bluuebunny/crossref_metadata_2025_split huggingface dataset:
Genesis of a Vertisol and an Associated Mollisol in Northern Utah
Authors: Graham R. C. , Southard A. R. 
Published: July 2010

AbstractThe genetic relationship between a Vertisol (Chromoxerert) and an associated Mollisol with an argillic horizon (Palexeroll) was investigated. These soils occur in the Wasatch Mountains of northern Utah and have similar parent materials, altitudes, and slope gradients. Erosion is prevalent on the Vertisols because the wyethia (Wyethia amplexicaulis) plant community does not adequately cover the soil surface during the wet season of fall through early spring. Dense stands of Gambel oak (Quercus gambelii) and a continuous O horizon on the Mollisols protect them from erosion.The Mollisol subsoil and the Vertisol solum both had cracks, slick‐ensides, high clay contents, high coefficient of linear extensibility (COLE) values, and smectite as the dominant clay mineral. These characteristics of high shrink‐swell activity were most strongly expressed in the Vertisol. The Mollisol subsoil clay was overlain abruptly by a loam surface soil. The textural difference was attributed to lessivage, in‐situ clay formation in the subsoil, and eolian contributions mixed with pre‐existing surface soil by soil animals. Eolian additions were inferred from the presence of easily weathered silt and clay‐size minerals in the Mollisol A horizons and within the zone of mixing in the Vertisol. These minerals were not present or were less abundant in the Mollisol subsoil and the Vertisol C horizon. The formation of these Vertisols was probably initiated when erosion removed the A horizons of the Mollisols, or their precursors, exposing the cracking, clayey argillic horizons at the surface.Modification of vertic subgroup criteria to include all soils with significant shrink‐swell activity in subsoils close to the surface, regardless of surface cracking, is recommended.
The Influence of Forest and Pasture on the Genesis of a Humid Temperate‐Region Ultisol
Authors: Daniels W. Lee , Amos D. F. , Baker J. C. 
Published: July 2010

AbstractThe influence of pasture vs. forest vegetation on the properties of a Typic Hapludult from the Blue Ridge Province of Virginia was examined. Three study sites containing both forest and pasture cover were chosen from a group of 20 randomly selected initial sites by a typical pedon computer program which used A horizon thickness, Bt horizon clay content, Ca + Mg content at a depth of 145 cm, and slope as selection parameters. Detailed soil analyses were conducted under pasture and forest vegetation at each of the three final study sites. Pasture B horizons were deeper, higher in clay content, and weaker in structure grade than forest B horizons. The influence of liming was pronounced in the pasture soils and resulted in significant downward movement of Ca and Mg over time. Residual liming and P fertilization effects were apparent after 25 years of forest occupancy on a formerly cropped site. These data indicate that morphological and chemical changes occur in these soils following forest to pasture conversion. These changes, particularly in B horizon morphology, may occur much more rapidly than commonly assumed.
Interlaboratory Comparison of Soil Characterization Data—North Central States
Authors: Rust R. H. , Fenton T. E. 
Published: July 2010

AbstractIn a study initiated in 1977, eight laboratories representing experiment stations of the North Central Region plus the USDA‐SCS National Soil Survey Laboratory determined some of the most common soil properties used for classification and other purposes. Ten horizon samples were selected from soils throughout the region with the intent to include a variety of differences in physical and chemical properties. Estimates of the standard deviation from the mean of physical and chemical properties were derived. There were no significant differences among laboratories in the determination of Ca, Na, base saturation, available P, and CaCO3 equivalent but there were significant differences in determination of Mg, K, H, cation exchange capacity, organic carbon, and pH in water and in CaCl2. These differences suggest that uniformity in procedures among laboratories must be emphasized.
A New Plant Growth Technique for the Most‐Probable‐Number Estimation of Rhizobium
Authors: Garvin S. , Lindemann W. C. 
Published: July 2010

AbstractA new system for growing plants in the most‐probable‐number (MPN) estimation of Rhizobium is described. Beans, peanuts, and alfalfa were grown in small plastic cone‐tainers and inoculated with suspensions of rhizobia. The number of rhizobia in pure culture, inoculants, and soil was satisfactorily estimated using cone‐tainers for host plant growth. Most‐probable‐number counts of R. phaseoli were comparable in growth pouches and cone‐tainers. The cone‐tainer system saves bench space and costs less than other presently used techniques.
Sodium Hypochlorite Methods for Extracting Microelements Associated with Soil Organic Matter
Authors: Shuman L. M. 
Published: July 2010

