bluuebunny/crossref_metadata_2025_split huggingface dataset:
Atmospheric Deposition and Ionic Concentrations in Forest Soils of Isle Royale National Park, Michigan
Authors: Stottlemyer Robert , Hanson David G. 
Published: July 2010

AbstractA 64‐wk study of throughfall and soil solution was conducted on five ecosystem strata in Isle Royale National Park, MI, to examine the fate of atmospheric ionic inputs in mature boreal conifer and hardwood forests. Volume‐weighted pH of bulk precipitation was 4.65. Weighted bulk throughfall pH was 4.6 under spruce [Picea glauca (Muench) A. Voss] and 5.2 under aspen (Populus tremuloides Michaux)‐birch (Betula papyrifera Marsh). The forest canopy significantly increased the concentrations of Ca2+, Mg2+, and K+ in throughfall, and decreased the concentration in H+ beneath aspenbirch. Relative to precipitation, concentrations of Ca2+, Mg2+, Na+, and SO2‐4 significantly increased in soil solution of both forest types while NO‐3 decreased. Within the soil ecosystem, K+, NO‐3, and H+ were strongly conserved. Concentration of soil solution SO2‐4 is higher under conifers, and its flux two‐ to three‐fold greater. This suggests the possibility that boreal conifer forests may be more susceptible to cation leaching by mobile anions as SO2‐4 from atmospheric inputs.
The Monophase Model for Magnesium‐Saturated Montmorillonite
Authors: Kittrick J. A. , Peryea F. J. 
Published: July 2010

AbstractSolubility data for Belle Fourche montmorillonite plotted on 2pH — pMg2+ vs. pSi (OH)04 axes, demonstrate that the monophase model can accurately represent smectite formulas in hydrolysis reactions. The smectite was equilibrated with gibbsite and goethite over a pH range of 3.26 to 8.16. Equilibration was from both undersaturation and supersaturation with regard to Si(OH)04, H+, and Mg2+. When the composition of the smectite phase actually controlling sample solubility was accurately known, experimental and predicted solubility results agreed within experimental error. Such favorable circumstances may be rare, but when they occur they show that metastable equilibria can be determined for complex aluminosilicates.
Potential Agronomic Value of Calcium in Some Phosphate Rocks from South America and West Africa
Authors: Hellums D. T. , Chien S. H. , Touchton J. T. 
Published: July 2010

AbstractPhosphate rock (PR) has been used for decades as a P fertilizer for plants. Apatite is a basic P mineral that could have agronomic value as a source of Ca. Little information is available in literature on this possibility, however. A greenhouse experiment (6 wk) was conducted to compare the Ca value of six PRs (Bahia Inglesa, Chile; Bayovar, Peru; Capinota, Bolivia; Tilemsi Valley, Mali; Tahoua, Niger; and Hahotoe, Togo) with respect to CaCO3. The soil used was an acid (pH 4.5) Bladen sandy loam (Typic Albaquult). Calcium was applied at rates of 0, 200, 400, and 800 mg kg−1. All treatments received 400 mg P kg−1 as KH2PO4 so that P was not a limiting factor on plant (maize) growth. In general, the effectiveness of Ca response by maize to various PRs followed the order of the PRs' reactivity except in the case of Capinota PR which had a substantial amount of free carbonates. Dry‐matter yield, Ca uptake, and soil exchangeable Ca increased with increasing Ca rates from the various Ca sources. The relative agronomic effectiveness (RAE) of various PRs with respect to CaCO3 (100%) in terms of increasing dry‐matter yield and Ca uptake ranged from 28 to 88% and from 8 to 58%, respectively. The results showed that PRs with medium or high reactivity have potential Ca value, in addition to their use as a P source, when directly applied to acid soils.
Fate of Subsurface‐Banded and Broadcast Nitrogen Applied to Tall Fescue
Authors: Raczkowski C. W. , Kissel D. E. 
Published: July 2010

