bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Surface Catalyzed Hydrolysis of Parathion on Kaolinite
Authors: Saltzman Sarina , Yaron Bruno , Mingelgrin Uri 
Published: July 2010

AbstractThe decomposition of parathion on various monoionic kaolinites was investigated. The degradation was found to proceed via the hydrolysis of the phosphate ester to p‐nitrophenol and diethyl thiophosphate. The kaolinites were found to catalyze the hydrolysis. The nature of the exchangeable cation greatly affected the rate of hydrolysis. Ca‐kaolinite was the most active in inducing the degradation of parathion, the hydrolysis being twice as fast as in a water solution at pH 8.5 at the same temperature. The presence of a large excess of water decreased the catalytic effect of the kaolinite. The mechanism of the hydrolysis is via adsorption of the parathion upon the exchangeable cation or its hydration shell. The temperature dependence of the process is consistent with this proposed mechanism. The significant catalytic activity of kaolinites and its dependence on the exchangeable cation is important to the understanding of the degradation of parathion in soil and may be utilized in the formulation of parathion for various purposes.
Humods in Relation to Volcanic Ash In Southern Alaska
Authors: Rieger Samuel 
Published: July 2010

AbstractAnalyses of Spodosols in southern Alaska indicate that Humods—well‐drained Spodosols in which the free iron‐carbon ratio in at least part of the spodic horizon is less than 0.2—apparently form only in ashy materials, though not all Spodosols developed in volcanic ash are Humods. Spodosols formed in other materials may have similar morphological properties, but all have narrower ratios and are classified as Orthods. The distribution of the two groups of soils in this cool, humid area is apparently not dependent on differences in precipitation rates, temperatures, or vegetative cover. Wider Fe/C ratios in the ashy Spodosols result from lower concentrations of free Fe rather than from larger accumulations of illuvial C in the spodic horizon. A possible reason for the affinity between low‐iron Spodosols and ashy parent materials is a more ready availability of aluminum from volcanic ash as opposed to the more rapid release by weathering of iron in other materials.
Accretion and Dilution of Nutrients in Young Corn, as Affected by Yield Response to Nitrogen, Phosphorus, and Potassium
Authors: Terman G. L. , Allen S. E. 
Published: July 2010

AbstractHybrid corn (Zea mays L.) was grown in infertile soil fertilized with none and three nonzero rates of N, P, or K in separate treatment series; other nutrients were applied in each series at uniform levels. Near‐linear increases in uptake of N, P, or K with amount applied occurred during 25, 41, and 53 days' growth. Concentrations of N, P, or K increased with amount applied and decreased with continued growth in each series; uniformly applied P and K, N and K, or N and P were diluted with increase in dry matter resulting from continued growth and yield response to increasing amounts of the third nutrient. Yield‐concentration relationships in the N response series were similar for N, Ca, Mg, Mn, and Zn. Response to P or K resulted in dilution of all other nutrients. Concentrations of total cations increased with concentrations of N in each response series; the reverse was true with P and K. Thus, the results suggest that a positive relationship between dry matter yields and total cations (C), total inorganic anions (A), and C‐A depends on whether yield response is due to N or to other growth‐limiting factors.
Lime Induced Plant Growth Depression in an Alluvial Entisol from Costa Rica
Authors: Velez J. , Zantua M. I. , Blue W. G. 
Published: July 2010

AbstractPoor plant growth in field experiments following clearing of a forested virgin Entisol in eastern Costa Rica and the subsequent detrimental effect of lime on growth of warm‐season grasses were studied in greenhouse and laboratory experiments. Greenhouse experiments were carried out with pangolagrass (Digitaria decumbens Stent) by sterilizing a virgin surface soil, limed with 0, 4, and 8 meq/100 g of CaCO3, with heat and gamma radiation. Incubation experiments in the laboratory were conducted with a differentially limed surface soil that had been in pasture for 8 years and its subsoil. Every 2 weeks, for 10 weeks, samples from the incubating soils were extracted with water. Calcium, Mg, K, Na, NO3, SO4, P, and Cl were determined in the water extracts. Electrical conductivity in the soil was measured before and after water extractions. After 10 weeks of incubation, electrical conductivity was measured in saturated soil extracts. Soil organic matter was determined before and after incubation.The negative effect of lime persisted in the sterilized soils; however, water leaching of unlimed and limed virgin soils markedly improved pangolagrass growth. Laboratory studies showed considerable increases in water‐extractable Ca, NO3, and SO4 ions with increasing lime rates and incubation time in the pasture surface soil and its subsoil. Electrolytes reached a maximum at 2 weeks of incubation. Conductivity measurements higher than 4 mmhos/cm in saturated soil extracts after 10 weeks of incubation indicated harmful concentrations of electrolytes which were apparently derived from lime and biological decomposition of soil organic matter.
Water and Nitrogen Economy of Rainfed Rice as Affected by Soil Puddling
Authors: De Datta S. K. , Kerim M. S. A. A. A. 
Published: July 2010

