bluuebunny/crossref_metadata_2025_split huggingface dataset:
Root Cation‐Exchange Capacity and the Mineral Nutrition of Eastern White Pine and Eastern Redcedar
Authors: Vimmerstedt John P. 
Published: July 2010

AbstractA field study showed that redcedar (Juniperus virginiana L.) foliage had a lower monovalent to divalent cation ratio than foliage of white pine (Pinus strobus L.). It was hypothesized that this difference resulted from redcedar roots having a higher cation exchange capacity (CEC) than white pine roots. Greenhouse experiments with seedlings grown on natural soils of contrasting fertility, and synthetic soils composed of crushed quartz and kaolinite, failed to support the hypothesis. The experiment with natural soils showed no interspecific difference in root CEC. In the experiment with synthetic soils, white pine roots had the higher CEC but redcedar had the lower monovalent‐divalent cation ratio. It was concluded that root CEC was not the factor causing the difference in cation ratios between species and that cation ratio in the soil had a strong influence on cation ratio in the trees.
Hydraulic Properties of a Clay Loam Soil and the Field Measurement of Water Uptake by Roots: III. Comparison of Field and Laboratory Data on Retention and of Measured and Calculated Conductivities
Authors: Brust K. J. , van Bavel C. H. M. , Stirk G. B. 
Published: July 2010

AbstractSoil water characteristics obtained on soil cores in the laboratory at air pressures < 1 bar agreed substantially with pressure‐water content relations determined in the field. Thus, in field studies of soil hydraulics, measurement of either water content or pressure potential may suffice.When the laboratory data were supplemented with a doubletube measurement of the saturated conductivity, the relation between water content and conductivity was calculated using two methods. Of these, the one due to Millington and Quirk gave less accurate agreement with actual field measurements than did the method proposed by Laliberte, Corey and Brooks. The latter method, when based on double‐tube measurements in the field and pressure cells or similar measurements on cores in the laboratory, appears useful.Retention values measured with the pressure membrane method on disturbed soil samples were out of line with both field and core results, even when the disturbing treatments were minimized.
Calibration and Field Test of Soil Heat Flux Plates
Authors: Fuchs M. , Tanner C. B. 
Published: July 2010

AbstractSoil heat flux plates were calibrated in the laboratory in steady‐state conditions and checked in the field vs. the soil temperature gradient thermal conductivity measurements of heat flux density. Good agreement was obtained after correcting for the flux divergence in the layer of soil where the temperature gradient was measured. Soil heat flux density measurements in a bare soil indicated that the heat storage in a 5‐cm layer of soil above the flux plates contributes significantly to the diurnal soil heat flux wave.
Clay Accumulation in Some Hapludalfs as Related to Calcareous Till and Incorporated Loess on Drumlins in Wisconsin
Authors: Allan R. J. , Hole F. D. 
Published: July 2010

AbstractA distinct boundary (γ) between the dark‐colored, acid solum and the paler calcareous dolomitic sandy loam till in 24 representative Hapludalf profiles on drumlins in southeastern Wisconsin is related to carbonate content of the till (b′ = 0.61 and r = 0.75) and depth of a silty covering (b′ = 0.68), (R2 = 67). In the absence of a silty covering, clay accumulation above the γ was apparently not influenced by the carbonate content of the till (r = 0.16 and R2 = 3) because the solum deepened by leaching of the till at the same rate as clay accumulated.Clay accumulation is also attributed in part to the admixture into till of loess different from that of the discrete silty coverings and attributable, on the basis of mineralogical studies of five profiles, to a distant source. Coarse silt of the silty coverings is mineralogically similar to the coarse silt of the till beneath the sola, except for that indicated by a higher content of Zr in the coverings.Eluviation of clay of the loess has been important in the genesis of the argillic horizon in these soils.Leaching of the till usually has resulted in the concentration of coarser and less weatherable fractions in the lower B horizon adjacent to the γ boundary. In most profiles clay did not accumulate notably immediately above the coarser of the sandy loam calcareous tills. Dolomite content of the Carbonate fraction of the till 5 cm below the γ boundary of six profiles averaged 95.6% compared with 97.0% at 55 cm still lower, indicating that the dissolved carbonate from the solum did not form a distinct Cca horizon.
Mechanism for Soil Potassium Release by Drying
Authors: Scott A. D. , Smith S. J. 
Published: July 2010