AbstractThe purpose of this study was to determine why N uptake and forage production by tall fescue (Festuca arundinacea Schreb.) in southeastern Kansas are greater from subsurface‐banded (knifed) than from broadcast N applications. The fate of urea N fertilizer applied to tall fescue either broadcast or banded in 1982 was determined using a urea ammonium nitrate (UAN) solution containing 15N tagged urea and measuring various components of the N balance. Plant uptake of residual urea N was measured during 1983. In 1982, 62% of the banded urea N was recovered in harvested forage, whereas only 40% was recovered in the broadcast treatment. Tagged N remaining in the soil as residual N at the end of 1982 amounted to 40 and 45% for broadcast and band treatments, respectively. Most of this residual N was not available to plants in 1983 since only 1.4 kg fertilizer N ha−1 (5–6% of the residual N) was recovered in the forage. About 1% of the banded N was unaccounted for, indicating that gaseous losses (denitrification and ammonia volatilization) were about 1% of the applied urea N, whereas 23% of the broadcast urea N was unaccounted for, indicating probable significant gaseous losses. These results suggest that the improved efficiency of knifed N over broadcast N observed in southeastern Kansas may be due to reduced gaseous N losses.
Characterization of Garnets in a Typic Cryoboralf (Gray Luvisol) from Saskatchewan, Canada
Authors: Ghabru S. K. , Mermut A. R. , St. Arnaud R. J. 
Published: July 2010

AbstractGarnets separated from the 250‐ to 2000‐µm sand fractions of a Typic Cryoboralf (Orthic Gray Luvisol) and beach sands by a liquid magnetic separator, heavy liquid, and an optical microscope were used to study to composition, surface morphology, and distribution with regard to garnet weathering in a present day Boreal environment. Garnets constituted 0.2 to 0.3% of the 250‐ to 2000‐µm sand fractions and 16 to 29% of the heavy mineral fractions in the profile. The sand garnet/total soil quartz ratios for soil horizons were relatively constant, ranging between 3 × 10−3 to 4 × 10−3 within the profile. There were no striking differences in weathering among the garnets within the profile or between the soil and lake garnets, suggesting very limited pedogenic weathering since the last deglaciation of the area. The pits that were attributed to dissolution were likely produced by ancient weathering. Despite the high Fe content, and evident surface weathering that had taken place before the last glaciation of the area, it is concluded that these garnets are highly resistant to chemical weathering in present Boreal soils. The association of diatoms with soil and lake garnets suggests that the parent material is of lacustrine origin. Light pink and dark pink garnets were the two varieties present. X‐ray diffraction and chemical analyses revealed their composition was close to the end member almandine. Scanning electron microscopic studies showed extensive evidence of crescentic and several other morphological pits in all the samples. Different type of hillocks were also present, but they were less frequent than the pits. The type of pits and hillocks varied from grain to grain and also within individual grain surfaces. Limited occurrence of vein‐like poorly crystalline tubules were observed in the primary fissures of some garnet grains.
Prediction of Cadmium Complexation in Solution and Adsorption to Montmorillonite
Authors: Hirsch D. , Nir S. , Banin A. 
Published: July 2010

AbstractEffects of inorganic complexation in solution, ionic strength, and clay concentration on Cd adsorption to montmorillonite were investigated. Increased ionic strength decreases Cd adsorption. The presence of a complexing anion such as Cl‐ inhibits Cd adsorption. When the complexing anion was HCO‐3, disappearance of Cd from equilibrium solution was enhanced compared to the case where the anion was ClO‐4, which does not form complexes with Cd. The explanation of the latter phenomenon is still incomplete, the two possibilities being either strong binding to the clay of the complex CdHCO+3, or precipitation of otavite (CdCO3). Raising clay concentration enhances Cd adsorption. A model that predicts cation binding and cation exchange in clay suspensions and calculates the surface potential, the concentrations of the species bound to the clay surface, in the double layer and in the equilibrium solution, was coupled with a subroutine to calculate complexation reactions in solution. Agreement between observed and calculated values of adsorbed Cd was fairly good. The binding coefficients that best fit the data are 1, 10, and 30 for Na+, Cd2+, and CdCl+, respectively.
Infection Unit Method of Vesicular‐Arbuscular Mycorrhizal Propagule Determination
Authors: Franson Raymond L. , Bethlenfalvay Gabor J. 
Published: July 2010

