bluuebunny/crossref_metadata_2025_split huggingface dataset:
Adsorption of Phosphorus by Lake Sediment
Authors: Harter Robert D. 
Published: July 2010

AbstractThe sediment of an eutrophic lake is capable of adsorbing a large amount of phosphorus from the water. To study the sorption mechanism, between 0 and 2.2 mg P was added to 0.1‐g sediment samples (1:50 sediment‐solution ratio). After equilibrium had been established, P remaining in solution was determined, and adsorbed P was extracted with 0.5N NH4F and 0.1N NaOH. Whereas all P adsorbed into the NaOH‐extractable fraction appeared to occur as an iron phosphate, NH4F apparently extracted P bonded by two different mechanisms. When less than about 0.1 mg P was added, NH4F extracted a tightly bonded form of P, probably occurring as an aluminum phosphate. When more than 0.1 mg P was added, additional P in a more loosely bonded form was adsorbed into the NH4F‐extractable fraction. The loosely bonded P appeared to be independent of Al content of the sediment, and could be removed by successive water extraction. The capability of the sediment to adsorb considerable loosely bonded P means that large influxes of P into the lake may be held temporarily and subsequently released to growing plants and algae.
Urease Activity in a Black Spruce Humus Sterilized by Gamma Radiation
Authors: Roberge M. R. , Knowles R. 
Published: July 2010

AbstractThe activity of urease was studied in a black spruce (Picea mariana (Mill.) BSP.) surface organic horizon from Baie‐Comeau, Quebec. Samples were sterilized by 60Co radiation, incubated with urea for 8 hours at 20C and analyzed for ammonia. Urease activity decreased with an increase in humus decomposition. Field fertilization with 450 kg urea‐N/ha 2 years prior to humus sampling increased the urease activity by 40%. Laboratory preincubation of field‐fertilized and unfertilized humus with 3,500 ppm of urea‐N resulted in increased urease activity of 90%. Enzyme assays performed with 21,000 and 63,000 ppm of urea‐N gave similar relative activities to those performed with 3,500 ppm. Some mineralization of N occurred during and following irradiation in the absence of any added substrate. A direct relationship was found between enzyme activity and total and ureolytic numbers of microorganisms.
Distribution of Chlorinated Insecticides in Cultivated Soil
Authors: Nash R. G. , Woolson E. A. 
Published: July 2010

AbstractThe 1966 distribution of nine chlorinated insecticides in a 38 cm profile was determined in a Congaree sandy loam soil which had received accumulations of 73 or 146 kg/ha as frequently repeated foliar applications during the 1951, 1952, and 1953 growing seasons. Residues of aldrin (pure and technical—determined as dieldrin because only trace amounts of aldrin were detected), dieldrin, isodrin + endrin, endrin, heptachlor + heptachlor epoxide, chlordane, BHC, toxaphene, and Dilan were found throughout the profile. BHC and isodrin were more uniformly distributed throughout the profile than aldrin, dieldrin, Dilan, toxaphene, and chlordane. Between 85 to 90% of the latter insecticides were concentrated in the upper 23 cm, which probably corresponds to the cultivated layer. Residues were greatest in the 7.6 to 23 cm depths and least below the 23 cm depth. The relative mobility of the insecticides was: BHC ≥ isodrin > heptachlor > endrin > toxaphene ≥ dieldrin ≥ aldrin ≥ Dilan ≥ chlordane.
Uptake of Native Potassium by Plants from Natural Soil Aggregates of Different Sizes
Authors: Tabatabai M. A. , Hanway J. J. 
Published: July 2010

AbstractThe uptake of the native K by ryegrass (Lolium multiflorum) from undried soil aggregates > 9, 5–9, 3–5, 2–3, and 1–2 mm in diameter was studied in 14 soil samples. Yields of K and percentage K in the plants were highly correlated with the exchangeable K in the undried soils, irrespective of aggregate size. Early in the cropping period, plant yields were slightly higher, and slightly more K was taken up by the plants from the smaller aggregates than from the larger aggregates.
Nomographic Calculation of Linear Extensibility in Soils Containing Coarse Fragments
Authors: Holmgren George G. S. 
Published: July 2010

