bluuebunny/crossref_metadata_2025_split huggingface dataset:
Antecedent Rainfall and Tillage Effects upon Infiltration
Authors: Freebairn D. M. , Gupta S. C. , Onstad C. A. , Rawls W. J. 
Published: July 2010

AbstractInfiltration characteristics of a Port Byron (fine‐silty, mixed, mesic, Typic Hapludoll) silt loam soil located in the karst terrain of southeastern Minnesota were determined using both ponded water and simulated rainfall. Three tillage treatments, with and without surface cover, were studied to provide a range of soil physical conditions. Simulated rainfall was applied after various amounts of both natural and artificial rain had fallen since tillage. Large differences in infiltration characteristics were attributed to the development of a surface crust. In the absence of a crust, this soil was highly permeable (>200 mm h−1) while surface‐crusted infiltration rates were as low as 10 mm h−1. Infiltration characteristics were related to depth of rainfall since tillage, cover, and random roughness. Statistical analysis showed that >77% of variation in infiltration rate, Green and Ampt hydraulic conductivity, and curve number was explained by the depth of rainfall since tillage, surface cover, and random roughness. A procedure is suggested that describes the change in infiltration characteristics as a function of rainfall since tillage for various tillage conditions.
Slope and Phosphogypsum's Effects on Runoff and Erosion
Authors: Warrington D. , Shainberg I. , Agassi M. , Morin J. 
Published: July 2010

AbstractThe effect of slope on runoff and erosion has been studied mainly in stable soils. Loamy soils from semiarid regions have unstable structures and tend to seal during a rainstorm. The permeability of the seal is sensitive to water quality. The effect of slope angle (5–30%) and addition of phosphogypsum (PG), which changes the water quality, on the infiltration rate (IR), runoff and erosion from an unstable sandy loam soil material (Typic Rhodoxeralf) was studied using a rain simulator. Increasing the slope slightly reduced the amount of runoff and increased the final infiltration rate. The increase in final IR was due to seal erosion. The PG application increased the permeability of the seal, tripled the final IR of the soil sample and decreased the volume of runoff by 50%. Phosphogypsum application also reduced erosion by 60% at the gentlest slope angle. Change in slope angle from 5 to 25% doubled soil loss in the PG‐treated soil samples but increased by seven‐fold soil loss from the untreated soil samples. Gypsum treatment releases electrolytes into the percolating and runoff water. Its effect on soil erosion is due to decreasing the fraction of runoff water, stabilizing the soil structure at the soil surface, and increasing the rate of sediment deposition. The dramatic effect of PG in reducing erosion from steep slopes may be used in stabilizing soil structures on steep slopes.
Root Zone Physical and Chemical Characteristics in Southeastern Spruce‐Fir Stands
Authors: Kelly J. M. , Mays P. A. 
Published: July 2010

AbstractBecause of their remote location and relatively limited extent, soils in the southeastern spruce‐fir zone have not been extensively characterized either physically or chemically. The objective of this study was to describe and characterize the soils found in most of the major spruce‐fir areas in the Southeast as a first step in evaluating potential growth changes in the region. Fifty‐two soil profiles, randomly distributed within the spruce‐fir cover type, were described and samples were collected for physical and chemical analysis. Soils sampled were classified into the following taxonomic subgroups: Lithic Borofolists, Umbric Dystrochrepts, Lithic Haplumbrepts, Typic Haplumbrepts, Pachic Haplumbrepts, and Lithic Haplorthods. The data set was further condensed by focusing only on the rooting zone as defined for each pit by field measurements. Mean rooting depths ranged from 17 to 39 cm. All profiles were strongly to extremely acid (pH 3.6–4.6), with CECs in the 28 to 39 cmol kg−1 range and base saturation less than 4%. Considerable variability was seen among soils in organic matter (132–312 g kg−1) and total Kjeldahl N (TKN) content (5.4–11.0 g kg−1). Statistically significant (P = 0.05) differences also occurred in exchangeable base cations, while total cations exhibited less variability among groups. Extractable P varied little among these subgroups with only the Pachic Haplumbrepts having significantly higher concentrations. Total P exhibited more variability in concentration. Acetate‐soluble SO4‐S ranged in concentration from 0.08 to 0.67 g kg−1. Extractable and exchangeable Al concentrations were generally lowest in the Lithic Borofolists and highest in the Lithic Haplumbrepts. Observed variations are attributed primarily to differences in organic matter accumulation and to the impact of soil creep/soil mixing due to general slope instability.
Modeling and Field Measurements of the Effect of Nitrogen Source on Nitrification
Authors: McInnes K. J. , Fillery I.R.P. 
Published: July 2010