AbstractSince hydrogen peroxide (H2O2) and sodium pyrophosphate (Na4P2O7) dissolve portions of the manganese and iron oxide fractions, respectively, sodium hypochlorite (NaOCl) was studied as an alternate organic fraction extractant for microelements. Six top soils were extracted for Mn, Cu, Fe, and Zn in a boiling water bath with NaOCl alone (5.3%), NaOCl plus 0.005M DTPA (diethylenetriaminepentaacetic acid), or NaOCl with DTPA added during the last few minutes of extraction. Other variahles were time (15 or 30 min) and one or two extractions. The effects of each method on the Mn oxide and amorphous Fe oxide fractions were evaluated. A second extraction increased the amounts of metal ions extracted. Increasing extraction time solubilized additional Mn and Zn but the effect was less for Cu and Fe. NaOCl + DTPA extraction values for the metals were not different from those for NaOCl alone. Adding DTPA during the last few minutes of extraction greatly increased the amounts of extractable metals. When DTPA was added at the end, metal values for the Mn oxide and amorphous Fe oxide fractions were significantly less than for the other two treatments. Two 30‐min extractions with NaOCl alone are recommended. Since it appeared to extract microelements from the oxide fractions under these conditions, DTPA should not be added.
Genesis and Properties of Paleustalfs of North Central Texas: Morphological, Physical, and Chemical Properties
Authors: Stahnke C. R. , Wilding L. P. , Moore J. D. , Drees L. R. 
Published: July 2010

AbstractThe Windthorst and Chaney soils are characterized physically by relatively sandy surfaces, well‐developed argillic horizons that have a clay maximum in the upper Bt, and substrata that are dominated by sandstone. Chemically, they are characterized by a moderately acid to neutral reaction and an exchangeable cation suite dominated by Ca and Mg. A genetic relationship between these soils and the sandstone substrata is suggested by transect studies, morphological data, and particlesize data. However, particle‐size data also strongly indicate a substantial influence by parent materials other than sandstone. Field relationships, namely a marked lateral change in soil texture and other properties near the limestone‐sandstone contact, and evidence of downslope pedisediment transport of limestone residuum cast doubt on the importance of eolian additions as a primary pedogenic process responsible for observed textural differentiation. Though major eolian additions appear improbable, localized wind‐reworking of surface horizons of these soils has likely been significant. Shale and siltstone interstratified with sandstone have contributed to the clay content of some pedons, but interbedded argillaceous sediments are not prerequisite for the formation of these soils. However, gradual sedimentary grading from sandstone to finer‐textured strata during bedrock formation cannot be ruled out as possible clay sources for the argillic horizon. Microfabric analyses verify the concurrence between textural clay maxima and strongly developed argillic horizons. Between 9 and 15% of the cross‐sectional area of upper Bt horizons is comprised of moderately to strongly oriented illuvial void and grain ferriargillans. Abundance and the illuviated character of argillans decrease with depth to Cr horizons which have granular fabrics with thin, embedded, and free‐grain argillans inherited during sandstone formation.
Micromorphology of Polygenetic Soils in the Teays River Valley, Ohio
Authors: Thompson Michael L. , Smeck Neil E. 
Published: July 2010

AbstractSoils in the preglacial Teays River Valley in Jackson County, Ohio, are polygenetic. Modern sola are developed in 50 to 60 cm of loess over loamy or silty colluvium which, in turn, overlies either weathered bedrock, old river alluvium, or thick lacustrine clay. Micromorphological observations of heterogeneous plasmic fabrics and embedded argillans and aggregates support the field identification of a paleosol developed in colluvium and buried hy loess. Abrupt changes in plasmic fahrics over short distances in thin section are interpreted to represent mixing of soil materials during colluviation. Compound argillans with varying degrees of orientation and disruption suggest that at least two periods of clay illuviation occurred. Discontinuous banding of plasma and silt particles suggests that the colluvium moved down valley walls during periods of solifiuction. We hypothesize that solifluction occurred about 18,000 RCYBP, when Wisconsinan ice had advanced to about 50 km northwest of the Teays Valley.
Changes in a Sandy Forest Soil Under Northern Hardwoods after 5 Years of Sewage Effluent Irrigation
Authors: Harris A. Ray , Urie Dean H. 
Published: July 2010

