bluuebunny/crossref_metadata_2025_split huggingface dataset:
Genesis of Argillic Horizons in Celina and Morley Soils of Western Ohio
Authors: Smeck Neil E. , Wilding L. P. , Holowaychuk N. 
Published: July 2010

AbstractVariation in the mode and magnitude of development of argillic horizons in Celina and Morley soils of western Ohio was studied by physical, chemical, mineralogical, and morphological means to explain the difference in Bt/C clay ratios between these Hapludalfs. Although Celina may have formed on a somewhat older land surface than Morley, parent material must be considered the chief factor responsible for differences in genesis of sola since other soil‐forming factors are quite similar. Both soils are derived from Wisconsin‐age till deposits but, in this study, till associated with Celina soils has a mean clay content of near 23% and a calcium carbonate equivalent of near 40% whereas till underlying Morley soils has near 33 and 25%, respectively. Mean maximum clay content in Bt horizons is near 41% for Celina and near 50%; for Morley which yields a Bt/C clay ratio of 1.8 and 1.5, respectively.Carbonate particle‐size distribution in C horizons indicates very coarse sand, coarse sand, and coarse silt generally have the highest calcium carbonate equivalents whereas coarse clay contains <10% and fine clay <1% carbonates. Reconstruction of gains and losses of clay in Bt horizons were calculated both on a weight and volume basis. These results indicate that most of the difference in Bt/C clay ratios is due to carbonate dilution of clay in C horizons and that the remaining difference can be attributed to a larger clay gain in Celina Bt horizons.Other differences in genesis of argillic horizons in these soils are indicated by mineralogical and micromorphological data. Clays with a 17.7A d‐spacing when glycolated which is indicative of montmorillonite were found in Celina argillic horizons but these clays were not apparent in Morley argillic horizons. Thin section studies suggest that upper Bt horizons of Celina soils are actively undergoing degradation and the meager quantity of fine clay gain is due to montmorillonite and vermiculite being diagenetically transformed from illite in situ. Illuviation of clay accounts for the majority of the large clay gain in the lower Bt horizons of Celina soils. The clay gain in Bt horizons of the Morley soils is accounted for by illuviation of clay from overlying horizons and in situ formation of vermiculite. Both processes account for similar quantities of clay gain but together do not form as large a clay increase in the Bt horizons of Morley as Celina soils.
Two North Carolina Coastal Plain Catenas: II. Micromorphology, Composition, and Fragipan Genesis
Authors: Nettleton W. D. , McCracken R. J. , Daniels R. B. 
Published: July 2010

AbstractA study of two soil catenas of different age in the middle Coastal Plain of North Carolina compares the micromorphology and composition of fragipan and nonfragipan soils. The two catenas differ principally in that one has bisequal sola and fragipans in the less well‐drained members, whereas the other has thinner sola with well‐developed argillic horizons but no fragipans. Presence of papules, as well as high packing density and proximity indices, indicate that collapse of the soil matrix has caused the high bulk density of the fragipan horizons. The relatively low amounts of clay in fragipan horizons is believed to be a result of the greater susceptibility of clay to translocation and possibly destruction during reduction and removal of the iron. Translocation of this clay is confirmed by the marked increase of illuvial clay bodies, primarily illuviation cutans and grain argillians, in B′2t horizons below the fragipan (A′2gx). Relative to their clay content, fragipan horizons contain more fine clay with infrared absorption bands in the 2.9µ H‐bonded OH region than do nonfragipan horizons. This clay lacks definite crystalline form and is thought to be amorphous. Stable at lower temperatures, the infrared absorption band at 2.9µ is lost along with the fragipan brittleness at 300C. Though of low free iron content, this clay has a high pH dependent charge. Under the low pH conditions (4.5–5.0) found in fragipan horizons, this clay may develop strong hydrogen bonds with quartz and other silicates.
The Effect of Soil‐Mineral Weathering on the Sodium Hazard of Irrigation Waters
Authors: Rhoades J. D. , Krueger D. B. , Reed M. J. 
Published: July 2010