AbstractThe movement of N in relation to water movement and plant uptake is, in part, determined by the rate of nitrification. Nitrifying bacteria are known to be inhibited by low pH. A laboratory incubation and a field experiment were conducted to study nitrification of NH4 supplied by ammonium sulfate (AS), diammonium phosphate (DAP), and urea, N sources that produce environments with different pH, particularly when applied to moderately acidic, poorly pH‐buffered soil. The field site was located on a texture contrast soil (sandy, thermic Natric Durixeralf) at Merredin, Western Australia. The incubations were performed on a sample of the surface 100 mm of this soil. The initial pH and the pH‐buffer capacity of the sample were 5.4 and 4 mmol kg−1 (pH unit)−1, respectively. Nitrification rates were found to vary with the inherent alkalinity of the N source, viz., urea > DAP > AS. The nitrification process was modeled taking into account the effect of pH on nitrifier growth and activity. A linear relation in the model between pH, and both the specific growth rate and activity of the nitrifiers accounted for most of the variability between N sources. In the field experiment, 15N remained largely in nonnitrate form for the first month after application, presumably because of low temperatures, but after 53 d production of NO3 was greater with urea than AS. With the slow rate of nitrification, the leaching of NO3 was minimal.
Adsorption Isotherms of Polyanions on Soils Using Tritium Labeled Compounds
Authors: Nadler Arie , Letey J. 
Published: July 2010

AbstractAlthough the effects of polymers on various soil physical properties have been investigated, adsorption of polymers by soils has not been extensively studied. Adsorption isotherms were determined by the batch technique for three tritium‐labeled polyanions on one soil which received various pretreatments. Two polyacrylamide (PAM) compounds in which the NH2 was substituted with OH at 2% (2J) and 21% (21J), rendering them negatively charged, were used. Additionally, a guar compound (4246) used in the study was negatively charged and had a lower molecular weight than PAM. The soil was used without pretreatment and also with pretreatment to create a Ca soil, Na soil, organic matter‐depleted soil, and high‐pH soil. Polyanion type had a relatively greater effect than did soil pretreatment on adsorption, except for the Na soil, which had very low adsorption as compared to the other soil pretreatments. The more negatively charged polyanions (21J and 4246) had linear adsorption isotherms except for 21J on the Na soil. The 2J had adsorption isotherms that plateaued at higher concentrations. The amount of adsorption was in the general order 21J > 4246 > 2J. The exception was for the Na soil in which adsorption for all polymers was low and in the order 4246 > 2J > 21J. Aggregate stability was determined by wet sieving on all the samples. No direct association between the amount of adsorption and aggregate stability was found. The general effectiveness of the polyanions for improving aggregate stability of the natural soil was in the order 2J > 21J > 4246. The reverse trend was observed for the Na soil.
Cultivated and Adjacent Virgin Soils in Northcentral South Dakota: I. Chemical and Physical Comparisons
Authors: Blank R. R. , Fosberg M. A. 
Published: July 2010

