bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ant (Formica exsectoides) Pedoturbation in a Forest Soil
Authors: Salem M. Zarif , Hole Francis D. 
Published: July 2010

AbstractTwenty‐five active mounds of the common eastern moundbuilding ant (Formica exsectoides) had an average height of 0.37 m and basal diameter of 1.1 m in a long, narrow neverplowed clearing of 1,040 m2 on the edge of a woodland in southern Wisconsin. The mound volume ranged from 0.01 to 0.6 m3 and averaged 0.13 m3. The ant nests, extending at least 160 cm below the soil surface occupied 1.9% of the area of the surface of a Typic Hapludalf (Gray‐Brown Podzolic), Dubuque silt loam, formed in thin loess over reddish cherty clayey residuum on dolomitic limestone. Mounds were virtually bare and were largely composed of silty clay. Detailed studies were made of a soil profile through a large mound and of an intermound soil profile nearby. Calculations indicated that the ants have moved to the surface the equivalent of 1.25% of a plow layer or 2,500 kg of soil (dry wt) per 1,040 m2 and in the process have reduced the bulk density of the material from 1.5 to 0.8 g/cm3 and increased the contents of available nutrients in the soil. Voids 0.2 to 2.3 cm in diameter, on the average occupied 20% by volume of the mound and about 10% of the buried A horizons. The mound contained about 50% silt, 46% clay, 4% sand; 4% free iron oxides, and 3% organic matter. Corresponding figures for the A2 and IIB23 horizons of the Dubuque are: 78, 18, 4; 2 and 3; 15, 83, 2; 6 and 0.3. Disturbance of soil profiles by this species of ant is restricted to small areas, apparently because colonies are established and mounds developed only in temporary openings in forests.
Linear Extensibility as Calculated from Natural‐Clod Bulk Density Measurements
Authors: Grossman R. B. , Brasher B. R. , Franzmeier D. P. , Walker J. L. 
Published: July 2010

AbstractUse of a coating that is flexible permits measurement of bulk density of natural clods at more than one moisture content. Linear extensibility, expressed as a coefficient (COLE) or as change in horizon thickness, can be calculated from the increase in bulk density between the water content at ⅓‐bar tension and oven dryness. Extensibility data are given for a Marias soil (Entic Chromoxerert). Composition of the Marias soil remains similar with depth but the structure changes. COLE values are affected by the change in structure as are also PVC test results, but liquid and plastic limit values are affected little.
Soil Water Storage During Fallow in the Central Great Plains as Influenced by Tillage and Herbicide Treatments
Authors: Smika D. E. , Wicks G. A. 
Published: July 2010

AbstractSoil water storage during the fallow period of winter wheatsorghum‐fallow (Triticum aestivum and Sorghum vulgare) and alternate winter wheat‐fallow rotations was measured during three fallow periods. Storage was greater when herbicides rather than conventional tillage practices were used to control weeds. The storage increase of nearly 4 cm of available water as a result of treatments was distributed throughout the profile in the 3‐year rotation, but the greatest increase occurred in the upper 60 cm of soil. In the 2‐year rotation the nearly 14‐cm increase in available water due to treatment was also present in the entire profile, but most of the storage increase occurred to a depth of 210 cm, with soil water content to a depth of 180 cm being at or near field capacity.Soil water storage for the total fallow period of the 3‐year rotation ranged from 18.6 to 22.3 cm, having corresponding storage efficiencies of 35.4 and 42.4%, for conventional tillage and complete herbicide treatments, respectively. Water storage for the complete fallow period of the 2‐year rotation ranged from 18.6 cm with spring plowing (bare soil) to 23.8 cm with tillage stubble mulch to 32.5 cm with complete use of herbicides, and had storage efficiences of 25.0, 32.0, and 43.7%, respectively.
Effects of Salts on Oxygen Diffusion Rate Measurements in Unsaturated Soils
Authors: Rickman Ron W. 
Published: July 2010