AbstractLinear extensibility is a variable being used by the Soil Survey Laboratories to characterize the expansion‐contraction properties of soil. It is calculated from bulk density data and must be corrected for coarse fragments when they are present in the field. A pair of nomographs is presented to facilitate these calculations. The volume percent of fine‐earth fabric (F) is determined from the first nomograph and transposed to the second nomograph where it serves to correct the extensibility as determined on the fine‐earth fabric. The value F may also be used to facilitate conversion of other laboratory data to a field basis where coarse fragments are present.
Some Chemical and Physical Properties of Different‐Sized Natural Aggregates from Iowa Soils
Authors: Tabatabai M. A. , Hanway J. J. 
Published: July 2010

AbstractThis study presents data concerning different chemical and physical properties of various‐sized, undried aggregates from seven surface soils and seven subsoils from Iowa.There was little or no difference in exchangeable K, extractable P, pH, or the percentages of sand, soilt, or clay in the different‐sized aggregates from any one soil sample. In some soils, organic carbon content tended to increase, and bulk density tended to decrease as the aggregate size decreased. The bulk densities of the aggregates were inversely related to the percentages of organic carbon in the aggregates.
The Influence of Ionic Strength and Ion‐Pair Formation Between Alkaline‐Earth Metals and Sulfate on Na‐Divalent Cation‐Exchange Equilibria
Authors: Rao Talur S. , Page A. L. , Coleman N. T. 
Published: July 2010

AbstractThe Na‐Ca and Na‐Mg ion‐exchange equilibria were studied in two soils and in an ion‐exchange resin by batch equilibration procedures. The apparent equilibria, in terms of concentrations, were different for the anions chloride or sulfate. The differences were reduced but not eliminated by ion activity corrections based on ionic strength. A more satisfactory agreement between the results in chloride and sulfate systems was obtained when allowance was made for solution phase activities and ion‐association of Ca and Mg with SO4 ions.
Mineralization of Nitrogen in Grass Roots
Authors: Power J. F. 
Published: July 2010

AbstractThe mineralization of fertilizer N immobilized in grass roots (Bromus inermus L.) is of major importance in regulating the use of N fertilizers on grassland. Grass roots varying in N content were therefore incubated with soil for 10 weeks at 30C, and the net rate of mineralization was measured. Rate of N mineralization during incubation was controlled to a large extent by the N content of the root material—mineralization of N contained in grass roots followed much the same pattern as for that in any other plant tissue. Incubation of unfertilized grass roots (0.84% N) resulted in net immobilization of mineral N. Incubation of N‐fertilized grass roots (containing 1.44% N) resulted in a net increase in mineral N. For both root materials the changes in mineral N were in proportion to the amount of root material added.
The Influence of Nitrification Suppressants on the Rate of Ammonium Oxidation in Midwestern USA Field Soils
Authors: Sabey Burns R. 
Published: July 2010

AbstractThe effectiveness of 2‐chloro‐6‐(trichloromethyl) pyridine, 2‐amino 4‐chloro 6‐methyl pyrimidine, and a resinous polymer coating in suppressing nitrification in the field was studied. Soil samples treated with (NH4)2SO4 alone and with (NH4)2SO4 plus the above materials, were placed in plastic bags and buried in field plots and allowed to incubate during the fall, winter and spring periods. Determinations for NH4+‐N and NO3‐‐N were made throughout the incubations.Nitrate‐N accumulation occurred at rates as high as 2.5 ppm/day prior to April 15 in samples treated with (NH4)2SO4 alone. Samples treated with the resinous coated (NH4)2SO4 fertilizer had higher NO3‐‐N accumulation rates (up to 4.1 ppm NO3‐‐N/day), whereas samples treated with (NH4)2SO4 and 2‐chloro‐6‐(trichloromethyl) pyridine or 2‐amino 4‐chloro 6‐methyl pyrimidine had rates of nitrification only as high as 2.3 and 1.6 ppm NO3‐‐N/day, respectively, prior to April 15. Although 2‐amino 4‐chloro 6‐methyl pyrimidine appeared slightly more effective after the end of April than 2‐chloro‐6‐(trichloromethyl) pyridine in suppresing nitrification, there were relatively small differences. Both compounds, added according to recommended rates delayed rapid nitrification for about 1 month.
Effect of Partial Removal of Soil Organic Nitrogen with Sodium Pyrophosphate or Sulfuric Acid Solutions on Subsequent Mineralization of Nitrogen
Authors: Stanford George 
Published: July 2010

