bluuebunny/crossref_metadata_2025_split huggingface dataset:
Soil Shrinkage Relationships of Texas Vertisols: I. Small Cores
Authors: Yule D. F. , Ritchie J. T. 
Published: July 2010

AbstractSoil shrinkage‐water content relationships are needed to describe pore size distribution, bulk density function, and potential vertical movement of Vertisols.Ten‐centimeter long, 10‐cm diam cores were collected from the 10‐ to 20‐, 40‐ to 50‐, 70‐ to 80‐, 100‐ to 110‐, and 130‐ to 140‐cm depths of eight central Texas Vertisols. Four sites were adjacent mound and depression samples from two gilgai complexes. Profile description and analytical characterization were obtained for each site. Soil shrinkage was measured vertically and horizontally during a drying cycle from field water content to oven‐dry. Some field matric potential profiles were obtained at sampling.The shrinkage curves are described in terms of structural, shrinkage, and residual water loss phases. All cores had normal, equidimensional shrinkage. Only sites sampled at matric potentials > −300 cm of water had structural water loss. The intersection between the structural and shrinkage phases (the swelling limit) was generally sharply defined when present and occurred at about −0.3 bar. Structural water loss increased with depth due to increasing matric potential, and the soil air content at the swelling limit was about 0.05 cm3/cm3. The water content at the swelling limit was related to the cation exchange capacity (CEC) and the −0.3 bar water content. The shrinkage limit was relatively constant (0.09–0.11 g/g) for seven of the sites, and all residual water loss occurred at < −15 bars. The total vertical shrinkage and the normal water loss were related to the CEC and to the coefficient of linear extensibility (COLE).
Deficit, High‐frequency Irrigation of Sugarbeets with the Line Source Technique
Authors: Miller D. E. , Hang An N. 
Published: July 2010

AbstractStudies were conducted on sandy and loam soils to determine the effect of deficit, daily sprinkler irrigation on sugar production from sugarbeets (Beta vulgaris L.) using the line source technique. With a loam soil near the upper limit of available water at the start of the irrigation season, daily sprinkler irrigation rates of sugarbeets were reduced to 35 to 50% of estimated evapotranspiration (ET) rates without reducing sugar yields. On a sandy soil, sugar yields increased with irrigation rates up to 100% estimated ET, the maximum rate applied.
Dependence of Dioscorea Tuber Growth Rate on Water Content of an Andept Soil
Authors: Dawson Ray F. , Shrum Jeffrey E. , Mohammed Robert A. 
Published: July 2010

AbstractUnexpectedly low tuber yields of a pharmaceutical crop (Dioscorea species) on an Andept soil in Central America led to a study of soil‐related limitations. Readily available water (0 to −20 cbar) controlled tuber growth rates to a far greater extent than other environmental factors. Relative tuber growth rates of seedlings increased linearly as soil water content increased from 0.14 to 0.45 cm3 cm−3. Growth increases occurred with water contents above field capacity provided that soil porosity was not reduced by compaction. Most efficient tuber dry solids accumulation occured at the mid‐range of soil water contents employed and amounted to about 2.0g liter −1 of water consumed by the plant. Total plant (tuber, vine, and roots) water use efficiency was 6.2 g liter −1 at the same soil water content.Water use efficiency in general was related to soil water content in a bifunctional manner, whereas stomatal activity as measured by leaf diffusive resistance increased continuously with increase in soil water content. Thus, highest rates of deposition of photosynthate in the tubers were accomplished by highest but least efficient rates of water consumption.The results indicate that low bulk density, free‐draining Andept soils limit Dioscorea tuber growth rate by an inability to deliver without interruption the required volumes of lowtension water.
Nutrient Changes in Decomposing Loblolly Pine Forest Floor
Authors: Jorgensen J. R. , Wells C. G. , Metz L. J. 
Published: July 2010

