bluuebunny/crossref_metadata_2025_split huggingface dataset:
Community Meetings: A Device for Distributing Soil Survey Reports and for Training in Their Use
Authors: Bidwell O. W. , Bohannon R. A. 
Published: July 2010

AbstractCommunity meetings for the distribution of soil survey reports were held in the Kansas counties of Saline, Geary, and Brown during the years of 1959, 1960, and 1961. Cooperation of the USDA Soil Conservation Service, the USDA Agricultural Stabilization & Conservation Service, the Kansas Agricultural Extension Service, and the Kansas Agricultural Experiment Station was essential in the planning and execution of the meetings. Other important elements which made the meetings successful and brought out an average of 480 persons to each of the three series of county meetings included: (1) the selection of local farm leaders to help publicize and conduct the meetings; (2) withholding distribution of the soil survey reports until the meetings; (3) bringing the party chief back to take part; and (4) using visual aids such as soil profile monoliths, soil texture samples, a large colored county soil map, and growing plants to illustrate soil deficiency symptoms.
Isotopic Exchange of Potassium in an Illite under Equilibrium Conditions
Authors: Sumner M. E. , Bolt G. H. 
Published: July 2010

AbstractThe kinetics of K exchange in an illite were studied using K42. The influence of various pretreatments was investigated, and a comparison was made between exchange with K42 under equilibrium conditions during 1 week and repeated extraction with 0.5 N NH4NO3 and 0.5 N NaNO3. Except for the samples containing 0.5 N CaCl2 the K42 exchange appeared to be very fast and no further increase could be observed during shaking from 6 hours up to 1 week.Prolonged pretreatment with 0.5 N CaCl2 apparently caused an opening up of the clay lattice. The 0.5 N NH4‐extraction following this treatment always removed considerably more K than was exchangeable against K42 under equilibrium conditions.On the other hand, extraction with 0.5 N NaNO3 removed even less than was exchangeable against K42, indicating that part of the exchangeable K was still in interlattice positions.
Controlled Release of Fertilizer Minerals by Incapsulating Membranes: I. Factors Influencing the Rate of Release
Authors: Oertli J. J. , Lunt O. R. 
Published: July 2010

AbstractThe availability of nutrients from inorganic fertilizer salts can be regulated through coating such materials. The release rate was investigated in several elution and leaching experiments. The release approached linearity for a considerable period; thereafter the rate dropped off. The release rate was largely independent of the pH of the elutant and of the soil pH. An increase in temperature from 10° to 20°C. almost doubled the initial release rate. The release could be regulated very efficiently through the coating thickness. There was an effect of ionic species, nitrate and ammonia being given off more rapidly than potassium or phosphates. The release was only slightly reduced under sterile conditions. It was concluded that diffusion is the most likely release mechanism and proposed that discrepancies such as the high Q10 value could be explained through possible changes in membrane properties. Coated fertilizers thus possess the properties required for regulation of the availability of nutrients: they may reduce leaching losses and provide a steady prolonged nutrient supply to plants.
Model of a Rising Nitrogen Profile in Nile Valley Alluvium, and Its Agronomic and Pedogenic Implications
Authors: Jenny Hans 
Published: July 2010

AbstractNitrogen‐depth functions in Nile Valley alluvium appear similar to those of Brunizems, but their genesis must be entirely different. Since fresh Nile mud is very rich in total nitrogen, it is proposed that the annual depositional layers, 1 mm. in thickness, undergo nitrogen losses as a result of microbial decomposition, and that for each layer the losses continue in the buried state, though at reduced rates. This model predicts quantitatively the N‐depth function actually observed. In comparison to residual soils, the Nile Valley profiles—in fact many young alluvial and loessial profiles—are inverted, the youngest horizon being on top, the oldest at the base.
Soil Hardpan Formation as Affected by Rate of Moisture Loss, Cyclic Wetting and Drying and Surface‐Applied Forces
Authors: Gerard C. J. , Cowley W. R. , Burleson C. A. , Bloodworth M. E. 
Published: July 2010

