bluuebunny/crossref_metadata_2025_split huggingface dataset:
Using Regionalized Variables to Estimate Field Variability of Corn Yield for Four Tillage Regimes
Authors: Cassel D. K. , Upchurch D. R. , Anderson S. H. 
Published: July 2010

AbstractIn selecting an appropriate tillage system for a specific crop and field, it is desirable to choose one that maximizes yield for the field as a whole; however, various areas in a field often give different responses to the same tillage system. The theory of regionalized variables was used to evaluate corn [Zea mays L.] grain yield response to the following four tillage systems (tandem disking, tandem disking followed by bedding, in‐row‐subsoiling and bedding, and chisel plowing). These treatments were randomized, replicated three times, and stripped across the 198‐m‐long field of Norfolk soil (Typic Paleudults), which had a tillage pan and variable depth to B horizon. Grain was harvested in adjoining 15.2‐m‐long plots in each strip. Analysis of directional semivariograms for relative corn grain yield in the along‐the‐row direction, showed a different variance structure for each tillage treatment. Because only three separation distances were available to compute grain yield semivariance values in the across‐the‐row direction, a composite directional semivariogram in this direction was developed by combining relative grain yield‐semivariance values for all four treatments. A global semivariogram was constructed for each tillage treatment by combining the specific along‐the‐row semivariogram specific for each treatment with the composite across‐the‐row semivariogram, and was used to krige the relative corn grain yield for the entire field for each tillage treatment. Patterns of the kriged yields were appreciably different throughout the field for each tillage treatment. Corn grain yields, estimated using jackknife kriging at each location in the field where grain was harvested, compared favorably with the measured yields for all treatments.
A Method to Estimate the Probability that Subsoiling will Increase Crop Yields1
Authors: Vepraskas M. J. 
Published: July 2010

AbstractCrop yield responses to subsoiling are determined by the amount and distribution of rainfall and soil properties. Because growing season rainfalls are not known in advance, the likelihood of subsoiling increasing yields at a given site can only be stated in terms of probabilities based on current soil properties and historic rainfall patterns. In this study, the probability that subsoiling would increase tobacco (Nicotiana tabacum L.) yield as compared to a nonsubsoiled treatment was estimated for 20 coarse‐textured soils in the southeastern USA where significant yield increases from subsoiling had been observed previously or were expected. Using data collected from 1981 through 1984 for yields of subsoiled and nonsubsoiled treatments, soil physical properties, and rainfall from the 20 sites, a regression model was first developed to describe yield differences between treatments on the basis of specific weekly rainfalls and the sand percentage and water retention of selected horizons. The regression model was then used to estimate yield differences between treatments using physical properties of each of the 20 sites and rainfall histories of two Coastal Plain locations for the years 1930 through 1986. For each rainfall history, the number of years that the estimated yield differences between treatments were ⩾300 kg ha 1(significant differences in yields at the 0.05 level) was tabulated for each site and divided by 57 to compute the proportion of years that subsoiling would have significantly increased yields in the soils considered. These proportions were assumed to be the probabilities that subsoiling would increase yields for a given rainfall history and set of soil properties. The estimated probability mean and standard deviation were 0.69 ± 0.12 across all 20 sites and both rainfall histories. This indicated that on the average, subsoiling would be expected to increase tobacco yield in approximately 7 out of every 10 yr. Probabilities were < 0.50 in only two sites that had relatively high water retention values. The probability values decreased as E‐B horizon water retention increased and Ap horizon sand percentage decreased. These results pertain to Costal Plain soils that had bulk densities ⩾ 1.63 Mg m−3 in either the Ap or E‐B horizon, and sand percentages ⩾ 73% in the Ap horizon.
Phosphorus Dynamics of Pinyon‐Juniper Soils following Simulated Burning
Authors: DeBano Leonard F. , Klopatek Jeffrey M. 
Published: July 2010