AbstractThe extent to which the release of solutes from soil‐mineral weathering processes changes the composition of applied irrigation waters has been evaluated for six arid‐land soils. Soil samples were packed in plexiglas permeameters and pretreated to remove readily soluble organic matter, to minimize subsequent microbial activity, and to equilibrate the soil exchange‐complexes with the irrigation waters. Soil solutions were displaced from the nearly saturated columns and analyzed at biweekly intervals until a steady composition was attained. The effluent solutions were 3 to 5 meq/liter higher in total salt content than the applied waters. The gains were accounted for primarily by Ca + Mg and HCO3 ions. The net effect of these changes in solution compositions was a 30 to 90% reduction in the SAR values of the applied solutions. The SAR reductions were greatest for the waters of lower salt concentrations, but were significant even for waters containing as much as 15 to 20 meq of salt per liter. This phenomenon reduces the Na hazard expected with certain irrigation waters, and should be considered in water‐quality evaluation.
The Driving Force on an Ion in the Absorption Process
Authors: Olsen R. A. 
Published: July 2010

AbstractWhen identical root samples are placed in an exchanger suspension of low electrolyte content and in the equilibrium dialyzate we find that the rate of absorption of Rb+ is equal from each medium. If the two media are carefully maintained at equilibrium conditions, the equality in rate of absorption is observed for a period of many hours. The results support the hypotheses that the driving force on an ion is the electrochemical potential gradient extending at right angles through the periphery of the root and that ion absorption is a relatively simple diffusion process.
Age and Comparative Development of Desert Soils at the Gardner Spring Radiocarbon Site, New Mexico
Authors: Gile L. H. , Hawley J. W. 
Published: July 2010

AbstractRadiocarbon ages have been obtained from seven buried charcoal horizons in a desert area of southern New Mexico. Several deposits of highly calcareous alluvium range in age from less than 1,100 to somewhat greater than 5,000 years and are therefore of Recent age. Pleistocene deposits much older than 5,000 years also occur. Pleistocene soils of adjacent topographic highs were a major source of the Recent sediments. Evidence in this area indicates that the present climate is warmer and drier than the Pleistocene pluvial climates. This change to a drier and warmer climate could have decreased the vegetative cover in places and started strong erosion of Pleistocene soils in these areas.The dated charcoal also establishes a maximum, and in some instances a minimum age for several soils formed in the deposits. With increasing age of soil during Recent time, the progression of soil development appears to have been marked by development of an A horizon, destruction of thin sedimentary strata, slight accumulation of carbonate, development of structure in materials of sufficiently fine texture, and, with continued carbonate accumulation, development of a weak calcic horizon. In contrast, soils of Pleistocene age can have distinct argillic horizons and strong horizons of carbonate accumulation. It is postulated that the wetter climates of Pleistocene pluvials, associated with greater vegetative cover and landscape stability, were required for development of argillic horizons in these highly calcareous parent materials.
Rupture Parameters of Soil Aggregates
Authors: Rogowski A. S. , Moldenhauer W. C. , Kirkham Don 
Published: July 2010

AbstractRupture stress values of air‐dry aggregates of various sizes taken from nine surface soils containing from 7 to 53% clay are given as load in dynes per unit area. Corresponding rupture strain values are given as change in polar diameter at rupture per unit length of polar diameter. The rupture modulus defined as the stress/strain ratio is also listed. The values depend on the assumption that aggregates approximate spheres. Earlier work and visual observation show that this assumption is valid for 2‐ to 8‐mm aggregates. Experimental stress‐strain curves indicate that Hooke's law is valid up to rupture. Values of rupture stress, rupture strain and rupture modulus were found to be significantly correlated with percent clay, percent organic carbon, aggregate bulk density, aggregate size distribution and soil erodibility.
Influence of Soil Structure on Water Relations in Low Humic Latosols: II. Water Movement
Authors: Sharma M. L. , Uehara G. 
Published: July 2010

AbstractExperiments were carried out to study the effect of two aspects of structure, macrofabric (arrangement of peds) and microfabric (arrangement of primary particles within the ped), on water movement. Two latosolic soils of nearly similar composition and varying greatly in soil fabric were used. Capillary conductivity of the soils and their water‐stable aggregates were obtained. The results showed that the effect of macrofabric on water movement was more pronounced in the lowtension range (0–0.2 bar). Identical flow rates were obtained for the same size water stable aggregates of both soils, suggesting that intra‐ped pores did not significantly contribute to water flow in this tension range. It was suggested, however, that microfabric might influence fluid flow properties in the high tension range.
Isotopic Exchange Characteristics of Aluminum‐ and Iron‐bound Fractions of Soil Phosphorus
Authors: Tandon H. L. S. , Kurtz L. T. 
Published: July 2010

