bluuebunny/crossref_metadata_2025_split huggingface dataset:
Using Ground‐Penetrating Radar to Update Soil Survey Information
Authors: Schellentrager G. W. , Doolittle J. A. , Calhoun T. E. , Wettstein C. A. 
Published: July 2010

AbstractRapid changes in land use in many areas of the USA, and evolving concepts of soils and soil mapping have resulted in the need to update information gathered as part of the National Cooperative Soil Survey Program. In Florida, because of optimum soil conditions, large amounts of soils information can be gathered at a rapid rate by using ground‐penetrating radar (GPR). The information is being used to update soil surveys. Soil maps of the older soil survey report were evaluated first in order to determine if the map unit delineations consistently separate mappable landform and vegetative features. Using GPR, transects were made within randomly selected map unit delineations. Soils were identified and classified using conventional methods and their respective proportion and distribution along the transects were determined using the GPR imagery. These data were statistically analyzed to estimate the variability and composition of closely similar soils within each map unit and to justify correlation decisions. These data are presented in descriptive as well as tabular form in the published soil surveys. When compared to costs for traditional methods, the costs for updating soil survey information with GPR were dramatically reduced.
Analysis of Erodibility of Two Tropical Soils Using a Process Model
Authors: Lo A. , El‐Swaify S. A. , Rose C. W. 
Published: July 2010

AbstractField‐scale runoff and sediment data obtained by rainfall simulation are conventionally analyzed to derive empirical erodibility such as the K‐factor in the universal soil loss equation (USLE). In this study such data were obtained under standardized rainstorms on two highly weathered tropical soils from Hawaii (Typic Torrox and Hydric Dystrandept). In addition, a simplified version of a physicallybased model which embodies the processes of rainfall detachment, runoff detachment (entrainment) and deposition (sedimentation) was used to analyze the same data set. Higher USLE erodibility values corresponded well with higher values for the entrainment efficiency of overland flow. It was concluded that this process‐based model can complement the empirical USLE to provide a transferable quantitative understanding of soil susceptibility to erosion.
Etch‐Pit Measurements on Scanning Electron Micrographs of Weathered Grain Surfaces
Authors: Cremeens D. L. , Darmody R. G. , Jansen I. J. , Norton L. D. 
Published: July 2010

AbstractDigital image analysis (DIA) was successfully used to evaluate the size and shape distribution of etch pits on the surfaces of weathered hornblende and microcline grains. An interpretative tracing of the image of etch pits and grain perimeter from projected SEM micrographs was used. Histograms of size‐frequency distributions of etch pits proved useful for comparisons between grains, while plots of shape factors of etch pits allowed an evaluation for individual grains. Manual calculation of etch‐pit density with a dot grid overlay gave results similar to those with DIA, although with less variation on replication. Precision with both methods was associated with operator interpretation of the grain surface, and consistency in interpretation.
Reduction of Organic Sulfur in Soils with Tin and Phosphoric Acid
Authors: Pirela H. J. , Tabatabai M. A. 
Published: July 2010

AbstractThe chemical nature of organic S in soils is not well understood. In this study, a Sn‐H3PO4 reagent was used for reduction of organic S in soils to H2S for subsequent determination as methylene blue. The reduction of soil organic S was compared with that of model S compounds, and with the fractions reduced with HI and with Raney Ni. Results showed that, in general, most of the reduction of organic S in 13 Iowa and 7 Chilean surface soils occurred after distillation for 1 to 3 h, but some soils continued to release H2S for up to 10 h of distillation with this reagent. Expressed as a percentage of total organic S in Iowa surface soils, the amounts of Sn‐H3PO4‐reducible S ranged from 15 to 64% (avg = 35%) and from 42 to 91% (avg = 60%) for 1 and 10 h of distillation, respectively. The corresponding percentages of the Chilean surface soils were from 8 to 73% (avg = 25%) and from 29 to 100% (avg = 55%). The Sn‐H3PO4‐reducible S values were significantly correlated with organic S [r = 0.71*** (P < 0.001) and 0.88*** for 1 and 10 h of distillation, respectively]. The amounts of organic S potentially reducible (Sr) with this reagent ranged from 35 to 86% (avg = 61%) of organic S in Iowa surface soils. The corresponding values for the Chilean soils ranged from 33 to 100% (avg = 66%). The times required to distill 50% of Sr ranged from 0.3 to 1.7 h (avg = 0.8 h) for the Iowa soils, and from 0.4 to 9.2 h (avg = 3 h) for the Chilean soils. Studies with five Iowa soil profiles showed that the percentages of organic S reduced with Sn and H3PO4 in 1 and 10 h of distillation varied with depth of sampling and that these values were similar, lower, or greater than those obtained with the HI‐reducing mixture.
Comparison of Aluminon and 8‐Hydroxyquinoline Methods in the Presence of Fluoride for Assaying Phytotoxic Aluminum
Authors: Noble A. D. , Sumner M. E. , Alva A. K. 
Published: July 2010