AbstractThinned and unthinned plots in a 50‐year‐old beech (Fagus sp.)‐maple (Acer sp.) stand in northwestern lower Michigan were irrigated with sewage lagoon effluent. After 5 years of effluent application at rates of 38 and 76 mm/week, litter weights were reduced, leaching was increased, and forest floor humus weights were increased. Irrigation also resulted in decreased organic matter in the mineral soil. Nitrogen and P were leached from the litter; Ca, Mg, and Na were retained in forest floor humus and mineral soil, greatly increasing the pH and base saturation. Nitrogen concentrations measured in leachate from the 120‐cm soil depth were consistently below 10 mg·L−1. Sodium was the predominant cation in the leachate. Irrigation over 5 years with wastewater effluent has had such minimal effects that higher irrigation rates might be considered without posing serious environmental risks.
Nitrogen Fertilizer Efficiency in Bermudagrass Production
Authors: Westerman R. L. , O'Hanlon R. J. , Fox G. L. , Minter D. L. 
Published: July 2010

AbstractEfficient N applications are necessary to maximize bermudagrass (Cynodon dactylon L.) dry matter yield and N uptake in forage. Significant losses of NH3 from surface applications of urea and NH4‐N fertilizers by volatilization have been reported. Field experiments were conducted over a three‐year period under a wide range of climatic and soil conditions in Oklahoma to determine the efficiency of N applications for dry matter production and N uptake in bermudagrass forage. Four locations were selected in 1978 and one each in 1979 and 1980, representing four typical soil types for bermudagrass production with a pH range of 4.7 to 6.9. Anhydrous ammonia (AA) and ammonia passed through a Cold‐Flo adapter (ACF) were injected into bermudagrass sod and urea‐ammonium‐nitrate (UAN), urea, and (NH4)2SO4 (AS) were broadcast. Rates of N were 0, 112, 224, and 448 kg·ha−1 initially as well as 224, 336, and 448 kg·ha−1 in split applications. An additional experiment was established in 1980 to evaluate the effect of S on yield and N uptake. Rates of S were 0 and 64 kg · ha−1 and sources were elemental S, CaSO4 · 2H20, MgSO4, and AS. There were two harvests at each location in 1978, three in 1979, and two in 1980.Yield and N uptake from AA and ACF applications were not significantly different, but generally were lower than with broadcast UAN, urea, and AS. Yield and N uptake generally were lower from urea than UAN and AS. Relative efficiency of N sources obtained from averaging across N response experiments were in the order of AS > UAN > urea > AA > ACF. Split application of N in 1978 and 1980 did not increase yield, but in 1979 an increase in yield was obtained with more even rainfall distribution during the growing season. Sulfur fertilization decreased N:S ratios in forage, but did not increase yield or N uptake or improve N efficiency. Potential losses of NH3 by volatilization from broadcast urea, UAN, and AS in these experiments were considered minimal.
Effects of Permanent Charge on the Electrical Double‐Layer Properties of Clays and Oxides
Authors: Kleijn W. B. , Oster J. D. 
Published: July 2010

AbstractTwo complimentary models which describe the surface chemistry of, respectively, clay minerals and oxides submersed in an aqueous solution are presented. Both models incorporate isomorphous‐substitution charge, specific adsorption of counter ions at the inner Helmholtz plane, and a diffuse double layer outside the outer Helmholtz plane. In addition, one of the models allows for adsorption of potential‐determining ions at the surface plane, which is located inward of the inner Helmholtz plane. General algorithms to solve surface chemistry models are given and methods to determine the associated empirical parameters are discussed. With the model which includes adsorption of potential‐determining ions, it is shown that isomorphous substitution may be of great importance to the adsorption properties of oxides. Based on published data for NaCl/Al2O3 and KCl/SiO2, computations are made which show that changes in the charge density of the potential‐determining ions adsorbed at the surface plane tend to be equal in magnitude but opposite in sign to changes in the isomorphous‐substitution charge density (σo). However, this cancellation is not perfect, and especially for KCl/SiO2 systems, the counter‐ion exchange capacity and its pH dependency and the zeta potential are strongly dependent on σo. The dependence on σo is particularly strong in the region where σo is small (−0.04 < σo < 0.02 C/m2). This implies that small amounts of isomorphous substitution may have a dramatic effect on the physico‐chemical properties of oxides. The ion‐adsorption behavior of montmorillonite cannot be explained with our generalized model for oxide surfaces. Thus, our calculations confirm the long‐standing view that the basal planes of clay minerals do not adsorb H+ and OH‐ as potential‐determining ions.
Determination of Total Arsenic in Soil by Differential Pulse Polarography
Authors: Elkhatib E. A. , Bennett O. L. , Wright R. J. 
Published: July 2010