AbstractThe objective of this study was to determine the effect of a simulated prescribed fire on P compounds in a Lithic Ustochrept soil supporting a pinyon‐juniper woodland in Arizona. Soil, litter, and duff collected from beneath pinyon pine (Pinus edulis E.) and Utah juniper [Juniperus osteosperma (Torrey) Little] and adjacent interspaces were used to reconstruct laboratory microcosms in clay pipes that were burned when soils were wet or dry. Soil temperatures were monitored continuously throughout the microcosms during burning. Total, bicarbonate‐extractable (BEP), microbial, and organic P; phosphatase activity; and organic C were measured in the soil, litter, and duff before and immediately after burning and 45 and 90 d later. Soil texture, pH, and CaCO3 equivalents were also determined on unburned soils. Organic P and phosphatase activity were significantly higher in unburned juniper soils than under pinyon and interspaces. Total P and BEP were higher in unburned juniper litter than in pinyon litter. Organic P made up <35%, and BEP <5%, of total soil P. About 50% of total P was lost from the litter during burning. Burning significantly increased BEP in pinyon and juniper soils, but the increases were short‐lived and became statistically insignificant after 45 d. Phosphatase activity was significantly reduced in pinyon pine and juniper soils when burned dry. Burning over wet soils did not affect phosphatase activity or the concentration of P compounds.
A Method for Determining Sulfur‐34 Abundance in Soil and Plant Sulfur Fractions
Authors: Schoenau J. J. , Bettany J. R. 
Published: July 2010

AbstractThe variation in 34S abundance has been shown to be a valuable tool in studying S cycling in natural systems. Unfortunately, the measurement procedure is complicated, and the existing literature lacks sufficient information to allow the method to be easily duplicated. We describe a simple system for preparing SO2 for mass spectrometric analysis from different fractions of soil and plant S. The system employs a Johnson‐Nishita apparatus to convert soil S to Ag2S and a compact vacuum combustion system to convert Ag2S to SO2. Standard deviations of 0.1 to 0.4‰ were typical for soil and plant S fractions.
Transport of a Conservative Tracer in the Field Under Continuous Flood Irrigation
Authors: Jaynes D. B. , Rice R. C. , Bowman R. S. 
Published: July 2010

AbstractA 5‐cm deep pulse of bromide‐tagged water was applied to four small field subplots and leached under continuously flooded conditions for 7 d. During leaching, solution samples were periodically withdrawn through suction samplers from seven depths within each subplot. Pore water velocities, vs, and dispersion coefficients, D, were calculated by fitting the one‐dimensional solution of the advection‐dispersion equation to the concentration vs. time curves from each sampler. Both vs and D were best described by a log‐normal distribution rather than a normal distribution. D values were very large compared to values reported for laboratory experiments, but similar to other field values measured under similar conditions. Neither vs nor D showed any significant correlation with depth or time, but the dispersivity (ratio of D to vs) did show a weak positive correlation with depth. The relationship between ln D and ln vs was linear with a slope near 1.0. However, when vs and D data measured in an earlier study under an intermittently dosed irrigation regime at the same site were included, ln D was no longer a simple linear function of ln vs. The ratio between the calculated pore water velocities and the velocities calculated from the surface flux divided by the average water content was equal to or slightly <1.0 for all depths >0.6 m. At depths <0.6 m the ratio was considerably >1.0, indicating that a fraction of the soil water was being bypassed or not participating in the leaching process. This result is in contrast to an earlier study conducted on this site when irrigated under a dosed irrigation scheme in which the ratio was consistently >1.0 at all depths.
Early Stages of Mine Soil Genesis as Affected by Topsoiling and Organic Amendments
Authors: Roberts J. A. , Daniels W. L. , Burger J. A. , Bell J. C. 
Published: July 2010

AbstractTopsoil substitutes offer alternative reclamation options in many surface mining regions, particularly where native topsoil materials are of poor quality. The objective of this study was to measure effects of various amendments on mine soil properties and the early stages of pedogenesis. Treatments applied to 2:1 sandstone/siltstone spoil mixtures were inorganic fertilizer (control): 112 Mg ha−1 sawdust: 30 cm of local topsoil: and 22, 56, 112, or 224 Mg ha−1 of municipal sewage sludge. Morphologically distinct A horizons and transitional AC and C1 horizons developed in all pedons between 1982 and 1985, primarily due to plant rooting. The depth and nature of transitional AC and C1 horizons was strongly influenced by organic additions. Water availability after 3 yr was enhanced by sawdust applications. Mine soil pH decreased over time as basic cations leached, but sludge additions moderated the rate of decline. Organic C accumulation rates ranged from 700 to 1500 kg C ha−1 yr−1 and were accelerated by sludge additions. Soil total N generally increased as well, and both C and N accumulations were associated with A horizon formation. Extractable Fe increased significantly in the surface of all treatments over time. Sludge additions dominated mine soil chemistry for multiple seasons. Total cation exchange capacity (CEC) was greatly increased by sludge additions, but decreased significantly over time due to leaching of Ca and Mg. Changes in soil chemical and physical properties reflect rapid pedogenesis and effects of organic matter additions to mine soils. Organically amended spoils can equal or surpass native topsoil materials in forgage productivity.
Basal Mixing Zones in Loesses of Louisiana and Idaho: I. Identification and Characterization
Authors: Schumacher B. A. , Lewis G. C. , Miller B. J. , Day W. J. 
Published: July 2010

