bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaporation Reduction from Soil with Wheat, Sorghum, and Cotton Residues
Authors: Unger Paul W. , Parker Jessie J. 
Published: July 2010

AbstractWheat (Triticum aestivum L.), grain sorghum [Sorghum bicolor (L.) Moench], and cotton (Gossypium hirsutum L.) are major irrigated crops on the Southern Great Plains. While irrigated wheat residue mulches increase soil water storage and decrease evaporation, very limited data are available regarding the effectiveness of grain sorghum and cotton (stalk) residues for this purpose. Therefore, this study was conducted to compare the effectiveness of wheat, grain sorghum, and cotton residues for decreasing evaporation under three potential evaporation conditions and to determine which residue characteristics are most effective for decreasing evaporation.The laboratory tests were conducted on Pullman elay loam soil columns at potential evaporation rates of 0.66, 0.92, and 1.29 cm/day. Besides a bare soil (check) treatment, residue treatments were 4, 8, 16, and 32 metric tons/ha for sorghum and cotton, and 8 metric tons/ha for wheat. About 16 metric tons/ha of sorghum and more than 32 metric tons/ha of cotton residues were needed to decrease evaporation to levels obtained with 8 tons/ha of wheat residue. Multiple regression analyses indicated that residue thickness most strongly affected cuniulative evaporation and evaporation rates at selected days of the study. Other independent variables considered were potential evaporation, relative humidity, and residue specific gravity, application rate, and surface coverage.
Contribution of Subsurface Flow from the Upper Slopes of Forested Watersheds to Channel Flow
Authors: Beasley R. S. 
Published: July 2010

AbstractOverland flow and subsurface flow from 0.054‐ and 0.089‐ha plots on the upper slopes of forested watersheds were intercepted and measured in trenches located at the bases of the plots. Channel flow was measured in flumes at the watershed outlets and intensity, duration, and amount of rainfall were measured by gages on the watersheds. Over a 3‐year period, 115 storms produced little overland and subsurface flow above the B‐horizon. Subsurface flow over an impermeable clay layer was as much as 90% of rainfall during a calendar quarter. Thirty‐six of the storms produced subsurface flow on one or both plots. For these storms, subsurface flow from the upper third of the watersheds was equivalent to 26% of the channel flow on one watershed and to 27% on the other. For 27 of the 36 storms, subsurface flow from the plots peaked sooner than channel flow. Twelve storms produced subsurface flow within 20 min of the onset of rainfall, and 15 storms produced channel flow within the same time. Subsurface flow often began shortly after rainfall began even when there was neither saturation at the point of outflow nor high antecedent soil moisture. Interconnected channels through the soil formed by decayed roots and animal burrows are the best explanation for the quick subsurface flow responses. The similarity in timing of subsurface and channel flows indicates that subsurface flow from upper slopes can contribute significantly to storm hydrographs in forested areas where permeable surface soils overlie an impermeable stratum.
Hexafluorosilicic Acid Reagent Modification for Quartz Isolation
Authors: Jackson M. L. , Sayin Mahmut , Clayton R. N. 
Published: July 2010

AbstractUp to three sequential 3‐day treatments with commercial H2SiF6 were required to remove feldspar XRD peaks from many samples of loess and glacial till. Two such repeated treatments lowered the yield of isolated quartz by about 10%. For example, with Memphis C horizon loess from Yalobusha Co., Miss., the yield dropped from 29 to 19% of the 1–10 µm size fraction. Pretreatment of the H2SiF6 with finely ground quartz (1–100 µm size fraction) raised the quartz yield after one or two 3‐day treatments about 10%, for example from 29 to 39% of the initial 1–10 µm fraction of Yalobusha loess. After a third 3‐day treatment the yield was 32%. The quartz of this loess was of 100% purity after one 3‐day H2SiF6 treatment, as established by XRD and XRS. The oxygen isotope delta value was affected a little, the δ18O declining from 17 to 16‰ for the 1–10 µm quartz isolates treated one to three times with H2 SiF6, and fine quartz particles were released (SEM) from clusters in fine chert contained in the loess.
Fitting Solute Breakthrough Equations to Data Using Two Adjustable Parameters
Authors: Elprince A. M. , Day P. R. 
Published: July 2010

