bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Stones on the Hydraulic Conductivity of Relatively Dry Desert Soils
Authors: Mehuys G. R. , Stolzy L. H. , Letey J. , Weeks L. V. 
Published: July 2010

AbstractThe objective of this study was to determine whether moisture transmission properties of stony soils could be evaluated using samples of the same soil in which the stony fraction (> 2 mm) had been excluded. Experiments were conducted in the laboratory on soil columns with and without stones. Unsaturated hydraulic conductivity (K) was measured with a transient outflow method over the matric potential range of −0.05 to −50 bars using tensiometers and soil psychrometers. The soils studied were Rock Valley gravelly loamy sand (Mojave Desert, Nevada) and Tubac and Rillito gravelly sandy loams (Sonoran Desert, Arizona). On a weight basis, these soils contain up to 40% stones > 2 mm in diameter.If expressed as a function of matric potential, hydraulic conductivity values were similar, with or without stones. Soil water potential as measured by tensiometers or by thermocouple psychrometers is not affected by stones because these instruments respond to moisture changes in the soil portion only. When K was expressed as a function of volumetric water content, the apparent conductivities were higher for a given water content when stones were present. A simple correction of water contents of stone‐free samples, based on the stone volume of each soil, adequately accounted for differenecs observed when water contents were computed on a total volume basis.
Sulfur Fractions and Carbon‐Nitrogen‐Phosphorus‐Sulfur Relationships in Some Brazilian and Iowa Soils
Authors: Neptune A. M. L. , Tabatabai M. A. , Hanway J. J. 
Published: July 2010

AbstractCurrent knowledge concerning the percentage distribution of the various S fractions in soils is mainly derived from studies of S in surface soils of temperate regions. This study was conducted to determine the S fractions and C‐N‐P‐S relationships in some subtropical soils from Brazil and to compare the values in these soils with those in soils of a temperate region from Iowa.Analyses for S fractions in some Brazilian and Iowa surface soils indicated that, unlike Iowa soils, Brazilian soils contain adsorbed inorganic sulfate S. Expressed as percentage of total S in soils, the Brazilian soils studied contained from 5 to 23% inorganic sulfate S, from 20 to 65% ester sulfate S, from 5 to 12% C‐bonded S, and from 24 to 59% unidentified organic S. The corresponding percentages in the Iowa soils were: from 2 to 8% inorganic sulfate S, from 43 to 60% ester sulfate S, from 7 to 18% C‐bonded S, and from 31 to 39% unidentified organic S. No inorganic nonsulfate S could be detected in any of the Brazilian and Iowa soils analyzed.Tests showed that the Brazilian soils studied have capacities for adsorption of sulfate S. There were considerable variations in C, N, P, and S relationships among the Brazilian soils as compared with those among Iowa soils.
Lycopodium Fairy Rings: Effect on Soil Respiration and Enzymatic Activities
Authors: Spalding Brian , Duxbury J. M. , Stone E. L. 
Published: July 2010

AbstractLycopodium species (L. tristachyum, L. clavatum, and L. complanatum) sometimes occur as fairy rings—dense annuli of plants, 1 to 1.5 m wide, that grow radially outward at a rate of 20 to 50 cm/year and die within. The impact of these fairy rings on soil organic matter was investigated through studies of soil respiration and selected enzymatic activities. Respiration was enhanced in the soil under lycopodium rings compared with soil either outside or inside the rings. The activities of phosphatase, protease, dehydrogenase, catalase, polyphenol oxidase, amylase, and dextrinase were found to be independent of soil location. However, significant increases in cellulase, invertase, polygalacturonase, and peroxidase activities were observed in the soil under lycopodium rings. A model based on the infection of the lycopodium plant by its endophytic fungus and subsequent peroxidative degradation of soil organic matter is presented to explain both the increases in enzymatic activities and nutrient availability under lycopodium fairy rings.
Landform‐Soil‐Vegetation‐Water Chemistry Relationships, Wrigley Area, N.W.T.: I. Morphology, Classification, and Site Description
Authors: Walmsley M. E. , Lavkulich L. M. 
Published: July 2010