AbstractThe thickness and character of basal mixing zones in loess with different underlying materials and in different climates were studied in Louisiana and Idaho. Peoria loess in Louisiana is underlain by sandy braided stream deposits, clayey alluvium, and an older Sicily Island loess. In Idaho, materials underlying loess deposits include glacial till, basalt, Pliocene sediments, and a paleosol developed in loess. Multiple criteria, divided into primary and secondary indicators, were used in the identification of basal mixing zones. The primary indicators of basal mixing zones were field morphology and particle‐size distribution. Secondary indicators include total elemental analyses, clay mineralogy, CaCO3 equivalence, exchangeable cations and soil reaction listed in order of decreasing sensitivity. In Louisiana, basal mixed zones varied in thickness from 61 to 124 cm while in Idaho, basal mixed zones were between 8 and 40 cm thick.
Distribution and Characteristics of Windthrow Microtopography on the Cumberland Plateau of Kentucky
Authors: Cremeans D. W. , Kalisz P. J. 
Published: July 2010

AbstractThe abundance and characteristics of microtopography resulting from the uprooting of trees were examined on five landtypes on the northern Cumberland Plateau. Plots, 10 m by 25 m, were established at 180 locations on randomly‐oriented systematic grids located in 12 first‐order watersheds. The area and depth of soil disturbed were measured for each of the 524 uprootings encountered. In addition, all windthrow microtopography in a single representative hollow, 11.3 ha in area, was mapped and measured. Soil disturbance by uprooting was least on ridges, intermediate on side slopes, and greatest in coves and on lower north slopes. Percentage disturbance of the ground surface ranged from 0.4% on ridges to 2.4% in coves; number and mean area disturbed by individual uprootings ranged from 50 to 112 ha−1, and from 0.5 to 2.1 m2 along the ridge‐to‐cove gradient. The lower abundance of windthrow microtopography on ridges was attributed to a relatively high incidence of stem breakage vs. uprooting. Stem breakage seemed particularly common in scarlet oak (Quercus coccinea Muenchh.) which dominated ridges and south slopes. Observations made during the course of this study also suggested that concentrated subsurface water flow and concomitant decreases in tree stability may contribute to uprooting in coves and on lower slopes. Windthrow, viewed as a pedogenic process, clearly does not operate uniformly over this mountainous landscape.
Use of Acetylene Reduction for Estimating Nitrogen Fixation in Woody Debris
Authors: Hendrickson O. Q. 
Published: July 2010

AbstractBoth endogenous C2H4 formation and C2H4 arising from reduction of C2H2 must be accurately measured in N2 fixation studies using C2H2 reduction. Previous work with forest soil has shown that C2H4 formed in air is not an appropriate control for endogenous C2H4 formation. This study compared different controls for endogenous C2H4 formation during C2H2 reduction studies of woody logging debris. Amounts of C2H4 formed by decaying wood in the presence of C2H2 plus either of two noncompetitive inhibitors of C2H2 reduction (CO, (NH4)2SO4) were greater (p <0.01) than amounts of C2H4 formed in air. Ambient air controls therefore underestimated endogenous C2H4 formation, and would overestimate N2 fixation rates. Controls using (NH4)2SO4 were not suitable for routine use due to alteration of sample moisture content. With CO as an inhibitor, endogenous C2H4 formation averaged 23% of total C2H4 formed in the presence of C2H2 across a range of moisture contents. Field data on C2H4 produced by logging slash in the presence of C2H2 alone are discussed in light of these findings. In the future, C2H2 reduction studies of N2 fixation in decaying wood should employ CO controls for endogenous C2H4 formation.
Multivariate Statistical Analysis of Potassium and Chloride Redistribution from a Line‐source Sprinkler Experiment
Authors: Tillotson W. R. , Biggar J. W. , Nielsen D. R. , Shumway R. H. 
Published: July 2010