AbstractA nutrient solution study was conducted to evaluate the effects of varying pH (4.2, 4.5, and 4.8), Al (0, 20, 40, and 80 µM Al) and F‐ (0, 10, 20, and 40 µM F‐) on soybean [Glycine max (L.) Merr. cv. Lee] root growth. The ability of Al fractions measured by the modified aluminon and 8‐hydroxyquinoline methods in predicting the phytotoxic component of Al was also investigated. In the presence of Al up to 40 µM, increasing levels of F‐ resulted in an increase in root length. Aluminum speciation in solutions predicted by GEOCHEM program showed an increase in concentration of F‐ complexed Al species with an increase in concentration of F‐. A very poor relationship was observed between tap root length and the sum of predicted concentrations of F‐ complexed Al species. Thus, F‐ complexed Al species would appear to be less phytotoxic than the other Al monomers. A highly significant correlation was found between tap root length and predicted concentration of Al3+ (R2 = 0.971). The relationship was further improved when sum of predicted concentrations of Al3+ and hydroxy‐Al species was considered (R2 = 0.986). Tap root length was poorly correlated with the concentration of monomeric Al determined by the modified aluminon method, which included a larger portion of less phytotoxic F‐ complexed Al species. In contrast, a highly significant correlation (R2 = 0.984) was found between tap root length and the concentration of labile Al determined by the 8‐hydroxyquinoline (15‐s reaction) method. The labile Al may include only a very small fraction of F‐ complexed Al species. Therefore, in solutions containing varying concentrations of F‐, Al measured by the 8‐hydroxyquinoline (15‐s reaction) method is a better predictor of Al phytotoxicity than that measured by the modified aluminon method.
Thematic Mapper and Digital Elevation Modeling of Soil Characteristics in Hilly Terrain
Authors: Lee Kyoo‐seock , Lee G. B. , Tyler E. J. 
Published: July 2010

AbstractTransformed thematic mapper (TM) data and topographic information from a digital elevation model (DEM) were combined to determine soil characteristics of hilly terrain in southwestern Wisconsin. Map units from a rasterized soil map were compared with a combination of spectral classification obtained from TM, and DEM derived elevation and slope data. Five soil classes were differentiated. Three were silt loams, varying in landscape position and drainage characteristics. The fourth was comprised mainly of well‐drained loamy soils, while the fifth was a Histosol. These results suggest that a general identification of soils is possible by this method. There was 72% agreement between the soil map and the classification used in the study. Simple addition was found to be accurate and efficient when combining TM and DEM data. The importance of topographic data in the differentiation of hilly soils was demonstrated.
Measurement of Exchange Properties of Andisols by the Compulsive Exchange Method
Authors: Gillman G. P. , Hallman M. J. 
Published: July 2010

AbstractFollowing recent criticism that the compulsive exchange method for the determination of cation exchange capacity (CEC) and anion exchange capacity (AEC) is not appropriate for Andisols, the method has now been applied to 22 samples from eight Andisol profiles from Papua New Guinea. Results obtained for CEC and AEC compared favorably with those obtained by a Schofied‐type method, and amounts of soil exchangeable cations could be explained by the CEC values measured. Specific adsorption of sulphate, if it occurs, following addition of MgSO4 in the procedure, does not affect the CEC value obtained.
Modeling the Transport of Inorganic Ions Through Undisturbed Soil Columns from Two Contrasting Watersheds
Authors: Jardine P. M. , Wilson G. V. , Luxmoore R. J. 
Published: July 2010