AbstractIn a field experiment conducted to study the water and nitrogen economy of rainfed rice (Oryza sativa L. variety, ‘Tongil’) grown on montmorillonitic clay, much more water was lost from nonpuddled soil than from puddled soil. In rainfed treatments, the crop suffered from moisture stress for 2 weeks during panicle development. During this time soil moisture tension 10 cm deep was 70 centibars in nonpuddled soil compared with 25 centibars in puddled soil. Water‐use efficiency was calculated by dividing the grain yield values by the amount of water received from rain or applied through irrigation. Water‐use efficiency of rice in the irrigated controls, was 2.5 times higher in the puddled soil than in the nonpuddled soil.Ammonium and nitrate nitrogen in the soil and plant nitrogen were determined periodically. The large losses of water from nonpuddled soil caused greater nitrogen losses and less nitrogen uptake by rice at all stages of growth. As a result, grain yields of rice grown on nonpuddled soil were significantly lower than yields of rice grown on puddled soil, with or without nitrogen.
Response by Flooded Rice to Phosphate Rocks Varying in Citrate Solubility
Authors: Engelstad O. P. , Jugsujinda Aroon , De Datta S. K. 
Published: July 2010

AbstractStudies were conducted in the greenhouse and in the field to evaluate several phosphate rocks for flooded rice (Oryza sativa L.). A close relationship was found to exist between first‐crop yield response to applied P and citrate solubility in a series of phosphate rocks representing the theoretical range in this parameter. Greenhouse (TVA) and field data (Thailand) showed quite similar results in this respect.The same general pattern of effectiveness among sources persisted through the second crop as found for the first crop. The residual effectiveness of triple superphosphate (TSP) remained higher than that of the phosphate rocks; however, the relationship between initial citrate solubility of the phosphate rocks and relative effectiveness in the second crop was rather poor.A procedure is presented which enables one to make the choice of P source on the basis of both agronomic effectiveness and prices of P in TSP vs. phosphate rock.
Artificial Weathering of Oxidized Biotite: IV. The Inhibitory Effect of Potassium on Dissolution Rate
Authors: Gilkes R. J. , Young R. C. 
Published: July 2010

AbstractRates of dissolution of oxidized biotites in 0.1M 0.01M HCl are severely depressed in the presence of 1M KCl. The amounts of Al, Mg, Mn dissolved in the first extraction are similar to those found without KCl, however, subsequent extractions remove these elements at 10–20% of the corresponding HCl rates. This effect may be due to a decreased rate of vermiculite formation, thereby reducing the effective basal area exposed to attack. A decrease in dissolution rate with increasing ferric iron content was still apparent in the presence of 1M KCl.
Effect of Gypsum, Soil Disturbance and Tile Spacing on the Amelioration of Huey Silt Loam, a Natric Soil in Illinois
Authors: Sharma A. K. , Fehrenbacher J. B. , Jones B. A. 
Published: July 2010

