bluuebunny/crossref_metadata_2025_split huggingface dataset:
Intensive Site Preparation and Sediment Losses on Steep Watersheds in the Gulf Coastal Plain
Authors: Beasley R. S. 
Published: July 2010

AbstractThe hydrologic effects of three methods of intensive site preparation—brush chopping, shearing and windrowing, and bedding on contour—were measured during the 1976 and 1977 water‐years on three small watersheds on steep terrain in northern Mississippi. After site preparation, the treated watersheds were fertilized, limed, sown with clover (Trifolium subterranean L.), and planted with loblolly pine seedlings (Pinus taeda L.). An undisturbed watershed served as a control. Site preparation exposed soil on 37% of the chopped watershed, on 53% of the sheared and windrowed watershed, and on 69% of the bedded watershed. First‐year sediment losses for the chopped, sheared, bedded, and control watersheds were 12.5, 12.8, 14.2, and 0.6 metric tons/ha, respectively. Sediment concentrations for the four watersheds were 2,471, 2,837, 2,808, and 2,127 mg/liter of stormflow. Most of the first‐year sediment losses occurred during months of highest stormflows, November, January, February, and March. Stream channel scouring was a major source of sediment on the site prepared watersheds.Second‐year sediment yields from the chopped, sheared, and bedded watersheds decreased to 2.3, 2.2, and 5.5 metric tons/ha, while sediment from the control watershed decreased to 0.1 tons/ha. Sediment concentrations were 670, 794, 2,346, and 393 mg/liter for the four watersheds. In relation to annual precipitation, total stormflow decreased on all treated watersheds the second year.
Cole Determination by Thermomechanical Analysis
Authors: Hajek B. F. 
Published: July 2010

AbstractThe coefficient of linear extensibility (COLE) is used as a criterion to differentiate vertic from typic subgroups. The ratio, (Lm − Ld) ÷ Ld, in which Lm is the length at 1/3 — bar moisture tension and Ld is the air‐dry length of a soil clod, is used to calculate this coefficient. Length changes can be obtained from measurements of moist and dry soil cores. COLE can also be calculated from moist and dry bulk density values. The objective of the study was to evaluate the use of the thermomechanical analyzer (TMA) for the measurement of soil ped length change as the ped is dried. The TMA unit is available as a plug‐in module for thermal analysis systems. Field moist (approximately at field capacity) and 1/3 — bar soil peds were selected from six soils and analyzed by this method. TMA‐COLE values from 0.126 to 0.010 were calculated from length change values. About 30 min was required for each measurement of field moist peds. This is a rapid procedure for shrinkage estimation since it requires essentially no preliminary preparation.
Dispersion in Soil Columns: The Snow Plow Effect
Authors: Starr J. L. , Parlange J.‐Y. 
Published: July 2010

AbstractMiscible displacement and tracer techniques were utilized to study the exchange and transport of cations in a column of soil with a low cation exchange capacity. The specific case studied was one in which an unlabeled CaCl2 solution was at least 10 times greater than that of the initially labeled Ca present in the soil solution and on the exchange. Most of the exchange was observed to take place at the front of the in coming solution, resulting in a labeled solute concentration at one pore volume of the breakthrough curve that is much greater than the initial concentration of the labeled soil solution and complete removal of initially adsorbed ions in two pore volumes. A theoretical approximation is developed which predicts the phenomenon adequately.
Variability of Mechanical Impedance in a Tilled One‐hectare Field of Norfolk Sandy Loam
Authors: Cassel D. K. , Nelson L. A. 
Published: July 2010