AbstractIn two loblolly pine stands (Pinus taeda L.), 11 and 32 years of age at study inception, nutrients in litterfall and throughfall were measured, and declines in nutrient content were observed as forest floor layers decomposed for up to 8 years. The forest floors up to 8 years of age in the two stands had similar rates of nutrient release. After 8 years of decomposition, 67% of the C, 27% of the N, 63% of the P, 91% of the K, 67% of the Ca, 79% of the Mg were released from the forest floor materials. In the younger stand, release from the forest floor accounted for 34, 59, 47, and 65%, respectively, of the N, P, K, Ca, and Mg assimilated annually into the aboveground biomass. In the older stand, the forest floor release accounted for 86, 104, 73, 72, and 71%, respectively, of the N, P, K, Ca, and Mg, indicating that as the stand matures, the importance of the forest floor increases in the nutrient cycling process. Nitrogen content of the forest floor appeared to increase through the third year of decomposition and then to decrease when needles and branches were assumed to be the only forest floor inputs. However, when fine particles and throughfall were included as forest floor inputs, no increase in forest floor N was observed.
A Finite Element Calculation for Determining Thermal Conductivity
Authors: Riha Susan J. , McInnes K. J. , Childs S. W. , Campbell G. S. 
Published: July 2010

AbstractA new simple method for in situ measurement of thermal conductivity of porous materials was developed. A heated or cooled Al or glass probe was placed in soil, and its temperature was monitored over time. Thermal conductivity was determined using a finite element method to solve the radial heat flow equation for the temperature of the heated or cooled probe. The probe temperature, as a function of time, was modeled, and model thermal conductivity was adjusted until predicted probe temperatures agreed with measured values. Conductivities for sand, silt loam, and forest litter were measured over a range of water contents. Values obtained using a glass probe were not significantly different from those obtained using an Al probe. Conductivities were in good agreement with those obtained using a water bath method or computed from the deVries equation. There were significant differences between values obtained with heated and cooled probes in sand at intermediate water content.
Soil Distribution and Soybean Plant Accumulation of Manganese in Manganese‐Deficient and Manganese‐Fertilized Field Plots
Authors: Wilson D. O. , Boswell F. C. , Ohki K. , Parker M. B. , Shuman L. M. 
Published: July 2010

AbstractManganese (Mn) additions are required on certain southern Coastal Plain soils for maximum yield of soybeans (Glycine max (L.) Merr.). This study was conducted to determine the soil profile distribution of added Mn, the accumulation of Mn in soybean plant tops, and the production of plant dry matter in field plots having five rates of Mn and two soil‐pH levels. ‘Ransom’ soybeans were grown on an Olustee‐Leefield sand, an Ultic, Haplaquod‐Arenic, Plinthaquic Paleudult, adjusted to pH levels of 6.3 and 7.0 and supplied with Mn at 0, 5.6, 11, 22, and 56 kg/ha each year for three years. Near the end of the growing season in the first and third years, dry matter production and plant accumulation of Mn were determined on whole plants (R6 growth stage). At the end of the third year, extractable (DTPA and double‐acid) soil Mn was determined in 15‐cm increments to a depth of 90 cm.Considering all Mn rates and pH levels, < 0.5% of the added Mn could be accounted for in the plant tops. Soil depth samples showed that most of the added Mn remained in the upper 30 cm of soil, even though at the high Mn rate, a total of 168‐kg Mn/ha had been applied. Summation of the Mn contents of all soil depth increments revealed that double acid extracted 32 to 57% and DTPA 2.6 to 7.2% of the total amount of applied Mn. Total dry matter production was reduced at the 0‐ and 5.6‐kg Mn/ha rates at the high pH level compared to the 56‐kg Mn/ha rate. Maximum dry matter production was obtained on treatments producing plants containing as little as 59‐g Mn/ha. Correlations between plant top Mn content (g/ha) and extractable‐soil Mn (kg/ha) in various depth increments gave r‐values significant at the 1% level for both extractants. DTPA‐extractable Mn accounted for 72%, however, but double acid only 22% of the variation in plant top Mn, considering all Mn rates over both pH levels.Nearly all of the broadcast Mn applied to this very sandy soil remained in the rooting zone. Only a small fraction was accumulated into the tops of soybean plants, despite the fact that, in some treatments, the plants were under Mn‐deficiency stress. These results emphasize the inefficient utilization of broadcast Mn by soybean plants and suggest that other methods of application, such as foliar or band, should result in more efficient use of applied Mn.
Microband Fabric in Seasonally Frozen Soils
Authors: Mermut A. R. , St. Arnaud R. J. 
Published: July 2010

