bluuebunny/crossref_metadata_2025_split huggingface dataset:
Identification and Genesis of Fragipans in Ochrepts of North Central Wisconsin
Authors: Habecker M. A. , McSweeney K. , Madison F. W. 
Published: July 2010

AbstractThe morphological and physical properties of a fine‐loamy, mixed, frigid Aquic Fragiochrept at two locations in Taylor County, Wisconsin were examined. At both sites, the fragic zone occurs in bisequal soils beneath eluvial horizons and transgresses a lithologic discontinuity where the loess cap grades into a dense sandy loam till. This study evaluated the utility of several field and laboratory tests for demarcation of the fragipan, and it examined the morphological and physical features of the fragipan in relation to its potential origin. Bulk density was measured using the saran‐coated clod and Uhland ring methods. The upper boundary of the fragipan was distinguished from the overlying horizons by its higher bulk density with the Uhland ring method. Hydraulic conductivity (Ksat) of saturated soil was measured using two methods (falling‐head permeameter and Guelph permeameter). Although Ksat values were low in the fragic zones (10−5.06–10−7.60 m s−1), they were not significantly lower than those measured in underlying nonfragic, dense till horizons. Soil strength tests showed that the site with >10% clay in its fragic horizons had twice the strength of the site with <10% clay. Various macro‐ and micromorphological features indicate that the upper part of the second parent material may be a debris flow sediment, rather than dense basal till and that the fragic zone may have been influenced by permafrost. This influence is seen by the presence of a suite of characteristics associated with permafrost such as vesicular porosity, platy structure, reverse sorting, and silt coatings superimposed on clay coatings or papules.
Nine‐year Response of Thinned Slash Pine to Nitrogen, Phosphorus, and Potassium
Authors: Shoulders Eugene , Tiarks Allan E. 
Published: July 2010

AbstractDiagnostic procedures are needed for determining response of slash pine (Pinus elliottii Elngelm. var. elliottii) plantations on productive sites to N, P, and K fertilizer late in the rotation. A 25‐yr‐old slash pine plantation (site index = 21 m at 25 yr) in southwest Louisiana was thinned to a residual basal area of 18 m2 ha−1 and fertilized at rates of 0 to 448 kg N ha−1, 0 to 171 kg P ha−1, and 0 and 56 kg K ha−1 at selected levels of N and P. Separate experiments were established to determine response of stands and individual dominant and codominant trees to added nutrients. During 9 yr after application, N fertilizer stimulated diameter but not height or volume growth of stands. The effect of N on diameter growth decreased with increasing tree diameter at breast height (dbh) at age 25. Nitrogen had no significant effect on diameter, height, or volume growth of individual dominant or codominant trees. Phosphorus fertilizer significantly increased diameter, height, and volume growth of stands and individual trees. Regression analyses showed that diameter growth culminated with 110 kg added P ha−1 and volume growth culminated with 132 kg added P ha−1. Height growth increased lineally over the range of 0 to 71 kg added P ha−1. In otherwise comparable treatments, individual trees that were fertilized with 56 kg K ha−1 grew faster in diameter, height, and volume than those receiving none. Currently available diagnostic procedures would have identified the plantation as one that should respond to P and K fertilizer, but not to N.
Iron‐Rich High‐Charge Beidellite in Vertisols and Mollisols of the High Chaouia Region of Morocco
Authors: Badraoui Mohammed , Bloom Paul R. 
Published: July 2010

AbstractThe mineralogy of Vertisols and Mollisols, associated in a hydrotoposequence in the western part of the phosphate plateau of Morocco (High Chaouia), was studied using x‐ray diffraction, interlayer swelling with alkylammonium cations, chemical analysis, and infrared spectroscopy. The swelling behavior of Li‐ and K‐saturated clays demonstrated the beidellitic character of the expandable 2:1 layer silicates that dominate the clay mineralogy of these soils. The beidellite has a heterogeneous layer charge, as measured by the swelling with alkylammonium cations, that ranged from 0.50 to 0.66 charges per half unit cell. The swelling of Li‐saturated clays with alkylammonium cations after heating at 300 °C confirmed the tetrahedral location of the charge. Structural formulas calculated for the fine clays showed that the beidellite is similar in all three soils and confirmed that these clays have a high charge density and are Fe rich. Infrared spectroscopy demonstrated that these beidellites contain substantial amounts of Fe3+ in the octahedral sheet. Kaolinite, chlorite, palygorskite, and quartz were also present, especially in the coarse‐clay fractions and in the subsoil. The presence of this Fe‐rich, high‐charge beidellite in the soils helps explain the behavior of soil K and also offers an explanation of K soil test interpretation problems.
Automated Spray System for Application of Solutes to Small Field Plots
Authors: Ghodrati Masoud , Ernst Frederick F. , Jury William A. 
Published: July 2010