AbstractEvaluation of the effects of cultivation on soil properties in Ustic Mollisols has generally been limited to surface horizons. To examine the effects of cultivation on both surface and subsurface horizons, six paired virgin and cultivated pedons of Williams soil (fineloamy, mixed Typic Argiboroll) or variants of Williams from northcentral South Dakota were compared for differences in various chemical and physical properties. When similar horizons were compared, chemical differences between cultivated and virgin pedons averaged as follows: (i) organic C content was 26% less in Ap horizons; (ii) water‐soluble Si was 49, 46, and 21% greater in A, Bt, and Btk horizons of cultivated pedons, respectively; (iii) water‐soluble Mg, Na, and K were 42, 32, and 18% lower in C horizons of cultivated pedons, respectively; (iv) oxalate‐extractable Fe was 28 and 56% higher in Ap and Bt horizons of cultivated pedons, respectively. When similar horizons were compared, physical differences between cultivated and virgin pedons averaged as follows: (i) bulk density was 18% greater in Ap horizons; (ii) Ap horizons contained 38% more very fine sand and 10% less silt; (iii) A and Btk horizons of virgin pedons possessed greater wet aggregate stability; and (iv) A horizons of virgin pedons average 30% more water retained at 0 MPa tension.
Spring Wheat Plant Parameters as Affected by Fallow Methods in the Northern Great Plains
Authors: Tanaka D. L. 
Published: July 2010

AbstractConservation tillage and no‐tillage practices for wheat (Triticum aestivum L.) production reduce soil erosion, conserve soil water, and alter crop environments. A study was conducted on a Williams loam (Typic Argiboroll) to determine the influences of stubble mulch, reduced tillage, and chemical fallow on grain yield and yield components, N and P concentrations in grain, water‐use efficiency, and straw production in a spring wheat‐fallow rotation. Average quantity of surface resldue prior to seeding spring wheat on chemical fallow plots (1371 kg/ha) was about three times the quantity on stubble‐mulch plots (399 kg/ha) and two times the quantity on reduced tillage (703 kg/ha) averaged over the 4‐yr study. The greater quantity of surface residue on chemical fallow plots in 1985 and 1986 resulted in significantly greater stored soil water to 1.70‐m depth when compared to stubble‐mulch plots. However, greater stored soil water did not result in significantly higher grain yield, although straw production for chemical fallow plots (2831 kg/ha) was significantly higher than for stubble‐mulch plots (2036 kg/ha) in 1985. Results of this study suggest that during years of crop stress resulting from limited soil water and above normal early spring temperatures, chemical fallow may produce more spring wheat than stubble‐mulch fallow. However, with limited water or temperature stress, stubble‐mulch fallow may produce more spring wheat than chemical fallow. Grain N concentrations were similar for all years except 1983 when N concentrations were greater for stubble‐mulch plots than chemical fallow plots. Fallow method did not influence grain P concentration. Grain water‐use efficiency was greater for wheat grown on stubble‐mulch plots than on chemical fallow plots.
Surface Hydrologic Response of Soils to No‐Tillage
Authors: Dick W. A. , Roseberg R. J. , McCoy E. L. , Haghiri F. , Edwards W. M. 
Published: July 2010

AbstractNo‐tillage (NT) crop production is practiced on approximately 5% of the total cropland in the USA. The effect of NT on soil surface hydrology is not well understood. In a 0.5‐ha watershed containing Rayne silt loam (Typic Hapludult) of 9% slope to which NT had been continuously applied for 16 or more years, storms with 1‐min intensities >76 mm h−1 were required before surface runoff could be generated. Approximately 96% of the annual surface runoff occurred as a result of these intense storms. To provide more detailed and statistically relevant information of NT effects on surface soil hydrology, a study was conducted using undisturbed lysimeters (4.8 by 1.7 m) containing a Canfield silt loam soil (Aquic Fragiudalf). During the 6 yr of the study, the amount of water that percolated through the soil and left the lysimeters as leachate was two times greater under NT as compared to conventional tillage (CT). Leachate equaled 55% of the precipitation input for the NT lysimeters and 24% for the CT lysimeters, with the greatest amounts leaving the lysimeters during the winter and spring seasons. The amount of leachate, expressed as a percentage of total water (sum of runoff plus leachate), leaving the lysimeters was 88% for the NT treatments and 60% for the CT treatments. Amounts of surface runoff were two times greater under CT than NT. Cross correlation analysis indicated a similar temporal pattern between leachate production and precipitation for both tillage treatments. A stronger temporal relationship existed between precipitation and runoff for the CT than for the NT treatment, however. The effect of NT on surface soil hydrology was clearly evident only 3 yr after the last tillage operation.
Urea Phosphate Effects on Infiltration and Sodium Parameters of a Calcareous Sodic Soil
Authors: Ryan John , Tabbara Hadi 
Published: July 2010