AbstractNegative adsorption of anions reduces the volume of liquid available for the transport of electrolytes in the soil, and hence affects the nature of the breakthrough curve. A similar problem arises when there are appreciable volumes of soil solution which are essentially stagnant, and thus do not contribute significantly to the convective flux. These effects can be taken into account by introducing a second adjustable parameter (the effective solution volume) into the transport equation, in addition to the dispersion coefficient. The calculations demonstrate in a given example that a least squares procedure, applied simultaneously to the two parameters during the curve‐fitting process, resolves the apparent discrepancy between the theoretical breakthrough curve and the experimental data.
Effect of pH on Adsorption of Arsenic and Selenium from Landfill Leachate by Clay Minerals
Authors: Frost R. R. , Griffin R. A. 
Published: July 2010

AbstractAdsorption of As(V), As(III), and Se(IV) anions from municipal landfill leachate solutions by the clay minerals kaolinite and montmorillonite is strongly dependent upon solution pH.The H2AsO4‐ and HSeO‐3 ions are the apparent primary As(V) and Se(IV) species being adsorbed by the clay minerals. Activation of the anion adsorption sites on the clay minerals by H+ ions is important in determining the amount of HSeO3‐ ions adsorbed by the clay minerals, but it is apparently not important in determining the amount of H2AsO4‐ ions adsorbed.Montmorillonite adsorbed more As(V), As(III), and Se(IV) anions than kaolinite. Although no definite proof is given, the higher adsorption by montmorillonite is attributed to a higher edge surface area.The results of the study suggest that disposal of As and Se wastes in municipal landfills, especially under alkaline conditions, could produce ground water contamination by As and Se.
Influence of pH on the Sorption of Co2+, Zn2+ and Ca2+ by a Hydrous Manganese Oxide
Authors: Loganathan P. , Burau R. G. , Fuerstenau D. W. 
Published: July 2010

AbstractThe uptake of Co2+, Zn2+, and Ca2+ by δ‐MnO2 at 24.0 ± 0.5°C as a function of pH and salt concentration was investigated. At pH values < 5, δ‐MnO2 released structural Mn to solution phase during the sorption of Co2+ and to a lesser extent during Zn2+ sorption. Calcium sorption did not release any Mn to solution phase. In addition Co2+, Zn2+, and Ca2+ were shown to adsorb specifically at the δ‐MnO2 surface by exchange with bound H. The pH values had very little influence on the sorption of these cations.At pH values above 6, abrupt increases in the sorption of Co2+ and Zn2+ in narrow pH ranges were observed whereas no such marked increase of Ca2+ sorption was found up to pH 9.2. This type of sharp increase in sorption is due to specific adsorption and is related to hydroxylation of the metal ions. Measurements of microelectrophoretic mobility of δ‐MnO2 in the presence of Co2+, Zn2+ and Na+ suggested that Co(OH)2 or Zn(OH)2 may be nucleated at the δ‐MnO2 surface at pH values lower than those thermodynamically calculated (no supersaturation) which would result in precipitation of the pure hydroxides in bulk solution.At pH values between 5 and 6 any of the above mechanisms may be operative.
Changes in the Rhizosphere Due to NH4+ and NO3‐ Fertilization and Phosphorus Uptake by Corn Seedlings (Zea mays L.)
Authors: Soon Y. K. , Miller M. H. 
Published: July 2010

AbstractCorn (Zea mays L.) seedlings were grown for 11 days on 3 soils of pH 7.1, 5.5, and 4.3, and fertilized with monocalcium phosphate, and either (NH4)2SO4, Ca(NO3)2, or CaCl2.Rhizocylinder (roots plus adhering soil) and bulk soil solutions were isolated by centrifugal filtration and analyzed for pH and phosphate.The pH of the rhizocylinder solution was lowered by the absorption of NH4+ and increased slightly by NO3‐ absorption. Reduced rhizocylinder pH was associated with increased rhizocylinder solution phosphate concentration and P uptake by corn seedlings. The difference in P absorption between NH4+‐fertilized and NO3‐‐fertilized corn can be explained by induced changes in the H2PO4‐concentration associated with rhizocylinder pH. But, in addition, NH4+ and NO3‐ enhanced P absorption probably as a result of increased physiological capacity to absorb P and/or increased root growth.
Measurement of Isotopic Exchangeable Soil Phosphorus and Interrelationship among Parameters of Quantity, Intensity, and Capacity Factors
Authors: Dalal R. C. , Hallsworth E. G. 
Published: July 2010