AbstractFive landforms occurring in the intermittent permafrost region of the Mackenzie Valley are described. The five landforms, consisting of distinct soil and vegetative characteristics occur on a transect from the 1170 m ASL (above sea level) position at the summit of Cap Mountain, Wrigley area, N.W.T., to approximately 500 m ASL at the base of the slope. Two soils meet the requirement of a histic epipedon. An area of stone stripe and stone ring formation was encountered at approximately 1000 m ASL and an extensive area of lichen‐covered polygonal bogs occurred at approximately 500 m ASL. The soils are described in relation to environmental factors and the processes of cryoturbation causing intermittent horizons are discussed.
Yields and Water‐Use Efficiencies of Dryland Winter Wheat and Grain Sorghum Production Systems in the Southern High Plains
Authors: Jones Ordie R. 
Published: July 2010

AbstractGrain yields and water‐use efficiencies were compared for conservation bench terraces, bench terraces, and common systems of dryland production of winter wheat (Triticum aestivum L.) and grain sorghum (Sorghum bicolor [L.] Moench). Grain production and water‐use efficiency were highest on a bench terrace cropped in continuous grain sorghum. Conservation bench terraces and continuous grain sorghum grown on sloping land also had higher water‐use efficiences and grain production than the common dryland systems of wheat‐sorghum‐fallow on graded terraces and continuous wheat or wheat‐fallow on sloping land. The management factors greatly influencing water‐use efficiencies were crop selection and land leveling to conserve potential runoff.
The Distribution of Creosotebush in West Texas and Eastern New Mexico as Affected by Selected Soil Properties
Authors: Hallmark C. T. , Allen B. L. 
Published: July 2010

AbstractMorphological, physical, chemical, and mineralogical studies were made on 32 pedons from west Texas and southeastern New Mexico to evaluate edaphic factors related to creosotebush [Larrea tridentata (D.C.)] distribution.Creosotebush grows on soils with a wide range of properties. The soils studied were well drained and generally moderately developed, as indicated by horizonation and carbonate redistribution. The data indicate that gravel content and depth to free CaCO3 are the most important soil factors affecting distribution of the shrub in the study area. Soils low in gravel and noncalcareous at the surface tend to be devoid of the shrub. Soils that support creosotebush are generally calcareous throughout the profile and many have significant amounts of gravel. The complex interactions among other edaphic factors such as texture, available water, salinity in deeper horizons, and gypsum content greatly complicate the resolution of properties influencing distribution.
Nitrate Measurements Using a Specific Ion Electrode in Presence of Nitrite
Authors: Francis C. W. , Malone C. D. 
Published: July 2010

AbstractThe presence of the nitrite anion (NO2‐) may lead to a significant error in measuring NO3‐N concentrations with a specific ion electrode. Interference by nitrite was found to be eliminated by complexing the nitrite with sulfanilamide in 0.01 N H2SO4. In this manner, nitrate levels can be read directly in concentrations ranging from 10 to 5000 ppm NO3‐N. The method is particularly useful in denitrification studies where HCO3‐ and CO3‐ anions as well as NO2‐ preclude direct NO3‐N measurements.
A Hydraulically Driven Soil Auger for Sampling Fine‐Textured and Wet Soils
Authors: Byrnes Bernard H. 
Published: July 2010

AbstractA core‐type bucket auger was modified to fit the drive bar of a hydraulic soil probe with a rotor head. This auger satisfactorily samples claypan, fine‐textured and moderately fine‐textured soils in a wet condition. The auger system can readily be used alternately with tube core samplers.
A Laboratory Rainfall Simulator for Infiltration and Soil Detachment Studies
Authors: Römkens M. J. M. , Glenn L. F. , Nelson D. W. , Roth C. B. 
Published: July 2010

