bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rubidium‐Sodium Exchange on a Weak Acid Resin as Influenced by Ionic Strength
Authors: Kunishi H. M. , Heald W. R. 
Published: July 2010

AbstractChanges in the selectivity coefficient, Ks, for Na‐Rb exchange on IRC, a weak acid resin with carboxylic functional groups, were observed when the concentration of the external solution was increased from 10‐3M to 10‐1M. These ionic strength effects on Ks were interpreted in terms of an ion pair‐diffuse double layer model. Increasing Ks favoring Rb over Na with increasing ionic strength may be attributed to an increasing fraction of adsorbed ions in the ion‐pair form.
Miscible Displacement of Gases Through Soil Columns
Authors: Rolston D. E. , Kirkham Don , Nielsen D. R. 
Published: July 2010

AbstractThe mixing that occurs as one gas displaces another within columns of soil or glass beads was examined by using O2, He, and air for selected combinations of gaseous flow rates and column lengths. After columns were initially flushed with air or He, a second gas pumped at a constant flow rate was introduced at one end of the column. The concentration of the second gas in the gaseous effluent at the opposite end of the column was monitored during the displacement process. Elution curves (concentration of second gas versus volume of effluent) were analyzed by using a mathematical model that includes mixing by molecular diffusion, mass transport at a constant velocity, and sorption (interaction of gas with soil particle surfaces and solution of gas in water present in air‐dry soil) by a linear sorption isotherm. Although apparent diffusion coefficient values were not constant with flow velocity, the general behavior of the mixing process was adequately described by the model. Difficulties stemming from the varying gas velocity from point to point within the porous media are discussed in light of previous miscible displacement studies with liquids.
Exchange Adsorption of 3‐Amino‐1,2,4‐Triazole by an Organic Soil
Authors: Nearpass D. C. 
Published: July 2010

AbstractAdsorption of 3‐amino‐1,2,4‐triazole by soil organic matter is greatly reduced by increasing pH. The main adsorped species is the aminotriazolium cation formed by protonation of the adsorbed molecule, but some direct physical adsorption of the latter also occurs. The aminotriazolium cations are adsorbed more strongly than sodium ions, and can be fully displaced by exchange with calcium ions.
Electron Microprobe Analysis of Thin Sections of Soil to Observe Loci of Cation Exchange
Authors: Hill D. E. , Sawhney B. L. 
Published: July 2010

AbstractTo observe the loci of cation exchange in natural soils, (16 cm3) cubes of soil with such micromorphological features as silt and clay varves, isolated clay bodies in a silty matrix, and clay and silt skins on ped surfaces, were leached repeatedly with CsCl. After the soil cubes were saturated with Cs, they were dried and impregnated with a polyester resin.X‐ray images and Cs activity measurements, determined on thin sections with the electron microprobe, demonstrated that Cs sorbed by microstructures enriched with clay was nearly twice that of silty matrices. These observations illustrate that the loci of cation exchange are heterogeneously distributed within the undisturbed soil horizon and are influenced by micromorphological features produced by geologic and pedogenic processes.Cesium sorbed by weathered biotite sand grains was eight times greater than by clay bodies. The greater exchange capacity of the weathered biotite was attributed to the loss of interlayer potassium and conversion to a vermiculite‐like mineral. The smaller exchange capacity of the clay was attributed to the presence of illite, chlorite, and kaolinite, of low exchange capacity, to pedogenic weathering and aluminum interlayer formation in vermiculite and to the presence of 40 to 50% pore space. Although weathered biotite sand grains constituted only 1.6% of the whole soil, they contributed about 15% to the total exchange capacity of Charlton soil.
Control of Potassium Release and Reversion Associated with Changes in Soil Moisture
Authors: Bates T. E. , Scott A. D. 
Published: July 2010