AbstractA hypothesis was proposed by Gerard et al. (1) to explain the role of soil moisture loss in hardpan formation in cultivated and virgin soils of the Lower Rio Grande Valley. Additional laboratory studies were conducted to clarify the proposed hypothesis. Results of the studies indicate that a slow rate of drying was an important factor in causing more intense close‐packing of soil particles or a greater degree of soil hardness.The formation of a compacted layer in the Willacy fine sandy loam as affected by wetting and drying cycles and externally applied force to the surface at different moisture levels also was determined. The data indicate that rate of moisture loss, surface‐applied forces, wetting and drying cycles and temperature influenced the degree and/or rate of soil compaction. This soil was especially susceptible to compaction when the average moisture centent of the 0‐ to 7‐inch soil‐depth was 12.5%.
Influence of Vegetation Cover on Soil Moisture in Southeastern Ohio
Authors: Marston Richard B. 
Published: July 2010

AbstractTo obtain some information in the central United States of the effect of forest watershed vegetation on the amount of water available for streamflow, soil mositure to a depth of 36 inches was studied for 22 months in southeastern Ohio on oak, pine, broomsedge, brush, and cleared plots. Moisture content near the end of the dormant season was used as a measure of field capacity. It varied from 11.49 inches of water on the pine plots to 13.12 inches of water on the broomsedge plots. Generally, soil moisture declined throughout the summer and increased during the winter, but occasionally summer rainstorms were large enough to rewet the soil to field capacity. Late‐summer soil moisture deficits were greatest under oak and least under cleared, whether calculated on the basis of measured field depths or on the basis of equal volumes of soil. Water used in a 6‐month growing season ranged from 21 inches under cleared to 25 inches under pine. Additional water was withdrawn during the dormant season. The 2‐year average amount of precipitation required to refill the soil was 6.5 inches greater under pine than under broomsedge—broomsedge being the minimum cover practical here. Good opportunities exist in Ohio to affect streamflow and flood control through the manipulation of the forest cover.
Effect of Electrolyte Concentration on Donnan Systems and the Resulting Uptake of Cations by Plants
Authors: Franklin R. E. , McLean E. O. 
Published: July 2010

AbstractDonnan systems were prepared by dialyzing bentonite and illite clay suspensions against equal volumes of water. The electrolyte concentration was varied from 0 to 10 me. per liter. Ca45 and Rb86 were used as tracers for Ca and K in the systems.Greater amounts of Ca were absorbed by corn plants from the clay suspension phase than from the dialyzate phase provided that the electrolyte concentration was low enough. The differences in absorption from the two phases decreased as the electrolyte concentration was increased, and the uptake of Ca from the two phases was equal at about 0.1 symmetry concentration of electrolyte depending on the absorption time and saturation of the clay. A similar trend was observed for K absorption though less pronounced.Various measurements supported the theory that clays have a low degree of dissociation and thus give rise to relatively small Donnan effects.The apparent failure of Donnan theory to accurately describe clay‐water systems in studies by certain investigators was likely due to the assumption that the colloid is completely dissociated. In addition, differences or similarities observed in uptake of cations from suspensions and corresponding equilibrium dialyzates appear to be the result of variation in concentration of electrolyte present.
Response of Natural Stands of Shortleaf Pine to Thinning and Fertilization With Nitrogen and Phosphorus
Authors: Curlin James W. 
Published: July 2010

AbstractThis paper reports the results of fertilizer experiments conducted with thinned and unthinned natural stands of shortleaf pine. Nitrogen and phosphorus were applied singly and in combination on both thinned and unthinned plots. The plots were located on three soil series found in close association in the Great Valley Region of eastern Tennessee.Four‐year response in basal area growth per tree was increased as much as 300% over the unthinned check by thinning and application of nitrogen. An increase of up to 40% over the thinned check was achieved with nitrogen alone. These responses were still evident 4 years after fertilization. Basal area growth response to phosphorus was erratic throughout the study period.The results indicate that stand density must be low enough at the time of nitrogen application to allow growth to proceed unhindered.
Sorption of Cesium by Soils and Its Displacement by Salt Solutions
Authors: Coleman N. T. , Lewis R. J. , Craig Doris 
Published: July 2010