AbstractUniform application of chemical solutions onto the soil surface is an important step in solute transport field research. An automated spray system is described which facilitates the application of a spatially uniform solution volume to small plots. The system consists of a portable frame which mounts over the plot, a traveling spray boom, and a pressure activated tank. The motorized spray boom allows for a consistent, uniform application of known volumes of solution over the plot area. This sprayer was designed and used for surface application of pesticide, tracer, and dye solutions to plots of 1.5 by 1.5 m. An application uniformity of over 95% was obtained for each chemical within the inner 1‐ by 1‐m area. The range of relative deposition over this inner area was from 95 to 109% of the plot average. The exact design principles could be used to construct similar systems for spraying larger plots.
Measurement of Soil Water Content during Three‐Dimensional Axial‐Symmetric Water Flow
Authors: Kachanoski R. G. , Van Wesenbeeck I. J. , Von Bertoldi P. , Ward A. , Hamlen C. 
Published: July 2010

AbstractThe objective of this work was to develop a method of measuring soil water content during three‐dimensional axial‐symmetric water flow in a laboratory column. A small plexiglass box with a pair of straight and a pair of curved, parallel transmission lines was constructed, packed with soil, saturated with water, and then left to dry out. Soil water content measurements using the time‐domain reflectometry (TDR) method were made using both curved and straight transmission lines. A large laboratory flow box was also constructed with numerous curved TDR probes at different radial distances from one vertical edge of the box. The box was packed with soil and then water was applied from a small surface disc source, (radius = 15 mm) at the corner of the box. Soil water content was measured during the three‐dimensional infiltration experiment. Measured soil water contents were essentially identical (r2 = 0.98) for both the straight and curved lines. The method gave soil water content as a function of time for different radial distances from the point source, or the spatial distribution at different time intervals. The estimated amounts of infiltrated water obtained by numerical integration of soil water content vs. radial distance at 1 and 2 h were within 3% of the measured infiltration amount. The method can be used to test and study the theory of three‐dimensional axial‐symmetric flow of water into soil.
Cation Exchange Isotherms Obtained with Batch and Miscible‐Displacement Techniques
Authors: Bond W. J. , Phillips I. R. 
Published: July 2010

AbstractIn order to predict the transport of reacting solutes through soils, it is necessary to quantify their partitioning between the solution and surface phases. Conventional batch techniques for measuring adsorption isotherms have limitations for many surface reactions, which may be overcome by using miscible‐displacement methods. In this study, an improved miscible‐displacement technique for measuring adsorption isotherms was developed and its results compared with those from a standard batch method for cation exchange in a strongly aggregated, heavy clay soil. The new technique is based on destructive sampling of unsteady, unsaturated flow experiments and an improved method for simultaneously measuring solution‐ and exchangeable‐cation concentrations. Isotherms were obtained by the miscible‐displacement method for total solution concentrations of between 20 and 200 mmolcL−1 from experiments that were terminated after 6 to 24 h. These isotherms were identical with each other and were also not significantly different from those obtained by the batch method for both Na‐Ca and K‐Ca exchange. This confirms that exchange equilibrium was reached in the miscible‐displacement method and that this technique is suitable for measuring exchange isotherms. The results also permit some observations to be made about the rate of approach to equilibrium of ion‐exchange reactions in aggregated soils and the suitability of equilibrium exchange isotherms for application to natural flow regimes.
Critical Coagulation Concentrations of Sodium and Potassium Illite as Affected by pH
Authors: Hesterberg Dean , Page A. L. 
Published: July 2010

