bluuebunny/crossref_metadata_2025_split huggingface dataset:
Adsorption of s‐Triazines by Montmorillonite As a Function of pH and Molecular Structure
Authors: Weber J. B. 
Published: July 2010

AbstractThe effect of pH on the adsorption of 16 structurally related s‐triazines by Na‐montmorillonite was investigated. Slurry type adsorption techniques were used. The compounds included ametryne, desmetryne, prometryne, GS 14253, GS 14260, GS 16065, atrazine, SD‐15418, dyrene, atratone, prometone, GS 28533, melamine, ammeline, ammelide, and benzoguanamine. Maximum adsorption occurred at pH levels in the vicinity of the pKA of each compound. The amount of adsorption which resulted was related to the substituent groups on the triazine ring. Comparisons of compounds substituted in the 2‐position indicated that adsorption of the s‐triazines by montmorillonite decreased in the order: ‐SC2H5 > ‐SCH3 > ‐OCH3 > OH > ‐Cl. Substitutions made in the 4 and 6 positions indicated that dialkylamino compounds were adsorbed in greater amounts than monoalkyl substituted compounds and that adsorption decreased in the order: C4H9(t) > C4H9(s) > C2H5 > C3H7(i) > CH3 > C(CH3)2CN. The more basic compounds were adsorbed in greater amounts than compounds of lower basicity.
Factors Affecting Soil Arylsulfatase Activity
Authors: Tabatabai M. A. , Bremner J. M. 
Published: July 2010

AbstractA study of the effects of various soil pretreatments on soil arylsulfatase activity showed that storage at −10C is a satisfactory method of preserving field‐moist soil samples for assay of arylsulfatase activity. Storage of field‐moist soils at 5C or 22–24C for 3 months led to a decrease in arylsulfatase activity (average, 8% at 5C, 18% at 22–24C), but storage at −10C for the same period did not significantly affect this activity. Air‐drying of field‐moist soils at 22–24C caused a marked increase in arylsulfatase activity (average, 43%), and oven‐drying (105C) caused a marked decrease (average, 54%). A slow decrease in arylsulfatase activity was observed when air‐dried soils were stored at 22–24C.Arylsulfatase activity decreased markedly with depth in six soil profiles examined. This decrease was associated with a decrease in organic matter content, and studies with surface soils differing markedly in physical and chemical properties showed that soil arylsulfatase activity was significantly correlated with soil organic matter content.Soil arylsulfatases were not deactivated by most of the reagents used to study the sulfur status of soils.
Soils of Steeply Sloping Landscapes in the Southern Appalachian Mountains
Authors: Losche C. K. , McCracken R. J. , Davey C. B. 
Published: July 2010

AbstractAt two locations in the southern Appalachian Mountains, soils at two slope positions on north‐ and south‐facing landscapes were described, sampled, and analyzed to determine the relative effect of slope aspect and position upon the differentiation of the parent rock into soil profiles. At the southwestern Virginia study area, the parent rocks are highly siliceous sandstone and siltstone, whereas, the parent rock in southwestern North Carolina is a granitic biotite gneiss.Soils developed from the siliceous parent material were very similar in morphological, physical, chemical, and mineralogical properties irrespective of aspect and slope position. In contrast, there was a high degree of soil profile differentiation at the two slope positions and on the two aspects in North Carolina. In addition to differences in morphological and physical properties, there are distinct differences in the clay mineral suites on opposing aspects. Kaolin and the pedogenic 2:1–2:2 intergrade minerals are predominant in the soils of the north‐facing landscapes, whereas, gibbsite is the major clay mineral in the soils of the south‐facing landscape.
Thin Section Preparation Using an Epoxy Impregnation for Petrographic and Electron Microprobe Analysis
Authors: Innes R. P. , Pluth D. J. 
Published: July 2010

AbstractImproved apparatus for controlling temperature and pressure during impregnation with the epoxy Scotchcast No. 3 resulted in complete impregnation of high bulk density soil clods. Advantages of the epoxy as a soil impregnating medium were simple preparation, suitable pot life, low viscosity, a 1.53 refractive index, short polymerization period, low relief in polished thin section, and high thermal stability. Technique for transfer of a polished thin section to a circular slide for electron microprobe analysis utilized two thermo‐setting plastics of differing softening points.
Gaseous Loss of Ammonia from Prilled Urea Applied to Slash Pine
Authors: Volk Gaylord M. 
Published: July 2010