AbstractThe changes in exchangeable K that occur when soils are dried and rewet, and the affect of organic additives on these changes were determined with 20 soils from the North Central Region of the USA.The release of K associated with drying was essentially eliminated by adding dextrose to the soils before drying. The use of dried samples for the determination of the exchangeable K in field‐moist soils will be limited to some extent, however, because some soils fix K when they are dried and dextrose does not prevent fixation.In most cases, a decrease in exchangeable K occurred when air‐dry soils were rewet. A greater decrease in exchangeable K was attained with all soils when the air‐dry, rewet samples were redried in the presence of octanol. In some cases, only the reversion of K released by drying was involved, and the decrease was not enough to reduce the exchangeable K level to that in undried soil. In others, K fixation occurred and the heated soils contained less exchangeable K after treatment than they had in their field‐moist state. Nevertheless, the octanol treatment resulted in improved estimates of plant‐available K and of exchangeable K in undried soil samples over those obtainable with either air‐dry or air‐dry rewet samples.
Influence of Culture Filtrates of Soil Fungi on the Absorption of 144Ce and 90Sr by Excised Roots
Authors: Zwarun A. A. , Miller R. H. , Franklin R. E. 
Published: July 2010

AbstractCulture filtrates from Aspergillus niger, Aspergillus spp., and two species of Penicillium were studied for their effect on absorption of 144Ce and 90Sr by excised roots of soybean and barley. Filtrates from both species of Asperigllus and one of the Penicillium markedly decreased the absorption of 144Ce but had little effect on 90Sr. Citric acid was found in the three active filtrates while an unidentified organic acid was found in the other. The reduced absorption of 144Ce could be duplicated by citric acid at concentrations > 10‐2M. Kojic, glucuronic, and 2‐ketogluconic acids had no effect on absorption of 144Ce, but kojic and 2‐ketogluconic acids reduced 90Sr absorption by soybean roots.
Relationships among Adsorbed Phosphate, Silica, and Hydroxyl during Drying and Rewetting of Kaolinite Suspension
Authors: Bar‐Yosef B. , Kafkafi U. , Lahav N. 
Published: July 2010

AbstractKaolinite suspensions after 1 week of equilibration with tagged phosphate solution were dried isothermally (24C) from an initial water: clay weight ratio of 24:1 to 0.89:1. At eight points along the drying process triplicate subsamples were removed and kept sealed until the final point of the drying stage was reached. The concentrations of 31P, 32P, and silica were determined in the supernatant. The equilibrium concentration of phosphate in the solution remained unchanged along the drying process. The silica concentration increased while drying, but to a lesser extent than would have occurred in the absence of the clay. The pH changed irregularly within the limits of 6.1 ± 0.4. Kaolinite at a moisture content of 0.89 ml water per 1 g clay was rewetted to the initial water content and equilibrated for seven days. Part of the air‐dried kaolinite was oven‐dried (110C) for 48 hours and then rewetted to its original moisture content. The amount of adsorbed P released into the solution when the pH increased from 6.5 to 11.0 was smaller in the oven‐dried clay than in the air‐dried sample. This is attributed to an increase in the negative charge of the surface of the oven‐dried kaolinite. Increasing the pH, the silica was readsorbed to a maximum at pH 9.2, as expected, and released at higher pH values in accordance with the negative surface charge.
Grain Yield of Maize (Zea mays L.) in Relation to Nitrogen, Phosphorus, Sulfate, Chloride, Zinc, Boron, Manganese, and Plant Population
Authors: Fuehring H. D. , Mirreh H. F. , Ahmad Nazir , Soltanpour P. N. 
Published: July 2010

AbstractExcellent climatic conditions for maize (Zea mays L.) production in the Beqa'a Plain of Lebanon led to a series of eight multivariate irrigated field experiments on a calcareous clay soil typical of much of the Middle East. The objective was to determine which factors, in addition to N and P deficiencies, may become important as grain yields are increased to levels in the range of 12 to 18 tons/ha or more. Central composite, rotatable, experimental designs and regression analysis were used.Applied N was the only variable having an appreciable first order effect and most of the yield variation was attributed to the various two and three‐factor interactions involved. Although the soil was well‐drained and the quality of the irrigation water good, amounts of applied chloride and sulfate needed to be minimized due to negative P‐Cl, P‐S, and N‐P‐S interactions when N and P were applied at necessary levels of about 300 kg/ha. Positive interactions of applied Zn with plant population and applied P with population along with the positive Zn‐B‐population and P‐B‐population interactions indicated a requirement for relatively high levels of applied P, Zn, B, and plant population. Positive response to applied Zn and B occurred up to the 90 to 180 kg/ha level indicating the need for these elements at high yield levels. However the efficiency of use was low for the application method used (somewhat dispersed band about 5 cm below the seed) and further work is needed.The experiments were exploratory pointing the way to further investigation of nutrient balance and plant population. The micronutrient requirements of maize appear to be especially critical at very high yield levels and the detrimental effect of applied sulfate on grain yield requires further work in relation to anion balance.
One‐Degree Increments in Soil Temperatures Affect Maize Seedling Behavior
Authors: Walker John M. 
Published: July 2010