AbstractWhen large flakes of edge‐weathered biotite were air‐dried, some of the silicate layers were forced apart while others were brought closer together. Since the space between the separated layers developed into visible cracks that penetrated the inner mica core, the dry flakes provide visual evidence for a mechanism by which interlayer K can be released when soils are dried. The collapse of part of the lattice can give rise to a simultaneous occurrence of K fixation.
Transport in Soils: The Balance of Momentum
Authors: Raats P. A. C. , Klute A. 
Published: July 2010

AbstractThe mechanics of the fluid phase(s) of a soil is discussed on the basis of a balance of momentum for each phase. Saturated as well as unsaturated soils are considered. It is shown that with certain assumptions the balance of momentum for a fluid phase reduces to Darcy's law. The meaning and some possible generalizations of the various assumptions are considered. The form of Darcy's law appropriate to soils whose solid phase undergoes a deformation is deduced.
Adsorption and Desorption of Diquat, Paraquat, and Prometone by Montmorillonitic and Kaolinitic Clay Minerals
Authors: Weber J. B. , Weed S. B. 
Published: July 2010

AbstractThe adsorption of diquat, paraquat, and prometone by montmorillonite and kaolinite clays and their desorption using several extracting solutions has been investigated. Diquat and paraquat were adsorbed by the clay minerals to approximately the cation‐exchange capacity of the clays. Approximately 80% of each of the herbicides was displaced from kaolinite clay with Ba2+ ions. A total of 5% of each of the compounds was removed from montmorillonite using 1M BaCl2 solutions. The two herbicides were found to exchange for one another on both clay minerals in a one‐for‐one manner. Paraquat was preferentially adsorbed over diquat by both clays in competitive ion studies and was also found to be more difficult of the two herbicides to displace.Prometone which was adsorbed by the montmorillonite clay was more readily desorbed with deionized water than with 1M BaCl2. Small amounts of prometone which were adsorbed by the kaolinite clay were also readily desorbed by deionized water.
Behavior of Sulfate Sulfur and Elemental Sulfur in Three California Soils in Lysimeters
Authors: Jones M. B. , Martin W. E. , Williams W. A. 
Published: July 2010

AbstractThree soils from diverse climatic regions of California were placed in free‐draining lysimeters, and sulfur was applied as gypsum, fine elemental S (particles <0.1 mm), or pelleted elemental S (0.5 to 0.9 mm in diameter), at the rate of 56 kg S/ha (1,135 mg S per lysimeter). All S fertilizers were tagged with radioactive S. Sulfur uptake by soft chess (Bromus mollis), and S in leachate, and in runoff was measured. Recovery of S by the plant was greater in the fine elemental S treatment than in the gypsum treatment on the two soils where the loss of gypsum S by leaching was greater. Concentrations of S in the leachate were generally highest in the gypsum treatment in the first year after treatment. Timewise, concentrations were generally highest when the first percolate of the rainy season came through the soil. From 80 to 90% of the applied gypsum S, about 50% of the fine elemental S, and 10 to 15% of the pelleted elemental S was accounted for in a 4‐year period. Most of the gypsum S was accounted for in the first year. In contrast, most elemental S was recovered in subsequent years. Willits loam held gypsum S against leaching much better than did soils of the “Hebron” or Sehorn series, and the uptake of gypsum S was higher from Willits soil than from the other two soils.
Soil Swelling: Laboratory Measurement and Relation to Other Soil Properties
Authors: Franzmeier D. P. , Ross S. J. 
Published: July 2010

AbstractSoil swelling is measured using saran‐coated natural‐fabric samples to obtain the coefficient of linear extensibility (COLE) in soil genesis and characterization studies. It is measured using crushed and sieved samples to obtain the potential volume change (PVC) for on‐site investigations of potential building sites. For 30 samples from various horizons of soils in 10 states, the two measurements have the general relationship COLE × 60 = PVC. In coarse‐textured soils and in clayey soils high in kaolinite or mica but with no montmorillonite COLE ranges up to 0.03, and PVC up to 2.9; in clayey soils high in montmorillonite COLE ranges from 0.03 to 0.18, and PVC from 1.5 to over 9.0. The range of swelling potential in the montmorillonitic samples is related to the amount of clay and the fabric of the soil.
Tracing Soil Movement with Fluorescent Glass Particles
Authors: Young R. A. , Holt R. F. 
Published: July 2010