AbstractWater treatment effects on K and Cl redistribution in a field soil were quantified using a particular multivariate analysis of variance method, profile analysis. A field experiment was conducted using the line‐source sprinkler system for the determination of water treatment effects on K and Cl redistribution through comparisons of K and Cl mean redistribution profiles. For a water treatment, the solute mean redistribution profile is obtained by averaging individual concentration‐with‐depth profiles from 25 field locations. Five water treatments covered a range of cumulative applied water and solute redistribution times equal to 110 to 450 mm and 27 to 305 d, respectively. Three of the water treatments resulted from the sprinkler system and two from rainfall. Soil profiles were sampled at depth intervals of 0 to 15, 15 to 30, 30 to 60, 60 to 90, and 90 to 120 cm. Samples were analyzed for water soluble K and Cl, and gravimetric water content. A logarithm transformation of the K and Cl data was sufficient for approximate population multivariate normality. Profile analysis identified the water treatment effects of parallelism among the ln K mean redistribution profiles, and symmetry and coincidence among the ln Cl mean redistribution profiles. Identification of specific effects among the mean profiles amounted to the determination of kinematic similarity in K and Cl redistribution. Comparisons of mean profiles corresponding to the depth variables were also analyzed. Profile analysis fills a void in the quantification of water treatment effects on solute redistribution not filled by other data analysis procedures.
Color, Organic Matter, and Pesticide Adsorption Relationships in a Soil Landscape
Authors: Fernandez R. N. , Schulze D. G. , Coffin D. L. , Van Scoyoc G. E. 
Published: July 2010

AbstractSoil color, organic matter content, and adsorption of the pesticide diuron [3‐(3,4‐dichlorophenyl)‐1,1‐dimethylurea] were measured for the silt loam or silty clay loam Ap and Bt or Bg horizons of two toposequences of soils occurring within the same soil landscape in Tippecanoe Co., IN. Close linear relationships (r2 > 0.9) were obtained between Munsell value, organic matter content, and diuron adsorption. Color‐organic matter relationships within this landscape appear to be much better than previously reported relationships developed for soils over wider geographic areas. Sensors for measuring soil organic matter content as equipment moves across a field are more likely to be successful if they are calibrated on a field by field basis rather than utilizing relationships developed over a wide geographic area.
Soil Organic Carbon, Nitrogen, and Phosphorus Quantities in Northern Great Plains Rangeland
Authors: Aguilar R. , Heil R. D. 
Published: July 2010

AbstractSoils were characterized in North Dakota rangeland along toposequences formed in sandstone, siltstone, and shale parent materials to evaluate quantities of organic C, N, P, and total P. Distribution of these soil constituents varied systematically with parent material and landscape position along the three toposequences, and generally increased upon moving downslope. The fine‐textured soils formed in shale had greater quantities of organic C, N, and total P than the coarser‐textured soils derived from sandstone and siltstone parent materials. Soils formed in sandstone had greater quantities of organic P on all landscape segments. Greater quantities of organic constituents on lower landscape segments were attributed to both greater vegetative productivity and accretion of soil organic matter through sediment deposition. Variable total‐P contents along the toposequences reflected changes in parent material and redistribution of sediments by erosion.
A Method for Measuring Incorporated Crop Residue and Associated Soil Properties
Authors: Allmaras R. R. , Pikul J. L. , Wilkins D. E. , Kraft J. M. 
Published: July 2010

