bluuebunny/crossref_metadata_2025_split huggingface dataset:
Desorption of Ammonia from Soil During Displacement
Authors: Rolston D. E. , Nielsen D. R. , Biggar J. W. 
Published: July 2010

AbstractThe displacement and desorption of ammonia from ovendry and moist soil were evaluated using a miscible displacement technique. An ammonia saturated soil atmosphere was displaced from soil columns with nitrogen at flow velocities of approximately 2.5 cm min‐1. Samples of gas from within and at the end of soil columns, analyzed by titration methods, were used to obtain elution curves. Two different soils were studied at several water contents. Experimental, steady‐state sorption isotherms (sorption as a function of gaseous concentration) were determined for oven‐dry soil. An assumption that gas is perfectly mixed within the soil column during desorption was used to derive a model describing displacement with ammonia desorbing according to a nonlinear isotherm. This perfect mixing model in conjunction with calculated sorption isotherms adequately predicted the displacement of ammonia from oven‐dry and moist soils during desorption.
Reduction of Inorganic Compounds by Soil Microorganisms
Authors: Bautista Elena M. , Alexander M. 
Published: July 2010

AbstractIsolates of Pichia guillermondii and Micrococcus sp. obtained from soil converted selenate, selenite, tellurate, and tellurite to the elemental forms, vanadate to a vanadyl compound, molybdate and molybdenum trioxide to a molybdenum blue compound, arsenate to arsenite, MnO2 to the manganous ion, nitrate to nitrite, and chlorate to a less oxidized form. Resting cell suspensions and cell‐free extracts of the two organisms also effected the reduction of most of the inorganic compounds and anions. The capacity to reduce selenate, selenite, tellurate, tellurite, vanadate, molybdate, molybdenum trioxide, arsenate, chlorate, and MnO2 was found to be common to soil microrganisms. It is suggested that these microbial reactions may be important in changing the solubility, availability, or toxicity of certain elements in soil.
Iron and Silica in Water, Acid Ammonium Oxalate, and Dithionite Extracts of Some North Carolina Coastal Plain Soils
Authors: Gamble E. E. , Daniels R. B. 
Published: July 2010

AbstractSequential water, oxalate, and dithionite extracts of a Paleaquult and two Paleudults were analyzed for iron and silica. The ratio of oxalate iron to dithionite iron (active iron ratio) suggests that there is little accumulation of amorphous iron compounds in the Paleudults. It also suggests goethite may be the main iron oxide mineral. The active iron ration in the gray matrix of the Paleaquult shows that the common fine yellowish or brownish flecks and mottles contain a high proportion of amorphous iron compounds that have not aged sufficiently to become crystalline. Water table studies suggest these may be associated with the seasonal variations of water table depth. The silica extracted, especially by the dithionite, probably comes directly from the quartz sand and kaolinitic clay rather than from dissolution of iron compounds.
Effect of Probe Condition on Ultrasonic Dispersion of Soils by Probe‐Type Ultrasonic Vibrators
Authors: Genrich D. A. , Bremner J. M. 
Published: July 2010

AbstractPitting of the probe tip occurs when probe‐type ultrasonic vibrators are operated for approximately 10 hours. This reduces the output of ultrasonic energy from the probe and increases the vibration time required for dispersion of soils by ultrasonic vibration of soil‐water suspensions. The effect of pitting can be eliminated by polishing the probe tip with fine emery paper after every 30 min of probe operation. A simple method of checking the performance of probe‐type vibrators is described.
Spectrophotometric Determination of Soil Water Content
Authors: Bowers S. A. , Smith S. J. 
Published: July 2010

AbstractThe absorbance at 1.94µ by a soil‐methanol extract was used for measuring the soil water contents of three different textured soils. A linear relation between absorbance and soil water content was adequate for moisture determinations ranging from air dry to the moisture equivalent. For Quincy loamy sand and Barnes loam soils, calibration based only on laboratory standards was sufficient. For Houston Black clay, calibration against oven‐dry samples was necessary. Determination time was approximately 1 hour.
A Limiting Flux Condition in Infiltration into Heterogeneous Porous Media
Authors: Watson K. K. , Perrens S. J. , Whisler F. D. 
Published: July 2010

