bluuebunny/crossref_metadata_2025_split huggingface dataset:
Soil‐Stratigraphic Correlation of a Doline in the Valley and Ridge Province
Authors: Crownover S. H. , Collins M. E. , Lietzke D. A. 
Published: July 2010

AbstractDolines of the Valley and Ridge Province of eastern Tennessee act as sediment traps and can provide detailed information on the recent geomorphic history of the surrounding landscape. The objective of this study was to determine the soil stratigraphy, age, morphology, and late Quaternary history in an upland doline on the Mascot Formation in eastern Tennessee. Soils were sampled on the doline rim (DR), upper sideslope (US), lower sideslope (LS), and near the doline center (DC). Pedogenesis of this large upland doline is related to parent material and geomorphic processes. Stratigraphy, age, and morphology varies among the soils. Pedon DC has two buried soil profiles. The upper buried A horizon (2Ab) was radiocarbon dated to 320 ± 70 years before present (YBP). This horizon separates a weakly developed, yellowish brown soil above, with 10 to 20% chert that formed in post‐European agricultural‐related sediments (late 18th and 19th centuries) with laminae, from silty pre‐European sediments (middle to late Holocene) that are low in chert but contain an argillic horizon. The second buried horizon (3Ab) was dated at 6100 ± 100 YBP and provides evidence of landscape stability during the middle Holocene, probably during the Hypsithermal Interval. Below this horizon, the soil has less clay and chert content varies. In contrast, Pedon DR has only a veneer of cherty silt loam late Holocene colluvium and cherty clay Mascot residuum. Geomorphic processes of mass wasting and slope wash on the doline sideslopes have provided a variety of sediments that have been trapped within this doline and subsequently subjected to pedogenesis.
Parent Materials and Stratigraphy of a Doline in the Valley and Ridge Province
Authors: Crownover S. H. , Collins M. E. , Lietzke D. A. 
Published: July 2010

AbstractA variety of contrasting parent materials have been preserved within a ridgetop doline in the Valley and Ridge Province of eastern Tennessee. These materials, related to current and past slope processes, were differentiated based on morphologic properties. Matrix color and texture and the nature and content of chert fragments were particularly important in this discrimination. The doline rim was host to several distinct parent materials, including: (i) Copper Ridge residuum, (ii) mixed ancient alluvium and colluvium, and (iii) ancient toeslope colluvium. Mass wasting and fluvial processes emplaced these “ancient” materials, which currently have no source area, during the late Pliocene or early Pleistocene. The doline sideslopes contain parent materials composed of stacked layers of cherty colluvium that are late Pleistocene and Holocene in age. These colluvial deposits were derived from upslope residual and “ancient” toeslope colluvial soils via recent mass wasting. Parent materials in the doline center have a completely different morphologic character than upslope deposits. A silty material, possibly late‐Wisconsinan loess eroded into this doline during the Holocene, is devoid of chert fragments. These materials have been sorted and deposited by active slope wash and originated from either locally derived loess deposited on upper doline sideslopes, the A and E horizons of soils located upslope, or both. At 1.3 m these silty materials rest directly on a buried A horizon (2Ab) that has been radiocarbon dated to 9170 ± 140 years before present (YBP). Beneath this buried surface, alternating layers of thick noncherty and thin cherty silt loam materials represent cycles of late Quaternary landscape stability and instability.
Fallow Management and Overwinter Effects on Wind Erodibility in Southern Alberta
Authors: Larney Francis J. , Lindwall C. Wayne , Bullock Murray S. 
Published: July 2010