AbstractA technique was developed for the determination of total arsenic (As) in soil using differential pulse polarography. Soil samples were digested with a combination of HNO3 and H2SO4. Total As was determined in 1M HCl after reduction of As(V) to As(III) with hydrazine sulfate. Soil and fly ash standards were analyzed by this method and agreement within one standard deviation between replicates was obtained. Approximately 99% recovery of As was obtained from spiked soil samples.
Net Charge Characteristics of Dystrandept B and Theoretical Prediction
Authors: Wada Koji , Okamura Yutaka 
Published: July 2010

AbstractThe net charge characteristics of five Dystrandept B samples containing components with variable charge were described by combining the two empirical equations that relate the retention of NH4+ and Cl‐ with the pH (4 to 8) and NH4Cl concentration (0.005 to 0.1M) of the solution. There were two characteristic pH values; the point of zero charge (PZC) and the point of constant charge (PCC). The variation of PZC with NH4Cl concentration was appreciable, whereas that of PCC was very small or insignificant. The PZC was found in the range from pH 4.4 to 6.3, and the PCC pH was 4.9 to 6.0. The small net charge at PCC was positive for the soils containing allophane and imogolite and negative for the soil containing 2:1 layer silicates and gibbsite but not containing allophane and imogolite. The effects of the pH and NH4Cl concentration on the magnitude of the net charge are compatible with those calculated using the Stern theory of the electric double layer with an assumption that the thickness of the Stern layer (0.3 to 0.5 nm) decreases with increasing electrolyte concentration. The order of magnitude of the net charge measured is in agreement with that calculated.
Peroxy Radical Interactions with Soil Constituents
Authors: Pohlman A. A. , Mill T. 
Published: July 2010

AbstractInteraction of peroxy (RO2·) radicals with soil constituents in dilute aqueous solutions and suspensions at 50°C was examined using p‐isopropylphenol (PIP) as a probe. Dissolved and suspended humic substances as well as suspended silicate surfaces were found to trap RO2· radicals. Competitive trapping of RO2· radicals occurs with 10 mg·L−1 of solid suspended humic acid polymers and by 1.0% silicate suspensions containing 3–74 mg·kg−1 of total organic C. Electron and H‐atom transfer between RO2· radicals and solid surfaces is attributed to the availability of electron‐donating or phenolic functional groups and not to total organic C content.
Improved Corrective Fertilizer Recommendations Based on a Two‐Step Alternative Usage of Soil Tests: III. The Bray‐1 Test on Soils with Concretions
Authors: Mostaghimi S. , McLean E.O. 
Published: July 2010