AbstractThe applicability of various techniques to measure isotopically exchangeable phosphorus for widely different soils was investigated. The E‐values obtained in the laboratory by carrier‐free (E‐value) and carrier‐methods (Ec value) were comparable to L‐values obtained in the greenhouse in low‐phosphorus fixing soils but were very much higher in high phosphorus fixing soils. In the latter group E‐values obtained by inverse‐dilution technique (EI.D. value) were more comparable to L‐values.The parameters for available phosphorus in terms of quantity, intensity and capacity factors were discussed in relation to soil properties. The E, Ec, and Q0 values were influenced primarily by total phosphorus content of soils whereas L value was significantly correlated with exchangeable Ca and Mg, soil pH, organic C and oxalate, and dithionite extractable Fe (Feo and Fed) of soils. EI.D. value was correlated with oxalate extractable Al and organic C of soils. Thus both L and EI.D. values were affected by soil characteristics that influence the availability of phosphate in soil. The intensity factor was mainly influenced by soil reaction. The parameters of capacity factor, both phosphate buffering capacity (PBC) and maximum buffering capacity (Mb) were significantly correlated with dithionate extractable Al (Ald) of soils. It is suggested that since parameters of quantity, intensity, and capacity factors were generally influenced by different soil characteristics, plant available phosphorus can be described better by consideration of more than one factor.
Fertilization of Trifolium Subterraneum L. Growing on Serpentine Soils
Authors: Jones M. B. , Williams W. A. , Ruckman J. E. 
Published: July 2010

AbstractSerpentine‐derived Henneke soil from 23 sites was tested in greenhouse studies to determine nutrient deficiencies for subclover (Trifolium subterraneum L.), and to evaluate for soil Ca status.The soils (pH 6.3–6.9) were generally very deficient in P and S. When P and S were supplied, Ca increased subclover yields on 17 of the 23 soils, K on 10 soils, and Mo on 14 soils.Applications of P and S increased these two elements in clover tops from below critical levels to adequate.Yields were correlated with Ca and Mg in the plant and soil by the equation: Y = a[1−b exp (−cX)], where Y = relative yield, X = the variable under study, and a, b, and c are coefficients which determine the characteristics of the curve. The R2 values which are a measure of goodness of fit, occurred in descending order as follows: Percentage of Ca in clover tops > exchangeable Ca expressed as a percentage of the cation exchange capacity > exchangeable soil Ca > ratio of Ca/Mg in clover tops = ratio of exchangeable Ca/Mg in the soil > exchangeable Ca expressed as a percentage of the sum of the exchangeable cations. The R2 values were significant at the 1% level.
Soil Formation on Loess in Southwestern Indiana: I. Loess Stratigraphy and Soil Morphology
Authors: Harlan P. W. , Franzmeier D. P. 
Published: July 2010

AbstractThin loess deposits and underlying Sangamon paleosols were studied and related to modern soil development. Ninety‐one sites were sampled along four traverses extending 60–80 km eastward from the lower Wabash River, the main loess source. The ground soils, located mostly on primary divides, have a parent material sequence of silty loess (Peoria), sandy loess, upper part of Sangamon paleosol, and lower part of Sangamon paleosol. The paleosols developed in till or outwash of Illinoian age or in residuum of Pennsylvanian or Mississippian age.Soil development increases with increasing distance from the loess source. Thick loess (> 2m) soils have an A‐B2t‐C horizon sequence, whereas the thinner loess (1–2 m) soils have an A‐B2t‐(A′2)‐Bx horizon sequence. Soils with < 0.75 to 1 m of loess have B2t horizons in both loess and residuum and usually do not have fragipans. Fragipans tend to be associated with sandy loess, but usually do not coincide with it. They may be just above the sandy loess, coincident with it, or in some combination of sandy loess and adjacent parent materials. It is believed that soil moisture relations influenced by the sandy loess, or the underlying paleosols, or both promote fragipan development.
Soil‐landscape Relationships in the Occidental Plateau of São Paulo State, Brazil: I. Geomorphic Surfaces and Soil Mapping Units
Authors: Lepsch I. F. , Buol S. W. , Daniels R. B. 
Published: July 2010