AbstractThe transport of several inorganic cations and anions (i.e., Mg2+ NH+4, Br−, NO−3), via saturated flow, through large undisturbed soil columns from two contrasting watersheds was investigated. The mobility of nonreactive tracers was described well with the convection‐dispersion (CD) equation using flux‐averaged solute detection in the effluent. Reactive tracers were also modeled well using various linear and nonlinear, equilibrium and nonequilibrium, transport codes based on the CD equation. Appropriate independent estimates of model predicted chemical retardation were possible only through experimental development of “dynamic isotherms” using a steady flow method on small undisturbed soil columns. The latter condition can accurately predict solute retardation on large soil columns, since tracer movement is largely controlled by the physical aspects of the soil (e.g., preferential flow zones). Adsorption isotherms generated on disturbed soils using a batch equilibration method, overestimated the amount of solute retardation from displacement experiments on the large undisturbed soil columns. The use of batch adsorption measurements in curve‐fitting transport models to describe data from saturated column displacement experiments on undisturbed soils, may result in erroneous transport parameter estimates.
Analysis of Chemical Kinetics Data from Dilute, Dispersed, Well‐mixed Flow‐through Systems
Authors: Schnabel R. R. , Fitting D. J. 
Published: July 2010

AbstractFlow‐through techniques for studying chemical kinetics in soils are gaining acceptance. Of these techniques, those resulting in dilute, dispersed, well‐mixed suspensions minimize the hydrologic control on effluent concentration. The increased understanding of chemical kinetics gained by minimizing hydrologic control can be lost by improper data analysis. The following research was performed to develop a procedure for analyzing the kinetics of chemical retention by soil in a dilute, dispersed well‐mixed flow‐through system. The results of the research demonstrate that data analysis must account for the mass of unreacted chemical in the reactor. Failure to do so results in systematic underestimation of rate coefficients. Data analysis based on measured effluent concentration, rather than on secondarily calculated chemical retained, is more versatile and minimizes propagation of errors.
Effect of Land Clearing Method on Chemical Properties of an Ultisol In the Amazon
Authors: Alegre J. C. , Cassel D. K. , Bandy D. E. 
Published: July 2010

AbstractThis study quantified soil chemical properties as affected by land clearing method and subsequent soil management. It was conducted on a Yurimaguas soil (fine‐loamy, siliceous, isohyperthermic Typic Paleudults) covered by a 20‐yr‐old evergreen forest in the Amazon Basin of Peru. The experimental design, a split plot replicated three times, included six main plot treatments: (i) slash and burn clearing; (ii) bulldozer clearing with a straight blade; (iii) straight blade clearing followed by chisel plowing 25 cm deep; (iv) bulldozer clearing with shear blade, vegetation burned, followed by disking 30 cm deep; (v) shear blade clearing and rototilling with a 10‐KW tractor; and (vi) shear blade clearing, 30‐cm‐deep disking, followed by rototilling. Three post clearing soil management practices (subplots) were: (1) flat planted with no fertilizer or lime; (2) flat planted with fertilizer and lime applications incorporated, based on soil test recommendations; and (3) soil bedded at 1.1‐m spacings, and fertilizer and lime applied as in Subplot 2. Five successive crops, rice (Oryza sativa L.)‐soybean [Glycine max (L.) Merr.]‐corn (Zea mays L.)‐rice‐corn were grown from July 1980 to July 1982. Soil samples collected before or just after harvest of the first, second, and third crops were analyzed for chemical properties. Burning dried vegetation resulted in higher concentrations of Ca, Mg, P, and K in the 0‐ to 45‐cm soil layer. No significant differences due to main treatments were found for the other chemical properties. The pH of the surface soil increased from 4.0 to 5.2 for all limed subplots. Percent aluminum saturation decreased from 82 to 7%, and P, Ca, Mg, and effective cation capacity increased. The decrease in topsoil organic carbon at 14 wk for all mechanically cleared treatments was probably due to increased oxidation rates due to tillage and higher soil temperatures. Concentrations of Cu, Fe, and Mn in the soil were unaffected by treatment.
The pH Dependency of Aluminum Phytotoxicity Alleviation by Calcium Sulfate
Authors: Noble A. D. , Sumner M. E. , Alva A. K. 
Published: July 2010