AbstractCurrent‐voltage curves determined with tips of platinum electrodes touching a solution surface were used to evaluate the effect of solution electrical conductivity and specific ions on measurements of oxygen diffusion rates in unsaturated soil. Current was found to be dependent upon electrical conductivity in pure monovalent cation solutions. In divalent cation solutions, or mixed monovalent‐divalent cation solutions, current was only slightly affected by electrical conductivity of the solution. The presence of divalent cations caused a lower measured current with identical solution‐electrode geometry and measured electrode potential than when only monovalent ions were in solution. Based upon the assumption that these determinations reflect at least the magnitude of such phenomena that occur in soils, conditions are described under which the platinum electrode should operate most satisfactorily or have a minimum interference from salt.
Hydraulic Load‐Cell Lysimeter, Construction, Calibration, and Tests
Authors: Black T. A. , Thurtell G. W. , Tanner C. B. 
Published: July 2010

AbstractThe construction and calibration of two 35‐metric ton, hydraulic load‐cell lysimeters with suction drainage systems are described. The butyl‐nylon load cells contain an ethylene glycol‐water mixture and pressures are measured with a capacitive pressure transducer. Lysimeter sensitivity is 0.02 mm evaporation. Daily evaporation from the lysimeter and the two independent micrometeorological methods agreed to within 5%. On a June day, lysimeter measurements of evaporation from bare soil lagged measurements using the two other methods by almost 1.5 hours. Differences between the lysimeter thermal regime and that in the surrounding soil accounted for the lag. By using foam plastic insulation of the tank walls, thermal regime differences were minimized.
Leaching Requirement for Exchangeable‐Sodium Control
Authors: Rhoades J. D. 
Published: July 2010

AbstractA method is described for estimating the leaching fraction required to keep the sodium‐adsorption‐ratio (SAR) at the lower limit of the plant‐rooting zone below some limiting value. The choice of the limiting SAR depends on plant tolerances to sodium and on soil permeability. The method is based on an equation that satisfactorily predicts the SAR values of waters draining from a calcareous soil under various leaching regimes.
A Portable Injector for Dispensing Liquid Anhydrous NH3 in the Field
Authors: Smiley R. W. , Papendick R. I. 
Published: July 2010

AbstractA portable injector for metering and dispensing small aliquots of anhydrous NH3 rapidly and with good precision in the field has been constructed and tested. The device is versatile and should be equally suitable for dispensing other high‐pressure solutions in the field. The portable injector is simple in design, easily operated, and readily transportable. Injecting liquid NH3 with the portable injector produces little soil disturbance compared with usual application methods.The absolute mass of a single injection of anhydrous NH3 in the field may be determined by direct calibration in the field or by a laboratory calibration and a calculated correction for temperature. The latter method appears to be more practical and involves no more error than that involved in a direct field calibration.A procedure for sampling soil by taking successive hemispheres around the injection point was found to be satisfactory for characterizing NH3 concentrations and pH in the retention zone.
The Drying Through the Top Surface of a Vertical Porous Column
Authors: Heller J. P. 
Published: July 2010

AbstractMicroscopic and macroscopic descriptions are given of the process of drying from a long porous and permeable column, initially saturated fully with a liquid which wets its grains. A comparison is made with the process of drainage, and it is shown that the “first stage of drying” corresponds with the extension down into the pack of a saturation profile derived from the capillary pressure curve. In the second stage of drying this profile penetrates still deeper; its upper end coincides with a “bone dry front,” the progress of which down the pack is controlled by diffusion of vapor to the surface. Results of the analysis are compared to measurements of front position during the drying of unconsolidated fluorite packs.
Iron‐Rich Montmorillonite Formation in Soils Derived from Serpentinite
Authors: Wildman W. E. , Jackson M. L. , Whittig L. D. 
Published: July 2010

AbstractMontmorillonite, identified by X‐ray diffraction, is the predominant clay mineral in the B horizons of four widely separated California soils (Henneke, Dubakella, and Fancher series and one from the New Idria area) derived from serpentinite. The < 0.2µ fractions contain respectively, 81, 68, 71, and 33% montmorillonite as determined by CEC determination. These fractions contain 57.5, 54.9, 62.5, and 50.0% SiO2; 17.2, 18.4, 17.6, and 7.5% combined Fe2O3 (by chemical analysis after removal of free Fe2O3); 7.2, 4.3, 8.7, and 25.0% MgO; and 4.3, 10.4, 1.0, and 6.1% Al2O3. Much of the MgO can be attributed to < 0.2µ serpentine minerals, identified by electron microscopy. The montmorillonite has a high content of Fe in octahedral position, represented by the range in octahedral sheet formula, Fe1.8–2.7Al0.2–1.8Mg0–1.1, calculated for the four soil clays. Mg is the predominant exchangeable cation in the < 2 mm soil (67–96% of the total exchangeable cations). The parent serpentinite contrasts with the soil clays in having lower SiO2 (43.3, 38.1, 40.0, and 39.8%) and Fe2O3 (6.6, 3.6, 8.9, and 3.1%, after magnetite removal from the parent rock samples), higher MgO (33.7, 41.0, 42.2, and 40.3%), and lower Al2O3 (0.4, 2.4, 1.5 and 0.7%). Leaching of serpentinite removed much of the Mg; concurrently Si, Fe, and Al were enriched in the pedogenic montmorillonite which formed.
Effect of Moisture Regimes and Harvests on Efficiency of Water Use by Ten Forage Crops
Authors: Powell R. D. , Kardos L. T. 
Published: July 2010