AbstractThe spatial variability of field‐measured values of mechanical impedance makes it difficult to detect significant differences in impedance effected by different management and/or tillage practices. This study was conducted to examine sources of cone index (CI) variation and to develop models to predict CI in a 1‐ha field of Norfolk sandy loam for three different tillage practices.Cone index measurements, obtained using a hydraulic cone penetrometer, were collected in four randomized blocks (B) for each of three tillage treatments imposed prior to planting. Tillage treatments were mold‐board plowed plus disked (N); chiselplowed (C); and subsoiled plus bedded (S). Penetrometer probes in each plot were taken at seven positions (P) on four transects normal to the soybean [Glycine max (L.) Merr.] rows and to a depth (D) of 41 cm. The maximum CI value within the 0‐ to 14‐, 14‐ to 28‐, and 28‐ to 41‐cm depth increments for each probe was used in the statistical analyses.The best predictive model for each tillage treatment was selected based upon the correlation coefficient, coefficient of variation, standard deviation, and the normality of the residuals as tested by the Kolmogorov‐Smirov statistic. Using these statistics, it was determined that the CI data must undergo a log transformation prior to model development. As much as 40% of the observed spatial variability for treatment N was explained by the full model. The depth variable (D) was the only significant term. The D, P, and P × D terms in the CI model were significant at the 0.01 probability level for treatment S and the full model containing these terms accounted for 71% of the variation. Finally, the D and B terms were significant at the 0.01 probability level and the model accounted for 63% of the spatial variability encountered in treatment C.
An in‐situ Dewpoint Hygrometer for Soil Water Potential Measurement
Authors: McAneney K. J. , Tanner C. B. , Gardner W. R. 
Published: July 2010

AbstractAn in situ device for determining the soil water potential by measuring the dewpoint temperature depression is described. A saturated ceramic plug is used to provide hydraulic contact between the soil and an air‐tight measuring chamber housing a four‐terminal thermojunction. The ceramic and the thermojunction references are thermally clamped to the copper body of the instrument in order that temperature differences between the vapor source (the internal evaporating surface of the ceramic) and the reference junctions are minimal. Thus, the device reduces the major source of error that plague conventional soil psychrometers in the presence of temperature gradients. A hygrometer placed perpendicular to an imposed thermal gradient in a soil column recorded a maximum zero offset voltage of 0.22 µV as compared with 130 µV from a Wescor psychrometer under the same conditions.Provided the ceramic remains saturated, the response of the hygrometer to changes in soil water matric potential is extremely rapid. Two bean plants (Phaseolus vulgaris L., c.v. “Tender‐green”) growing in a 2‐liter container of silt loam soil were subjected to wetting and drying cycles in the laboratory. Simultaneous measurements of leaf and soil water potential illustrate the capacity of the soil hygrometers to track changes in soil water matric potential.In the presence of solutes, the instrument is diffusion limited. The time constant for salt equilibration, with our geometry and using KCl as the solute was 23 hours. This is consistent with a diffusion coefficient of 2 to 3 × 10−6 cm3 sec−1. For this reason the application of this design should be restricted to circumstances where the osmotic contribution to the total water potential is either small or not changing rapidly. These criteria are generally satisfied in the humid regions.
Sulfuric Acid Treatment of Calcareous Soils: Effects on Phosphorus Solubility, Inorganic Phosphorus Forms, and Plant Growth
Authors: Ryan John , Stroehlein Jack L. 
Published: July 2010

AbstractThe purpose of this study was to examine the effects of acid (H2SO4) application on three P‐deficient calcareous Arizona soils. The acid was mixed with the soils in order to reduce their respective buffering capacities, as measured by the acid titratable basicity (ATB), by 20, 40, 60, 80, and 100%. Two soils, Cave and Comoro, were cropped with tomatoes (Lycopersicum esculentum) after treatment. Significant responses in dry matter yield and P uptake persisted through three successive growth periods. Treatment significantly increased water‐soluble P and P‐supplying‐capacity of the soils. Increasing the H2SO4 rate reduced the H2SO4‐P fraction, increased NH4Cl‐P and NH4F‐P, and to a lesser extent NaOH‐P but had little effect on reductant soluble‐P. Both extractable Al and Fe increased with increasing amounts of H2SO4 applied. Though difficulties may be encountered in field application, these results show that H2SO4, a waste product mainly from the copper smelting industry, has potential for improving P‐deficient calcareous soils.
Microbial Effects on Soil Erodibility
Authors: Gasperi‐Mago Rafael Ricardo , Troeh Frederick R. 
Published: July 2010