AbstractFluorescent glass particles with a density similar to that of natural soil particles were developed and tested under simulated rainfall for their effectiveness in tracing soil particle movement. From 10 to 38% of the various size ranges of particles used were successfully traced on the test plots. During a simulated rainstorm of 6.35 cm of rainfall in one hour, 11.8, 2.9, 0.7, and 0.6% of the largest to smallest size range of particles used, respectively, moved a distance of 10.37 m to the bottom of the plots. Lateral movements of up to 182.9 cm and upslope movements of up to 61.0 cm, as a result of raindrop splash action, were also detected.From the field test, glass particles appear to be potentially useful in work where knowledge of the movement of soil sized particles is desired.
Clay Mineralogy of Certain Soils of Colombia
Authors: Mejia G. , Kohnke H. , White J. L. 
Published: July 2010

AbstractAllophane was found to predominate in the soil derived from volcanic ash in the Colombian Andes. The allophane is transformed into halloysite. The soils of the superhumid tropical forests derived from marine deposits are high in kaolinite and low in gibbsite. Other clay minerals found in Colombian soils include vermiculite, montmorillonite, chlorite, and illite.
Effect of Topsoil Removal on Nitrogen‐Supplying Ability of Pullman Silty Clay Loam
Authors: Eck Harold V. 
Published: July 2010

AbstractUnder irrigation, removal of the surface 10, 20, 30, and 41 cm of soil decreased N yields 40.6, 47.5, 58.7, and 64.7%, respectively. Respective decreases under limited moisture were 20.0, 36.3, 53.9, and 62.4%. Total N in the surface 15 cm of soil and N yields were closely related.Relationships among drymatter yields of grain sorghum (Sorghum vulgare), associated N uptake, and N treatments (soil NO3‐N + fertilizer N) were used to estimate maximum yields attainable and to determine the internal N requirement of grain sorghum. That requirement was almost a constant (1.0%) despite the widely different yield maxima attained under the contrasting moisture regimes.Under irrigation, similar yield potentials were attained on all except the treatment with the greatest topsoil removal (41 cm). Undefined factors, other than N, P, or water, reduced the yield potential on that treatment. Under limited moisture, fertilizer treatments did not restore drymatter yields on any depth of soil removal. Differences are attributed to differences in water storage and use.Efficiency of uptake of available N was not directly affected by topsoil removal but was affected by the N status of the plants. It remained relatively constant until the plant N requirement was met, and then declined.
Influence of Soil Structure on Water Relations in Low Humic Latosols: I. Water Retention
Authors: Sharma M. L. , Uehara G. 
Published: July 2010

AbstractExperiments were carried out to study the effect of two aspects of soil structure, macrofabric and microfabric, on the water retention characteristics of two latosolic soils. The soils were selected because of similarity in composition but differences in structure.Moisture retention curves of the soils and also of their water stable aggregates were obtained. On the basis of results it was concluded that for strongly structured soils, water retention was greatly influenced by macrofabric in the tension range between 0 to 0.3 bar, while the effect of microfabric was more prominent beyond this range. The influence of microfabric was also demonstrated by applying the surface tension, radius of curvature, pressure relationship on selected aggregate fractions.
Denitrifying Activity in Solodized Solonetz Soils of Eastern Australia
Authors: McGarity J. W. , Myers R. J. K. 
Published: July 2010

AbstractDenitrifying activity was studied in 17 solodized solonetz profiles from eastern Australia using a Warburg manometric technique. Three distinct depth‐distribution patterns of activity were observed. In the first pattern, denitrifying activity declined with depth from a maximum in the Al horizon; this decline was positively correlated with decreasing organic C and total N contents. In the second pattern, denitrifying activity increased in the upper Bt horizons to levels slightly in excess of the A2 horizon above. The significant relationship between denitrification rate and organic matter was less consistent in these profiles. In the third type, denitrifying activity increased in one or more Bt horizons to levels greatly in excess of the A2 horizon above. No significant correlations were obtained between denitrifying activity and organic matter parameters for profiles of this group. It is suggested that high denitrifying activities in subsoil Bt horizons may be a transient property affected by environmental influences, and consequent on accumulation of small quantities of energy rich available organic matter.
Ammonium and Nitrate as Nitrogen Sources for Pinus radiata and Picea glauca
Authors: McFee W. W. , Stone E. L. 
Published: July 2010