AbstractThe alleviation of Al toxicity by CaSO4 is partly due to an increase in formation of less phytotoxic AlSO+4 species. Since ion‐pair formation is dependent on the solution pH, the magnitude of alleviation of Al toxicity by CaSO4 may be influenced by pH. In the present study, the alleviation of Al toxicity (80 µM) to soybean [Glycine max (L.) Me root growth by CaSO4 (625–10 000 µM) was investigated in dilute nutrient solutions at pH 4.2 or 4.8. The concentration of monomeric Al (by a modified aluminon technique) in these solutions ranged from 69.3 to 77.7 µM. An increase in CaSO4 in solution (625–10 000 µM) increased the root length by 3‐ and 2‐fold in solutions at pH 4.2 and 4.8, respectively. The predicted activity of Al3+ decreased while that of AlSO+4 increased with an increase in added CaSO4. The magnitude of alleviation of Al toxicity by CaSO4 was smaller at pH 4.8 than at pH 4.2. This pH dependency is due to lesser formation of AlSO+4 at pH 4.8 than at pH 4.2, together with an increase in formation of Al(OH)+2 at pH 4.8. Root length was poorly correlated with the predicted activity of Al3+ (R2 = 0.346) or sum of the activities of Al3+, hydroxy‐Al, and AlSO+4 species (R2 = 0.366). However, the relationship was improved when the sum of the activities of Al3+, Al(OH)2+ and Al(OH)+2 species was considered (R2 = 0.624) and further improved (R2 = 0.841) when the activities of these species were corrected for their respective valence. A good correlation was also found (R2 = 0.88) between root length and calcium aluminum balance; CAB = [2log(aCa2+)] − [3log(aAl3+) + 2log(aAl(OH)2+) + log (aAl(OH)+2)] index.
Distribution of Sulfur Fractions in Soil as Influenced by Management of Organic Residues
Authors: Castellano S. D. , Dick R. P. 
Published: July 2010

AbstractThere is increasing concern about the long‐term effects of crop management on soil properties that may be affecting soil productivity. Consequently, a study of the long‐term (55 yr) effect of organic residue and inorganic N applications on the distribution of S fractions (inorganic sulfate, C‐bonded, ester sulfate, residual, and sulfolipid S) in a Typic Haploxeroll under a wheat‐fallow (Triticum aestivum L.) rotation was undertaken. The biennial treatments were: (i) straw (control), (ii) straw plus fertilizer (+N) (34 kg N ha−1 from 1931–1966 and 90 kg N ha−1 from 1967–1986), (iii) straw plus 2.24 Mg ha−1 of pea vine residue (PV), and (iv) straw plus 22.4 Mg ha−1 of strawy manure (M). There was a significant treatment effect (P < 0.01) with the M treatment having 7 to 41% greater total S, and 9 to 22% greater ester sulfate hydriodic reducible S), and nearly two times more C‐bonded (Raney‐Ni reducible S) and sulfolipid S than the remaining treatments. The lowest level for total S occurred in the +N treatment (114 vs. 161 mg S kg−1 soil in the M treatment). A significantly lower level of residual S (nonreducible) for the +N treatment suggests that the addition of inorganic N causes a depletion of S from the residual pool. On a biennial basis, treatments receiving only straw (control and +N) had net inputs (amount of S added with residue minus S removed in grain) of −0.51 and −1.72 kg S ha−1, respectively, and PV and M treatments had net S inputs of 1.92 and 31.05 kg S ha−1, respectively. Calculation of the coefficient of simple determination (r2) among S fractions and other soil properties showed that whereas organic C and total N had a high r2 value (0.81), total S had a low r2 (0.29) with organic C and was more closely related to total N (r2 = 0.55). The r2 values among the organic S fractions were quite low (<0.23), except for sulfolipid S and C‐bonded (r2 = 0.45).
Phosphorus Sorption of Subtropical Acid Soils as Influenced by the Nature of the Cation Suite
Authors: Russell J. S. , Kamprath E. J. , Andrew C. S. 
Published: July 2010

AbstractPrevious field studies with pasture on subtropical acid soils in eastern Australia showed a long residual effect of relatively low rates of fertilizer P. Samples of six soils from eastern Australia were collected to determine their P sorption characteristics. Monocalcium phosphate solutions containing 0.005 M CaCl2 were equilibrated with samples which were untreated, limed or CaCl2‐leached. Measurements were made of the amount of P sorbed and P remaining in solution. The soil chemical properties affecting P sorption, P buffering and amount of P sorbed needed to provide 0.2 µg P mL−1 were determined by multiple regression analysis. Phosphorus sorption and buffer capacity increased with increasing CuCl2‐extractable Al and decreased with increasing exchangeable Na saturation or increased soil solution Na. Amounts of sorbed P needed for 0.2 µg P mL−1 in the soil solution were relatively small for the untreated and limed Natrustalfs and ranged from 13 to 37 mg P kg−1 soil. A given application of P fertilizer will provide a higher soil solution P in subtropical soils which contain appreciable Na, such as Natrustalfs, than those in which Ca is the dominant cation.
Drop Impact Energy‐Soil Exchangeable Sodium Percentage Interactions in Seal Formation
Authors: Shainberg I. , Singer M. J. 
Published: July 2010