AbstractInfiltration into a porous medium in which the hydraulic conductivity increases with depth is shown to approach at quite early times a limiting flux condition. This condition is defined by a pressure head profile in the saturated zone becoming tangential to the water entry value profile. Equations are presented enabling the values of the limiting flux (fl) and the elevation of the point of contact (zl) to be calculated in terms of the material properties and the boundary conditions. Below zl an unsaturated zone exists and wetting up in this zone continues under the condition of limiting flux. A method is presented whereby the pressure and water content profiles for this zone can be determined.
Nitrogen‐Fixing Activity in Upland and Flooded Rice Fields
Authors: Yoshida T. , Ancajas Rosabel R. 
Published: July 2010

AbstractThe acetylene reduction and 15N methods showed that under field conditions of rice (Oryza sativa L.) culture nitrogen fixation ranging from about 3 to 63 kg/ha occurred in soil, water, and the rice plant rhizosphere. The greatest fixation occurred in the rhizosphere and was more pronounced under flooded than under upland conditions. The nitrogen‐fixing activity in flooded soils increased after the panicle initiation stage of the rice plant. It was higher in the planted soil than in the unplanted soil.
Soil Enzymes in Relation to Old Field Succession: Amylase, Cellulase, Invertase, Dehydrogenase, and Urease
Authors: Pancholy Sunil K. , Rice Elroy L. 
Published: July 2010

AbstractAmylase, cellulase, invertase, dehydrogenase, and urease activities in soil were determined every other month for a year in two old‐field successional stages and a climax stand in each of three vegetation types; tall grass prairie, post oak‐blackjack oak forest and oak‐pine forest. The activities of amylase, cellulase, and invertase were highest generally in the first successional stage, intermediate in the second stage, and lowest in the climax stand. On the other hand, dehydrogenase and urease activities were generally lowest in the first successional stage, intermediate in the second stage, and highest in the climax. These trends were observed in all three vegetation types throughout the year. No correlation was found between soil enzymatic activity and amount of organic matter or soil pH. The type of vegetation and thus the type of organic matter added to the soil during succession seem to be the chief determiners of the activity gradients of the enzymes under study.
Influence of Steam Treatment and Fumigation of Soil on Growth and Elemental Composition of Avocado Seedlings
Authors: Martin J. P. , Farmer W. J. , Ervin J. O. 
Published: July 2010

AbstractSteam treatment or fumigation of Greenfield sandy loam and Fallbrook sandy loam with D‐D, chloropicrin, ethylene dibromide, propylene oxide, or carbon disulfide decreased P absorption by Mexicola avocado (Persea americana) seedlings subsequently grown in the soils. The P deficiency was corrected by applications of 135 to 540 ppm P to the soils. Fumigation with D‐D, chloropicrin, or ethylene dibromide caused halide injury on the older plant leaves. In general injury was more severe following D‐D or chloropicrin treatment than following ethylene dibromide fumigation. Tests with KCl and KBr, however, indicated that Br‐ was more toxic than Cl‐ to the seedlings. Phosphorus additions to the soil accentuated the halide injury and relative growth retardation related to halide excesses. Leaf Mn was increased up to 10 fold by steam treatment or fumigation with D‐D, chloropicrin, or carbon disulfide. Additions of P to the soil enhanced Mn absorption. Leaf Mn although attaining concentrations of > 1,000 ppm did not appear to be directly related to plant growth. The treatments exerted little effect on leaf Ca, Mg, K, Na, Cu, Zn, or Fe concentrations.
Ammonification and Nitrification of N as Influenced by Soil pH and Previous N Treatments
Authors: Dancer W. S. , Peterson L. A. , Chesters G. 
Published: July 2010

AbstractThe effect of soil pH on rates of ammonification and nitrification was studied. Soil samples which ranged in pH from 4.7 to 6.6 from an established lime and N fertility experiment were used. Soil pH values in the lime plots have been relatively constant for several years. Soil pH did not affect rates of ammonification appreciably; however it had a significant effect on nitrification rates. Length of the delay period (t′) was increased and rate of NO3‐ accumulation (Km) decreased with a decrease in soil pH. Previous field N treatments increased the length of t′ at low pH and decreased t′ and Km at high pH. Nitrification rates and production of NO3‐ were similar for soil pH values of 5.3, 6.0, 6.3, and 6.6 with a different pattern at pH 4.7.
Soil Changes Caused by Erosion Control Treatments on a Salt Desert Area
Authors: Wein Ross W. , West Neil E. 
Published: July 2010