AbstractGaseous loss of NH3 from prilled urea, surface applied at 100 kg N/ha to undisturbed dry organic residue over moist soil under slash pine (Pinus elliottii Engelm. var. elliottii), averaged 4% in 7 days as compared with 2% for an area that was control‐burned 5 weeks previous, and 5% for one from which loose debris had been removed. This was approximately equivalent to removal by burning. Residual urea recovery of 41% for the burned area as compared with 16 and 12% for the undisturbed and cleaned areas, indicated urease inactivation and partial soil sterilization by burning. Where urea had been applied to moist undisturbed organic residue, hydrolysis approached completion in 3 days and was accompanied by 9% N loss as NH3. Various types and orientations of needle‐bearing portions of branches of slash pine were submitted to a 75–100 cm drop of prilled urea at 100 kg N/ha. From 0.32–0.87 g of pellets were retained per meter of branch. Aspiration tests under typical alternating night and day humidities and native urease activity showed only 3% loss of this retained urea‐N as NH3 in 4 days. At 8 days an average of 52% of the initially retained N was still dilute‐acid soluble from macerated bark plus needle stubs, with a ratio of seven parts urea N to three parts NH4+‐N. The remainder, except for the small gaseous loss, probably was assimilated.
Comparison of Iron and Aluminum Hydroxy Interlayers in Montmorillonite and Vermiculite: I. Formation
Authors: Carstea D. D. , Harward M. E. , Knox E. G. 
Published: July 2010

AbstractHydroxy‐Al and ‐Fe interlayers were formed in montmorillonite and vermiculite by adding AlCl3 or FeCl3 and NaOH in amounts to give a wide range of pH. The resulting chloritic intergrades were examined aften 10 days, 6 months, and 1 year.Aluminum‐interlayered montmorillonite formed at pH 4.6 after 10 days showed the essential X‐ray characteristics of chlorite. The best iron interlayers in montmorillonite prevented collapse upon K‐saturation and heating but did not prevent expansion upon solvation. Aluminum‐interlayered vermiculite showed partial collapse on K‐saturation and heating.Acid conditions favored interlayer formation with aluminum and iron in montmorillonite and with aluminum in vermiculite. Iron interlayers in vermiculite were favored by alkaline conditions.Iron interlayers decreased with time. Aluminum interlayers formed in montmorillonite with acid conditions decreased sharply with time. Aluminum interlayers in vermiculite and those formed under alkaline conditions in montmorillonite, showed some tendency to increase with time.
Estimation of Surface Charge Density of Mica and Vermiculite by Competitive Adsorption of Diquat2+ vs. Paraquat2+
Authors: Philen O. D. , Weed S. B. , Weber J. B. 
Published: July 2010

AbstractCompetitive adsorption of diquat2+ (1,1′‐ethylene‐2,2′‐dipyridinium ion) vs. paraquat2+ (1,1′‐dimethyl‐4,4′‐dipyridinium ion) by external surfaces of vermiculite and mica appeared to be linearly related to the surface charge densities of the adsorbents. This suggested a means for estimating surface charge of soil layer silicates. Soil clays, treated for removal of free iron and kaolin, exhibited surface charge densities in the range 7.3–8.7 × 104 esu/cm2.
Clay‐Rich Horizons Over Limestone—Illuvial or Residual?
Authors: Ballagh T. M. , Runge E. C. A. 
Published: July 2010

AbstractThe formation of fine clay horizons over limestone in the soils studied results from illuviation and is not residual material resulting from the dissolution of limestone. This conclusion is reached on the basis of 14C dating of the carbon complexed with the clay, X‐ray diffractograms, and clay size.
Comparison of Methods for Identifying Crystalline Phosphates Produced by Interaction of Orthophosphate Fertilizers with Soils
Authors: Bell L. C. , Black C. A. 
Published: July 2010

AbstractFor identifying crystalline phosphates formed in soils treated with Ca(H2PO4)2·H2O, NH4H2PO4, and (NH4)2HPO4, various methods investigated ranked as follows in decreasing order of sensitivity: optical examination of soil ≥ optical examination of glass‐fiber filter paper inclusion > X‐ray diffraction examination of glass‐fiber filter paper inclusion > X‐ray diffraction examination of soil. Ca8H2(PO4)6·5H2O was identified in one soil but not in the paper inclusion. Differences were more frequent with calcite inclusions. Where there was a difference in phosphates identified between calcite inclusions and calcareous soil, the more acid phosphates seemed more stable in soil than on calcite inclusions, and the more basic phosphates seemed more stable on calcite inclusions than in soil.
Specific Chloride Injury in Persea americana
Authors: Fenn L. B. , Oertli J. J. , Bingham F. T. 
Published: July 2010