AbstractControlled placement and depth distribution of crop residues are major objectives for tillage management. Appropriate methodology has provided quality information about surface placement, but the distribution of buried crop residue has not been readily measurable. A method was developed to measure dry bulk density (ρb), incorporated coarse organic matter (COM), and organic carbon (C) concentration using one soil sample. Cores, each 0.3‐m long, were taken with a specially constructed sampler (19‐mm diam.); each 0.3‐m core was separated into 20‐mm increments for subsequent analysis. After air‐drying, COM was estimated as that crop residue retained on a 0.5‐mm mesh sieve; C concentration measurements and an associated conservation‐of‐C algorithm were used to estimate COM because the incorporated crop residue could not be completely separated from contaminant soil. These ρb and COM had a CV of 5 and 20%, respectively. A depth function of ρb distinguished primary tillage from secondary tillage and traffic; a tillage pan produced by the moldboard base was usually detected by ρb. Moldboard plowing vs. sweep or chisel tillage consistently produced different depth distributions of COM; at least 85% of the COM was above 0.1 m when tilled with a chisel or sweep and >45% was below 0.1 m when moldboard plowed. Total COM in the profile ranged from 68 to 23% of that measured at harvest, respectively, 28 wk earlier in a wheat‐peas rotation and 82 wk earlier in a wheat‐fallow rotation. Long‐term use of a moldboard plow vs. a chisel or sweep for primary tillage produced consistently different profiles of organic C concentration.
Colorimetric Determination of Oxidizable Carbon in Acid Soil Solutions
Authors: Bartlett Richmond J. , Ross Donald S. 
Published: July 2010

AbstractA simple and sensitive method is described that determines, colorimetrically, oxidizable organic matter in solutions from acid soils. It relies on measuring the loss of color by a Mn(III)‐pyrophosphate complex as Mn(III) becomes reduced by organic C in the presence of concentrated H2SO4. The method is applicable to 1‐mL samples containing 0.08 to 4.0 µmol of organic C and is practically free of interferences in aerobic solutions.
Automated In Situ Measurement of Unsaturated Soil Water Flux
Authors: van Grinsven J.J.M. , Booltink H.W.G. , Dirksen C. , van Breemen N. , Bongers N. , Waringa N. 
Published: July 2010

AbstractA device is presented which, based on new operation principles, intercepts unsaturated soil water fluxes within an error of 10% and can yield samples for subsequent chemical analysis and calculation of convective solute fluxes. Operation is controlled by a microprocessor which automatically adjusts the vacuum imposed on a porous filter cloth such that identical matric potentials are maintained just above the cloth and at the same depth in the neighboring soil. Contact resistances and internal resistance of the device are implicitly corrected by adjustment of suction. Laboratory and field tests in a loamy sand under steady and transient flow conditions showed that cumulative water fluxes could be measured within 10% of those calculated from storage changes, and from numerical and analytical flow models.
Cultivation Effects on Carbohydrate Contents of Soil and Soil Fractions
Authors: Dalal R. C. , Henry R. J. 
Published: July 2010

AbstractThe distribution of monosaccharides in the acid hydrolysate of soil fractions and whole soils subjected to variable periods of cultivation (0–45 yr) were studied because carbohydrates constitute a substantial proporation of soil organic matter and affect soil aggregation, both of which are affected by cultivation. Monosaccharides in soil acid hydrolysates were analyzed as their alditol acetates by an improved procedure using 1‐methylimidazole as acetylation catalyst. Carbohydrate constituted from 8 to 16% of soil organic matter in virgin soils and generally increased with the clay content (18–78% clay). Of this, 27 to 43% of carbohydrate was present in the light fraction (<2 Mg m−3), which also contained proportionally more carbohydrate‐C than did total organic matter. Upon cultivation, the light fraction declined rapidly, resulting in substantial loss of carbohydrate, especially in clayey soils. In these soils, carbohydrate losses also occurred from sand‐size and silt‐size fractions but clay‐size carbohydrates were less affected. Glucose and galactose were normally the predominant monosaccharides in the acid hydrolysates of the soils and soil fractions. The effects of cultivation on the net amounts of carbohydrate‐C in the various fractions and the whole soil in the three soil series studied, were generally similar to those on the total organic C, showing thereby that carbohydrate fraction of the soil organic matter was no more liable than the total organic C.
Developmental Aspects of Water‐Repellency of Sandy Soils
Authors: Hubbell David H. 
Published: July 2010

AbstractIncrease in water‐repellency of some sandy soils has been reported to be induced by conditions of high relative humidity. Incubation studies in a closed system were used to study mechanisms by which a wettable soil and a Bacillus isolate from it were able to partially suppress the expected increase in water‐repellency, normally induced by high relative humidity, in some water‐repellent soils. Evidence indicates a volatile product(s) is responsible for suppressing increases in water‐repellency.