AbstractA distinctive type of banded fabric occurring in sandy, seasonally frozen soils is described. It consists of fine lenticular units < 1 mm thick and 1 to 3 mm long, exhibiting an accumulation of plasmic material in the upper part of the band or lens. The units are separated by planar voids oriented parallel to the soil surface. Such fabric differs from previously described forms of banded fabric recognized in eluvial soil horizons of grassland and forested soils within central Saskatchewan, Canada, inasmuch as the units are smaller, and it occurs at variable depth and in calcareous soil horizons. Although such structure is often almost imperceptible in the field, macro‐scopically it can sometimes be related to faint platy structure. Climatically, it occurs in a region subjected to a high freezethaw frequency and can be attributed to the effects of frost action. It is most pronounced in sandy soils of uniform, fine sand size, containing < 10% clay. Its presence and degree of expression are invariably related to texture and degree of water saturation within the profile.
Contribution of Magnetite to Oxalate‐Extractable Iron in Soils and Sediments from the Maumee River Basin of Ohio
Authors: Rhoton F. E. , Bigham J. M. , Norton L. D. , Smeck N. E. 
Published: July 2010

AbstractMagnetic separations of whole soil and sediment samples from the Maumee River Basin (Ohio) commonly produced small but significant quantities of detrital magnetite. These magnetites were soluble in acid solutions of ammonium oxalate and were also more reactive than a standard magnetite sample of comparable particle size. Differential thermal analyses suggested that the enhanced reactivity of the soil and sediment magnetites may be due to altered grain surfaces. Since detrital magnetite is a common constituent of the sand and silt fractions of many soils and sediments, care should be exercised when evaluating “amorphous” iron data obtained by any of the popular oxalate procedures.
ATP Concentration and Soil Respiration at Reduced Water Potentials in Arid Soils
Authors: Knight W. G. , Skujins J. 
Published: July 2010

AbstractAdenosine triphosphate (ATP) concentrations and soil respiration rates of two arid and one subalpine forest soil were evaluated as a function of water potential (ψw) in the range −2 to −100 bars. Water potential was determined by thermocouple psychrometry, CO2 release from soil by titrimetry; ATP was extracted from soil with cold sulfuric acid and assayed by luciferin‐luciferase methology. ATP concentrations increased in the ψw range −2 to −20 bars in the arid soils and was negatively correlated (r2 = 0.92) with exponential decreases in respiration rates for the same ψw range. In the subalpine forest soil, the highest ATP concentration was at the highest measured water potential (−2 bars) and decreased with decreasing respiration rates (r2 = 0.93) and decreasing ψw values. It was concluded that the soil microflora may exhibit diverse physiological responses to water and, consequently, to available carbon‐source induced stresses in soils from environmentally different areas.
Carbon Flux to Surface Mineral Soil After Nitrogen and Phosphorus Fertilization
Authors: Kelly J. M. 
Published: July 2010

AbstractThe movement of organic carbon into the mineral soil profile was increased by a factor of 2 to 3 following urea application to the forest floor. Approximately 74% of the organic carbon movement occurred during the first 3 months following treatment. Phosphorus treatment and the interaction of nitrogen and phosphorus did not produce a statistically significant response.
Cation Release from Sodium‐ and Calcium‐Saturated Clay‐Sized Soil Fractions
Authors: Suarez Donald L. , Frenkel Haim 
Published: July 2010

AbstractThe cation release of sodium‐ and calcium‐saturated clay fractions of two montmorillonitic and one vermiculitic aridland soils was compared with that of specimen Ca‐ and Na‐saturated montmorillonites. The clays were reacted with distilled water (0.25, 0.5, 1.0, and 2.5% wt/v) at 25°C. Hydrolysis rates of soil clays were roughly comparable to those of the specimen montmorillonites. Sodium hydrolysis exceeded calcium hydrolysis for soil clay fractions, whereas Na and Ca hydrolysis rates were about equal for the specimen montmorillonites, due to the dissolution of other silicates in the soil clays. Sodium kaolinite hydrolyzed so rapidly that it could not be prepared free of Cl without almost total loss of exchangeable Na. The suspensions were filtered after about 500 hours, and the solution compositions were used to determine ion activity products for the various montmorillonites and other silicate phases. Solutions were slightly supersaturated with respect to crystalline gibbsite. Most soil‐clay solutions were also supersaturated with respect to kaolinite, montmorillonite, K mica, and illite. Although the major cation chemistry of the Ca‐saturated soil clay suspensions was predominantly controlled by the surface hydrolysis reactions, the Na‐saturated suspensions were affected by dissolution of non‐smectite minerals. The weathering of less stable minerals also resulted in additional silica and aluminum release. This is consistent with feldspar undersaturation and montmorillonite supersaturation in the soil‐clay suspensions. The pure montmorillonites gave activity product values consistent with published montmorillonite stabilities.
Boron Adsorption by Soils Using a Phenomenological Adsorption Equation
Authors: Mezuman U. , Keren R. 
Published: July 2010