AbstractThis study was conducted in a 70.8 km2 area that includes most of the soils and landscapes present in the Occidental Plateau region of São Paulo State, Brazil. Surficial deposits of unknown derivation and age and Cretaceous age carbonate cemented sandstone are the soil parent materials. Both geomorphic surfaces and soils were mapped. Surface and subsurface soil chemical and physical characteristics of 103 sites were summarized to evaluate the soil variation of geomorphic surfaces and soil mapping units.Soil properties that are expressions of weathering indices are related to geomorphic surface, but clay illuviation, base saturation, and carbon content do not regularly increase or decrease from the oldest to the youngest surface.More than one soil mapping unit can be found on one geomorphic surface. Most soil physical and chemical properties have smaller coefficients of variation when grouped by soil mapping unit than when grouped by geomorphic surface.
Time as a Factor in the Genesis of Four Soils Developed in Recent Alluvium in Pennsylvania
Authors: Bilzi A. F. , Ciolkosz E. J. 
Published: July 2010

AbstractFour soils developed in recent alluvium in the Ridge and Valley physiographic region of central Pennsylvania were studied in an attempt to relate chronologic age to pedologic age. Wood or charcoal found at the boundary between a recent and a buried soil profile at each site was radiocarbon dated. These dates were as follows: (i) < 205, (ii) 320 ± 80, (iii) 470 ± 80 and (iv) 1955 ± 80 years B. P., and indicate the maximum age of the alluvium in which the recent soil profiles developed. The relative distinctness of horizons evaluated by a field morphology rating scale, the volume (in cross section) of oriented illuvial clay films and the in situ weathering of clay minerals in these soil profiles indicate that morphological properties are effective in distinguishing chronologic age differences in alluvial soils which differ by approximately 1,500 years in age, but are not effective when the age differences are only a few hundred years. The data also indicate that cambic horizons can develop in <200 years and are still present after 2,000 years of soil formation.
Profile Modification of a Fragiudalf to Increase Crop Production
Authors: Bradford J. M. , Blanchar R. W. 
Published: July 2010

AbstractRoot development and crop yields are greatly reduced in soils having fragipan layers because of restricted air and water movement, high bulk densities and soil strength, and high acidity. In the first year after soil profile modification by trenching of a Missouri Typic Fragiudalf, available water storage and yields of grain sorghum (Sorghum bicolor (L.) Moench) were increased. Within unmodified areas, sorghum yields averaged 1,841 kg/ha. Deep trenching without chemical or physical additives increased yields to 4,322 kg/ha. Mixing lime, fertilizer, and sawdust with the soil material within the trenches increased grain sorghum yields to 5,987 kg/ha. The sawdust significantly increased water storage and water extraction, resulting in the grain yield increase.Reexcavation of a pit used by the Soil Conservation Service for soil series identification of the Hobson soil showed no signs of soil density or strength reformation during the 16‐year period since the pit was refilled.
Chemical Detoxication of Atrazine by Dexon
Authors: Brown C. B. , Rahman S. F. 
Published: July 2010

AbstractThe nonphytotoxic analogs of atrazine (2‐chloro‐4‐ethylamino, 6 isopropylamino‐s triazine) are hydroxyatrazine and protonated hydroxyatrazine. Distinctive infrared bands of these compounds appear at 1620, 1680, and 1740 cm‐1, respectively. By monitoring these distinctive bands of the compounds, it has been demonstrated that in a combination of atrazine and dexon (p‐[dimethylamino] benzenediazo sodium sulphonate) there is a time‐dependent chemical change of some atrazine to protonated hydroxyatrazine indicating a reduction in phytotoxicity of the s‐triazine. A part of dexon‐atrazine antagonism—the reduction of atrazine toxicity to certain plants in the presence of dexon—is due to chemical reaction.
Soil Moisture Conservation and Yield of Crops No‐Till Planted in Rye
Authors: Gallaher Raymond N. 
Published: July 2010