AbstractStudies were conducted with Chester loam and Elliott clay loam soils to determine the relationship between amounts of N extracted by Na‐pyrophosphate solutions and reduction in capacities of the soils to mineralize N under anaerobic conditions. By employing wide variations in concentration and pH of the extractant, number of extractions, temperature, and extraction time, a broad range was achieved in total amounts of N extracted (40‐1,200 ppm). Accompanying reductions in soil N mineralization during 10–11 weeks ranged up to 125–170 ppm, respectively, with the Elliott and Chester soils. A close similarity in susceptibility to mineralization of N extracted from the two soils is indicated, although relative amounts of extractable N differed appreciably.Acid hydrolysis of Elliott soil with 6N H2SO4 for 12–16 hours reduced N mineralization capacity of the soil to zero. These findings may have important implications in defining criteria for selecting the concentration of an extractant suitable for use in assessing the N status of soils.
The Distribution of Gold in the Silt Fraction of Some Soil Profiles and its Genetical Significance
Authors: Yassoglou N. J. , Nobeli Catherine 
Published: July 2010

AbstractThe distribution of gold in the silt fraction of 13 soil profiles was studied. The element was determined by neutron activation analysis. Activation analysis can be successfully employed for the determination of gold in soil materials, where it is usually found in extremely small quantities ranging from 3 to 120 parts per billion (ppb).It was found that silt and clay contain much higher amounts of gold than does sand. Parent materials which have undergone one cycle of soil formation seem to contain gold in the silt in the resistant metallic form. In other cases, the elements is associated with easily weatherable minerals and it is progressively lost from the silt fraction during processes of soil genesis. Gold could be used as an index of soil weathering, either as a resistant or as a removable constituent of the silt, depending on the composition and the origin of the parent material of the soil. It can also be used as an index of the lithological continuity of soil profiles.
Vesicular Pores of Pumice by Mercury Intrusion
Authors: Borchardt G. A. , Theisen A. A. , Harward M. E. 
Published: July 2010

AbstractThe pore size distribution of pumice was measured with a mercury intrusion porosimeter. Effects of particle to particle pores were minimized by use of separates based on size and density. Vesicular pores constituted about 98% of the fine porosity (<120µ diameter) in 1–0.5 mm fractions of pumice. Average diameters of internal pores of pumice were found to be in the range of 3 to 7µ. Distinctive curves were obtained for samples from Mt. Mazama, Glacier Peak, and Newberry Crater.
Solubility of Calcium Carbonate Precipitated in Montmorillonite Suspensions
Authors: Doner H. E. , Pratt P. F. 
Published: July 2010

AbstractCalcium carbonate precipitated in Ca‐ and Mg‐saturated montmorillonite suspensions was more soluble than calcite added to these suspensions. The CaCO3 precipitated from a clay suspended in Ca(OH)2 had a greater solubility than when the CaCO3 was precipitated by the addition of CaCl2 and NaHCO3. The difference in solubility between the two directions of approach to equilibrium was related to the amount of soluble Mg in the system. When CaCO3 was precipitated from CaCl2 and NaHCO3 in clay suspensions with Mg‐saturation as a variable, its solubility was related to the amount of Mg in solution with apparently no effect of the clay per se.
Interaction of Soil Reaction and Method of Seed Inoculation on Alfalfa
Authors: Baker A. S. , Mortensen W. P. , Dermanis P. 
Published: July 2010

AbstractComparisons of alfalfa (Medicago sativa L.) growth and survival were made at three sites in western Washington. The soil at each site was adjusted to different pH levels. Conventional seed inoculation and seed pelleted with limestone flour, skim milk, and peat inoculum using methylcellulose as the adhesive were compared at each reaction level. Optimum soil acidity levels for growth and survival of alfalfa were attained at a 0.01M CaCl2‐pH of 5.9 or higher and an exchange acidity level of 0.03 meq/100 g or lower. Both conditions had to be satisfied. Responses to seed pelleting occurred only where the soil was below the optimum acidity level. When soil moisture was adequate during establishment, maximum yields were attained with seed pelleting below optimum soil acidity levels. When moisture was severely limiting during establishment, maximum yields were not obtained with seed pelleting at less than optimum soil acidity levels. Moreover, soil acidity levels had to be closer to optimum to obtain a significant response to seed pelleting. The response to seed pelleting in the years following establishment was due to improved survival rather than individual plant vigor. A high water table during the winter accentuated the response to seed pelleting.
Moisture Characteristics of Pennsylvania Soils: II. Soil Factors Affecting Mositure Retention Within a Textural Class—Silt Loam
Authors: Petersen G. W. , Cunningham R. L. , Matelski R. P. 
Published: July 2010