AbstractThere are potential advantages to using acidic fertilizers, especially in irrigation systems. Such materials improve water infiltration and permeability in soils whose structure is adversely affected by excess Na. A laboratory study evaluated urea phosphate (0–20 g kg−1 solutions), which contains H3PO4, with respect to initial infiltration of the urea phosphate (UP) solution and subsequently with water alone. A calcareous clay soil was equilibrated in columns with saline solutions [electrical conductivity (EC), 1.5 dS m−1] with sodium adsorption ratios (SAR) of 5, 10, 20, 40 and 60, to give varying exchangeable sodium percentages (ESP). Initial infiltration rates (IR) were enhanced only with the dilute UP solutions, i.e., 1.0 and 2.5 g kg−1, while all UP solutions improved subsequent infiltration with water alone. As the UP concentration of the infiltration solution increased, decreases occurred in soluble Na from the saturation extract and exchangeable Na, and estimated SAR. The improvement in IR was probably due to H3PO4 solubilizing CaCO3 for exchange reactions of Ca2+ with soil Na+. Urea phosphate may therefore enhance water use efficiency in some irrigated soils as well as serving as an effective source of N and P.
Water‐Drop Kinetic Energy Effect on Water Infiltration in Calcium and Magnesium Soils
Authors: Keren R. 
Published: July 2010

AbstractThe effect of adsorbed Mg and Ca ions on the infiltration rate (IR) of two montmorillonitic soils (Calcic Haploxeralf and Typic Rhodoxeralf) at several kinetic energies of water drops was studied. The kinetic energy of the water drops, the type of adsorbed ion and the electrolyte concentration in the applied solution all have a strong effect on the IR of the soils saturated by Mg or Ca ions. The higher IR values of the soils exposed to electrolyte solution suggests that clay dispersion takes place in Mg and Ca soils exposed to deionized water from simulated rainfall. The IR of the soils decreased with increasing kinetic energy and the values were always lower for Mg soils than for Ca soils. This difference was attributed to the higher width of the hydration shell of the adsorbed Mg than the Ca ion. Breakdown of the soil aggregates and clay dispersion are the two mechanisms that appear to be operative in seal formation when soils are saturated by either Ca or Mg ions exposed to deionized water. Magnesium adsorbed by montmorillonitic soils has a specific effect on IR, whether the soils contain CaCO3 or not.
Herbicide Reactivity of Soil Organic Matter Fractions in No‐Tilled and Tilled Cotton
Authors: Stearman G. K. , Lewis R. J. , Tyler D. D. , Tortorelli L. J. 
Published: July 2010

AbstractBecause of the increased use of herbicides in no‐tilled soils and the difference in organic C distribution between tilled and no‐tilled soils, it is important to compare herbicide activity in different tillage systems. Soil humus fractions and characteristics were determined on surface Lexington silt loam soil (fine, silty, mixed, thermic Typic Paleudalf) samples of no‐tilled and tilled cotton field plots in West Tennessee. Soil humic and fulvic acid were extracted by standard methods. Total C ranged from 9.9 g kg−1 in the tilled soil to 13.5, 16.6 and 23.5 g kg−1 in the no‐tilled soils, with rye (Secale cereale L.), vetch (Vicia villosa Roth) and crimson clover (Trifolium incarnatum L.) cover crops, respectively. The tilled soil had the largest fraction of extractable C and fulvic acid, relative to total soil C. Humic acid was characterized by 13C‐NMR (nuclear magnetic resonance spectroscopy), titration of functional groups, and elemental analysis. Carboxyl groups determined by 13C‐NMR ranged from 6.1 to 7.7 mol kg−1 humic acid and compared more closely with total acidity than with carboxyl‐group determinations by titration. A greenhouse herbicide bioassay was conducted and sorghum [Sorghum bicolor (L.) Moench] growth was measured to indicate soil organic‐matter effects on the phytotoxicity of two herbicides. Herbicide activity was inversely related to soil C, extractable C, carboxyl groups of humic acid, and fulvic‐acid C. Fulvic‐acid C correlated best with herbicide activity. Decreased herbicide activity in tilled (no cover crop) soil was largely attributed to the C in tilled soil being in a more reactive state than C in no‐till (cover cropped) soil.
Solid‐state Carbon‐13 Nuclear Magnetic Resonance and Infrared Spectroscopy of Composted Organic Matter
Authors: Inbar Y. , Chen Y. , Hadar Y. 
Published: July 2010