AbstractOne‐degree differences in soil temperatures, ranging from 12 to 35C, induced changes in the growth and nutritional behavior of maize seedlings (Zea mays L.) amounting to as much as 30 to 40% per degree. An improved system was developed to provide the precise environmental control required. The system provided for nearly isothermal control of soil temperatures even when soil and air temperatures differed by as much as 15C. The system also provided for uniform control of air temperature within ±0.7C and relative humidity within ±1% throughout the growing region in the 2 by 2.75 by 2 m growth chamber.With each degree increase in soil temperature from 12 to 26C, total seedling dry weights were an average of 20% greater than weights at each previous soil temperature and an average of 12% smaller with each degree increase from 26 to 35C. Nutritional status, leaf lengths and numbers, stem lengths, and root numbers also were very dependent upon soil temperature. Of special interest, a soil‐temperature‐dependent disorder resembling Ca deficiency was observed in the maize shoot. Also, the uptake of B was uniquely different from that of other elements. Surprisingly, the same total uptake of B occurred regardless of the soil temperature below 21C.The desirability of rigidly controlling soil temperature in pot experiments and the importance of minor changes in soil temperature on plant behavior have been clearly demonstrated.
Foliar and Soil Nutrients in Relation to Sugar Maple Decline
Authors: Mader Donald L. , Thompson Bruce W. 
Published: July 2010

AbstractThe relationship of soil fertility to decline of the sugar maple (Acer saccharum Marsh.) was studied in forest and sugarbush stands by soil studies, foliar analyses and fertilization trials. Site studies of 21 stands indicated that foliar nitrogen was low among trees and stands exhibiting crown decline symptoms and reduced growth rates. Both low and high levels of total soil N were associated with low foliar N and poor growth. Foliar Ca and Mg were closely correlated with levels in the soil.Fertilizers were applied to three stands and their influence evaluated after one growing season by visual leaf response and foliar nutrient changes. Fertilization at the rate of 224 kg of N/ha increased the low foliar N levels in the two stands where decline was present, resulting in improved foliage color and condition.The studies demonstrated that foliar N deficiencies are a critical factor in sugar maple decline. Deficiencies were corrected by fertilization during a drought period. Drought is believed by many to be the cause of decline. Both N availability and uptake may be restricted during drought periods.
Soil Perfusion under Controlled Conditions of Soil Moisture Content and Soil Atmospheric Composition
Authors: Wildung R. E. , Biggar J. W. , Chesters G. 
Published: July 2010

AbstractA new soil perfusion system is described which allows the continuous recycling of an aqueous solution through a soil column under controlled environmental conditions. The system consists essentially of a perforated inner column for soil, jacketed by an outer column in which constant air pressure is maintained. Precise control of soil moisture content and soil atmospheric composition during perfusion is accomplished by regulation of pressure and composition of gases surrounding the soil column.
Thermo‐Osmosis Through Compacted Saturated Clay Membranes
Authors: Dirksen C. 
Published: July 2010