AbstractCesium was sorbed by montmorillonite, illite, and kaolinite in quantities corresponding to exchange saturation and was displaced readily on leaching with 1N KCl or CaCl2. Vermiculite and heated (600°C., 12 hours.) K‐montmorillonite bound Cs tightly against displacement by CaCl2 and AlCl3, but not by KCl or NH4Cl. Prolonged leaching with 1N KCl removed 97.5% of the Cs sorbed by heated K‐montmorillonite, while 1N CaCl2 eventually displaced 88%.Potassium and Rb sorbed on vermiculite were displaced more rapidly by Ca or Mg than by monovalent ions, but this was not the case with heated K‐montmorillonite.The exchange‐displacement behavior of Cs on vermiculite and heated K‐montmorillonite suggests that this ion is unique in that its sorption in interlayer spaces leads to interplanar distances which admit K and NH4 ions but greatly restrict the entry of Ca. Cesium, then, is not expected to follow the “fixation‐release” rules that have been developed for K and NH4.Heated montmorillonite samples leached with mixtures of CsCl and other salts sorbed more Cs when the complementary ion was Ca or Al than when it was K or NH4. Differences were especially pronounced at low equivalent fractions of Cs in the leaching solution, showing a larger preference by exchange sites for Cs over divalent than over monovalent ions. Apparent “specific sorption” of Cs against exchange with CaCl2 occurred at quite large Cs saturations.
Availability and Fixation of Added Potassium in Two California Soils When Cropped to Cotton
Authors: Page A. L. , Bingham F. T. , Ganje T. J. , Garber M. J. 
Published: July 2010

AbstractField studies have recently demonstrated the occurrence of K deficiency in California cotton fields, and, further, unusually high rates of K fertilizers were required to correct the deficiencies. A greenhouse and laboratory study demonstrated that fixation of the added K was the reason high K applications were required. Two soils from problem fields were treated with K at rates ranging from 0 to 400 ppm. K and cropped to cotton in the greenhouse. Response, as indicated by plant analyses, plant symptoms, and yields, was not obtained until the application rate equaled or exceeded 160 ppm. K. Exchange and Rb‐fixation capacities of the soils after cropping showed a progressive decrease as a function of the added K. Disregarding the K removed by the crop and assuming the decrease in exchange capacities was due exclusively to K fixation, 63 to 75% of the added K was fixed. Laboratory studies demonstrated that soils in the moist state would fix up to 900 ppm. K against neutral salt removal. The effect of the added K on the Mg content of the cotton plant is also reported.
Pan Horizons in Southeastern Soils: Micromorphology and Associated Chemical, Mineralogical, and Physical Properties
Authors: McCracken R. J. , Weed S. B. 
Published: July 2010

AbstractCertain Southeastern U.S.A. soils contain subsurface or subsoil horizons that differ from adjacent horizons by possession of one or more distinctive morphological features. Common terms for these are plowpan or traffic pan, brittle pan, organic pan, and fragipan. Results of micromorphologic studies of these pan types (claypans are excluded from this study) are reported, plus certain compositional characterization data to complement the thin section observations.Brittle subsurface layers in the Norfolk soils were found to occur in two positions in the profile, immediately below the Ap horizon or plow layer and at or near the base of thick A2 horizons. The former may be induced by implement pressure; the latter may occur at depths of 6 and more inches below the base of the Ap but within the A2 or at A‐B contact and seems to be pedogenic. The term “brittle layer” has been used to describe the latter; “arenapan” is suggested as a name for these subsurface, coarse‐textured brittle zones.Organic pans, as they are called locally, are apparent humus B horizons of Ground‐Water Podzols. Samples from the Leon soil were employed in this study.Fragipan development in the Southeastern United States is typified in the Grenada soil, formed from Southern Mississippi Valley loess. The fragipan in this soil occurs at the base of the B horizon, below a zone of slight clay accumulation.The Leon Bh (“organic pan”) and the brittle layers in the Norfolk A2 horizon show heterogeneous distribution of quartz sand separated by intergranular bridges of fine‐grained material. These pan layers appear highly porous in thin section, though many pores appear to be blocked by intergranular bridges. The Norfolk “plow pan” or traffic pan at the base of the Ap horizon exhibits close packing of quartzose sand and clay plus silt, with some humus inclusions. The Grenada fragipan is a close‐packed silty matrix containing a few areas of oriented clay and appreciable components of feldspar and mica.A clay mineral species or complex of 14.7 A. basal spacing, expandable to 17 to 18Å. with ethylene glycol solvation following treatment for removal of interlayer aluminum, appears to reach maximum concentrations in the pan layers of all profiles studied except Grenada. In the Grenada profile, there is a maximum relative concentration of this clay mineral immediately above the fragipan.
Movement of Water as Effected by Free Energy and Pressure Gradients III. Restriction of Solutes by Membranes
Authors: Kemper W. D. , Evans N. A. 
Published: July 2010

