 1.24, 1.24, and 1.38 metric tons/ha with disk, sweep, limited‐, and no‐tillage treatments, respectively, were not significantly different. Grain yield of wheat planted after sunflower averaged 4.17 metric tons/ha. There were no significant residual effects of the tillage treatments on wheat yields. For 1977 and 1978, wheat yields in this study (excluding limited‐tillage) averaged 3.40 metric tons/ha compared with 2.22 metric tons/ha in an irrigated wheat‐fallow‐dryland grain sorghum [Sorghum bicolor (L.) Moench] study with the same tillage treatments. The wheat‐sunflower rotation resulted in more timely planting and higher yields of wheat than the wheat‐sorghum rotation. The wheat‐sunflower rotation allows timely planting of wheat and sunflower, provides for two crops in 2 years, and thus should increase total yields as compared with systems involving an extra fallow period.