AbstractThe mode of chloride injury in avocado plants (Persea americana) was studied at variable Cl levels. The experiment revealed that when leaf burn occurred, it was associated with abnormally high content in total and leachable salt in the leaves. The substantial leachable fraction presumably represents high concentrations of extracellular salt, which accumulates in tips and margins of the leaves after termination of a vigorous growth. In avocado trees, the salt that builds up at the higher substrate Cl levels is associated with what appears to be a mass flow salt movement into conductive tissues causing, possibly, greater salt transport to the leaves than can ultimately be absorbed by leaf cells. The extracellular salt concentrations break down the gradients of osmotic pressure that are necessary to maintain turgor pressure, leading to characteristic tip and marginal necrosis associated with excessive accumulations of Cl. Growth reduction is probably due to energy spent in excessive salt accumulation and loss of photosynthetic area.
Evaluation of Soil Moisture Measurements in Oklahoma as Soil Characteristics for Classification
Authors: Nichols J. D. , Stone J. F. 
Published: July 2010

AbstractSoil moisture measurements were evaluated as soil moisture characteristics specified in the new soil classification system. Soil moisture measurements were made with a neutron probe at about weekly intervals and were available for 3 to 6‐year periods at four sites with a range in mean annual precipitation of 45 cm to 80 cm. The cumulative days were counted when the soil moisture was below −15 atm pressure in either or both of the 0 to 23‐cm increment and the 23 to 38‐cm increment. The count was also made for the control section of the 23 to 38‐cm increment and the 38 to 53‐cm increment. The data yielded close fitting linear regression lines for cumulative days dry in each year against the measured precipitation for that year. The regression lines for the two tested control sections were nearly alike. The neutron probe method seems to be a satisfactory method for determining days dry. Some adjustment of the data will likely be necessary in translating the data for use in the classification system.
Effects of Different Aqueous Buffers on the Zinc Extractability of Dithizone
Authors: Pietz R. I. , Adams R. S. , MacGregor J. M. 
Published: July 2010

AbstractThe effect of several aqueous buffers on the Zn extractability of dithizone was examined on three Minnesota soils: Zimmerman s, Brainerd sl, and Blue Earth sicl. The five aqueous solutions used with dithizone were water, 1N NH4OAc, 1N NaOAc, 1N Ba(OAc)2, and 1N Ca(OAc)2. Dithizone‐1N NH4OAc extracted the greatest amounts of Zn and dithizone‐water extracted the least. The data indicated that the variation in dithizone extractable Zn with different buffers may be related to the buffering capacity of the aqueous solutions, the NH4 ion, and the soil organic matter present.
Survival of Bacteriophage in Soil “Sterilized” with Gamma Irradiation
Authors: Robinson J. B. , Corke C. T. , Jones D. A. 
Published: July 2010

AbstractNaturally occurring bacteriophage for Bacillus megaterium strain KM was found to survive in soil following up to 5 megarads of gamma irradiation. While the number of survivors was small, they might nevertheless be a factor in controlling growth of bacteria experimentally introduced into gammasterilized soil.
Fragipans in Pennsylvania Soils: A Statistical Study of Laboratory Data
Authors: Petersen G. W. , Ranney R. W. , Cunningham R. L. , Matelski R. P. 
Published: July 2010