AbstractConstant intensity rain (40 mm h−1) with 3.2‐mm drops falling from 0.25‐, 0.90‐, and 2.63‐m heights and impact energies of 1.8, 7.6, and 18.6 kJ m−3, respectively, was used to produce seals on two soils in 55‐mm deep by 82‐mm diam acrylic cylinders. Soil exchangeable sodium percentage (ESP) was altered to ESP 0 (Casaturated soil), 5, and 10 before rain was applied. Infiltration rate (IR) and hydraulic conductivity (HC) of A horizon material from the Wyman (fine loamy, mixed, thermic Typic Haploxeralfs) and Wyo (fine loamy, mixed, thermic Mollic Haploxeralfs) soils decreased due to formation of soil seals as raindrop energy and ESP increased. The Wyo was more susceptible to sealing than Wyman despite its higher organic C content because of its higher (17 vs. 9%) clay content. Seal formation on Ca‐soils (ESP 0) increased gradually with increasing drop impact energy. Soils with ESP 5 and 10 were more susceptible to sealing at low energy rain than were ESP 0 soils. Relative HC and final IR (FIR) decreased with increasing ESP with all rainfall energies and with the no rain treatment on both soils. Aggregate dispersion by raindrop impact and chemical dispersion by sodicity are two complementary processes leading to seal formation. A 5‐Mg‐ha−1 phosphogypsum treatment applied to the Wyman surface reduced seal formation and maintained HC and FIR near the unrained‐on values for the 1.8 and 7.6 kJ m−3 treatments. The 18.6 kJ m−3 raindrop energy produced a seal on the gypsum treated soil with relative HC and FIR more than four times as high as the untreated Wyman.
Effect of Soil Depth and Erosion on Yield in the Mississippi Blacklands
Authors: Hairston J. E. , Sanford J. O. , Rhoton F. E. , Miller J. G. 
Published: July 2010

AbstractFarmer fields were used 4 consecutive yr (1982–1985) to determine effects of soil depth and other parameters on soybean [Glycine max. (L.) Merr.] yield in the Mississippi Blackland Prairie. Soybean yields were sampled on 25 miniplots (1.8 m2) at each of two sites the first 2 yr and from six sites the third and fourth years. Soil depth ranged from 100 to 1500 mm across the miniplots at each site, and most plots had a silty clay texture. Soil samples were collected the second, third and fourth years from the 0‐ to 150‐mm depth and analyzed for pH, organic matter and extractable nutrients. Seasonal rainfall distribution was measured at each site the third and fourth years. Grain yields were variable from year to year for specific sites as well as from site to site within a given year. Regression analyses indicated that differences from site to site were due to variation in soil organic matter and rainfall distribution; whereas, differences within a site were influenced by organic matter, soil depth, and other parameters such as pH and available K which were related to depth. Grain yields ranged from near zero to over 2.5 Mg ha−1, depending on depth, organic matter content and seasonal rainfall distribution. Differences due to fertility were less pronounced. Soil depth was a much better predictor of yield at sites with low organic matter, especially when rainfall was also low. A regression model for depth vs. yield indicated that 10 mm of soil was worth an average of 0.006 Mg ha−1 of soybean grain within the 500‐ to 1500‐mm depth but worth 0.06 Mg ha−1 within the 50‐ to 150‐mm depth.
Variations in Surface‐Layer Color, Texture, pH, and Phosphorus Content Across Prairie Dog Mounds
Authors: Carlson D. C. , White E. M. 
Published: July 2010

AbstractSpatial variations of soil surface color, texture, pH, and phosphorus content were studied so the effects of relict and modern prairie dog (Cynomys ludovicianus) pedoturbation on soil surface properties will be more predictable in southwestern South Dakota. When first formed, prairie dog mounds are made of surface soil. In time, lower‐layer materials are added to the surface. The overall textural variation usually increases with pedoturbation because the original surface layer has a different texture than the subsoil. The mound pH is usually greater than the adjacent soil because calcareous subsoil is deposited in the mound. With time, the mound pH decreases as carbonate leaches and the color becomes darker as organic matter accumulates. The color hue gradually changes to a 10YR if the subsoil was not originally a 10YR hue. Fecal and skeletal phosphorus are deposited in and on the mound to increase areal variation in phosphorus content as a mound continues to be used.