AbstractSoil samples taken in the environs of gully plugs and contour furrows installed in shale‐derived saline‐sodic soils showed that the physical and chemical characteristics differed from the control profile. Physical measurements of moisture holding capacity, bulk density, and infiltration, varied because of fine clay deposition in the catchment basins of these structures and because of the mechanical disturbance of the shale during gully plug and furrow construction.Electrical conductivity and sodium measurements differed from the normal profile due to leaching since construction. The movement of salts was related to the rainfall received rather than to the season. These edaphic changes would have a profound effect on the establishment, development, and growth of introduced species seeded on the treatments.
Comparison of Zinc Sulfate and Zine EDTA as Zine Fertilizer Sources
Authors: Boawn Louis C. 
Published: July 2010

AbstractField experiments were performed to compare the agronomic effectiveness of a chelate Zn source (ZnEDTA) with that of an inorganic Zn source (ZnSO4 · H2O). Effectiveness was determined on the basis of Zn in bean plans (Phaseolus vulgaris L.) at the 4‐compound‐leaf stage and at early bloom, and Zn in corn plants (Zea mays L.) just before tasseling. Comparisons were made using three methods of Zn fertilizer application: (i) broadcast and plowed down, (ii) banded prior to planting, and (iii) broadcast and leached with sprinkler irrigation. The latter method was intended to approximate application of Zn by injection into sprinkler‐applied irrigation water.Where the Zn sources were broadcast and plowed down, 1 unit of Zn applied as the chelate was equivalent to approximately 2 to 2.5 units applied in sulfate form. The effectiveness ratio appeared to be slightly greater, at least 2.5, when Zn was banded prior to planting. Where the Zn sources were broadcast and leached in with sprinkler irrigation, increasing rates of ZnSO4 had no effect on the amount of Zn in bean plants. In contrast, ZnEDTA was a highly effective source of Zn when applied in this manner.
Effect of Endogone Mycorrhiza on Phosphorus Uptake by Soybeans from Inorganic Phosphates
Authors: Ross J. P. , Gilliam J. W. 
Published: July 2010

AbstractSeed yields of soybean (Glycine max L. Merr) mycorrhizal with Endogone were compared to yields from nonmycorrhizal plants in a P‐deficient soil fertilized with various phosphate sources. Mycorrhizal outyielded nonmycorrhizal plants by 79, 530, 0, and 56% when fertilized with Al, Fe, rock, or monocalcium phosphate, respectively. Yields from mycorrhizal plants fertilized with Fe phosphate were ⅙ and ⅕ those fertilized with monocalcium or Al phosphate, respectively.In a selective phosphate depletion experiment, mycorrhizal and nonmycorrhizal soybeans were grown in soil from Ap horizon of a Norfolk sandy loam with dilute acid extractable P contents of 70 to 162 ppm. Aluminum, Fe, Ca, and reductant soluble phosphates were determined in soil samples taken at planting and 10 and 23 weeks later. Soil planted to mycorrhizal soybean contained 5 and 8 µg of Al P/g of soil less than soil from nonmycorrhizal plots at the last two sampling dates, respectively. Mycorrhizal soybean plot soil contained 2.4 µg Fe P/g of soil less than nonmycorrhizal soil 23 weeks after planting. No differences were detected in Ca or reductant soluble phosphate fractions.The increased P absorption by mycorrhizal soybean plants grown under P stress is principally from those phosphate sources most available under nonmycorrhizal conditions.
The Effect of Ammonium and Urea Phosphates With and Without a Nitrification Inhibitor on Growth and Nutrient Uptake of Wheat
Authors: Spratt E. D. 
Published: July 2010

AbstractFive fertilizers, monoammonium orthophosphate (MAP), ammonium polyphosphate (APP), triammonium pyrophosphate (TAPP), urea orthophosphate (UOP), and urea polyphosphate (UPP) were compared in the field and growth chamber using wheat (Triticum aestivum L.) as the test crop. They were tested with and without the nitrification inhibitor 2‐chloro‐6‐(trichloromethyl)‐pyridine (N‐Serve).In both the field and growth chamber tests, the use of the nitrification inhibitor, to maintain greater levels of ammonium‐N in the soil, with the ammonium and urea phosphates increased the percent P and P‐uptake of vegetative wheat plants prior to heading significantly above the levels obtained without the nitrification inhibitor. However, the increased uptake of P during early stages of growth did not affect the yield of grain significantly.Ammonium polyphosphates (APP and TAPP) and urea phosphates (UOP and UPP) were more effective fertilizers than MAP in both the field and growth chamber. In the field, wheat receiving ammonium polyphosphates and urea phosphates sustained its dry matter production and P‐uptake after heading (adding 23% of their dry matter and 22% of their P‐uptake between heading and harvest) while wheat with MAP added little to its total dry matter or P‐uptake after heading.Using phosphate fertilizers increased P levels in wheat and depressed Ca, Mn, and Zn concentrations in the herbage. In the case of Zn, TAPP showed less depressive effect on concentration than MAP; the Zn levels were 13.2, 15.7, and 25.9 ppm for MAP, TAPP, and no P, respectively.
Local Soil‐Landscape Relationships in Western Iowa: I. Distributions of Selected Chemical and Physical Properties
Authors: Huddleston J. H. , Riecken F. F. 
Published: July 2010