AbstractSoils sampled for laboratory characterization in Pennsylvania were separated into those profiles with fragipans and those without fragipans to determine statistically the soil properties consistently related to fragipan occurrence. Fragipans occurred in the following five parent material groups: aeolium, fluvium, lacustrine deposits, glacial till, and colluvium. Comparisons were made with horizons from comparable depths from nonfragic soils in these same parent material groups, except for colluvial soils, which in every case contained fragipans. Data were analyzed from 773 samples from 254 soil profiles. Fragipan bulk densities of the <2‐mm material were significantly higher at the 1% level than nonfragipan horizons within till and fluvial parent materials, but were not significantly different within aeolian and lacustrine deposits. Multiple regression analyses using 16 soil variables indicated no relationships between these variables and bulk density. Plots of soil textures showed clustering of fragipan samples in loam and silt loam textural classes, whereas nonfragipan samples were more widely spread over other textural classes. Fragipans had significantly lower organic carbon, lower Ca:Mg ratios, and higher mean base saturations with less alteration of illite to vermiculite than nonfragipan horizons. Chemical and mineralogical data indicate that fragipans are less leached and less weathered than comparable nonfragipan horizons.
Indices for Characterizing Soil‐Water Repellency Based upon Contact Angle‐Surface Tension Relationships
Authors: Watson C. L. , Letey J. 
Published: July 2010

AbstractThe relation between apparent liquid‐solid contact angle and surface tension was established for three water repellent materials using both a series of aqueous ethanol solutions and organic liquids. The media included two artificially treated sands and one naturally occurring soil. With one exception there was an approximate linear relationship between the cosine of the contact angle and the surface tension. The relationship for the forest soil tended to be curvilinear when using ethanol solutions of high surface tension. The repellency of the materials was best differentiated by using their intercepts with cos θ = 0. A simple drop test using the same materials and ethanol solutions placed the materials in the same order of repellency. The drop test was further developed to allow classification of porous media on the basis of (i) 90° surface tension (γn), and (ii) stability to water interaction. The tests can be readily performed both in the laboratory and the field. Two indices were then proposed to describe water‐repellent characteristies of soils. These indices will be valuable in assessing erosion and runoff problems, and also the feasibility of surfactants to promote infiltration.
Simulation of Heat Transfer in Soils
Authors: Wierenga P. J. , de Wit C. T. 
Published: July 2010

AbstractA computer model was developed to predict the temperature fluctuation in subsoil from the temperature variation at the soil surface, taking into account changes in the apparent thermal conductivity with depth below soil surface and soil temperature. The model makes use of S/360 CSMP, a recently developed simulation language for digital computers. Predicted soil temperatures were compared with soil temperatures observed at 2, 10, 15, 25, 30, and 75 cm below the surface of bare field profiles, before and after irrigation with 13.4 cm water. In wet soil observed and predicted temperatures were in close agreement. In dry soil significant differences were observed between measured and predicted soil temperatures during part of the day. The increase in apparent thermal conductivity with soil temperature had a negative effect on the magnitude of the difference between observed and predicted values in the dry soil. Agreement was found between soil heat flux density values predicted from the model and calculated with the temperature integral method. Use of a digital simulation language can save considerable programming time, and can be applied to movement of water and gases in soil profiles.
A Mathematical Solution to a Hillside Seepage Problem
Authors: Warrick A. W. 
Published: July 2010

AbstractA solution is presented for a two‐dimensional hillside seepage problem. The soil is assumed to be water‐saturated to the soil surface where the soil water is at atmospheric pressure. Seepage occurs into the flow medium along the upper part and out along the lower part of the sloping soil surface. The flow medium is infinitely deep and bounded laterally by vertical stream‐lines. Conformal transformations are used to find the hydraulic head and stream functions. Although the solution is analytic, a complex integral must be evaluated numerically for application. Numerical data presented includes flownets, seepage velocities, infiltration angles, and volume of flow as a function of slope.
The Diffusion of Copper, Manganese, and Zinc as Affected by Concentration, Clay Mineralogy, and Associated Anions
Authors: Ellis J. H. , Barnhisel R. I. , Phillips R. E. 
Published: July 2010

AbstractThe distributions of Cu2+, Mn2+, and Zn2+ diffusing in thin oriented clay films of water‐saturated montmorillonite, vermiculite, illite and kaolinite were obtained using a miniature probe attachment for an x‐ray emission spectrometer. Diffusion coefficients were calculated from these experimental distributions. Only small differences in the diffusion coefficients of Cu2+, Mn2+, and Zn2+ at comparable concentrations were found for a given clay. The range of diffusion coefficients for CuCl2 was 1.7 × 10‐7 cm2 sec‐1 at 0.01 meq/g of vermiculite clay to 52.1 × 10‐7 cm2 sec‐1 at 0.5 meq/g of kaolinite. The diffusion rates of copper, manganese, and zinc through the clay minerals were of the order: kaolinite > illite > montmorillonite >vermiculite. Some estimates of the diffusion coefficients in the liquid phase and in the adsorbed phase are given. The anions, Cl‐, NO3‐, SO42‐, and OAc‐ when diffusing with the cupric ion affected its diffusion rate. The order of diffusion coefficients at a concentration of 0.5 meq/g of montmorillonite clay were: CuCl2 > Cu(NO3)2 > CuSO4 > Cu(OAc)2; the respective diffusion coefficients were: 9.5, 8.3, 6.9, 2.7 × 10‐7 cm2 sec‐1.
Nitrous Oxide Formation by Nitrosomonas Europaea and Heterotrophie Microorganisms
Authors: Yoshida T. , Alexander M. 
Published: July 2010