AbstractThe source of most of the isotopically exchangeable P in widely different soils was found to be in the Al‐ and Fe‐P fractions. The relative contribution of Fe‐P to exchangeable P was greater at longer exchange periods, showing that Fe‐P had more slowly‐exchangeable components than Al‐P. The rate of exchange of Al‐ and Fe‐P varied from 28 to 162 ppm/hr and 22 to 72 ppm/hr, respectively, in the first half‐hour and was in no case greater than 2 ppm/hr after 24 hours of exchange. Ratio of specific activities of Al‐ or Fe‐P were used to compare the surface activities of the P fractions. The term “Relative Activity Number” (ratio of specific activities of Al‐ to Fe‐P in a soil) is proposed as an index of the relative activity of Al‐ and Fe‐P. RAN for soils studied varied from 1.11 to 2.80 showing that Al‐P was 1.11 to 2.80 times as active as Fe‐P. RAN in soils which had received P was smaller than RAN in untreated soils showing greater exchangeability of the reaction products in the Fe‐P form. In a few soils as much as ½ to ⅔ of Al‐ and Fe‐P was not exchanged in 147 hours. Thus, a considerable proportion of these P fractions is relatively “inactive.”.
Effect of Chelating Agents on the Availability of 54Mn Following its Addition as Carrier‐Free 54Mn to Three Different Soils
Authors: Wallace A. , Mueller R. T. 
Published: July 2010

AbstractCarrier‐free 54Mn was mixed into samples of three different soils and allowed to equilibrate for several days. The soils were Yolo loam (slightly acid), Hacienda loam (calcareous), and Dinuba fine sandy loam (neutral). Bush bean (Phaseolus vulgaris var. ‘Improved Tendergreen’) and corn (Zea mays var. ‘Golden Cross bantam’) were grown in the soils with the presence and absence of various chelating agents. Yields and 54Mn and total Mn were determined in the leaves and specific activities were calculated. After cropping, the control soils were assayed first for water soluble, then exchangeable 54Mn and Mn, and then easily reducible or 10‐3M EDDHA, EDTA, DTPA, and NTA soluble 54Mn and Mn. The 54Mn appeared to differentially label various forms of Mn in the soil. Bush bean leaves contained more 54Mn and Mn per plant than did corn. The specific activities of the 54Mn in bush bean leaves were more like those for the easily reducible Mn than for other Mn forms for the three different soils but the specific activities in the corn, in contrast, were more nearly like those in the exchangeable Mn in the soils. DTPA tended to increase the amounts of both 54Mn and Mn in plants with the Yolo and Dinuba soils with concommitant decreasing specific activity of Mn. With corn DTPA apparently added easily reducible Mn to the pool of available Mn. EDTA tended to increase uptake of the soluble and exchangeable Mn by the plants. NTA and EDDHA had little effect.
Properties and Mineralogy of Soils Derived from Argillized Tuff in the Mount Carmel Region, Israel
Authors: Singer A. 
Published: July 2010

AbstractTwo representative profiles of simple horizonation derived from argillized tuff material in the Mount Carmel region of Israel, near the Mediterranean sea coast, were investigated in the field and laboratory. A shallow profile developed in situ on a partly argillized tuff. Calcium carbonate has accumulated in larger quantities in the solum than in the C. This is attributed to release of Ca by weathering of primary minerals in the solum. The main clay mineral in the parent material is an iron‐rich saponite, similar to cardenite. In the clay fraction from the upper soil horizons a second, dioctahedral montmorillonite appears also, accompanied by small quantities of kaolinite and halloysite. In a second profile, developed on alluvium derived from the alteration products of a slightly altered black tuff, calcium carbonate accumulation is greater in the C than in the solum. The <2 µ alteration product of the tuff rock, as well as the clay from the soil, consists chiefly of an iron‐rich saponite. In the clay fraction from the upper horizon of the profile the saponite is accompanied by a second, dioctahedral montmorillonite. In both profiles a large part of the clay fraction is in sand and silt‐sized aggregates which are very difficult to disperse. Soil genesis in both profiles seems essentially to have accomplished a slight accumulation of organic matter and organization of structural soil units, accumulation and some translocation of calcium carbonate and formation of a dioctahedral montmorillonite and some kaolinite and halloysite. The absence of a marked contamination of the sand and silt fractions by aeolian quartz indicates youthfulness of these soils.
Studies of Clay Skins in a Cecil (Typic Hapludult) Soil: I. Composition and Genesis
Authors: Khalifa E. M. , Buol S. W. 
Published: July 2010