AbstractA laboratory rainfall simulator with high intensity precision and nearly uniform rain distribution was developed for studying rain infiltration into soils and soil detachability by rainfall. The rainfall simulator consists of an assembly of closely packed hypodermic syringes with plungers driven by a common plate. Rainfall intensity is determined by controlling the plunger speed at variable motor speeds. Rain is distributed uniformly by superpositioning three independent motions—rotation, and perpendicular and linear motions in the horizontal plane. Rainfall intensities were generally within 2.5% of predicted values. The average coefficient of variation of rain distribution for various rainfall intensities over a 100‐cm2 area was reduced from 31.9% with no motion to 8.5% with rotation and linear motions.
Precipitation of Calcium and Strontium Sulfates around Plant Roots and its Evaluation
Authors: Malzer G. L. , Barber S. A. 
Published: July 2010

AbstractThe flux of Ca2+, Sr2+, and SO42‐ to corn (Zea mays L.) roots was investigated to determine if accumulation at the root caused precipitates to form and if so to determine the influence of precipitate formation on Ca and Sr uptake. Autoradiographic techniques using 45Ca and 35S showed both Ca2+ and SO42‐ accumulated at root surfaces when supply by mass‐flow exceeded uptake. Petrographic studies of the roots confirmed the formation of CaSO4 precipitates.The influence of the root precipitate on the relative Ca and Sr uptake was studied by comparing uptake by plants grown where precipitates occurred with those grown without precipitate formation. The corn plants were grown in solution culture. In order to have CaSO4 precipitation without SrSO4 precipitation a Ca/Sr molar ratio of 3670 was used. When SrSO4 precipitation without CaSO4 precipitation was desired the molar ratio was 0.45. The Ca and Sr in solution were labeled with 45Ca and 85Sr either from 9 days to harvest or for only 7 hours before harvest. Harvests were made after 13, 17, and 24 days.Plant age at sampling did not affect the 45Ca/85Sr ratio absorbed, however the length of the labeling period did. When labeled for 7‐hours, and CaSO4 precipitate was present 45Ca uptake was reduced 16 to 20% relative to 85Sr uptake as compared to uptake where no precipitate was present. When labeled from day 9, no differences occurred. When SrSO4 precipitated, 85Sr translocation was reduced 10 to 20% compared to 45Ca with the long labeling treatment.With a Ca/Sr ratio of 3670, the roots selectively accumulated Sr, however with a Ca/Sr ratio of 0.45, the roots selectively accumulated Ca. The Ca/Sr ratio present in the root was not correlated with the Ca/Sr ratio translocated to the shoot.
Frequency Distribution of Tract Productivity Indexes and Examples of Their Utilization in Rural Land Assessment
Authors: Mausel P. W. , Runge E. C. A. , Carmer S. G. 
Published: July 2010

AbstractThe soil conservation needs inventory 2% sample of soil data for Illinois was combined with productivity indexes to obtain state, county, and subcounty soil productivity characteristics that were used to evaluate variations in rural land quality. State soil productivity distributions were developed to provide a general framework of soil quality. Frequency diagrams (histograms) of county soil productivity indexes were constructed. Ratios comparing soil productivity histograms for the state and each county were developed and analyzed. Productivity characteristics of soil associations were provided for each county by a table that gives the percentage of the county in each soil association, the percentage of each soil association in each of seven productivity index categories used in the histogram format, and compares ratios between state and county soil association productivity indexes within the seven productivity index categories. The productivity index data using formats developed can be applied to evaluate the relative quality of soil for agricultural use between counties and between soil associations within counties. These data should aid county and state officials in evaluating rural land assessments.
Response of Three Semidwarf Mexican Wheats to Different Aeration Conditions in the Rooting Medium at a Constant Salinity Level
Authors: Aceves‐N. Everardo , Stolzy L. H. , Mehuys G. R. 
Published: July 2010

AbstractThe response of three newly developed Mexican wheat (Triticum aestivum L.) varieties, Nuri 70, Inia 66, and Siete Cerros 66, to low oxygen at constant salinity of −4 bars in the rooting medium was tested in a water culture experiment under growth chamber conditions. Oxygen concentrations in solution were maintained at 1.5, 5.2, and 7.6 ppm by bubbling gas mixtures containing 0, 12, and 21% oxygen, respectively.All varieties were affected by low oxygen at high salinity, but Inia 66 had the greatest adaptability to low oxygen concentrations in the root zone. Oxygen concentrations of 0% in the aerating gas decreased plant dry‐matter production by 50%. Plant length was not affected, but the ability to produce tillers was inhibited. This same oxygen concentration reduced transpiration by 54, 66, and 65% for Inia 66, Siete Cerros 66, and Nuri 70. Root porosities increased with each decrease in oxygen content, with Inia 66 showing the largest increase. In general, for other measured plant characteristics, no significant differences were noted between plants grown at 12% oxygen and those at 21%.
Irrigation Method as a Determinant of Large Pore Persistence and Crust Strength of Cultivated Soils
Authors: Kemper W. D. , Olsen John S. , Hodgdon Alan 
Published: July 2010