AbstractNitrosomonas europaea oxidizes ammonium to nitrous oxide, a reaction that is enhanced by storing the bacteria at low temperature and by phosphate and high pH. Nitrous oxide is also formed from hydroxylamine by the autotroph. Nitrous oxide is apparently generated from an intermediate in nitrification, and the data suggest that the conversion of this intermediate to nitrite is inhibited by ammonium, hydrazine, or high temperature. Nitrous oxide is also formed during nitrate reduction by Bacillus subtilis, Escherichia coli, and Aerobacter aerogenes and during nitrite reduction by Aspergillus flavus and Penicillium atrocenetum. It is suggested that the production of nitrous oxide by the autotrophic nitrifier, Nitrosomonas, and by such heterotrophic organisms may be of biogeochemical importance.
Pedogenic Distribution of Zinc in Mollisols and Associated Entisols in Nebraska
Authors: Dankert Wayne N. , Drew James V. 
Published: July 2010

AbstractThe distribution of total Zn in a Udie Haplustoll (Moody) and a Typic Argiustoll (Holdrege) formed in Peoria loess in Nebraska is related to the accumulation of illuvial clay in these soils. In Typic Ustorthents (Crofton and Coly) formed in Peoria loess, a comparable distribution of noncarbonate clay and total Zn does not occur. Larger amounts of Zn in noncarbonate clay from the upper sola of the four profiles than in noncarbonate clay from their C horizons suggest that Zn is released from soil minerals and cycled by vegetation during biopedogenic weathering, then becomes associated with noncarbonate clay in the A horizons following decomposition of plant residues. In Moody and Holdrege, however, maximum amounts of Zn in the total soil occur in the B horizons of clay maxima, suggesting that Zn moves in association with clay from the A to the B horizons during the genesis of these soils.
Free Iron Oxides: Rapid Determination Utilizing X‐ray Spectroscopy to Determine Iron in Solution
Authors: Fanning D. S. , Korcak R. F. , Coffman C. B. 
Published: July 2010

AbstractX‐ray spectroscopy is a convenient and rapid way of measuring iron in solution, especially employing the inverted type spectrographs and cells sealed with mylar film for presenting the liquid in the spectrograph. These techniques were adapted to measuring free iron extracted by the citrate‐bicarbonate‐dithionite method and could easily be adapted to measuring iron in other extractants. The spectrograph is sensitive to iron over a range of several thousand µg/ml and gives a linear response up to at least 500 µg/ml. Colorimetric methods are only sensitive in the 0 to 4 µg/ml and atomic absorption is normally used over a 0 to 20 µg/ml range. Thus extracts normally must be diluted for colorimetric or atomic absorption, but not for x‐ray spectrographic, iron determination. Also the oxidation state of the iron is critical with colorimetric or titrimetric iron determination, but not with the x‐ray method. Determinations on the same extracts by Hsu's thiocyanate colorimetric method for soils representing a range of free iron contents.
208Tl and 24Na Gamma Sources for Identifying Soil Water Tagged with Deuterium
Authors: Hawkins R. H. , Overman R. F. , Corey J. C. 
Published: July 2010

AbstractIn situ tracing of soil water movement with the D2O‐24Na method has been limited by the need to reactivate the 24Na gamma source frequently (half‐life of 15 hours) in a nuclear reactor. Our laboratory study showed 208Tl produced the same neutron count rates from vials of D2O in dry and moist soil as did 24Na. The 1.9‐year effective half‐life of 208Tl in equilibrium with its parent nuclide 228Th is a significant advantage of 208Tl over 24Na. Recent commercial availability of 208Tl sources now makes in situ D2O tracing of soil water feasible for investigators not having access to a nuclear reactor.