AbstractThe relationships of morphology and other selected soil properties to mositure retained after equilibration at ⅓ and 15 atm (approx. 0.34 and 15.5 kg/cm2) tension was investigated within silt loams. This laboratory study was restricted to an individual textural class in an effort to hold texture relatively constant while scrutinizing the influence of other soil properties upon the soil moisture regime.Available moisture, which is assumed as the difference between moisture retained at ⅓ and 15 atm tension, was generally highest in the A, less in the B, and lowest in the C horizon. This moisture retention however, was more a reflection of coarse fragment content than of such horizon developmental features as clay accumulation, gleying, structural development, or fragipan characteristics. There was no significant difference between the moisture retention of cultivated and noncultivated horizons nor between the moisture supplying abilities of gleyed and nongleyed horizons. Nonfragic horizons retained almost twice as much available moisture as fragic horizons.Moisture retention decreases as coarse fragments increase and therefore moisture retention calculations should be corrected for coarse fragments. Available moisture remained almost constant as organic matter increased within silt loams. Weight percentage contents of kaolinite, illite, vermiculite, montmorillonite, chlorite, and interstratified clays were not significantly correlated with moisture retention. Correlation analyses suggested the 20‐5µ silt as the most important <2 mm size separate controlling available moisture and moisture retained at field capacity.
Standard Free Energies of Exchange for Alkali Metal Cations on Wyoming Bentonite
Authors: Gast R. G. 
Published: July 2010

AbstractStandard free energies of exchange, Δ Go, were determined for the exchange of Na with Li, K, Rb, and Cs and Li with K between 0.001N chloride solutions and 5% Wyoming bentonite gels at 25C. Values were also determined for Na → Rb, Na → Cs, and Rb → Cs exchanges between 0.0075N chloride solutions and 0.75% Wyoming bentonite suspensions. Application of the additivity rule indicates that the values are accurate to within ±50 to 100 cal mole‐1. Values for the 5% gels range from +48 cal mole‐1 for Na → Li exchange to −1,081 cal mole‐1 for Na → Cs exchange. There is a small but consistent increase in the ΔGo values for the 0.75% suspensions compared to those for the 5% gels. With the possible exception of Li, a linear relationship was found between ΔGo values and Debye‐Huckle parameters for the respective cations indicating that the adsorption of monovalent cations from strong electrolyte solutions is governed by their hydrated radii.
Clay Separation and Identification by a Density Gradient Procedure
Authors: Woolson E. A. , Axley J. H. 
Published: July 2010

AbstractA method was developed for the separation and partial identification of clays using a heavy liquid density gradient column. The columns consisted of five different layers, theoretically permitting seven different separations in one determination. To aid in separation, the original density of the clay was altered by saturation with H, Ca, K, or Cs. The resulting densities were related to changes in the clay interlayer distance as well as to the equivalent weight of the sorbed cations.This density gradient method is simple, quick, and requires only basic laboratory equipment. The density values aid clay mineral identification and in some instances may be the only information needed.
Micronutrient Cation Complexes in Soil Solution: III. Characterization of Soil Solution Ligands and their Complexes with Zn2+ and Cu2+
Authors: Geering H. R. , Hodgson J. F. 
Published: July 2010

AbstractAt least three groups of compounds were found to complex Zn2+ and Cu2+ in soil solution from the A horizon of a Williamson silt loam. A nondialyzable fraction of soil solution ligands had a poorly defined acid dissociation, pKa, ranging from 3 to 4.7. The dialyzable fraction had acid dissociation constants of 4.5 and 9.5, which were attributed to aliphatic and amino acids, respectively. The equivalent concentration of the nondialyzable acid fraction was only 1/40 that of the dialyzable fraction, but was more effective in complexing Zn and Cu in the soil solution. The average metal/ligand ratio was equal to unity in complexes of both the dialyzable and nondialyzable fractions with Zn2+ and Cu2+. Estimated, log10 (average formation constants) of the nondialyzable‐metal complexes were calculated on the basis of titratable acidity as 4.3 ± 0.1 and 5.5 ± 0.1 for Zn2+ and Cu2+, respectively.
Instrumental Analysis of Neutron Irradiated Soils
Authors: Kline J. R. , Brar S. S. 
Published: July 2010