AbstractThe total amounts and rates of depletion of soil water required to produce dry matter by 10 crops were studied. Two experiments with forages were conducted, one being managed to simulate pasture and the other being managed for hay. Three levels of soil moisture management were used in each experiment: control (M0), irrigation when the available soil water at the 10 cm depth was 85% depleted (M1), and irrigation when available soil water at the 10 cm depth was 30% depleted (M2).On the basis of total harvest for all the species, most efficient use of water occurred at the M0 irrigation level. Also, most efficient use of water occurred prior to the first harvest and least efficient use usually occurred during the period after the first harvest but prior to the second harvest. Ladino clover and ladino‐orchardgrass (Trifolium repens‐Dactylis glomerata) harvested to simulate pasture were less efficient in using water than the other forages which were managed for hay. Alfalfa swards (Medicago sativa) managed for hay were more efficient than the other swards and the legume‐grass combinations differed only slightly from legumes alone.Measured values for rates of moisture depletion per day of all unirrigated forages were generally smaller than values computed by using the Blaney‐Criddle formula. The measured values of the irrigated forages approached the Blaney‐Criddle values more closely.
Effect of Initial Clod Size on Characteristics of Splash and Wash Erosion
Authors: Moldenhauer W. C. , Koswara Jajah 
Published: July 2010

AbstractWash erosion increased as initial clod size increased from 0.5–2 mm to 8–30 mm on a Marshall silty clay loam except in the case of clods from continuous bromegrass (Bromus inermis). Wash losses increased as size increased despite a drop in runoff from the 8–30‐mm clods. Final splash loss rates were higher from the 8–30‐mm than from the smaller size clods from continuous corn (Zea mays). Splashed material was larger than washed material and both were larger than material forming the seal.
A Welding Technique for Peltier Thermocouple Psychrometers
Authors: Campbell G. S. , Trull J. W. , Gardner W. H. 
Published: July 2010

AbstractA welding technique is described for making improved themocouples for use in Peltier‐type thermocouple psychrometers. Junctions welded using this technique are compared with a commercial welded thermocouple and soldered thermocouples. Thermocouples produced (i) are more stable than soldered junctions, (ii) have greater range and sensitivity than available commercial welded thermocouples, and (iii) are more uniform in response than soldered junctions.
The Effect of Osmotic Pressure Gradients on Water Movement in Unsaturated Soil
Authors: Letey J. , Kemper W. D. , Noonan L. 
Published: July 2010

AbstractWater movement, in response to osmotic pressure gradients, was measured in clay loam and sandy loam soils at soil water suctions from 0.08 to 15 bars. Movement in response to osmotic pressure gradients were compared to movement in response to hydraulic pressure gradients in the soil water suction range from 0.08 to 0.65 bars. At suction less than 0.5 bars, the amount of water moved by osmotic pressure gradients was generally less than 4% of the water moved by hydraulic gradients of equal magnitude.
Analyzing Steady‐State Flow in an Inclined Soil Slab with an Electric Analog
Authors: Whisler F. D. 
Published: July 2010

AbstractAn electrical resistance network analog was used to analyze the steady‐state flow in sloping land modeled as an inclined soil slab for both saturated and unsaturated conditions. At saturation the equipotentials and surface fluxes are symmetrical about the vertical midplane of the slab and agree with an analytic solution. For “rainfall” rates lower than that necessary to saturate the slab, this symmetry is lost. For unsaturated flow a step function representation of the pressure head‐conductivity relationship gives comparable results to a more complicated function. As the angle of slope is increased, even though part of the slab may be unsaturated, the internal flow rate increases, especially at the lower outflow end of the slab. Although the results are presented for homogenous‐isotropic soils, they can be used for anisotropic soils by using a transformation process.
EDTA‐Ammonium Carbonate Soil Test for Zinc
Authors: Trierweiler J. F. , Lindsay W. L. 
Published: July 2010