AbstractA single, open‐system hillslope was studied in detail to determine the extent to which pedologic processes and geologic processes act both separately and jointly to produce modern characteristics of contiguous soils in the soil‐landscape system. Sixteen soil cores were taken at equal spacings between the hillslope summit and the water way center. Each core was described and subdivided into nineteen 10‐cm samples, which were then analyzed for percent carbonates, total phosphorus, free iron, and particle size distribution. The carbonate distribution demonstrates the geologic effects of landscape evoluation, which beveled calcareous, deoxidized loess, and left a thin leached sediment above the erosion surface. Both carbonate and free‐iron distributions indicate the effects of the processes of dissolution of carbonates and iron, local translocation, and reprecipitation in nodules. The distribution of geometric mean particle size shows the geological effects of loess stratification during deposition and the exposure of these strata during landscape evolution. Total phosphorus and clay distributions illustrate the effect of pedological redistribution. They also illustrate the effect of pedological redistribution. They also illustrate the interaction between the pedological process of vertical redistribution and the geological process of surface modification by landscape evolution.
The Relationship Between Rainfall Frequency and Amount to the Formation and Profile Distribution of Clay Particles
Authors: Goddard T. M. , Runge E. C. A. , Ray B. W. 
Published: July 2010

AbstractFor Typic Argiudolls in Illinois the amount of pedogenic clay particles formed, over that inherited from the calcareous Peoria loess, seems to be controlled by rainfall frequency. The amount of solution leaching through the soil, as inferred from the amount of rainfall, was not related to the amount of pedogenic clay particles formed. This finding may help explain why the clay minerals found in the argillic horizon of some soils are not in the clay mineral stability field predicted by dilute solution chemistry.The distribution of clay within the soil profile is related to the amount and distribution of rainfall (leachable water), depth of leaching, and natural drainage class.
Phosphate Sorption by Soils Evaluated by the Langmuir Adsorption Equation
Authors: Syers J. K. , Browman M. G. , Smillie G. W. , Corey R. B. 
Published: July 2010

AbstractThe sorption of added inorganic phosphate (P) by three soils which varied appreciably in their ability to sorb P was evaluated using the Langmuir adsorption equation. When the sorption data were plotted according to the conventional Langmuir equation, two linear relationships were obtained, indicating the presence of two populations of sites which have a widely differing affinity for P. Previous workers have obtained a single linear Langmuir relationship over the same equilibrium P concentration range (up to 14 µg/ml). The sites in part I (straight line corresponding to lower equilibrium P concentrations) had a very much higher (between 33 and 91 times) binding energy constant (K1), determined by regression analysis, than those in part II (straight line corresponding to higher equilibrium P concentrations). Between 40 and 52% of the total adsorption maxima was sorbed by sites in part I. A plot of the sorption data according to a rearranged form (Eadie‐Hofstee plot) of the Langmuir equation gave a curve which could not be resolved satisfactorily into two straight‐line components, suggesting the existence of three populations of sites. The rearranged form of the Langmuir equation was found to be preferable for evaluating P sorption at low equilibrium P concentrations. Predictions, based on the addition of high levels of added P, of the interrelationships between sorbed P and equilibrium P concentrations typical of the soil solution and soil‐water systems, such as runoff, may be in error because of the failure to consider the existence of sites with appreciably higher K1 values than those which sustain relatively high concentrations of inorganic P in solution.
Effect of Soluble and Exchangeable Aluminum on Pseudomonas stutzeri
Authors: Zwarun A. A. , Thomas G. W. 
Published: July 2010