AbstractGypsum is by far the most commonly used amendment for ameliorating natric or solonetzic soils. Previous laboratory leaching studies with these soils in Illinois indicated that gypsum was more effective on disturbed than on undisturbed soil columns of natric horizons. The present investigation, therefore, was undertaken to formulate an effective field procedure for ameliorating the natric soils in Illinois. Effects of the treatment combinations of 0, 24, and 62 tons/ha of gypsum mixed to 15 or 90 cm or chiseled to 60 cm in soil on plots not tiled or having tile spacings of 3, 9, or 18 m, were studied on Huey silt loam, a natric soil at Newton in south‐central Illinois in terms of corn yields (Zea mays L.), removal of extractable sodium from the soil, corn root growth and development, and water table fluctuations. Corn yields from 1964 to 1971 inclusive and removal of extractable Na from 1964 to 1972 inclusive were studied on all plots. Corn root growth and development studies in 1972 included four 9 m tiled plots with various gypsum and soil disturbance combinations. Water table fluctuations were studied from 1969 to 1972 inclusive on three plots with different treatment combinations.Of all the combinations studied, 62 tons/ha of gypsum mixed to 90 cm and tiled 3, 9, or 18 m, were the only effective combinations in improving corn yields, removing Na from the soil, and increasing water transmission in the soil. On plots with gypsum mixed to 15 cm only, tiling was not effective, but on plots with gypsum mixed to 90 cm, 3 m tile spacing was significantly better than 18 m spacing in increasing corn yields and improving soil conditions. Mixing the soil to 90 cm without gypsum resulted in reduced corn yields and no improvement in Na removal in comparison to the conventionally treated plots without gysum.
Powdered Metal Plates for Constructing Unsaturated Flow Cells
Authors: Bianchi William C. 
Published: July 2010

AbstractDescribed is the theoretical design, construction and observed characteristics of sintered stainless steel powdered metal plates which could be used in control sections of an unsaturated flow cell (J. W. Cary, 1968, Soil Sci. Soc. Amer. Proc. 32:3–5).
Scanning Electron Microscopy as Applied to Organo‐Mineral Complexes in Alkaline Extracts of Soil
Authors: Dormaar J. F. 
Published: July 2010

AbstractLyophilized alkaline extracts from a Black Chernozem (Udic Haploboroll) Ah horizon were scanned in a scanning electron microscope. The micrographs obtained show the physical associations of organic and mineral matter before and after acidification and purification. A large percentage of the organoclay mineral complexes present in humic acids is probably formed during acidification.
Electrochemistry of Sodium‐Montmorillonite Suspensions: I. Chemical Stability of Montmorillonite
Authors: Shainberg I. , Low P. F. , Kafkafi U. 
Published: July 2010

AbstractThe chemical stability of four Na‐saturated montmorillonites differing in their isomorphous substitution was studied by following the change of specific conductance, Na+ activity and pH of their aqueous suspensions at several clay concentrations. It was found that the change in specific conductance is proportional to the square root of time and that the proportionality constant is linearly related to the degree of octahedral substitution. Further, a linear relation exists between the change in specific conductance and the change in Na+ activity. A hypothesis to explain these observations is presented.
Virulence of the Alnus Endophyte after In Vitro Cultivation
Authors: Rogers R. D. , Wollum A. G. 
Published: July 2010

AbstractA technique has been devised for maintaining the virulence of the endophyte of Alnus glutinosa L. during in vitro cultivation. Essential to the technique are the inclusion of an ether extract of Alnus roots and cycloheximide and chloramphenicol to the artificial medium. Using the devised medium, endophyte virulence has been maintained for 14 days whereas in the absence of the ether extract and antibiotics, virulence was lost within 3 days. Nodules that are subsequently formed after inoculation of plants with the incubated endophyte are normal. Visible nodules were formed within 7 to 12 weeks after inoculation, a period which was comparable to the nodulation time of control plants inoculated with fresh crushed nodules. In addition, the nodules were capable of reducing acetylene which is indicative of nitrogen fixing activity. Also, during this study it was found that freeze‐drying nodules does not reduce the virulence of the nodule‐inducing endophyte.
Response of Crops to Sulfur under Greenhouse Conditions
Authors: Gupta Umesh C. , Veinot R. L. 
Published: July 2010