AbstractThe effects of saturating cation (Na or K) and pH on the critical coagulation concentrations (CCCs) of illite were measured. Flocculation series tests showed that between pH 6 and 11, the time‐invariant CCCs of Na illite increased from 6 to 58 mol Na m−3; release of interlayer K was controlled by adding 0.1 mol K m−3 to Na‐illite suspensions. The CCCs of K illite increased from 3 to 14 mol K m−3 over the pH range 6 to 10. The lower CCCs of K illite relative to Na illite were consistent with a higher surface affinity for K. Increasing CCC with increasing pH was explained by charge alterations on the edge surfaces due to surface‐specific proton interactions. A comparison of our Na‐illite CCCs to published Na‐kaolinite and Na‐montmorillonite CCCs revealed a greater pH dependence for Na‐illite and Na‐kaolinite CCCs.
Correlation between Soils and Sagebrush‐Dominated Plant Communities of Northeastern Nevada
Authors: Jensen M. E. , Simonson G. H. , Dosskey M. 
Published: July 2010

AbstractRelationships between sagebrush‐dominated plant communities and soil‐site variables were examined on 372 relatively undisturbed rangeland sites of the Humboldt National Forest in northeastern Nevada, USA. Site and soil‐physical variables that best discriminated between the 15 community types studied included mollic epipedon thickness, elevation, subsoil clay content, total soil depth, subsoil thickness, total water holding capacity, A‐horizon thickness, A‐horizon rock content, rooting depth, and subsoil rock content. Discriminant analysis indicated that 68% of the rangeland sites sampled could be correctly assigned to their appropriate community type based on site and soil‐physical variables. The percentage of sites correctly classified ranged from 25% within the Artemisia tridentata Nutt. ssp. tridentata/Festuca idahoensis Elmer community type to 100% in the Ar. longifolia Nutt./F. idahoensis type. Soil‐chemical variables effective in discriminating between community types included both surface (N, P, divalent/monovalent cation ratio, Ca, pH, base saturation, and organic‐matter content) and subsoil (divalent/monovalent cation ratio, Ca, base saturation, and pH) variables. Based on soil‐chemical criteria, only 32% of the study sites were correctly assigned to their appropriate community type. Results of this study suggest caution when inferring the soil properties of a site from plant community composition.
Ligand Concentration Effects on Aluminum Complexation by a Chestinut Leaf Litter Extract
Authors: Shotyk William , Sposito Garrison 
Published: July 2010

AbstractThe quenching of fluorescence at an emission wavelength dependent on the ligand concentration was used to measure organically complexed Al at pH 4.5 across a range of dissolved organic carbon (DOC) concentrations of chestnut (Castanea sativa L.) leaf‐litter extract. Simultaneous measurements of total inorganic Al were made by a 15‐s reaction with 8‐hydroxyquinoline. These data were combined to calculate quasiparticle model complex stability coefficients (cKT) for Al binding. For the range of DOC from 26 to 150 g m−3, the variation in the value of log cKT was not statistically significant. A conditional stability constant for a 1:1 quasiparticle Al/leaf‐litter complex was calculated after correcting cKT for Al hydrolysis and ligand protonation. Its mean value varied from 108.9 to 108.3 across the range of DOC investigated, but was also not significantly dependent on DOC according to statistical criteria. It was concluded that fluorescence quenching can be used to determine organically bound Al for an environmentally important range of leaf‐litter DOC concentrations.
Ground‐Penetrating Radar Study of Ortstein Continuity in Some Michigan Haplaquods
Authors: Mokma D. L. , Schaetzl R. J. , Doolittle J. A. , Johnson E. P. 
Published: July 2010

AbstractContinuity of ortstein affects many agricultural and urban land uses. This study was conducted to determine the utility of ground‐penetrating radar (GPR) in studying ortstein continuity. The GPR data were compared with those collected by conventional field techniques. The ortstein is generally strongly cemented and continuous in an area mapped as Saugatuck soils (sandy, mixed, mesic, ortstein, Aeric Haplaquods), and appeared to occupy 75 to 100% of each pedon. Tongues of E horizons and weakly cemented or noncemented materials in the ortstein horizon were easily identified by GPR. Such breaks in the ortstein are difficult to locate with conventional field techniques. These results demonstrate that GPR is useful in determining ortstein continuity.
Stratigraphy and Parent Material Relationships of Red Substratum Soils on the Allegheny Plateau
Authors: Waltman William J. , Cunningham Robert L. , Ciolkosz Edward J. 
Published: July 2010