AbstractThermo‐osmotic permeability of saturated Na‐kaolinite decreased less rapidly with increasing compaction pressure, Pc, than did hydraulic permeability, resulting in a moderate increase of thermo‐osmotic pressure difference Γ1. At Pc = 435 kg/cm2, a hydraulic pressure gradient of 1 cm water/cm caused still twice as much flow as a thermal gradient of 1C/cm (Γ1 = 0.54 cm water/C).For saturated Na‐bentonite at Pc = 7.0 kg/cm2, Γ1 decreased, but kT increased with increasing average temperature. Γ1 was about three times higher than that of Na‐kaolinite at Pc = 435 kg/cm2. A temperature gradient of 15C/cm was within the linear region for Na‐bentonite, but 22C/cm was not for Na‐kaolinite. All thermal flow of water occurred from the warm to the cold side and was generally less than that reported for liquid water in unsaturated soils at comparable water contents.The apparent activation energy of thermo‐osmotic water transport in Na‐bentonite was estimated to be about 29 cal/g water; the heat of transport was more than three orders of magnitude smaller. Identification of Γ1 with the heat of transport requires application of irreversible thermodynamics, which has not been done rigorously for soil water transport.
Effects of pH on the Contributions of Organic Matter and Clay to Soil Cation Exchange Capacities
Authors: McLean E. O. , Owen Eric J. 
Published: July 2010

AbstractThe cation exchange capacities versus pH of 12 soils from 10 states were determined by measuring Ba adsorbed by the unlimed soils from buffered solutions adjusted from pH 2.5 to 8.0, and K adsorbed from 1.0N KCl by incrementally limed (and incubated) soils. The contributions of organic matter and clay to soil CEC at various pH's were computed by multiple regression analysis of the CEC(BaCl2) and CEC(KCl) data for whole soils. The results indicated that the method can be used satisfactorily for either type of data, and comparison of the two sets of computed data revealed that organic exchange sites which were active for adsorbing Ba from the buffer at low pH were not active for adsorbing K from unbuffered KCl in soils of comparable pH. Evidently nonexchangeable Al was involved in the latter, since it generally correlated closely with organic matter content of the soils, and the average exchangeable Al doubled when OM was destroyed with H2O2.
Sodium Hazard of Bicarbonate Irrigation Waters
Authors: Pratt P. F. , Bair F. L. 
Published: July 2010

AbstractResults of a 6‐year lysimeter experiment show that the water quality value based on the precipitation index (PI) for CaCO3 satisfactorily estimated the effect of the water on the composition of saturation extracts of soil samples, except where Na precipitation occurred. Essential conditions for Na precipitation, presumably as a zeolite, were a pH above 8.6 and time for dissolution of reactants from the soil and/or formation of the product. Tree trunk diameter growth by lemon trees (Citrus limons) and evapotranspiration were linearly correlated with water quality values based on PI.
Micronutrient Availability in Three Soil Materials as Affected by Applications of Zinc, Lime, and Sulfur
Authors: Hoeft R. G. , Sorensen R. C. 
Published: July 2010

AbstractThree Nebraska soil materials were treated with S, CaCO3, and ZnSO4 and incubated or cropped with corn (Zea mays L.) in the greenhouse to determine essential factors affecting micronutrient release from these soils. The type of soil material had the greatest influence on plant dry matter production and nutrient composition. The application of Zn also showed important effects, but additions of S and CaCO3 had limited effect on most variables studied. The investigation indicates that increased attention must be given to the mineralogy of soils in order to discern their micronutrient‐releasing ability for crop production.
Prairie‐Forest Transition Soils of the South Dakota Black Hills
Authors: White E. M. , Johnson J. R. , Nichols J. T. 
Published: July 2010

AbstractSoils with at least weak development from prairie areas in the Black Hills Ponderosa pine forest have horizon differentiation that is more characteristic of forest than grassland soils. The lower A horizon contains more sand, but less clay and silt, and has more exchangeable hydrogen than is characteristic of prairie soils in western South Dakota. The platy or nearly structureless lower A horizons and the B horizons with reddish‐colored blocky structure are similar to those of the adjacent forested soils and probably developed under forest. Thus, the soils in the grasslands apparently were suitable for forest in the past and probably are not a factor in causing the prairie today.
Soil Factors Influencing Percolation Test Performance
Authors: Derr B. D. , Matelski R. P. , Petersen G. W. 
Published: July 2010