AbstractThe validity and method of using the self‐diffusion coefficient of water to estimate movement in response to free energy gradients are outlined.The dominant mechanism of water transport through these membranes is viscous flow, even when osmotic pressure differences are causing the flow. Osmotic pressure and hydraulic pressure differences are equally effective in moving water through a membrane when the solutes are completely restricted by the membrane. When solutes are not completely restricted, osmotic pressure differences are less effective than hydraulic pressure differences in moving water through membranes. Equations including the sizes of the solute molecules and the pores are developed which predict the rate at which osmotic pressure differences move water through uncharged porous media.
Non‐Darcy Behavior and the Flow of Water in Unsaturated Soils
Authors: Swartzendruber Dale 
Published: July 2010

AbstractCorresponding values of flow velocity and moisture gradient were calculated for water flow in unsaturated soil, using a graphical analysis of moisture profiles obtained during horizontal absorption of water into air‐dry Salkum silty caly loam. Plots of flow velocity vs. moisture gradient were straight lines through the origin at the higher moisture contents, but Darcy proportionality did not hold at the lower moisture contents.The observed deviations were of the same type as found in earlier studies for plots of flow velocity vs. hydraulic gradient for water‐saturated materials containing clay, and could be fitted by a modified flow equation developed previously for the water‐saturated materials. Physically, the non‐Darcy behavior is tentatively attributed to non‐Newtonian liquid effects caused by clay‐water interaction.Consideration of diffusion‐type analysis from the stand‐point of non‐Darcy behavior shows that the diffusivity D becomes a function of moisture gradient w as well as moisture content θ. This provides a way of accounting for the nonuniqueness of D(θ) recently reported in the literature.
Evaluation of Microbial Activity in Soil Aggregate Stabilization and Degradation by the Use of Artificial Aggregates
Authors: Harris R. F. , Allen O. N. , Chesters G. , Attoe O. J. 
Published: July 2010

AbstractA method for evaluating the mechanisms and factors involved in soil aggregate stabilization by microorganisms is introduced and data are presented to illustrate its use. This method involves the incubation of artificial soil aggregates of uniform and controlled physical and chemical properties, so that the effect of one or more variables of soil composition or environment on aggregate stability can be investigated.The stabilities of differently‐amended artificial aggregates of two diverse soil materials, incubated for up to 20 weeks, were determined by wet‐sieving the dried aggregates. The two soil materials, one obtained from the Ap horizon of a Kewaunee silty clay loam (Gray‐Brown Podzolic) and the other from the Al horizon of a Waupun silt loam (Brunizem), differed markedly in their contents of clay, nitrogen and organic carbon.Microbial gum‐amended Kewaunee aggregates possessed a higher initial stability and were more resistant to degradation with continued incubation than corresponding Waupun aggregates. Added nitrogen was associated with accelerated degradation of Kewaunee but not Waupun gum‐amended aggregates. Incubated sucrose‐amended Kewaunee aggregates showed a slower increase to maximum stability but retained stability longer than sucrose + nitrogen‐amended Kewaunee and sucrose‐ and sucrose + nitrogen‐amended Waupun aggregates. Nonamended and nitrogen‐amended aggregates of both soils were completely unstable throughout the incubation period. The stability of moist aggregates was a function of wetting rate and moisture status prior to sieving; aggregates moistened slowly to saturation were 100% stable to wet‐sieving.Periodate treatment of the aggregates indicated that, with the exception of incubated sucrose‐amended Waupun aggregates, “periodate‐oxidizable” polysaccharides were important in aggregate stabilization.Four days of incubation under highly aerobic or anaerobic conditions caused a rapid increase in the stability of sucrose‐amended Waupun aggregates. Continued aerobic incubation resulted in a rapid decrease in aggregate stability; aerobically incubated aggregates were totally unstable after 12 days. In contrast, continued anaerobic incubation was associated with an increase in stability; 100% aggregate stability was reached after 15 days and was still present after 4 weeks. Anaerobically‐stabilized aggregates lost their stability completely after 9 days of aerobic incubation.
Gray Wooded Soils of the Black Hills of South Dakota
Authors: Radeke R. E. , Westin Fred C. 
Published: July 2010