AbstractContinuous clay skins are found on ped faces, in pores, and around root channels in the B22t horizon of Cecil soils in North Carolina. Thicker, discontinuous clay skins are also observed along vertical pores in the Cl horizon. Compared to the whole peds from the B22t horizon the clay skins contain more clay, fine clay (<0.2µ), total iron, free iron, Al2O3, K2O, P2O5, and total nitrogen; less silica and gibbsite than the whole soil peds. The fine clay fractions (<0.2µ) of the A2 horizon and the clay skins of the B22t horizon are similar, both being finely divided and poorly crystalline compared to the fine clay from the whole peds of the B22t horizon and the clay skins in the Cl horizon.
Agricultural Use of Synthetic Metal Chelates
Authors: Brown J. C. 
Published: July 2010

AbstractSynthetic metal chelates have been used effectively to make iron available to plants in soils. Agricultural use of chelates has been influenced by cost of the materials, their stability, pH of the soil, and the kind of crop. There is competition between chelating agents and between roots and chelating agents, for nutrient elements. Differential uptake of the metal and ligand by the plant has been demonstrated. The use of synthetic metal chelates in agriculture appears as a stop‐gap measure until a more permanent solution is obtained for some of our micronutrient problems. Genetic variants as factors affecting plant nutrition may provide the permanence sought by providing a plant adapted to a particular soil.
Micronutrient Cation Complexes in Soil Solution: IV. The Chemical State of Manganese in Soil Solution
Authors: Geering H. R. , Hodgson J. F. , Sdano Caroline 
Published: July 2010

AbstractSoil solutions from several areas of the US were analyzed by atomic absorption for total Mn and by resin exchange for percent Mn complexed. Values for the latter (84%–99%) in soil solution from the A horizon were intermediate to those previously reported for Zn and Cu. Soil solution from a New York forest soil at pH 7 contained 13 ppm Mn, of which 93% was complexed. Spectrophotometric and polarographic methods were developed to determine the oxidation state of Mn in this soil solution. Both methods indicated the Mn in solution was present in the +2 oxidation state. The presence of such large concentrations of Mn2+ in a soil solution of a neutral soil was still less than that predicted from measured values of the Eh of the soil solution and the Mn2+/MnO2 half‐cell potential. Soil microorganisms oxidized and precipitated Mn2+, presumably as MnO2, but the presence of the neutral soil solution that contained 13 ppm Mn partially inhibited this precipitation.
Soil Respiratory Activity and Organic Matter Depletion in an Arid Nevada Soil
Authors: Lyda S. D. , Robinson G. D. 
Published: July 2010

AbstractIncorporation of mature crop residues of alfalfa (Medicago sativa), oat (Avena sativa), and sudan (Sorghum vulgare) into a fine sandy loam soil in southern Nevada stimulated the soil respiratory activity. A close correlation was observed between respiration rate and organic matter content; both decreased steadily over a 6‐month test period.Four mature crop residues (alfalfa, cotton (Gossypium hirsutum), oat, and sudan) were added to the same soil type in laboratory tests at 1, 2, 3, and 4% (weight/weight). Respiratory activity of these soils was followed for 10 weeks at 2‐week intervals. A maximum activity was noted at the first 2‐week period for the 2, 3, and 4% additions of all four residues.The respiration rate was proportional to the residue concentration but the increments were not additive. A linear relationship was noted when the reciprocal of the rate was plotted against the reciprocal of the residue concentration, similar to that of a first‐order reaction during the period of maximum activity. It was suggested that a given soil could become saturated with organic matter and reach a maximum respiratory activity; other factors would become rate limiting.
Noteworthy Features of Uruguayan Soils
Authors: Troeh Frederick R. 
Published: July 2010