AbstractA soil test was developed for the diagnosis of Zn‐deficient soils. The test consists of shaking 10 g soil with 20 ml of extractant (pH 8.6) containing 0.01M EDTA (ethylenediaminetetraacetic acid) and 1M (NH4)2CO3. After 30‐min shaking period the suspension is filtered, and Zn is determined directly in the filtrate by means of atomic absorption spectrophotometry. The new soil test was evaluated on 42 Colorado neutral and high lime soils whose response to Zn was determined in the greenhouse with corn (Zea mays) as the test crop. A critical level of 1.4 ppm of extractable Zn separated the Zn‐deficient from the nondeficient soils. The new Zn soil test compares favorably with the dithizone method and is an improvement over the 0.1N HCl method. Unlike strong‐acid extractants, the new procedure suppresses the dissolution of carbonates and oxides, and thereby avoids extraction of occluded Zn.
Equilibrium Relationships of Zn2+, Fe3+, Ca2+, and H+ with EDTA and DTPA in Soils
Authors: Lindsay W. L. , Norvell W. A. 
Published: July 2010

AbstractA general approach is developed by which the equilibria between chelating agents and metal ions in soils can be predicted from formation constants. Mole‐fraction diagrams are derived for EDTA (ethylenediaminetetraacetic acid) and DTPA (diethylenetriaminepentaacetic acid) in soils when the competing cations are either Fe3+, Ca2+, and H+, or Zn2+, Fe3+, Ca2+, and H+. These diagrams give the specific metal‐ligand complexes that form in soils and show how the concentration of each complex changes with pH. Evidence is presented to support the hypothesis that Zn reacts with amorphous SiO2 in soils to form ZnSiO3. The concentration of Zn2+ in equilibrium with solid phase ZnSiO3 and amorphous SiO2 is approximately 10‐6M at pH 6, and decreases 100‐fold for each unit increase in pH. This concentration of Zn2+ is approximately 100,000 times lower than that in equilibrium with ZnO or ZnCO3.
Iron Uptake Dependent upon Genotype of Corn
Authors: Brown J. C. , Bell W. D. 
Published: July 2010

AbstractGenetic variants are responsible for a differential uptake of Fe by ys1 and Pa 54 corn (Zea mays). Different degrees of iron stress were developed in the plants by supplying them with increasing amounts of FeHEDTA. Iron stress enhanced Fe uptake more in Pa 54 than in ys1 corn. Enhanced Fe uptake was also associated with the ability of the plant to lower the pH of the nutrient solution, Pa 54 > ys1. Uptake of P was accentuated more in ys1 than Pa 54 by adding CaCO3, or by adding KCl instead of K2SO4 as a source of K to the nutrient solution. Phosphate reduced Fe uptake more in ys1 than in Pa 54, and increased the incidence of chlorosis in ys1.
Studies of Clay Skins in a Cecil (Typic Hapludult) Soil: II. Effect on Plant Growth and Nutrient Uptake
Authors: Khalifa E. M. , Buol S. W. 
Published: July 2010

AbstractA greenhouse experiment was conducted to study the effect clay skins may have on plant growth and N, P, and K uptake. Wheat (Triticum vulgare, var. Wakeland) plants were grown in uncoated aggregates and in large and small clay skin‐coated peds from the B22t horizon of a Cecil (Typic Hapludult) soil for 4 weeks. Data obtained for dry weight and total N, P, and K content of the plants were statistically analyzed. Plants grown in the uncoated aggregates had higher dry weights and more total N, P, and K than those grown in either the large or small coated peds. Most of the plant roots grew outside of the coated peds with a concentration of fine roots on the surface of the clay skin. It is hypothesized that the clay skins reduced plant growth and nutrient uptake (especially P and K) either by serving as a barrier for root growth and/or by slowing ion diffusion from the soil peds into the inter‐ped soil solution.
Clay Mineralogy of Soils Formed on Mazama Pumice
Authors: Chichester F. W. , Youngberg C. T. , Harward M. E. 
Published: July 2010