AbstractTwo to four crops were grown in sequence in three series of pots on two soils, Charlottetown fine sandy loam (Chfsl) and Queens sandy clay loam (Qscl). The rates of applied S to the soils were: 0, 50, 100, and 150 ppm. None of the crops grown in the first sequence responded to S, but crops grown in later sequences responded to S in varying degrees. Sulfur applications resulted in about 2‐ to 4‐fold increases in the yield of rutabaga roots (Brassica napobrassica, Mill. cv. ‘York’). The plants deficient in S had thin roots and the leaves were reddish‐yellow with scorched edges. The kernel and straw yields of barley (Hordeum distichon L., cv. ‘Volla’) and wheat (Triticum aestivum L., cv. ‘Opal’) increased substantially with the addition of S. The S‐deficient plants of barley and wheat were lighter in color with thin stems. Alfalfa (Medicago sativa L., cv. ‘Saranac’) responded to S, with increases of much greater magnitude in the second and third cuts than those in the first cut. The S‐deficiency symptoms, noted as stunting and general yellowing of the entire plants, were mostly confined to the second and third cuts. Four‐ to five‐fold increases in cauliflower (Brassica oleracea botrytis L., cv. ‘Snowball’) yield with S3 and S4 treatments were obtained on Qscl, while on the Chfsl the yields decreased at S3 and S4 levels of S. The yield decreases on the Chfsl were caused by a severe Mo deficiency. Sulfur‐deficient cauliflower plants were stunted with general yellowing of leaf edges. The available soil SO4‐S levels of 2.0 and 2.4 ppm for alfalfa third cut and barley were in the deficiency range. The deficiency levels for wheat and cauliflower would likely be below 2.8 and 4.0 ppm, respectively.
Molybdate Adsorption Characteristics of Volcanic‐Ash‐Derived Soils in Chile
Authors: Gonzalez B. R. , Appelt H. , Schalscha E. B. , Bingham F. T. 
Published: July 2010

AbstractSoils derived from volcanic ash in Chile present a high adsorption capacity for molybdate. Competitive studies with chloride, sulfate and phosphate suggest that molybdate has a high affinity for the adsorption sites in these soils. The mechanism involved on the adsorption of molybdate is qualitatively explained by the theories developed by Hingston et al. (1968, 1972) for anion adsorption by iron and aluminum oxides.It is concluded that molybdate adsorption by volcanic‐ashderived soils is due mainly to the presence of allophane and amorphous aluminum, silicon and iron compounds and is not influenced by the organic matter content of this soil.
Influence of Sorbed Cations on Ammonia Retention Capacity of Tropical Soils
Authors: Shimpi S. S. , Savant N. K. 
Published: July 2010

AbstractThe NH3‐retention capacity of noncalcareous medium black soil and lateritic soil treated with 0.1N solution of HCl, AlCl3, MgCl2, CaCl2, NaCl or KCl followed the decreasing order: H‐soil ≈ Al‐soil > Mg‐soil ≈ Ca‐soil > Na‐soil ≈ K‐soil > check soil. The order of retention may be explained on the basis of formation of metal cation‐NH3 coordinated complexes having differential stability.
Effect of Daily Irrigation on Water Content and Suetion Profiles in Soils of Three Textures
Authors: Miller D. E. 
Published: July 2010

AbstractA growth‐room study was conducted to evaluate the water and suction profiles that develop in various soils irrigated daily at different proportions of Et. When irrigated to just replace Et, the water profiles that developed depended upon the flow characteristics of the soil. In the soil in which water moved readily (Shano silt loam), water distribution was nearly uniform with depth and did not change with time. In the soils in which water moved slowly, either because of slow internal water movement when wet (Ritzville loam) or low unsaturated conductivities at relatively low suctions (Sagehill sand), the upper soil became wetter while the lower soil water decreased by a corresponding amount. In all soils irrigated daily to replace all or more than Et, suctions in the upper soil were relatively low. With the soil profile initially wet, several weeks of deficit irrigation passed before surface soil water content changed markedly.
Conventional and Controlled‐Release Nitrogen Sources for Rice
Authors: Wells B. R. , Shockley P. A. 
Published: July 2010

AbstractTests were conducted for the years 1967–1972 with rice (Oryza sativa L., cv. ‘Starbonnet’) to compare various formulations of sulfur‐coated urea (SCU) and iso‐butylidene diurea, (I.B.D.U.) with urea and ammonium sulfate as nitrogen sources on both silt loam and clay soils. The N sources were applied either preplant or topdress at rates up to 235 kg/ha to drill‐seeded rice which was flooded at approximately 2 weeks following seedling emergence. Grain yields, dry weight, and N uptake indicated that the controlled‐release N sources could be used to regulate rate of N supply to the plant throughout the growing season. Growth of direct seeded rice was slowed considerably during the early part of the growing season due to the slow rate of N release but grain yields were not drastically altered. Grain yields on the silt loam soils following use of the controlled‐release N fertilizers were consistently equal to those following use of urea or ammonium sulfate. On the clay soils under intermittent flooding, use of SCU resulted in increased yields as compared to urea applied preplant, and in one year resulted in increased yields as compared to urea applied in split top‐dress doses. Both SCU and I.B.D.U. were suitable N sources for rice growing under the water management systems employed in these studies.
Prediction of Imbibition in a Horizontal Column
Authors: Morel‐Seytoux H. J. , Khanji J. 
Published: July 2010