AbstractThe relative value of ammonium and nitrate as N sources for Pinus radiata D. Don seedlings was determined under various conditions. Short‐term experiments varying from 3 weeks to 6 months' duration were conducted utilizing three growth media: solution, soil, and exchange resin beads. In the solution cultures N sources were compared at two levels of acidity (pH 3.6 and pH 5.9), three root‐zone temperatures (15, 20, and 25C), and three N levels (2.8, 11.2, and 22.4 ppm N). In the soil cultures N was added at five levels as NaNO3 or NH4Cl with a nitrification inhibitor. Three levels each of ammonium and nitrate were used in a factorial arrangement in the resin cultures.Radiata pine seedlings grown either in soil, solution culture, or exchange resins exhibited greater growth and N uptake with an ammonium source than with nitrate. This was true in experiments at several levels of acidity, in all three growth media and regardless of the root zone temperature or N level maintained. Increases in root zone temperature in solution cultures increased growth and N uptake and increased the differential response to N source.Eight‐fold differences in N concentration in the solution cultures produced only small differences in growth and N uptake. N levels of approximately 2.0 ppm N in solutions proved satisfactory for normal growth.Picea glauca (Moench) Voss seedlings were tested concurrently in the solution cultures and exhibited the same favorable response to ammonium N source.
Morphological Classification of Grass Phytoliths
Authors: Twiss P. C. , Suess Erwin , Smith R. M. 
Published: July 2010

AbstractOpal phytoliths derived from epidermal cells of grass leaves have been identified in atmospheric dust, soils, paleosols, Pleistocene loess, and deep‐sea sediments. By comparing oriented shapes of phytoliths in spodograms of 17 common grass species, four classes and 26 types are proposed which distinguish three groups of subfamilies of Gramineae. The Festucoid class contains eight types that are circular, rectangular, elliptical, or oblong forms. The Chloridoid class contains two types of saddle‐shaped bodies. The Panicoid class contains 11 types that are variations of crosses and dumbbells. The Elongate class contains five types that have no subfamily implications and occur in all 17 species. Because phytoliths of native tall grasses (Panicoid), short grasses (Chloridoid), and common domestic grasses of the humid regions (Festucoid) can be distinguished, it is possible to determine whether phytoliths in dust, soils, and sediments were derived from local or remote sources.
Argillic Horizons Without Clay Skins
Authors: Nettleton W. D. , Flach K. W. , Brasher B. R. 
Published: July 2010

AbstractAlthough the clay in some moderately fine and fine‐textured Bt horizons of soils of arid and mediterranean climates of the southwestern United States is highly oriented, no distinct illuvial clay skins can be recognized. The distribution of clay skins is related to shrink‐swell potentials. Clay skins are absent in horizons having a shrink‐swell potential of more than 4% or a masepic or omnisepic plasmic fabric; they are present in equivalent horizons having low shrink‐swell potentials and an insepic or mosepic plasmic fabric. The clay content, mineralogy, and moisture regime of a Bt horizon in turn largely determine its potential to shrink and swell and hence determine its plasmic fabric.Evidence that clay illuviation has indeed taken place in these finer textured Bt horizons is based on four pairs of geographically associated soils with horizons of clay accumulation. Bt horizons of the coarser textured members of pairs have clay skins and the finer textured members do not. The distribution of biotite pseudomorphs in some of these pairs parallels the distribution of clay skins, suggesting that oriented bodies of clay can be destroyed. Clay orientation in one of the horizons was reformed experimentally to show that the highly oriented soil fabrics do not acquire their orientation by illuviation of clay.The studies further indicate that bodies of oriented clay in medium and fine‐textured B horizons have been erroneously described as clay skins.
Contribution of Humic Acid and a Polysaccharide to Water Repellency in Sand and Soil
Authors: Savage S. M. , Martin J. P. , Letey J. 
Published: July 2010

AbstractA silica sand and Pachappa sandy loam were treated at various pH's with aqueous suspensions of three microbial humic acids, a soil and peat humic acid, a microbial polysaccharide, and metallic salts of the tested organic substances. Of all the substances tested, only one, a humic acid isolated from a Stachybotrys atra culture, caused water repellency in the sand and soil. The Fe3+ and Al3+ salts of this humic acid rendered the sand and soil practically impermeable to water. The organic matter content of the extremely water repellent sands was less than .05%. The final conclusion of the paper is that humic acid‐like substances and polysaccharides probably do not contribute much to water repellency in soils.
The Absence of Threshold Gradients in Clay‐Water Systems
Authors: Miller Raymond J. , Overman Allen R. , Peverly John H. 
Published: July 2010