AbstractAggregate size distribution (ASD) is influenced by tillage and climate and greatly affects wind erodibility of soils. This study determined the effects of fallow management and winter effects on ASD in the chinook belt of Alberta. Geometric mean diameter (GMD), geometric standard deviation (GSD), and erodible fraction (EF) <0.84 mm were determined in fall and spring on five fallow systems on a Lethbridge clay loam soil (fine‐loamy, mixed, Typic Haploboroll). The fallow systems were (i) tillage only, (ii) minimum tillage (herbicides and tillage), and (iii) zero tillage (herbicides only). In fall, one‐way disk and heavy‐duty cultivator fallow treatments had GMD values about 1 mm higher than blade cultivator or zero tillage treatments. The 1989–1990 winter with 90 cm of snowfall, 67 d of snow cover, and 101 d with a mean 2‐cm soil temperature between +2 and −2°C resulted in greater aggregate breakdown than the 1988–1989 winter, which had 129 cm of snowfall, 104 d of snow cover, and 68 d with 2‐cm soil temperatures between +2 and −2°C. Estimates of initiating wind velocities for erosion, based on residue cover and EF, were 13.3 m s−1 for the tillage treatments, 13.7 m s−1 for the minimum tillage treatment, and 15.4 m s−1 for the zero tillage treatment. However, the minimum and zero tillage systems had EF values >60% at more sampling times than the tilled treatments, indicating that wind erosion problems may occur if the residue cover was jeopardized.
Fertilizer Nitrogen Uptake by Rice from Urea‐Ammonium Nitrate Solution vs. Granular Urea
Authors: Wilson C. E. , Wells B. R. , Norman R. J. 
Published: July 2010

AbstractGranular urea is the primary N fertilizer source for rice (Oryza sativa L.) production in the southern USA. New cultivars respond to higher rates of N fertilizer applied preflood. Application of high rates often results in distribution problems when granular urea is used as the N source. Because liquid fertilizer sources can reduce distribution problems, this study was initiated to evaluate the efficiency of urea‐ammonium nitrate solution (UAN, 28‐0‐0) as a N source for rice. Each N fertilizer source was applied in three split applications at a rate of 84 kg N ha−1 just prior to flooding (preflood), 33.6 kg N ha−1 at 1.3‐cm internode elongation (IE), and 33.6 kg N ha−1 10 d after IE (IE + 10d) onto ‘Newbonnet’ rice that was seeded into microplots (0.58 m2). The fertilizer sources consisted of granular urea or UAN with either the urea, NH4, or NO3 labeled with 15N at each application time. At all three application times, the highest fertilizer N uptake occurred when granular urea was the N source. Application of granular urea resulted in 72.5% recovery of the fertilizer N in the plant compared with 52.6% recovery of the fertilizer N from UAN. Application of granular urea also resulted in significantly higher grain yields than UAN. Granular urea was superior to UAN as a N source for rice production due to the inefficient uptake of NO3‐N from the preflood application (9.8%). However, these data show that rice can efficiently utilize NO3‐N from applications made at IE or later (73.7% recovery).
Linear and Nonlinear Estimates of Fractal Dimension for Soil Aggregate Fragmentation
Authors: Rasiah V. , Perfect E. , Kay B. D. 
Published: July 2010

AbstractEstimates of nonlinear parameters may vary with the fitting procedure (linear or nonlinear) used. The objectives of this study were to compare (i) values of the fractal dimension, D, and the constant, k, obtained using linear (defined D1 and k1) and nonlinear (defined Dnl and knl) fitting procedures and (ii) the sensitivity of D1, Dnl, k1, and knl to variations in cropping and tillage practices and soil properties. Using aggregate mass‐size distribution data, from five different soils under two cropping and two tillage systems, obtained after wet sieving, 90 values were obtained for each of D1, Dnl, knl, and kl. The nonexistence of a 1:1 relation between Dnl and D1 indicated that the population of Dnl was different from that of D1. A similar trend was observed between knl and k1. The standard error of the estimates of Dnl was less than that of D1. Soil properties and cropping and tillage systems accounted for 84% of the variability in Dnl, 87% of knl, 81% of D1, and 46% of k1. The estimates of Dnl are accurate and can be predicted with greater confidence than those obtained using the linear procedure.
One‐Dimensional Model to Evaluate the Performance of Wick Samplers in Soils
Authors: Rimmer Alon , Steenhuis Tammo S. , Selker John S. 
Published: July 2010