AbstractThis experiment was conducted to evaluate soil water use by no‐till planted corn (Zea mays L.) and soybeans (Glycine max (L) Merrill) in rye (Secale cereale (L)) mulch (RM) vs. rye stubble (RS) where rye was removed. Soil water was measured throughout the summer months at 15 and 46 cm depths using electrical resistance gypsum blocks. Soil water curves showed that corn and soybeans went through three periods of severe moisture stress, which at times lasted as long as 2 weeks. Crops planted into killed RM, conserved soil water, were more drought tolerant, and showed evidence of greater use and earlier depletion of water by roots deep in the soil profile as compared to RS treatments. Corn grain and soybean yields were 45.6 and 30.3% greater, respectively from the RM as compared to the RS treatment. These data show the tremendous potential for increasing corn and soybean yields under no‐till mulch planting management.
Determination of Inorganic Phosphorus in Oxalate Extracts of Soils
Authors: Owens L. B. , Nelson D. W. , Sommers L. E. 
Published: July 2010

AbstractA simple and rapid procedure for the determination of inorganic phosphorus in acid ammonium oxalate extracts of soils was developed by modifying the ascorbic acid‐molybdenum blue colorimetric method. The oxalate interference in the determination of P was overcome by addition of excess ammonium molybdate. A molar ratio of molybdate to oxalate, in the final solution, of 2.51:1 was required in order to eliminate the oxalate interference.
Phosphorus Sorption Characteristics of Flooded Soils
Authors: Khalid R. A. , Patrick W. H. , DeLaune R. D. 
Published: July 2010

AbstractSurface soils representing Alfisols and Inceptisols were collected from various parts of Louisiana under rice (Oryza sativa L.) cultivation and incubated under oxidized (aerobic) and reduced (anaerobic) conditions for 2 weeks in a soil to 0.01M CaCl2 solution ratio of 1:5. The release of native soil P and the sorption of added inorganic P was investigated under these conditions. The soils selected for study were characterized for clay content, total carbon, extractable P, pH, and oxalate‐extractable Fe, soil properties associated with P sorption. The results show that generally more soil P was released under reduced than oxidized conditions, and this increase in soluble P under reduced conditions was significantly related to Bray no. 2 extractable P, clay content, and oxalate Fe. At high levels of added P, more P was sorbed under reduced conditions than under oxidized conditions in 14 out of 20 soils under study. However, in Midland fine sandy loam essentially all of added P was recovered in the equilibrium solution under both oxidized and reduced conditions, suggesting this soil had no capacity to sorb P. The relationship between P sorbed at 500 µg/g added P and oxalate‐extractable Fe was described by fitting two linear curves with different slopes. In the reduced soil samples the slope of Region I (≤ 3,000 µg Fe/g) suggests that 5.4 Fe sorbed 1 P and that this ratio did not change until all of the added P was sorbed. In the oxidized samples this ratio was about 16 Fe/1 P for Region I (≤4,500 µg Fe/g). The slopes for Region II of the linear curves for both reduced and oxidized samples were essentially zero. A closer relationship between P sorbed and oxalate extractable Fe under reduced conditions indicates that poorly crystalline and amorphous oxides and hydroxides of Fe play a primary role in P retention by flooded soils and sediments. A probable greater surface area generated by the transformation of oxyferric hydroxide to more reactive ferrous compounds may be responsible for greater P sorption under reduced conditions.
Charge Characteristics of Spodic Horizons
Authors: Laverdière M. R. , Weaver R. M. 
Published: July 2010

AbstractSurface charge properties of six Spodosol Bir horizons, enriched in sesquioxides and organic matter, were investigated by acid‐base potentiometric titrations and ion adsorption measurements. The results indicate that the horizons have electrochemical properties similar to constant surface potential colloids as the sign and magnitude of the net charge were dependent upon the pH and indifferent electrolyte concentration of the ambient solution. The pH values (pHzpc) at which the net surface charge underwent reversal ranged from 4.2 to 4.9, and the values obtained by acid‐base potentiometric titrations agreed fairly well with those obtained by ion adsorption measurements. Although sesquioxidic components in combination with organic matter apparently dominate the charge properties of these Bir horizons, there was evidence from the titration curves of small amounts of clay minerals with a permanent negative charge. The latter was confirmed by potentiometric titrations of two Bir horizons to which various quantities of montmorillonite had been added. While the electrochemical behavior of these Spodosol Bir horizons was qualitatively identical to that of reversible interface colloids, theoretical mathematical models applicable for a quantitative description of the latter, such as the Stern double layer model, were found to give an inadequate representation of the observed values of surface charge and potential.