AbstractA method is presented for quantifying infectivity of vesicular‐arbuscular mycorrhizal (VAM) fungal inocula by directly counting infection units in roots. Inocula of five isolates of VAM fungi [Glomus etunicatum Becker and Gerd., Glomus pallidum Hall, and Glomus mosseae (Nicol. & Gerd.) Gerd. and Trappe from California, Florida and Nevada] were assessed. Sorghum bicolor L. was grown for 14 d under controlled conditions in 100 mL growth tubes containing 48, 12, 3, or 0.75 g of each inoculum (96, 24, 6, or 1.5 for G. etuicatum) mixed with sterile soil to provide a total growth medium of 96 g. Discrete infection units were found for all isolates at all inoculum density levels, except for G. etunicatum (no infection at lowest density) and G. mosseae‐California (coalescing infection units at highest density). The relationship between inoculum density and discrete infection units per gram root fresh weight was linear (P < 0.01). This relationship is particularly suitable for determining amounts of inocula of equivalent potential for use in short‐term experiments.
On the Phytotoxicity of Polynuclear Hydroxy‐Aluminum Complexes
Authors: Parker D. R. , Zelazny L. W. , Kinraide T. B. 
Published: July 2010

AbstractIn a previous study we demonstrated the phytotoxicity of polynuclear hydroxy‐Al, a finding that disagrees with a number of existing reports. The objectives of this study were to examine how toxicity of polynuclear Al might vary with experimental conditions or with choice of test plants, and to identify and characterize the toxic polynuclear species. Wheat (Triticum aestivum L. cv. Tyler or Seneca) or soybean (Glycine max (L.) Merr. cv. Stafford) seedlings were cultured for 2 d in dilute CaCl2 solutions containing 15 µM total Al at a basicity (initial molar OH/Al ratio) of 2.0. Increasing rate of base addition, solution age, or levels of added phosphate decreased the fraction of reactive polymers (Alb) and increased that of precipitated Al (Alc) as determined by the ferron method. Mononuclear Al was consistently ≤3 µM and did not contribute to toxicity. Inhibition of root growth was well correlated with [Alb] for both plant species. That only 3 to 4 µM [Alb] was required to fully inhibit wheat root growth suggested that detection of toxic polynuclear Al may at times be difficult in chemically complex media. All plants tested were considerably more tolerant of Al3+ than of Alb, suggesting fundamental physiological differences in the toxicity of the two types of Al. This conclusion was further supported by the finding that the two wheat cultivars exhibited differential tolerance to Al3+, but not to Alb. Several analyses suggested that Alb was composed primarily of the so‐called Al13 polymer, which may form as a consequence of synthesis conditions. Given uncertainties in the occurrence of this polymeric species, both in the laboratory and in nature, several lines of future investigation are suggested.
Landform and Stratigraphic Influences on Variability of Loess Thickness in Northern Delaware
Authors: Rebertus R. A. , Doolittle J. A. , Hall R. L. 
Published: July 2010

AbstractA detailed study of the relationships between landform, surficial geology, and variability of loess thickness on uplands was conducted at two 2.32‐ha study sites in northern Delaware. The purpose of the study was to determine what factors are responsible for the short‐distance variability in loess thickness observed in this region. Thickness of loess and paleotopography of the subjacent Pensauken (Columbia) Formation were measured using ground‐penetrating radar at 1326 grid points within each plot. Present topography was measured using a transit at 676 points in one plot and 1326 points in the second plot. Surface grid diagrams and isopleth maps show a lack of relationship between loess thickness and landform and relief except along ephemeral drainages. Over short distances, the thickness and even the occurrence of loess is dependent on the topography of the paleosurface. The loess was deposited upon an uneven erosional surface and conforms on a gross scale to that paleosurface but has filled the concavities and low points, thus producing a more regular present topography. Modern denudation of the present land surface occasionally exposes the coarser‐textured Pensauken sediments at the surface over high points in the paleolandscape. The irregular erosional paleosurface has resulted in a high degree of short‐distance variability in loess thickness that is difficult to predict except where headslope dissection has been severe enough to produce gullying and the formation of ephemeral drainages. These drainages closely conform to the occurrence of paleodrainages. The high degree of variability in loess thickness and occurrence presents mapping difficulties that need to be addressed in design, naming, and description of soil mapping units.
Geochemistry of Hydric Soil Salinity in a Recharge‐Throughflow‐Discharge Prairie‐Pothole Wetland System
Authors: Arndt J. L. , Richardson J. L. 
Published: July 2010