AbstractWick samplers have become a valuable device for collecting soil pore water samples from the unsaturated zone. However, one of the problems with wick samplers has been that water and solutes bypass the samplers. Little work has been done on the nature of soil‐wick interrelations. Based on an analytical solution for a layered soil profile, a steady‐state solution was developed to predict the pressure head in a wick‐soil continuum. The solution was also used to match wick properties to a given soil type in order to minimize the bypass flow. The results of this analysis show that for a good match between wick and soil types, (i) their capillary length (α−1) needs to be similar, and (ii) the ratio of their saturated hydraulic conductivities should be similar to the inverse ratio of their cross section for flow. Examples for wick type selection based on these two requirements are given for two soil types and two wick types. For sandy soils, the optimal wick length is 30 to 40 cm, while for silt loams, the optimal length is >100 cm. Sampling with wick samplers in coarse‐textured soils was found to be less disturbing of the soil pressure head and moisture profile than sampling in fine‐textured soils. Hydraulic properties of fine‐textured soils require a large sampling area in order to create an undisturbed zone above the wick sampler.
Nitrate Leaching under Furrow Irrigation as Affected by Crop Sequence and Tillage
Authors: Meek B. D. , Carter D. L. , Westermann D. T. , Wright J. L. , Peckenpaugh R. E. 
Published: July 2010

AbstractThe potential for NO3‐N leaching after alfalfa (Medicago sativa L.) in irrigated crop production depends on cropping sequence and tillage practices. A 2‐yr field experiment in south‐central Idaho compared the NO3‐N leached following alfalfa of a conventional tillage bean‐bean (Phaseolus vulgaris L.) rotation with a silage corn (Zea mays L.)‐winter wheat (Triticum aestivum L.) rotation in a conventional tillage or no‐till system. Nitrate leaching was determined by: (i) sampling the soil solution below the root zone (1.2 and 1.5 m) using ceramic‐tipped samplers and calculating the N movement from the water balance, and (ii) measuring the change in soil NO3‐N at 1.35 to 4.5 m from soil samples taken in the fall and spring to 4.5 m. During the second growing season, average soil solution NO3‐N concentrations (below the root zone) were 28, 4, and 10 mg L−1 for the bean‐bean, corn‐wheat no‐till, and corn‐wheat tilled treatments, respectively. The soil NO3‐N in 1.35 to 3.3 m at the end of the study was 80 kg N ha−1 higher for the bean‐bean treatment than for the corn‐wheat treatments. The NO3‐N that moved below 1.35 m during the 2 yr was 53 kg ha−1 higher for the bean‐bean than for the corn‐wheat treatments. The soil NO3‐N in the 1.35 to 3.3 m depth after 2 yr was 21 kg ha−1 higher for the corn‐wheat under conventional tillage than under the no‐till system.
Construction and Installation of Acrylic Minirhizotron Tubes in Forest Ecosystems
Authors: Kloeppel Brian D. , Gower Stith T. 
Published: July 2010

AbstractGlass tubing has been the traditional material used when constructing minirhizotrons for studying fine root dynamics in managed and natural terrestrial ecosystems. However, we have found that rocky soils, swelling smectite clays, large structural roots, and freezing soils frequently have broken glass minirhizotrons. We have developed a system to construct and install durable acrylic minirhizotrons. Acrylic tubing costs 42% less than glass and requires only 13% of the preparation time, resulting in a 121% savings vs. glass. The major time‐saving device is a unique spring‐loaded etching trough that places accurate, evenly spaced circles along the length of the tube in minutes. The design can be easily modified for many applications. Preliminary results in a mixed western larch (Larix occidentalis Nutt.)‐lodgepole pine (Pinus contorta var. latifolia Engelm.) forest in western Montana indicate that the acrylic minirhizotrons are durable, the etching is visible, and the system can be used to examine fine root phenology.
Clay Differentiation in Aridisols of Northern Mexico
Authors: Ducloux J. , Petit S. , Decarreau A. , Delhoume J. P. 
Published: July 2010

AbstractAridisols with smectite B horizons are usually classified as Argids although the argillic characters may not always be present. In the Chihuahuan Desert of northern Mexico, some Aridisols have clayey horizons that do not seem to result from clay illuviation. Our purpose was to determine the origin of the clay enrichment and the mineralogical relationships between the parent materials and the B horizons. The study area is the Mapimi Playa, derived from a lutite lagoonal sediment parent material. A soil sequence from Orthids to Argids was identified. Four profiles were analyzed. The particle‐size distribution was determined by the sedimentation and centrifugation methods. The clay fractions were studied by x‐ray diffraction and peak decomposition, infrared spectroscopy, and chemical analyses. Soil water extracts were analyzed with an absorption spectrometer. From the Orthids to the Argids, clay enrichment in B horizons is controlled by the <0.2‐µm clay size fraction and small amounts of palygorskite. The B horizons contain prominent smectite, which has more Mg than the lutite smectite (parental material). The existence of the AIMgOH infrared vibrations in the soil clay suggests the neogenesis of a smectite different from the lutite smectite. The composition of the soil water extract suggests that Mg‐smectite and palygorskite may form in Mapimi soil profiles. The Argids of Mapimi Reserve result principally from clay neogenesis under current climatic conditions.
Small Spatial Scale Soil Water Content Measurement with Time‐Domain Reflectometry
Authors: Amato M. , Ritchie J. T. 
Published: July 2010