AbstractAir‐dried soils were wetted by flooding, immersion, slow immersion and capillary action; these actions resulted in successively slower rates of wetting. In general, slower rates of wetting left larger portions of the soil volume in large size pores. Slow capillary wetting of a weakly structured soil allowed retention of more large size pore space than was observed in a well structured soil that was wet rapidly.Modulus of rupture was determined on dried soils which had previously been wet by rapid immersion, capillary action, and capillary action followed by immersion. Breaking strength was much greater when those soils had been wet by rapid immersion than when wet slowly by capillary action. Immersion following capillary wetting resulted in soils with intermediate breaking strengths. A preliminary study on corn (Zea mays L.) seedling emergence showed that the range of soil strengths resulting from these irrigation methods on a weakly structured soil was sufficient to give < 50% emergence (flooding) up to essentially 100% (capillary wetting).
Utilization of Soil and Fertilizer Phosphorus Compounds by Slash Pine Seedlings in Relation to Their Solubility in Soil Test Extractants
Authors: Ballard R. , Pritchett W. L. 
Published: July 2010

AbstractEight P compounds, monocalcium and dicalcium phosphates, fluorapatite, colloidal aluminum and ferric phosphates, potassium taranakite, wavellite, and strengite were evaluated as sources of P for slash pine (Pinus elliottii var. elliottii Engelm.) seedlings grown on two acids soils in the greenhouse.Potassium taranakite and both colloidal phosphates were as effective P sources as monocalcium and dicalcium phosphate in stimulating tree growth. Fluorapatite was an effective source on a soil of pH 4.3 but was ineffective on a soil of pH 5.3. Wavellite and strengite were ineffective P sources on both soils. The uptake of P by seedlings corresponded closely to the amount of H2O‐extractable P present following 2 months of incubation of the P compounds in the soils.
Percolation Losses of Phosphorus, Calcium, and Potassium from Some Minnesota Forest Soils
Authors: Severson R. C. , Grigal D. F. , Arneman H. F. 
Published: July 2010

AbstractStudies were conducted on two soil types (Omega loamy sand and Cloquet sandy loam) representative of a large area of forested soils in the northcentral region of the United States. Three undisturbed soil columns were extracted from each soil under two vegetation types, hardwoods and conifers. The columns were leached both before and after laboratory‐simulated litterfall and following burning of the litter. Additional columns were extracted from an Omega‐conifer site which had undergone a prescribed burn in fall, and were used as a comparison with those burned in the laboratory. There were virtually no differences between ion concentrations in solution at the base of the columns following either laboratory burning or prescribed burning in the field. Severe leaching of freshly fallen litter or of burned litter resulted in similar losses of materials in solution. In general, all laboratory treatments had similar effects on ionic losses and in no case were losses large. The estimated annual losses from the soil were of the same magnitude as the annual inputs of ions to the soil system via precipitation. The small losses from the soil found in this study lead to the implication that major losses of materials following severe environmental disturbance are associated with surface runoff. If water percolates through soil material before entering streams, even after severe disturbance, small losses generally will occur.
Versatile Multirange Analytical Manifold for Automated Analysis of Nitrate‐Nitrogen
Authors: Jackson W. A. , Frost C. E. , Hildreth D. M. 
Published: July 2010

AbstractThis note describes a technique for extending up to 100 ppm the limits of determining nitrate‐nitrogen in solution using a Technicon Autoanalyzer system.3 The same modified analytical manifold can be used to determine three concentration ranges of nitrate nitrogen 0–1, 0–10, and 0–100 ppm. To change concentration range, change the sample entry point in the manifold and standardize the instrument within the proper range.
Two‐dimensional Transport of Solutes During Nonsteady Infiltration from a Trickle Source
Authors: Bresler Eshel 
Published: July 2010