AbstractUse of stabilized composts as horticultural container media has been a fruitful and desirable alternative in utilization of agricultural wastes. We prepared compost from cattle manure and investigated the products at various stages of the composting process. The objectives of this work were to measure, quantify and correlate changes in the organic constituents of separated cattle manure (CSM—the solid fraction obtained by centrifugal separators from a slurry of cattle manure) during composting by using both chemical and spectroscopical analytical methods. This research should provide the information necessary for the establishment of maturity indexes for CSM. Carbon‐13 NMR spectra acquired with Cross‐Polarization Magic Angle Spinning (CPMAS) and infrared spectra measured with a Fourier‐Transform InfraRed spectrophotometer (FTIR) were applied to bulk CSM samples without extraction. Both methods confirmed the presence of appreciable amounts of carbohydrates throughout the composting process. During the process the level of carbohydrates decreased while levels of alkyl C, aromatic C, and carboxyl groups increased. The higher rate of decomposition of the carbohydrates resulted in the accumulation of modified lignin. Changes in FTIR absorbance ratios of several distinct peaks were linearly and significantly correlated with various parameters of compost maturity. Crude fiber analyses showed lower concentrations of soluble organic matter, hemicellulose and cellulose while that of lignin increased. Cation exchange capacity increased from 63 to 181 cmol/kg OM, and humic substances content increased markedly from 38 to 71% of the organic matter, while the C/N ratio decreased from 27.1:1 to 8.7:1 during the 147‐d composting process. The proposed spectrometric procedures using CPMAS 13C‐NMR and FTIR measurements directly on decomposing organic matter without extraction, provide information exhibiting significant correlations with more conventional chemical parameters of compost maturity.
Bradyrhizobium japonicum Inoculation and Seed Priming for Fluid‐Drilled Soybean
Authors: Berg R. K. , Jawson M. D. , Franzluebbers A. J. , Kubik K. K. 
Published: July 2010

AbstractMicrobial inoculation coupled with seed priming has potential application in fluid‐drilled cropping systems. The feasibility of applying Bradyrhizobium japonicum during seed priming and at planting using cellulose‐based gels was evaluated with soybean, Glycine max (L.) Merr. A greenhouse study evaluated whether exposure to Strain USDA 110SK or 123SR for 24 h during seed priming increased soybean nodulation by those strains compared to a subsequently applied gel‐carried strain. Well‐nodulated soybeans resulted when inoculation occurred only during seed priming. However, whenever gel inoculation was used, soybean nodules were almost exclusively occupied by the strain applied with the gel, regardless of whether the root radicle had or had not emerged prior to inoculation at seed priming. Differences in condition of seedbeds and soils at planting, and between fluid and conventional planting systems, influenced results from two field sites in eastern Nebraska. Strain 123SR occupied 5 to 10% of nodules at a Sharpsburg‐soil (fine, montmorillonitic, mesic Typic Argiudoll) site when carried in a cellulose‐based fluid gel at planting. Inoculation during solid‐matrix seed priming had little effect on nodule occupancy and Strain 123SR was not recovered when peat was used as a carrier. In contrast, 123SR was rarely recovered, regardless of treatment, from a Kennebec soil (finesilty, mixed, mesic Cumulic Hapludoll). Fewer nodules formed on Kennebec‐ than Sharpsburg‐soil soybeans (17 vs. 31 nodules/plant). Increased grain yields were observed at the Kennebec site (2.87 vs. 2.24 Mg/ha) when fluid‐drilled soybean seed was solid‐matrix primed. Seed priming apparently aided soybean establishment under dry soil conditions. Field delivery of viable bradyrhizobia in gel was shown to be feasible for fluid‐drilled soybean. Short‐term exposure to Bradyrhizobium inocula during seed priming did not increase soybean nodulation by that strain.