AbstractA phenomenological equation was applied to boron adsorption by soils as a function of both pH and boron concentration. Experimental results obtained for four different soils were compared with results computed for each soil according to fitted adsorption parameters. The agreement between the calculated values and experimental results indicates that this model can be used to predict boron adsorption by soils. Experimental results of adsorbed boron by soils as a function of solution‐to‐soil ratio were compared with results computed according to the same fitted adsorption parameters. The agreement between the calculated and experimental results indicates that, within the tested range of solution‐to‐soil ratios, the water content does not affect the boron‐soil interaction.
Cadmium Adsorption by Soils and Uptake by Plants as Affected by Soil Chemical Properties
Authors: McBride M. B. , Tyler L. D. , Hovde D. A. 
Published: July 2010

AbstractThe quantity of Cd2+ adsorbed by soils from the northeastern USA was measured at a given equilibrium concentration (10−5M) of the metal in soil solution. This “retention capacity” was strongly related by a linear function to the exchangeable Ca2+ content of the soils. In addition, Cd2+ uptake by corn plants grown in these soils amended with 1‐µg Cd2+/g of soil was measured and found to be related to the retention capacity of the soil for Cd2+ by a curvilinear function. Although organic matter and clay in soil were able to limit Cd2+ uptake by the plants, the best soil indicators of Cd2+ availability were the retention capacity and exchangeable base (mainly Ca2+) content. The ability of exchangeable bases to account for most of the variability in Cd2+ adsorption by the soils as well as uptake by the plants is attributed to the important role of Cd2+‐Ca2+ exchange reactions in the soil.
Halloysite and Kaolinite Cesium Chloride‐Urea Intercalation Facilitated by a Trace of Water at Elevated Temperature
Authors: Higashi T. , Jackson M. L. 
Published: July 2010

AbstractAddition of 75 µliters of H2O to a mixture of 50 mg of partially hydrated spherical and tubular halloysite or coarse kaolinite and 250 mg of CsCl at 80°C for 48 hours followed by two washings with 10% urea solution produces a complete CsCl‐urea intercalation at a 10.4–10.6å x‐ray diffraction spacing. Washing with 10% urea solution enhanced the 10.4–10.6å peak by removal of the excess CsCl. Fireclay and fine kaolinites require 1–4 min of grinding in CsCl for complete expansion to 10.4–10.6Å spacing. As a result of 3 min of grinding, an additional 8–23% of SiO2 + Al2O3 is dissolved from such kaolinites during 2.5 min of boiling in 0.5N NaOH.
Soil Sorption of Nickel: Influence of Solution Composition
Authors: Bowman R. S. , Essington M. E. , O'Connor G. A. 
Published: July 2010

AbstractSorption/desorption isotherms were used to evaluate the effects of solution composition on the retention of nickel (Ni) by soils of varying physical and chemical properties. Soils examined included agricultural soils of New Mexico, as well as soils from potential chemical waste disposal sites. Sorption of Ni from 0.01N CaCl2 was extensive for all samples: more than 99% of added Ni was sorbed in some cases. Desorption in 0.01N CaCl2 was slight (extreme hysteresis). Ability to extract sorbed Ni with diethlyenetriaminetetraacetate (DPTA), however, indicated that Ni sorption was not completely lrreversible. Increasing the CaCl2 concentration to 0.1N lowered Ni sorption by up to 40%. This was due primarily to direct sorption competition by Ca, rather than to increased Ni‐Cl complex formation, as shown by parallel experiments using Ca(ClO4)2. Presence of small amounts of ethylenediaminetetraacetate (EDTA) in the equilibrating solution lowered Ni sorption by up to 98%. The extent of the chelate effect depended upon whether EDTA was present in the Ni solution before or after contact with soil.
New Methods of Studying Soil Detachment due to Waterdrop Impact
Authors: Al‐Durrah M. , Bradford J. M. 
Published: July 2010