AbstractRed (2.5YR 4/6 to 4/8) and brownish yellow (10YR 6/6 to 6/8) subsoils were studied in the Sweden soils (tentative classification: fine‐loamy, mixed, frigid Typic Hapludult) and the Dekalb‐Cook‐port‐Nolo catena (loamy‐skeletal, mixed, frigid Typic Dystrochrept, coarse‐loamy, mixed, frigid Typic Fragiuquult, and coarse‐loamy, mixed, frigid Typic Fragiaquult, respectively) on the unglaciated Allegheny Plateau. The red subsoil horizons are interpreted to be a pre‐Wisconsinan paleosol formed in colluvium and residuum that were derived from acid sandstones of the Huntley Mountain and Pottsville Formations mantling the plateau summits. The paleosol horizons are buried by 1 to 2 m of brown, sandy colluvium of Wisconsinan age, but can be clearly distinguished by an increase of clay content, higher free iron oxide content, extensive weathering and rubification of sandstone rock fragments, and strongly expressed argillic horizons. In the Cookport and Nolo soils, the paleosol occurs beneath a fragipan, with a stoneline marking the surface of the paleosol. The paleosol has been truncated, since A and E horizons are not preserved in the profiles. The paleosol horizons vary in color and iron oxide mineralogy across the catena sequence. The paleosol horizons of the Sweden and Cookport soils morphologically resemble pre‐Wisconsinan till‐derived soils of the Susquehanna Valley. From this study, only one pre‐Wisconsinan paleosol could be identified in the periglacial deposits of the Allegheny Plateau; it has been tentatively correlated with the Sangamon Interglacial. Three separate colluvial deposits were recognized on the plateau summits.
Poorly Ordered Silica and Aluminosilicates as Temporary Cementing Agents in Hard‐Setting Soils
Authors: Chartres C. J. , Kirby J. M. , Raupach M. 
Published: July 2010

AbstractHard‐setting is an important but poorly understood phenomenon in seasonally wetting and drying soils. This study was conducted to determine the role, if any, of chemical cementing agents in a hard‐setting soil. Undisturbed cores from the E horizon of an Aeric Albaqualf were leached in the laboratory with distilled water, 0.15 M ammonium oxalate (pH 3.0 in darkness) and 2 M NaOH/ethylene glycol. The leachates were analyzed for Si, Al, and Fe and the residual materials by infrared spectroscopy. After drying at 40 °C, tensile, shear, and compressive strengths of the cores were determined. All three reagents caused a total loss of tensile strength and decreased shear strength, but had little effect on compressive strength. Amorphous silica is probably the major cementing agent, but the results also indicate that an imogolite‐like aluminosilicate, a feldspathoid mineral, and possibly silica‐Fe complexes may play some part in cementation.
Water‐Droplet Energy and Soil Amendments: Effect on Infiltration and Erosion
Authors: Smith H. J. C. , Levy G. J. , Shainberg I. 
Published: July 2010

AbstractThe impact energy of water droplets from rain or overhead sprinklers can cause a seal to form at the soil surface. This constitutes a severe problem in agricultural lands in the arid and semiarid regions. Spreading a soil conditioner on the surface of the soil and providing a constant supply of electrolytes may prevent seal formation. The effect of droplet impact energy and water quality on infiltration and erosion was studied, using a tank drip‐type rain simulator, in a sandy loam soil (Typic Rhodoxeralf) treated with an anionic polyacrylamide (PAM) and phosphogypsum (PG). Three kinetic energies (KE) of 3‐mm diameter drops were obtained by varying their falling heights. The two qualities of water were distilled water (DW) and tap water (TW), to simulate rain and irrigation water, respectively. Increasing the impact energy reduced the infiltration rate (IR), cumulative infiltration (rain intake), and soil erosion in all treatments. Addition of PAM in the presence of electrolytes (either PG or TW) increased both final IR and cumulative infiltration by 7‐ to 8‐fold compared with the control, and was much more effective than PAM, PG, or TW alone. The PAM + electrolyte treatments decreased soil erosion by more than one order of magnitude compared with the control.
Slope, Aspect, and Phosphogypsum Effects on Runoff and Erosion
Authors: Agassi M. , Morin J. , Shainberg I. 
Published: July 2010