AbstractA simulation model for analyzing multidimensional simultaneous transfer of a noninteracting solute and water, applicable to infiltration from a trickle source, is developed. The equations describing transient two‐dimensional transport of a solute by diffusion and convection in unsaturated porous media are solved numerically by an approach that eliminates the effect of numerical dispersion. The noniterative alternating‐direction‐implicit finite difference procedure is used. Two mathematical models are considered: (i) a plane flow model involving the Cartesian coordinates x and z, and (ii) an axisymmetric flow model described by the cylindrical coordinates r and z. An example of transport in a homogeneous, isotropic and stable sand and loam soil systems is given. Results are shown for typical cases of trickle infiltration to demonstrate the effects of trickle discharge and soil‐hydraulic properties on the pattern of salt distribution in the wetted soil zone. The numerical results show that the approach presented may be useful in analyzing two‐dimensional solute transport processes in soils.
Interactions Between Organic Compounds, Minerals, and Ions in Volcanic‐ash‐derived Soils: II. Effects of Organic Compounds on the Adsorption of Phosphate
Authors: Appelt H. , Coleman N. T. , Pratt P. F. 
Published: July 2010

AbstractThe effects of organic compounds on phosphate adsorption by volcanic‐ash‐derived soils were studied using benzoate, p‐OH benzoate, salicylate, and phthalate, and by humic and fulvic acids extracted from a surface soil sample of a Typic Dystrandept. The adsorption of simple organic anions that are specifically adsorbed block to some extent the adsorption sites for nonspecifically adsorbed anions such as chloride and/or nitrate. But, organic anions did not compete for or block adsorption sites for phosphate anions, because of the much higher affinity of phosphates for the adsorption sites in these volcanic‐ash‐derived soils.Because of the characteristics of humic acid and noncrystalline alumino‐silicates (“allophane”) colloidal particles, humic acid‐allophane interactions are probably mainly between external surfaces because of steric hindrance. Hence, if there are blocking effects of humic acid on phosphate adsorption, they would affect only part (⅓) of the reactive surfaces of the “allophane.” The complexes formed between humic acid and soluble Al ions extracted from “allophane” are active in phosphate adsorption, and this reactivity depends on the OH/Al ratio of the complexed Alx(OH)y(3x‐y) species.
Interactions of Micronutrients in Barley Grown on Zinc‐polluted Soils
Authors: Singh B. R. , Steenberg K. 
Published: July 2010

AbstractBarley (Hordeum vulgare var. Varde) grown in zinc‐polluted soils with variable levels of Zn, Mn, and Fe showed no marked differences in the yield attributable to these variables in both soils investigated. However, in direct contrast to results reported by other investigators, concentrations of 65Zn and total zinc were found to increase with increased levels of added Mn and/or Fe with few exceptions. Similarly, concentrations of 54Mn and total Mn also increased with increased levels of Zn and/or Fe. The effects of Zn and Mn on the concentrations of 59Fe and total Fe were inconsistent. The concentration of Mo was found to decrease with increased levels of Zn, Mn, and Fe and the decrease was more pronounced in one soil than in the other. Although concentration of Cu also showed a slight tendency to decrease with Zn, Mn, and Fe application, the results were inconsistent in both the soils. In general, labelled nutrient elements were more mobile in barley plants than corresponding soil‐derived nutrients as evident in the relative percentage distributions between roots and tops.The percentage distribution of Zn, Mn, Fe, Mo, and Cu between roots and tops was apparently not affected by the presence of their interacting ions. The effects of Zn on Mn distribution and that of Mn on Mo distribution, were, however, noticeable.It is concluded that though Zn, Fe, and Mn ions in barley appear to have limited influence on translocation within the plant, these ions exert strong synergistic effects at the site of transport. There appeared to be pronounced antagonism between Mo‐Zn, Mo‐Fe, and Mo‐Mn in the metabolism of barley.