AbstractAn approximate analytical solution to the equations of water and air movement in a horizontal porous medium is presented. From the solution for the water content profile, imbibition rates can be predicted as a function of time. A comparison of predicted and experimental imbibition rates shows an excellent agreement. This result is particularly significant because no numerical integration of a differential equation is necessary to obtain the water content profiles and to obtain the imbibition rates. The method of solution requires only graphical constructions and integrations of curves simply related to the basic soil characteristics such as capillary head and unsaturated hydraulic conductivity.
Infrared Studies on Humic Acid in Deuterium Oxide: I. Evaluation and Potentialities of the Technique
Authors: MacCarthy Patrick , Mark H. B. 
Published: July 2010

AbstractInfrared spectra of deuterated humic acid and sodium humate and the Cu(II), La(III), and Fe(III) complexes of deuterated humic acid were recorded in D2O medium. Changes in the 1550 cm‐1 to 1750 cm‐1 region of the humic acid spectrum which occur on salt‐ and complex‐formation were readily observed in the wet (D2O) slurry samples. Replacement of active protons in humic acid by deuterium (D) eliminates the broad O‐H absorption band which occurs in the 2900 cm‐1 to 3600 cm‐1 region of the spectrum of the H‐form of humic acid. Consequently, the aliphatic C‐H stretching bands which occur at 2860 and 2920 cm‐1 in the spectrum of humic acid are observed with negligible background absorption and with little interference from the O‐D stretching band which occurs in the 2200 cm‐1 to 2800 cm‐1 region. The deuterium‐proton exchange reactions in humic acid were found to be rapid.
Measuring Soil Creep
Authors: Troeh Frederick R. 
Published: July 2010

AbstractSoil creep occurs so slowly that it is usually overlooked. Nevertheless, its persistence makes it significant to sciences that deal with soils or landscapes. Creeping soil can move landmarks and cause structures to tilt or collapse. But, the rate of movement by soil creep under various conditions is largely unknown. This paper describes a sensor that measures soil creep. The sensor is a sheet metal structure buried in a deep auger hole. Movement detectors mounted at four depths on the sensor are coupled to indicators at the soil surface to show how much movement has occurred. Readings from such sensors identify the location, depth, and rate of soil creep.
Dynamic Simulation of Water Storage in Fallow Soil as Affected by Mulch of Hydrophobic Aggregates
Authors: Hillel D. I. , van Bavel C. H. M. , Talpaz H. 
Published: July 2010

AbstractA mechanistic numerical model, based on fundamental physical principles and written in IBM S/360 CSMP language, was designed to compute the dynamic balance of water in a fallow soil through repeated cycles of infiltration and evaporation. The necessary inputs are: (i) hydraulic characteristics of the soil and of the surface crust or mulch layer; (ii) duration and intensity characteristics of rainstorms or irrigations; and (iii) the potential evaporation rate as it varies diurnally and from day to day. The output provides time‐dependent rates and cumulative quantities of infiltration, runoff, surface detention, evaporation, internal drainage, and changes in water content of different layers and of the profile as a whole. Computations carried out for a 4‐day simulation (including two rainstorms and four evaporation cycles) illustrate the use of the model for uniform, crusted, or mulched soil; and predict that the presence of a mulch of hydrophobic aggregates, several centimeters thick, can greatly increase the quantity of water absorbed and retained in the profile. This finding accords with previously‐published experimental results and indicates a promising approach to soil management for water conservation in dryland and irrigated farming.
Humus Accumulation in a Forested Haploboroll in South‐Central New Mexico
Authors: Anderson J. U. , Silberman D. , Rai Dhanpat 
Published: July 2010

AbstractA field study of a 65‐hectare area and a laboratory study of samples from two Boroll profiles and two Boralf profiles was conducted to determine why these extensive forested Borolls at high elevation have such an unusually high organic matter content. The study revealed that in these Rendzina‐like Borolls, organic litter decomposes much more slowly than in an adjoining Boralf, as indicated by differences in organic matter contents. This difference in rate of microbial oxidation does not depend primarily on nutrients supplied to the microorganisms or on invasion by locally indigenous microflora. Slow decomposition of Boroll organic matter probably results from protection afforded by its mixture with mineral soil in the gut of terrestrial snails (Ashmunella rhyssa).