AbstractThe transient pressure transducer technique was used to test for threshold gradients in 9, 30, 40, and 50 weight percent montmorillonite and <2µ and 2–20µ size fraction kaolinite. Threshold gradients were not found in any of the samples tested.
Soil Degradation of Malathion, a Phosphorodithioate Insecticide
Authors: Konrad J. G. , Chesters G. , Armstrong D. E. 
Published: July 2010

AbstractRates of malathion degradation in soils were related directly to extent of malathion adsorption, suggesting that degradation occurred by a chemical mechanism which was catalyzed by adsorption. Malathion degradation was rapid (50 to 90% in 24 hours, depending on the type of soil) in both sterile and nonsterile soil systems, and no lag phase occurred prior to degradation. In aqueous soil‐free systems inoclulated with a soil extract, a lag phase (7 days) occurred, followed by rapid malathion loss, likely due to microbial degradation. Thus in soils, complete chemical degradation of malathion occurred prior to microbial adaptation to malathion. To obtain information on the pathway and products of malathion degradation, chemical hydrolysis in soil‐free systems was investigated using liquid:liquid partition techniques with 14C‐labeled malathion. Hydrolysis did not occur in acid systems (> pH 2), was slow at pH 9 (< 50% in 20 days) and rapid at pH 11 (> 99% in 1 day). At pH 9 the hydrolysis resulted in formation of thiomalic acid and dimethyl thiophosphoric acid as final products with accumulation of diethyl thiomalate as an intermediate due to unequal rates of hydrolysis of the ester linkages. In soils, both ester linkages are hydrolyzed, although not at the same rate, resulting in the accumulation of diethyl thiomalate in some soils.
Steady State Studies of Nitrification in Soil: Theoretical Considerations
Authors: McLaren A. Douglas 
Published: July 2010

AbstractEquations are set up for consecutive reactions in an idealized soil column and solved for concentrations of metabolites as functions of time and depth within the column under steady state conditions. The reactions NH+4 → NO‐2 → NO‐3 were so expressed for columns with maximum numbers of nitrifying organisms.These equations for an open system can be modified to accommodate rates of metabolism for reperfusion experiments for the condition of maximum enrichment of nitrifiers.
Vapor Density of Soil‐Applied Dieldrin as Related to Soil‐Water Content, Temperature, and Dieldrin Concentration
Authors: Spencer W. F. , Cliath M. M. , Farmer W. J. 
Published: July 2010

AbstractVapor densities of dieldrin (principal constituent HEOD‐hexachloro‐epoxyoctahydro‐endo, exo‐dimethanonaphthalene) in dieldrin‐soil mixtures increased with temperature and dieldrin concentration but were not affected by soil‐water content until the water content decreased below that equivalent of one molecular layer of water. Vapor densities dropped to very low values when the water content fell below this level, but increased again as water was added to the dry soil, indicating that the drying effect is reversible. When more than a monomolecular layer of water was present in the soil, vapor density increased with increasing soil dieldrin (HEOD) concentration until a saturation vapor density equal to that of HEOD without soil [54, 202, and 676 ng HEOD/liter at 20, 30, and 40C, respectively (9)] was reached at approximately 25 ppm HEOD. This implies that surface applications of dieldrin and probably other similar chlorinated hydrocarbon insecticides will volatilize as rapidly from mineral soils as from the pure materials until the concentration at the surface falls to relatively low levels.The data indicate that loss of water, per se, is not required for significant rates of volatilization to occur from soils or other surfaces on which water can successfully compete for adsorption sites.
Nitrification in Soil: Systems Approaching a Steady State
Authors: McLaren A. Douglas 
Published: July 2010

AbstractEquations are set up for the consecutive reactions NH4+ → NO2‐ → NO3‐ in an idealized soil column and solved, for an open system with a constant rate of entry of a solution of ammonium, for concentrations of ions as functions of time of flow and distance within the column. The equations take into account growth of nitrifying organisms but it is assumed that diffusion and ion exchange within the soil and fixation of nutrients by the nitrifiers are of secondary importance.