AbstractThe test organism, Pseudomonas stutzeri, behaved as a typical cation exchanger having a CEC of 340 meq/100 g organism (oven dry wt). Increasing the acidity from pH 6.6 to 4.5 greatly reduced the number of surviving cells suspended for 3 hours in an acetate buffer. Although addition of 1 ppm soluble Al to the buffer produced no further reduction in survival, addition of 10 ppm soluble Al did significantly reduce the survival rate. Addition of 80 ppm soluble Al to the buffer proved to be lethal to the organism.Suspensions of Ca‐bentonite, Al‐bentonite, and Al‐bentonite in conjunction with 1 ppm soluble Al did not affect the organism's survival rate. However, Al‐bentonite in conjunction with 10 ppm soluble Al significantly reduced the organism's survival rate. Aluminum‐bentonite in conjunction with 100 ppm soluble Al was lethal to the organism.The toxic effects of Al on P. stutzeri were approximately exponential.
Spectral Reflectance of Selected Pennsylvania Soils
Authors: Mathews H. L. , Cunningham R. L. , Petersen G. W. 
Published: July 2010

AbstractSpectral reflectance curves of selected soil characterization samples and standard clay minerals were studied over the wavelength interval 0.5 to 2.6µm. Results reported include reflectance data from three Hagerstown profiles and the Ap horizons of a Berks, Penn, and Ellery profile. Hagerstown soils are developed from limestone while the Berks, Penn, and Ellery are developed from shale, sandstone, and glacial deposits, respectively. Spectral curves for standard clay mineral samples of nontronite, kaolinite, and illite are also included.Spectral reflectance data indicate that clay type and the amount of organic matter, free iron oxides and silt influence the intensity of energy reflected by soils in the 0.5 to 2.6µm range. High contents of organic matter and free iron oxides reduced reflectance intensity in the 0.5‐to‐1.2µm range while clay type influenced curve shape and intensity over the entire range studied. For the Hagerstown profiles silt is highly correlated with percent reflectance in the 0.8‐to‐2.5µm range.
The Nature of K‐Feldspars of Selected Soils in the Canadian Prairies
Authors: Somasiri S. , Huang P. M. 
Published: July 2010

AbstractThe nature of K‐feldspars of four soils developed from glacial till deposits and lacustrine sediments in Saskatchewan, Canada was studied. The K‐feldspars from the size fractions 20‐2,000µ were concentrated by heavy liquid separation at a specific gravity of 2.59. X‐ray diffraction analysis was used to identify orthoclase and microcline, to estimate the proportion of orthoclase to microcline, and to determine the obliquity of microcline. The K‐feldspars in the size fractions 50 to 2,000µ of certain soils were further studied by optical microscope and electron microprobe methods.The proportion of orthoclase to microcline increased with decrease in particle size. In the comparable size fractions of the soils developed from the glacial till deposits, the proportion of orthoclase to microcline increased from north to south in the region under study. The proportion of orthoclase to microcline was higher in the Orthic Black soil developed from the lacustrine sediments than in the Orthic Black soil developed from glacial till deposits. The data obtained show the bearings of soil parent material on the relative abundance of orthoclase to microcline. The obliquity values range from 0.81 to 0.89, indicating a high degree of exsolution. The presence of perthite, as revealed by X‐ray data, optical microscope, and electron microprobe studies, further elucidate the nature of exsolution.
Formation of Mica in Surface Horizons of Dryland Soils
Authors: Nettleton W. D. , Nelson R. E. , Flach K. W. 
Published: July 2010

AbstractA mineral with a 10Å X‐ray spacing is the dominant clay mineral in the surface horizon of many dryland soils in which vermiculite or vermiculite‐biotite is dominant in subjacent horizons. The mineral occurs in soils with aridic, torric, xeric, and ustic moisture regimes. To study its genesis we separated weathered mica flakes from soils developed in granitic‐textured rocks. The mineral has a refractive index of 1.64 to 1.65 and an exchange capacity of 24.7 to 44.0 meq/100 g. Its chemical composition shows that, except for its K content, it is as weathered as the vermiculite or vermiculite‐biotite of subjacent horizons. It has fixed NH4+ (5.4 – 8.0 meq/100 g) as well as K+. Together K+ and NH4+ amount to more than half of its total charge. Most of its charge comes from the tetrahedral sheet, and its tetrahedral charge is less than that of weathered mica flakes in B and C horizons. Since the weathered mica flakes in these soils contain relatively large amounts of K, small additions of K+ or NH4+ released by plant decay will collapse the minerals to 10Å. The process reduces the loss of K+ through leaching and may supply important amounts of N in soils that contain little organic matter.