AbstractAmorphous components predominated in the clay size fraction of samples taken across a climatic transect of soils from Mazama pumice in central Oregon. The amounts were greatest in the less intensely weathered horizons, i.e., in lower horizons and at drier sites of the transect. Crystalline minerals were present in relatively small percentages and were unexpectedly complex. The phyllosilicates included beidellite, montmorillonite, vermiculite, a micaceous component, chloritic intergrades, and chlorite. Non‐phyllosilicate minerals of the suite were gibbsite, plagioclase feldspars, and quartz. The amount and distribution of the individual clay size minerals varied within and between profiles.Results of clay mineral identification were evaluated with respect to environmental data available for the transect sites. The factors primarily controlling the processes responsible for 2:1 clay mineral genesis were hypothesized to be the vesicular structure and chemical composition of the pumice material. Other factors such as climate and vegetation were believed to govern local weathering intensity.
The Role of Vertic Subgroups in the Comprehensive Soil Classification System
Authors: DeMent James A. , Bartelli Lindo J. 
Published: July 2010

AbstractThe application of soil surveys to nonfarm as well as to farm uses is reflected in recent modifications of the Comprehensive Soil Classification System. A case in point is the creation of vertic subgroups. Soils of vertic subgroups fail Vertisols primarily because they lack gilgai relief, intersecting slickensides, and parallelepiped structural aggregates. However, in having cracking properties peculiar to Vertisols, they are inappropriate to typic subgroups of other soil orders. Data from selected soils indicate that the cracking properties are related primarily to mineralogy and clay content. Soils dominated by montmorillonitic clay and having a clay content exceeding 40% are most common to the vertic subgroups. In addition, these soils most commonly have a Unified Soil Classification of CH or MH. They have unstable behavior with regard to engineering structures and are referred to by engineers as having a high content of “fat” clays. The Comprehensive Soil Classification System allows discussion of this unique group of soils at the subgroup level.
Relation of Soil Properties to its Erodibility
Authors: Wischmeier W. H. , Mannering J. V. 
Published: July 2010

AbstractA soil's inherent erodibility, which is a major factor in erosion prediction and land‐use planning, is a complex property dependent both on its infiltration capacity and on its capacity to resist detachment and transport by rainfall and runoff. The relations of these capacities to soil physical and chemical properties were investigated in a 5‐year field, laboratory, and statistical study including 55 selected Corn Belt soils. Properties that contributed significantly to soil‐loss variance included percentages of sand, silt, clay, and organic matter; pH, structure and bulk density of plow layer and subsoil; steepness and concavity or convexity of slope; pore space filled by air; residual effects of sod crops; aggregation; parent material; and various interactions of these variables. An empirical equation was derived for calculating the universal soil‐loss equation's erodibility factor K for specific soils. Tests of the equation against soils of the older erosion‐research stations, for which the erodibility factor is known, substantiated its general applicability over a broad range of medium‐textured soils.
Weight and Nitrogen, Phosphorus, Potassium, and Calcium Content of Forest Floor Humus of Lodgepole Pine Stands in Colorado
Authors: Moir W. H. , Grier H. 
Published: July 2010

AbstractThe pine‐derived organic matter of the forest floor was sampled by horizon from eight Pinus contorta stands of contrasting densities, site indices, average dbh, and stand height. Tabular data are given for loss‐on‐ignition, mineral and ash content, and N, P, K, and Ca content of these horizons. Total quantities of forest floor humus ranged from 2.54 to 4.21 kg/m2 irrespective of stand density. Expressed as g/m2 the N content of the forest floor humus ranged from 31–54, P from 2–5, K from 7–17, and Ca from 10–25. The proportion of N increased with progressive decomposition of organic material. The most mobile nutrients, K and P, were generally most concentrated in the lowest of the four forest floor humus horizons whereas Ca concentrations differed little among each of the horizons.
Hexadecanol in Soil—Its Locational Stability and Influence on Modulus of Rupture
Authors: Myhrman Matts A. , Evans D. D. 
Published: July 2010

AbstractModulus of rupture was reduced 65% for a sandy loam soil and 57% for a silt loam soil by addition of 0.4% (by weight) dry powdered hexadecanol. Emulsified hexadecanol, powdered commercial tallow alcohol, and smaller dosages had less effect.Less than 2% of the 14C‐tagged hexadecanol placed in a 1‐cm thick layer of sandy soil moved under either saturated or unsaturated flow conditions. Movement probably took place in the form of small buoyant particles.