AbstractUruguay has an undulating landscape dominated by Pradera (Prairie) soils with thick, black, fertile A horizons. These soils have strong textural profiles but are only moderately deep (about 80 cm average), have high base saturations, and generally have Cca horizons. There is a typical soil catena that includes the Pradera soils along with Grumosoles and Plano‐soles. This catena occurs on a variety of parent materials in various parts of Uruguay.
Bias Error in Yield Functions as Influenced by Treatment Design and Postulated Model
Authors: Cady F. B. , Laird R. J. 
Published: July 2010

AbstractBias error occurs when the fitted or postulated model is not equal to the true functional relationship between the dependent variable and the independent variable(s). The concept of bias error is developed and the effect of various factors on magnitude of the bias error studied. The factors included in an empirical study are spacing and number of fertilizer levels and selection of the postulated model. The choice of a postulated model, a factor not under the control of the experimenter during the planning stages of an experiment, shows the largest influence on bias error. The selection of the postulated model is discussed and suggestions for the control of bias and variance error in response surface experimentation are given.
Opal Phytoliths in Bouteloua Eriopoda Torr. Roots and Soils
Authors: Pease D. S. , Anderson J. U. 
Published: July 2010

AbstractIdentification of phytoliths from Bouteloua eriopoda Torr. (black grama) roots was based on repetitive size and shape, low density, acid insolubility, and lack of crystallinity. Refractive index, and contents of water and SiO2 support identification as opal. These distinctive rectangular phytoliths were the most commonly observed form in the A horizons of several soils and paleosols.
A Disposable Aerator for Radioactive Hydroponic Culture
Authors: Wieland P. A. T. , Romney E. M. 
Published: July 2010

AbstractAn aerator for use with radioactive hydroponic media can be constructed with hypodermic needles and rubber or plastic tubing. The system described is inexpensive and adaptable to fit almost any size or configuration of an experiment. It can be disposed of easily in accordance with laboratory health and safety regulations.
Soil‐Water Movement in Response to Imposed Temperature Gradients
Authors: Cassel D. K. , Nielsen D. R. , Biggar J. W. 
Published: July 2010

AbstractRedistribution of soil water within insulated, uniformly packed, horizontal samples of unsaturated Columbia fine sandy loam at several soil‐water contents was studied in response to imposed temperature gradients ranging from 0.5 to 1.0C/cm. Soil bulk density and initial, transient, and final soil‐water‐content distributions were determined each 0.5‐cm along the column by gamma‐radiation attenuation. Initial, transient, and final soil temperature distributions were monitored by glass‐encased thermistors at 2‐cm intervals—both at the center and 0.3 cm from the column wall. Apparent thermal and isothermal soil‐water diffusivity values were calculated using transient water content data. The observed net water flux was found to increase with decreasing water content throughout the 0.077–0.274 cm3/cm3 range. For Columbia soil at 0.077 cm3/cm3 the observed mean net water flux across 1‐cm sections of the soil showed acceptable agreement with that predicted by the theory of Philip and deVries; Fick's law and the modified Taylor‐Cary irreversible thermodynamic equation both underpredicted the observed fluxes.
Applied Nitrogen Losses in Relation to Oxygen Status of Soils
Authors: Meek B. D. , Grass L. B. , MacKenzie A. J. 
Published: July 2010

AbstractThe decrease in soil nitrate nitrogen as related to redox potential was studied in the laboratory and in the field in Imperial Valley, Calif.Partial anaerobic conditions were induced in laboratory flasks containing an atmosphere of 21% oxygen by adjusting the soil‐water ratio. When the water content of a soil having a water saturation percentage of 48% was increased to 44.5% or above, large losses of N2 gas occurred both with and without addition of organic matter. Significant denitrification coincided with a decrease in the redox potential (Eh).Measurement of redox potential and nitrate concentrations of ground water sampled at various depths in an irrigated field indicated that nitrate concentration was high near the surface but decreased at depths approaching the water table. The diminishing nitrate concentration and redox potential, with depth, indicate that some nitrates were reduced to nitrogen gas before they reached the water table.Only 1.5% of the 280 kg N/hectare applied to a cotton crop (Gossypium hirsutum L.) was discharged in the tile effluent during the growing season. Denitrification in the soil profile apparently reduced the amount of nitrate reaching the tile drainage system.