AbstractPlants growing on stored soil water often exhibit symptoms of water deficit even though a relatively large quantity of soil water is available for uptake where roots are present in the subsoil. To explore the possibility that this less effective absorption phenomenon was related to nonuniform root distribution or root clumping around soil peds, we examined the suitability of time‐domain reflectometry for measuring soil water content distribution on a small spatial scale. Measurements were made on clay loam and sandy clay soils with 21‐mm‐long parallel balanced transmission lines and compared with gravimetric water content measurement. Water content values ranged from oven dry to saturation. To quantify the error in propagation time measurement using short transmission lines, measurements were made in air using rod lengths ranging from 10 to 150 mm. The coefficient of variation was quite high (2.8–7.3%) for times shorter than 100 ps for air‐dry soil. In this case, the technique proved less reliable. For longer times, corresponding to higher water contents, the coefficient of variation was <3%. A few samples of clay loam soil with water contents >0.29 m3 m−3 showed excessively high values of dielectric constant. Care should be taken in data interpretation at high water content for these media. Time‐domain reflectometry proved effective in measuring water content with the tested transmission line for values >0.07 m3 m−3. Thus, a tool is provided for in situ measurement of spatial variability or at a spatial scale compatible with many problems ranging from the water uptake of clustered roots to seed germination in the field.
Monitoring Solute Transport in a Multi‐Layered Sandy Lysimeter using Time Domain Reflectometry
Authors: Vanclooster M. , Mallants D. , Vanderborght J. , Diels J. , Van Orshoven J. , Feyen J. 
Published: July 2010

AbstractThe lack of detailed and high‐quality experimental data on the fate of solutes in soil puts a severe constraint on the development and testing of transport models. This study illustrates how detailed measured solute concentration data, collected by means of time domain reflectometry (TDR), are used to identify the governing transport processes in a vertical heterogeneous soil. A lysimeter was constructed, consisting of an undisturbed three‐layered soil monolith placed on an artificial sandy soil column. Tensiometer cups and solution samplers, together with TDR probes, were inserted horizontally at regular depth intervals to monitor pressure head, solution concentrations, soil water content, and bulk electrical conductivity. In the lysimeter, quasi‐steady‐state unsaturated water flow conditions were established and TDR‐estimated transport of solute was monitored during leaching. Solute fluxes at different depths were calculated, resulting in probability density functions of solute travel time to different depths. The first moment of the solute travel time revealed that approximately all soil water was used to transport solute in the top of the lysimeter. The boundary between the top soil and the sandy substratum probably induced instabilities, and hence, preferential flow. The dispersivity increased with depth in the topsoil but approached almost a constant value deeper in the lysimeter.
Quaternary Ammonium Surfactant Effects on Sorption of Trace Metals onto Quartz and Aluminosilicates
Authors: Hayes Kim F. , Chen Chia‐chen , McAvoy Drew C. 
Published: July 2010