AbstractSix soils from temperate and tropical regions and of wide range in P fixation tendency were treated with five rates of P. Portions of each P‐treated soil were equilibrated for 6‐weeks and tested for Bray‐1 P. Also, Bray‐1 P was computed for each soil and P treatment from P fixation factors determined by quicktest recovery of added P in Bray‐1 extract after a 2‐h equilibration. Actual amounts of fertilizer P required to reach sufficiency level of available P for near‐maximum yields (PSL = 20 µg·g−1 were obtained from the added P vs. Bray‐1 P relationship. Similarly, amounts of fertilizer P required for sufficiency levels in the soil were computed from constant 22.9% recovery for all soils, and from individual P fixation factors obtained by quicktest recovery of added P. The P‐treated soils were also cropped to corn (Zea Mays) in a growth chamber. Yields and P contents of tissue were measured. The computed fertilizer P values for PSL = 20 from quicktest recovery of added P after 2‐h equilibration were highly correlated with the actual amounts found by 6‐week equilibration (r2 = 0.831). Use of this second step, in which the quicktest‐computed values are regressed to the equivalent of actual (6‐week) values, make the average deviation from the actual values only 29 compared to 182% when computed on the basis of 22.9% recovery of P from all soils. When the Fe and Mn concretions in the Delicias soil (Oxisol) were crushed and the 2‐h equilibration extended to 24 h, the r2 value for computed vs. actual values was 0.983, and the average deviation of quicktest computed from the actual values for the six soils was only 15%. Quadratic regression showed that the Bray‐1 P accounted for 81% of the variation in the yields, while linear regression showed Bray‐1 P accounted for this same percent of the variation in P contents of the corn seedlings. When the soils were grouped into populations according to the factor for efficiency of recovery of available P, c1, correlation of the yield component data [log(A‐y)] with corresponding Bray‐1 soil available‐P component data (c̄1x in the Mitscherlich‐Bray equation gave r2 = 0.884.
Testing Chemical Criteria for Spodic Horizons on Podzolic Soils in Canada
Authors: McKeague J. A. , Wang C. , Coen G. M. , DeKimpe C. R. , Laverdiere M. R. , Evans L. J. , Kloosterman B. , Green A. J. 
Published: July 2010

AbstractApplication of chemical criteria of the spodic horizon to 220 Podzolic pedons from Canada excluded 157 of them from Spodosols. Failure of approximately 60% to meet the required ratio (0.2) of pyrophosphate‐extractable (Fe + Al) to clay was the principal factor. The requirement that at least one‐half of the dithionite‐citrate extractable (Fe + Al) be extractable by pyrophosphate was not met by approximately 40% of the Podzolic pedons. Modified chemical criteria for the spodic horizons are proposed.
Oven Drying as a Pretreatment for Surface‐Area Determinations of Soils and Clays
Authors: Ratner‐Zohar Yael , Banin A. , Chen Y. 
Published: July 2010

AbstractVarious procedures for drying soil and clay samples prior to surface area determination have been compared. The study was conducted on various soils—kaolinite, illite, and a number of minerals representing the smectite group. This research showed that 24 h of oven drying rather than P2O5 drying can be applied as a pretreatment for surface‐area determinations of soils and clays by the ethylene glycol monoethyl ether (EGME) method with the exception of illite and illitic soils. Surface‐area determinations following the two drying procedures were highly significantly correlated (at the 1% level) for smectites and soils, exhibiting coefficients of 0.996 and 0.986, respectively, between the oven‐ vs. P2O5 drying. Oven drying results in a 15% decrease in surface area of illite, suggesting that this procedure would not be recommended as a pretreatment for measurements on soils rich in illites. The oven drying procedure saves 4 to 5 d of the surface‐area determination procedure and is applicable to smectites and soils rich in montmorillonite and kaolinite.
Some Characteristics of Rhizobium meliloti Isolates from Alfalfa Fields in Oregon
Authors: Bottomley P. J. , Jenkins M. B. 
Published: July 2010

AbstractField populations of Rhizobium meliloti were sampled from root nodules of alfalfa (Medicago sativa L.) growing in 61 sites in five regions of Oregon. In four of the regions, 60 to 92% of the sites had no previous history of alfalfa. Most probable number (MPN) determinations of R. meliloti in the soils of these regions showed that 50 to 70% of the sites possessed < 104 R. meliloti/g of soil, and 17 to 50% had plants showing extremely poor nodulation. Neither preinoculation nor slurry/dusting inoculation practices had been completely satisfactory. In effectiveness studies, only 24 isolates out of 422 evaluated could be classed as superior N fixers. That is, they produced plants equal in weight to nitrate‐grown plants. Twenty‐eight to forty‐four percent of isolates within each region were inferior N fixers, and 40 to 58% of the sites in each region contained 50% or more inferior isolates. Only in 13% of sites were inferior isolates absent. The highest percentage of inferior isolates was found in the Willamette Valley, where most sites had (i) a long history of alfalfa, (ii) the largest soil populations of R. meliloti, and (iii) suboptimum fertility levels.