AbstractThe saturation‐paste extract (SPE) chemistry of samples collected in the wet‐meadow and shallow‐marsh zones of seven North Dakota wetlands was related to SPE electrical conductivity to investigate the development of hydric‐soil salinity. Study wetlands represent a local, depression‐focused groundwater‐flow system. Recharge wetlands recharge the groundwater whereas discharge wetlands receive the majority of their water as groundwater discharge. Throughflow wetlands receive water from as well as yield water to the system. Development of soil salinity generally followed the Hardie and Eugster model of closed‐basin brine evolution, which considers the composition of solutions undergoing evaporation to be the result of chemical changes imposed by the successive formation of evaporite minerals. Hydric soils of recharge wetlands were nonsaline and free of calcite (CaCO3) and gypsum (CaSO4·2H2O). The chemistry of these soils results from evapotranspiration, recharge hydrology, ionic mobility, and exchange relationships. Increases in SPE Mg2+, Na+, and SO2‐4 dominance in more saline throughflow and discharge wetlands are caused by calcite and gypsum precipitation, with the former controlling alkalinity and the latter Ca2+ concentrations. At high salinities produced by concentration through freezing, mirabilite (Na2SO4·10H2O) crystallizes and controls Na+ levels, resulting in hypersaline solutions enriched in Mg2+ and SO2‐4. Additional variation in the patterns of salinity development can be explained by dominance of recharge over discharge, mixing with fresh or chemically discrete water, and valence dilution effects.
Identification of Clay Coatings in an Older Quaternary Terrace of the Allier, Limagne, France
Authors: Feijtel T. C. , Jongmans A. G. , van Doesburg J. D. J. 
Published: July 2010

AbstractMicromorphologically three types of coatings were observed in B horizons of two planosol profiles (Albaqualfs): (a) nonlaminated isotropic limpid clay coatings, (b) nonlaminated anisotropic limpid clay coatings, and (c) microlaminated anisotropic dusty clay coatings. Micromorphological observations suggested that coating types (a) and (b) were genetically similar, resulting from weathering and neoformation. Coating type (c) originated from clay illuviation. Elemental compositions of clay coatings were obtained with a scanning electron microscope‐energy dispersive x‐ray analyzer technique. Alumina contents decreased from 38% in isotropic coatings to about 28% in illuviation coatings. The Al content was inversely related to contents of K, Mg, Ca, and Fe. Factor analysis indicated that two factors accounted for 56.5 and 22.8% of the total elemental variance. The first factor associated with coating type revealed the antithetic behavior of Al vs. K, Mg, Ca, and Fe, and accounted for about 90% in the variability of Al. The second factor associated with the sample location explained >70% of the variability in Ti and Si. Chemical classification of investigated samples was based on elemental similarity. Cluster analysis revealed that coatings of the same type were more alike than coatings originating from the same profile. About 83% of grouped samples were classified correctly as isotropic and anisotropic weathering coatings, and anisotropic illuviation coatings. Clay minerals associated with individual coatings were identified with an x‐ray step‐scan method after sampling microquantities of these coatings with a microdrill. Anisotropic illuviation and weathering coatings consisted of illite and kaolinite. Anisotropic weathering coatings, however, were found to contain less illite than illuviation coatings. Isotropic coatings were x‐ray amorphous, suggesting the presence of Al‐Fe‐Si gel.
Limited Release of Soluble Organics from Roots During the Centrifugal Extraction of Soil Solutions
Authors: Zabowski D. 
Published: July 2010

AbstractRadioactive isotopes were used to determine if the extraction of soil solutions via centrifugation was rupturing biological tissues and introducing cellular contents into the solution. Fungal cells labeled with 32P and root cells labeled with 14C were added to soil samples prior to centrifuging. No 32P was detectable in the soil solutions, and a maximum of 1% of the 14C in the roots was recovered in solution. A comparison of dissolved organic C extracted using low‐ and high‐speed centrifuging showed no change in soluble C at the higher centrifugal force. This suggests that cell contents are not being introduced into soil solutions during centrifuging.
Undisturbed Soils, Landscapes, and Vegetation in a North Carolina Piedmont Virgin Forest
Authors: McCracken R. J. , Daniels R. B. , Fulcher W. E. 
Published: July 2010