AbstractThe effect of slope, aspect (windward vs. leeward), and phosphogypsum (PG) application on rain amount, runoff, and erosion from a Grumusol soil (Typic Chromoxerert in Israel) was measured in small field plots (1 by 1.5 m) exposed to natural rainstorms. The amount of effective rain on the slopes, as measured with small rain gauges with orifices in a plane parallel to the slope, increased slightly on the windward aspect as slope increased to ∼58% and decreased thereafter. On the leeward aspect, the amount of effective rain dropped steadily to half of the meteorological rain at a slope of 100%. The amount of runoff was not affected by slope on the windward aspect but decreased sharply on the leeward aspect as slope increased. PG releases electrolytes into the percolating and runoff water, prevents dispersion of the particles at the surface, stabilizes the soil structure, and reduced soil erosion. PG applied at 5 Mg ha−1 reduced runoff to about 25% of that in the control and reduced soil loss to 1 to 3% of that in the control. The dramatic effect of PG on erosion increased with slope steepness.
Subsoiling for Sunflower Production in the Southeast Coastal Plains
Authors: Sojka R. E. , Busscher W. J. , Gooden D. T. , Morrison W. H. 
Published: July 2010

AbstractCrops grown on the Paleudult soils of the South Atlantic Coastal Plain often benefit from disruption of root‐restrictive subsoil layers. In this physiographic area, the response of sunflower (Helianthus annuus L.) to subsoiling was unknown. We hypothesized that in‐row subsoiling would benefit sunflower performance, and that plant performance could be related to profile penetration‐resistance patterns. Sunflower was grown on Norfolk loamy sand in Florence, SC, and on Orangeburg loamy sand (both fine‐loamy, siliceous, thermic Typic Paleudults) in Blackville, SC, in 1985 and in Blackville only in 1987. Plots were either subsoiled using 0.45‐m shanks or not subsoiled. Distribution (and, in most instances, magnitude) of cone indices were significantly different for subsoiled and nonsubsoiled profiles. Accumulation frequency of low cone indices was greater for Florence and Blackville in 1985 but not for Blackville in 1987. For subsoiled treatments, lower cone indices below planted rows persisted to late summer in 1985 at both locations, which favored plant growth. Reduction of soil profile strength produced increased seed yield, oil concentration, oil yield, and seed size in these cases. In 1987, accumulation frequency of soil strength was similar for non‐subsoiled and subsoiled plots shortly after tillage. In this case, plant parameters were not statistically improved with subsoiling. No tillage × N‐rate, hybrid × tillage, or hybrid × N‐rate interactions were observed. If low‐cone‐index isopleths persist throughout the season, then a positive response to subsoiling can be expected.
Corn Response to Seed‐Row Residue Removal
Authors: Kaspar T. C. , Erbach D. C. , Cruse R. M. 
Published: July 2010

AbstractNo‐till corn (Zea mays L.) yields in the central Corn Belt often are limited by slow soil warming caused by surface crop residues. A 3‐yr experiment with a split‐plot design was conducted near Ames, IA, to determine corn response to seed‐row residue removal. Whole‐plot treatments were a factorial combination of two tillage systems (no‐till and moldboard plow) and three residue types (corn, soybean [Glycine max (L.) Merr.], and fiberglass insulation). Residue was removed from bands of various widths (0, 8, 16, 32, and 76 cm) centered on the seed row for five split‐plot treatments. Corn seedlings reached 50% emergence 0.5 d earlier in plots with soybean residue than in those with corn residue. No‐till seedlings reached 50% emergence 0.8 d sooner and 50% tasseling 0.9 d sooner than in the mold‐board‐plow system. Residue removal from the seed row had greater effects on plant growth and yield than either tillage or residue type. Seed‐row residue removal reduced days to 50% emergence and tasseling, increased plant height, decreased grain moisture and barrenness, and increased yield. Removing residue from a 16‐cm wide band resulted in corn yields that were only 3% less than those from bare soil. Plant responses to width of the residue‐free band were described by logarithmic functions. Seed‐row residue removal may allow a compromise between erosion protection and crop yield.
Soil Water Diffusivity Determination by a Modified One‐Step Outflow Method
Authors: Mu'Azu S. , Skopp J. , Swartzendruber D. 
Published: July 2010

AbstractOne‐step outflow procedures represent potentially rapid and convenient procedures to obtain soil‐water‐diffusivity and unsaturated‐hydraulic‐conductivity data. This study presents modifications of the existing procedures that improve and simplify the estimation of the soil water diffusivity and associated water content. The derivation is similar to that of Passioura's. An equation is derived that describes the soil water diffusivity as a function of average soil water content rather than the water content at the top end of the soil core. The results may be used over a range of water contents similar to Passioura's original procedure. The modifications presented here provide a simpler analysis that is more readily applied to one‐step out‐flow experiments.