AbstractAn improved and inexpensive raindrop tower 8.9 m in height was designed so that a single drop will hit a soil target area 1.6 cm in diameter. The soil used in this study was taken from the surface 15 cm of an Ida silt loam (mesic Typic Udorthents). The surface shear strength was altered by remolding the soil to three bulk densities and by equilibrating the cores to matric potentials of −5, −19, −38, and −62 mbars. The weight of soil detached from the impact of single water‐drops 3.0, 4.6, and 5.6 mm in diameter was closely correlated with the undrained soil shear strength as measured by the Swedish fall‐cone device. A correlation coefficient of 0.97 was found between splash weight and a linear function of the ratio of waterdrop kinetic energy to the soil shear strength. The fall‐cone method of determining soil shearing strength is rapid, inexpensive, and could be easily adapted to field use.
The Calibration of the Richards Flow Equation for a Draining Column by Parameter Identification
Authors: Zachmann D. W. , DuChateau P. C. , Klute A. 
Published: July 2010

AbstractBefore the Richards equation can be used to simulate the flow of moisture through a soil it is necessary to estimate the water capacity and hydraulic conductivity functions which appear as coefficients. We present four parameter identification methods and one direct method for estimating these hydraulic properties. For the sample problem considered, the parameter identification method which used cumulative discharge data to estimate water capacity and hydraulic conductivity performed the best in predicting water content as a function of depth and time during drainage.
Hydraulic Gradients Across Simulated Rain‐Formed Soil Surface Seals
Authors: Sharma P. P. , Gantzer C. J. , Blake G. R. 
Published: July 2010

AbstractHydraulic potentials across surface seals on packed soil columns were measured with a tensiometer‐transducer‐data logger system. Matric potential drops during steady‐state infiltration across seals formed by simulated rainfall on 12 different soils ranged from 6.4 to 14.2 cm of water. The matric potential that developed just below the seal during steady‐state infiltration was nearly constant for a considerable depth range in the soil column. Cultural factors determining aggregate stability were found to be more significant than textural factors in influencing hydraulic properties of surface seals.
Effect of High Root Temperature and Rhizobium Strain on Nodulation, Nitrogen Fixation, and Growth of Soybeans
Authors: Munévar F. , Wollum A. G. 
Published: July 2010

AbstractThe effects of high root temperatures on nodulation, nitrogen (N) fixation, and dry matter production of ‘Lee’ soybean [Glycine max (L.) Merr.] plants inoculated with 13 different strains of Rhizobium japonicum were studied in the greenhouse. Plants were grown in vermiculite, and their root systems were submerged in thermostatically controlled water baths. A treatment without inoculation in which 12 mM of KNO3 was supplied with the nutrient solution was included.Increasing root temperatures from 28 to 40°C had a detrimental effect on the number of nodules, the specific nitrogenase activity, the N content, and the dry weight of tops and roots of inoculated plants. The magnitude of this effect was highly dependent on the rhizobial strain.For some strains, higher nodule weights and higher total nitrogenase (C2H2 reduction) activity were found at 33 than at 28°C, whereas for other strains, these variables declined with increasing temperatures. It appeared that, with increasing temperatures, the processes determining nodule initiation became susceptible at lower temperatures than those associated with nodule growth.When plants formed nodules under nonlimiting temperatures and then were transferred to stressing root temperatures, appearance of additional nodules, N fixation, and plant growth were restricted by high root temperature. These results indicate that the detrimental effect of increasing root temperatures on inoculated plants is due in part to the reduction in number of nodules formed and also to limitations imposed on other processes of the soybean‐Rhizobium association.The growth of plants supplied with combined N was also adversely affected by continuous high root temperatures. However, while a temperature of 34°C restricted the growth of plants depending on N fixation, it was stimulatory for the growth of plants supplied with combined N. Therefore, the effect of temperatures near 34°C on the growth of nodulated plants without combined N was due mainly to the effect on the symbiotic system and not on other physiological processes of the plant.The response of different Rhizobium strains in symbiosis with soybean plants to increasing temperature was related to their response to temperature in pure culture and modified the adverse effect of temperature on plant development. Therefore, pure culture screening of R. japonicum may be a useful tool to aid in the selection of strains better suited for soil environments where high temperature is a limiting factor for the symbiosis.