AbstractThe North Carolina Piedmont has been farmed for nearly 200 yr and there is considerable concern about the effect of soil erosion on the productivity of Piedmont soils. Most attempts to assess the effect of erosion on soil properties and productivity have few comparable virgin areas to use for baseline data. Fortunately, a 12‐ha virgin tract, mapped as Cecil sandy loam, B and C slopes, was located on the Guilford College campus in Greensboro, NC. The purpose of our study was to quantify the physical and chemical properties of a virgin Cecil soil map unit and to compare soil properties and distribution to that of cultivated sites. Detailed studies of the surficial sediments, geomorphology and soil morphology were made along five transects run at right angles to the topographic trend. Maps of hillslope sediment thickness and geomorphic surfaces were made using the information from the transects and bore holes. Pedons were sampled by landscape position for laboratory analyses. Horizon thickness and depth to residual material varied with landscape position. Nutrient status of all virgin soil horizons are very low, especially when compared to cultivated sites.
Effect of Traffic and In‐Row Chiseling on Mechanical Impedance
Authors: Radcliffe D. E. , Manor G. , Clark R. L. , West L. T. , Langdale G. W. , Bruce R. R. 
Published: July 2010

AbstractA compacted layer at 0.15 to 0.25 m frequently occurs in soils of the southern Piedmont. This hardpan can be caused by disk or other tillage but the effect that wheel traffic may have in the formation of this layer has not been shown. The objectives of this study were to determine the extent traffic may contribute to hardpan formation, the effectiveness of shallow in‐row chiseling, and the possible correlation of the hardpan with a morphologically identifiable soil horizon. A long‐term tillage experiment where traffic had been controlled was examined at the end of its eighth year. The soil was a slightly eroded Cecil sandy loam (clayey, kaolinitic, thermic Typic Kanhapludult). Summer crops of soybean [Glycine max (L.) Merr. ‘Ransom’] and grain sorghum [Sorghum bicolor (L.) Moench, DeKalb BR‐64] were double‐cropped with winter wheat (Triticum aestivum L. Thell, ‘Coker 747’, 1979–1982, ‘Stacy’, 1983–1986). Spring tillage treatments consisted of disk tillage (DT), in‐row chiseling (IC), and coulter planting or reduced tillage (RT). All tillage treatments were disked in the fall before planting wheat. Cone index was measured in 1987 and 1988 in five positions relative to the row and showed that a hardpan was present in all positions at 0.15 to 0.25 m. The hardpan was a result of disk tillage and wheel traffic. Traffic caused compaction to a depth of 0.28 and 0.18 m in DT and RT, respectively. In‐row chiseling was effective in disrupting the hardpan to a depth of 0.26 m and contributed to significantly increased yields in grain sorghum. The hardpan coincided with the Ap2 horizon in this soil. The top of the Bt horizon may act to confine compactive stresses to the soil horizon above.
Influence of Cover Crop and Wheel Traffic on Soil Physical Properties in Continuous No‐Till Corn
Authors: Wagger M. G. , Denton H. P. 
Published: July 2010

AbstractConservation tillage systems utilizing winter annual cover crops represent a different soil physical environment compared to conventional tillage systems. A field experiment was conducted for 3 yr on a Goldsboro fine sandy loam (fine‐loamy, siliceous, thermic Aquic Paleudults) in the North Carolina Coastal Plain to assess effects of cover crop type and row position on soil physical properties under no‐tillage corn (Zea mays L.) management. Bulk density (ρb), soil porosity, and hydraulic conductivity (Ksat) were measured in fallow, winter wheat (Triticum aestivum L.), and hairy vetch (Vicia villosa Roth.) systems with respect to three row positions (trafficked, untrafficked, and plant row). All traffic was controlled such that each corn row was bordered by a trafficked and untrafficked interrow. In general, soil physical properties were unaffected by cover crop type but strongly influenced by position. Bulk density was significantly higher in the trafficked vs. untrafficked position (1.74 vs. 1.52 Mg m−3) after 3 yr and tended to increase with time in the trafficked interrow. Associated with higher ρb values in the trafficked interrow were significantly lower values for soil porosity and Ksat. Total porosity in the trafficked position, averaged over cover crop type and 3 yr, decreased 21% below that of the untrafficked position. After 3 yr, Ksat was 0.019 and 0.002 mm s−1 in untrafficked and trafficked interrows, respectively. These results suggest that controlled traffic patterns may be an important component in the management of continuous, conservation tillage systems.