AbstractThe morphology, classification, and laboratory characteristics of the wooded soils of the Black Hills of South Dakota are reported. Field morphology studies involving parts of two summers tentatively established the classification of these soils in the Gray Wooded Soil Group. Paired profiles representing the central concept of the Gray Wooded group were sampled and laboratory characteristics determined. These soils resemble Gray Wooded soils reported for Canada, Montana, and the Northern Lake States. Additional paired profiles of giant or maximal Gray Wooded profiles and Gray Wooded intergrade profiles also were sampled and are characterized. A description of a pygmy or minimal Gray Wooded profile is described but was not sampled for analysis.
An Electric Point Gauge and Tube Orifice Plates for Measuring Flow Rates in Furrow Irrigation
Authors: Grover B. L. , Hotchkiss C. W. 
Published: July 2010

AbstractThe description of an electric point gauge and tube orifice plates for determining furrow flow rates is given. The gauge is a double‐pointed unit, constructed so that the head loss across the orifice plate is obtained as a single reading. The equipment is particularly useful in the evaluation of intake rates in furrow irrigation on small experimental plots, since it can be used with little or no damage to the plots.
Predicting the Solute Composition of the Saturation Extract from Soil Undergoing Salinization
Authors: Dutt Gordon R. , Doneen Lloyd D. 
Published: July 2010

AbstractA procedure utilizing a 1620 IBM computer was developed to predict the concentrations of Ca2+, Mg2+, and Na+ in saturated extracts from soils undergoing salinization with waters containing Cl‐ and SO42‐ salts of one or more of the above cations. This procedure was used to predict the concentration in saturated extracts for soils to be salinized with various mixtures of salts. These predicted values were in agreement with experimentally determined values both in systems where the salts remained in solution and where gypsum was precipitated. This procedure lends itself to routine analysis, and it should be possible to extend it to include other ions and slightly soluble salts that frequently are found in nature.
Characterization and Genesis of Pawnee and Adair Soils in Southeastern Nebraska
Authors: Millet John L. , Drew James V. 
Published: July 2010

AbstractPawnee and Adair soils occur on gently sloping to rolling uplands in southeastern Nebraska. They have clay‐textured subsoils and are somewhat similar morphologically except that Pawnee soil has a yellowish‐brown subsoil, whereas Adair soil has a reddish‐brown subsoil. Montmorillonite and illite are important minerals in the clay fraction of these soils.Field studies indicate that Pawnee soil has formed in Kansan glacial till whereas Adair soil has formed in poorly sorted and clayey material derived from Kansan till. This poorly sorted material overlies Kansan till and is identified in Nebraska as the colluvial phase of the Loveland formation. The Loveland formation often has a reddish‐brown color which is thought to be the result of weathering and soil formation during Sangamon time.Petrographic data indicate that the subsoil of Adair soil is more weathered than the subsoil of Pawnee soil. These data suggest that Kansan till was protected from weathering during Sangamon time by colluvial and upland (eolian) phases of the Loveland formation. Pawnee soil occurs in places where Kansan till was exposed by subsequent geologic erosion whereas Adair soil occurs in clayey remnants of colluvial‐phase Loveland.