AbstractSoils from a worldwide collection were analyzed by gamma ray spectrometry, after thermal neutron activation, to identify and measure trace elements in soils which can be studied by this technique, and to determine whether gamma ray spectra of soils can be used to identify specimens of soil and trace them to their geographical origin. Samples of 100‐mg size were irradiated for either 5 or 10 min in the Argonne CP‐5 reactor at a thermal neutron flux of 2 × 1013 n/cm2/sec. Gamma‐ray spectrometry of activated samples was delayed until 4 days after irradiation because of high levels of 24Na which obscured the longer‐lived nuclides. Therefore, nuclides with half‐lives shorter than 15 hours were not measured. Long‐lived nuclides, which could be observed after 4 days of delay are 140La, 46Sc, 82Br, 59Fe, 51Cr, 60Co, 152Eu, 154Eu, 153Sm, 181Hf, and 95Zr‐95Nb. Quantitative determinations were easily made by nondestructive methods for La, Sc, Fe, Co, Eu, and Sm. Amounts of Sc were correlated with amounts of Fe, Co, and Eu in soils of highly diverse origin. Similar correlations were not obtained with La. Elemental relationships sometimes resulted in similar gamma ray spectra for soils of dissimilar origin. These spectra, therefore, raised doubts as to whether they could be used without other supporting evidence to identify soil specimens or trace them to their place of origin when the analysis is done with NaI crystals and 400‐channel analyzers.
Stimulation of Soil Respiration by Volatiles from Alfalfa
Authors: Gilbert R. G. , Griebel G. E. 
Published: July 2010

AbstractVolatile compounds obtained by distillation of a water slurry of alfalfa hay increased the respiration rates of 12 soils three‐ to eight‐fold. The active volatiles are neutral organic compounds that rapidly penetrate the soil and cause an immediate increase in soil respiration. The intensity of the respiration enhancement is directly related to the relative concentration of the volatiles. Low RQ values of soil during exposure indicated the microflora utilized substrates low in oxygen. The optimal temperature for respiration enhancement of treated soil was 36C. The duration and magnitude of the soil respiration response were dependent on the volume of distillate used. The optimal volume maintained the increased respiration rate for 72 hours. Larger volumes reduced the duration of response to 2 hours, suggesting toxicity of the volatiles at higher concentrations.
A Study of Some Biosequences and Lithosequences in the Zone of Brown Forest Soils in Northern Greece: Morphological, Physical, and Chemical Properties
Authors: Yassoglou N. J. , Nobeli Catherine , Vrahamis S. C. 
Published: July 2010

AbstractEight soils developed in northern Greece under similar climatic, topographic, and age conditions were investigated. The results indicate that significant differences in the morphological, physical, and chemical properties among the soils are due to variations in the parent material and in the vegetational cover. Soils with cambic horizons have C horizons with lower base saturation than soils with argillic horizons. The distribution of the extractable aluminum seems to be influenced by the vegetational cover and the type of the parent material of the soils. Spruce (Picea excelsa L.) has affected soil properties more intensively than scotch pine (Pinus sylvestris L.) or grasses.
Water Solubility of Zinc in a Granular Mixed Fertilizer as Affected by Zine Source and Method of Addition
Authors: Richards G. E. 
Published: July 2010

AbstractEleven various water‐soluble, slightly‐soluble, and chelated Zn compounds were incorporated into an 8‐7‐6.6 (8‐16‐8) granular mixed fertilizer in a pilot plant operation by three methods: prior to ammoniation, after ammoniation, and as a coating. Total and water‐soluble Zn was determined in the products. Most of the Zn from chelated compounds remained in a water‐soluble form for all methods of addition. Less than 10% of the Zn in soluble compounds remained water soluble when incorporated prior to ammoniation; however, the level of water‐soluble Zn was higher when incorporated after ammoniation and further improved when applied as a coating. The level of water‐soluble Zn from basic Zn compounds of low solubility was highest when they were applied as a coating. Solubility of fritted Zn was unaffected by method of incorporation into fertilizer. Soluble Zn from non‐chelated sources increased as water‐soluble P increased and also as fertilizer pH decreased.
X‐Ray Emission Spectroscopic Determination of Potassium in Sub‐Milligram Mica Samples after Sample Treatment
Authors: Weed S. B. , Philen O. D. , Leonard R. A. 
Published: July 2010

AbstractPotassium in submilligram‐size samples of mica was satisfactorily determined by a thin‐specimen, X‐ray emission technique. The method utilizes Ti in the sample as an internal standard and involves the determination of the ratio KKα/TiKα. The technique provides a rapid and accurate means of determining K as a function of sample treatment, provided that the Ti content of the sample does not change.