AbstractThe variability of percolation test results is influenced by a complex association of soil and environmental characteristics. Statistical evaluation of 250 sites indicated considerable percolation test rate variation of individual tests within a single site. The variability of individual tests between sites on the same soil series was generally greater than the variability of individual tests within sites. The variation between sites on different soil series was even greater.The percent silt and coarse fragments of the subsoil were positively correlated with percolation rates, and percent clay and drainage class were negatively correlated. Factors not significantly correlated were bulk density, color value and percent sand in the subsoil, depth to bedrock, and depth classes. Variables, evaluated by analysis of variance, that showed significant relation to percolation rates were certain moist and wet subsoil consistence, grade of subsoil structure; subsoil texture, drainage classes, fragipans, parent material, slope class, and surface coarse fragments. Soil depth classes, color chromas and color values did not appear to be significantly related to percolation rates. The field designated permeability classes recorded during soil profile description, were generally lower than the determined percolation rates. Soil drainage classes were found to be closely related to percolation rates, with 82% of the moderately well, somewhat poorly, and poorly drained sites having rates slower than 2.5 cm/hour, and 76% of the 140 well‐drained sites having rates greater than 2.5 cm/hour.
Nitrogen Distribution and Accretion in an Alder Ecosystem
Authors: Voigt G. K. , Steucek G. L. 
Published: July 2010

AbstractAnalysis of plant and soil components of an alder (Alnus rugosa [Du Roi] Spreng.) community that had invaded the bed of an abandoned mill pond showed an average annual N accretion of about 85 kg/ha. Most (93%) of the N in the ecosystem was found in the soil and there was a strong correlation between soil moisture content and N concentration. This may have resulted in part from more favorable conditions for nodule functioning. The amount of N in the alder stand during the growing season was about equal to that contained in freshly fallen litter. About three‐fourths of the N in alder plants was found in stems and twigs but highest concentrations of N were found in leaves and nodules.
Response of Bitterbrush Seedlings to Nitrogen and Moisture on a Granitic Soil
Authors: Klemmedson J. O. , Ferguson R. B. 
Published: July 2010

AbstractGreenhouse studies were conducted to explore the influence of nitrogen and moisture on seedlings of bitterbrush (Purshia tridentata [Pursh] DC.), when grown in soil from three different layers. Seedlings were grown in pots in granitic soil collected from 0–15‐, 15–40‐, and 40–90‐cm soil layers with three nitrogen (N) treatments (0, 34, and 100 kg/ha) and low and high moisture regimes. Shoot and root weights of seedlings grown in surface soils without added N greatly exceeded those for seedlings grown in soil from lower layers. Added N caused seedling yields to decline on surface soils but to increase on the 40–90‐cm soil layer. Maintenance of a high moisture regime diminished the adverse effects of added N on seedlings grown in soil from the surface layer, but improved its effectiveness on seedlings grown in lower layer soils. Shoot‐root ratios and efficiency of water use by bitterbrush differed with respect to N and soil layer treatments. In subsequent experiments, six granitic soils (including the previously tested soil) proved deficient in N for barley. However, on the same soils, bitter‐brush responded negatively or gave no response to added N. The experiments showed that yields of bitterbrush declined when N in plants reached about 2.0%.
Evaluation of Urea‐Hydrocarbon Complexes as “Slow Release” Nitrogen Carriers
Authors: Paulson K. N. , Kurtz L. T. 
Published: July 2010

AbstractSeveral urea‐aliphatic complexes were made. The most stable of these, urea‐stearic acid complex, was found to hydrolyze slower than urea in Drummer silty clay loam, although not enough to make it useful as a “slow release” nitrogen carrier.
A Comparison of Two Methods for Determining Soil Water Diffusivity
Authors: Selim H. M. , Kirkham Don , Amemiya M. 
Published: July 2010

AbstractTwo methods were used concurrently to determine the soil water diffusivity from horizontal infiltration of water into a soil column. In the first (recent), water content measurements were taken at a fixed position as a function of time by using the gamma attenuation technique. In the second, water content distance distributions were determined as a function of distances from the water source at a fixed time by sectioning the same column. A comparison by the two methods of the diffusivity function for three soil materials showed that the first method is as reliable as the second. Agreement of the diffusivities obtained from the two methods is considered evidence of the validity of the unsaturated water flow equation.