AbstractThis study was conducted to investigate the potential impact of quaternary ammonium compounds (QACs) on trace metal ion desorption from soil constituents. Three soil constituents (quartz, kaolinite, and montmorillonite), two trace metal cations [Co(II) and Sr(II)], and three alkyltrimethylammoniumchloride surfactants (C8TMAC, C12TMAC, and C16TMAC) were chosen for this investigation. For the quartz system, Co(II) showed no desorption while Sr(II) showed a slight pH‐dependent desorption. For kaolinite or montmorillonite systems, desorption of Co(II) and Sr(II) by QACs occurred only for the fraction of the trace metal cations sorbed on permanent‐charge sites. In the case of montmorillonite, Sr(II) was significantly desorbed at all pH values. This was thought to be a result of the nearly exclusive sorption of Sr(II) to the permanent‐charge sites in this system. In all other clay systems studied [Sr(II), Co(II) on kaolinite; Co(II) on montmorillonite], desorption only occurred at lower pH from permanent‐charge sites. No desorption occurred at higher pH values where sorption to surface hydroxyl sites was indicated. In general, QAC‐induced desorption of trace metal cations was found to be significant only when QAC sorption equaled or exceeded the cation‐exchange capacity. Surfactant chain length was found to have little effect on the overall pH‐dependent desorption trends. As expected, higher surfactant concentration was required to cause trace metal ion desorption as the surfactant chain length decreased.
Parameters of Surface Heterogeneity from Laboratory Experiments on Soil Degradation
Authors: Pachepsky Ya. A. , Polubesova T. A. , Hajnos M. , Jozefaciuk G. , Sokolowska Z. 
Published: July 2010

AbstractIn this study, we examined the applicability of the theory of gas adsorption on heterogeneous surfaces to assess changes in soil particle surfaces in degrading soils. Soil degradation was simulated by laboratory treatments of gray forest soil (Udic Argiboroll), chernozem soil (Typic Haploboroll), and chestnut soil (Ustolic Orthid) samples. Water vapor adsorption data were used to estimate the frequency distribution of surface adsorption energy and to assess the strength of the surface attractive field. A modified Brunauer‐Emmett‐Teller equation provided a good fit of the water vapor adsorption isotherms on soil minerals for relative vapor pressures in the range of 0.05 to 0.85. This equation was used as a local isotherm equation. The piecewise distribution technique was applied to estimate the surface adsorption energy distribution. After a H2O2 treatment, the monolayer capacity and average adsorption energy decreased in the samples of all three soils. After cyclic wetting‐drying, the adsorption energy range decreased. After silica acid treatments, the monolayer capacity decreased, and the energy distribution became much narrower. All treatments resulted in a loss of the low‐energy adsorption sites and an increase in the number of layers retained by the surface at saturation vapor pressure. The exchangeable Ca content changed after the treatments in the same way as the monolayer capacity did. The exchangeable Mg content increased after organic matter oxidation and slightly decreased after the silica treatments. The exchangeable K content increased after both organic matter oxidation and the wetting‐drying treatments.
Erosion from Alfalfa Established with Oat under Conservation Tillage
Authors: Wollenhaupt N. C. , Bosworth A. H. , Doll J. D. , Undersander D. J. 
Published: July 2010

AbstractConservation tillage (CT) methods reduce soil erosion, but effects on establishing alfalfa (Medicago sativa L.) are not well known. Oat (Avena sativa L.) is often planted with alfalfa to reduce erosion during establishment, but results are not well documented. We hypothesized that the inclusion of oat during establishment would not be as effective as CT at reducing soil erosion. Moldboard plowing (MB) was compared with two CT practices of disking (DK) and no‐till (NT), with alfalfa planted alone (SOLO) or with a companion oat crop (COMP). The study was conducted in 1992 and 1993 on Rozetta silt loam soils (fine‐silty, mixed, mesic Typic Hapludalfs) following corn (Zea mays L.) each year. Simulated rainfall, 72 mm h−1 for 1 h, was applied twice per growing season, at planting (1 wk) and during oat canopy development (4 wk). Runoff was reduced from 28 mm in MB plots to 13 mm in CT plots at planting in 1992. Four weeks after planting in 1993, runoff was reduced from 47 mm in SOLO to 44 mm in COMP. Averaged across all simulations, sediment concentration was 23.3 g L−1 for MB and 3.2 g L−1 for CT. The 2‐yr mean soil loss dropped from 644 g m−2 in MB to 94 g m−2 in CT at planting. Mean treatment erosion was reduced 85% by canopy in 1992, a dry year. The wet 1993 growing season had several severe crusting rainstorms that induced large MB soil loss (2173 g m−2) 4 wk after planting. Companion cropping reduced MB soil loss 46% (from 2827 to 1520 g m−2) in 1993 and DK and NT further reduced soil loss to 235 and 123 g m−2. Forage biomass was unaffected by treatment in 1992.