AbstractThis study was undertaken to evaluate the effects of three microbial species on soil erodibility. Sterilized Ames (a Typic Albaqualf) and Nicollet (an Aquic Hapludoll) soils were inoculated with species of Pseudomonas, Streptomyces, and Penicillium. After 15 days of incubation, both treated and untreated soils were subjected to artificial rainfall to measure their erodibility. The Ames soil averaged 23% more runoff and 34% more sediment in the runoff than Nicollet, but 2.25 times as much Nicollet soil as Ames soil was caught on splashboards. Soil loss from sterile soil was more than from any other treatment, and that from the fungal treatment was the least. The unsterilized soil had runoff and erosion approximately equal to the average of the bacterial, actinomycetes, and fungal treatments used. The results show that all of the microbial treatments used had significant positive effects on erosion resistance and that the Penicillium sp. had the strongest effect.
Soil Water in Coarse Fragments
Authors: Hanson Carolyn T. , Blevins R. L. 
Published: July 2010

AbstractThe amount of availability of water contained in coarse fragments is often considered to be negligible, but may in fact play an important role in the water relations of soils containing numerous coarse fragments. The objective of this study was to measure the availability of water contained in two contrasting types and several size fractions of fragments. Field capacity, −15 bar potential, and wilting point (WP) measured by plant extractions were made on sandstone fragments from the surface layers of Cutshin soil and shale fragments from a Colyer soil. The sandstone fragments contained about 11% available water by volume, and the shaly fragments contained 23% available water by volume based on WP measurements by plant removal in the greenhouse. The −15 bar potential determined in the laboratory compared closely with WP measured by plant removal for the sandstone fragments, but the −15 bar potential indicated higher levels of moisture retained in the shale fragments than WP as determined in the greenhouse.
A Simplified Ethylene Glycol Monoethyl Ether Procedure for Assessment of Soil Surface Area
Authors: Cihacek L. J. , Bremner J. M. 
Published: July 2010

AbstractStudies with 33 soils selected to obtain a wide range in properties showed that the surface area values obtained by an ethylene glycol monoethyl ether (EGME) procedure that omitted the customary pretreatments to remove organic matter and saturate the soil sample with Ca2+ were similar to, and very highly significantly correlated with, the values obtained when these time‐consuming pretreatments were included. The surface area values obtained by the simplified EGME procedure were very highly significantly correlated with the clay contents and cation‐exchange capacities of the soils studied.
The Use of a Transformed Boundary Condition in Modelling Air Compression During Infiltration
Authors: Watson K. K. , Curtis A. A. 
Published: July 2010

AbstractA computer‐based numerical analysis incorporating a time‐dependent surface boundary condition transformation is of value in modelling the air compression effects which occur during ponded infiltration in bounded columns. However, the transformation requires clarification when used with materials which exhibit a well‐defined water entry value. Since the capillary pressure head has no meaning in the saturated zone, which develops from the surface downwards during the infiltration process, it is necessary to define a pseudocapillary pressure head for this zone. This concept assists in developing a consistent qualitative argument showing that the one‐phase, one‐dimensional analysis accurately models the bounded flow regime. The condition which governs the termination of the analysis upon air escape is also considered.
Solubility and Equilibria of Zinc in a Flooded Soil
Authors: Gilmour J. T. , Kittrick J. A. 
Published: July 2010

AbstractSoil solution composition data were obtained for flooded Crowley silt loam soil. These data were analyzed with a computer program which corrected for ion‐pair formation and computed soil solution Zn activities at 0, 50, and 90% complexation by soluble organic species. The computed values were compared to predicted soil solution Zn activities which would occur if ZnCO3(c), Zn2SiO4(c), Zn3(PO4)2·4H2O(c), or ZnS(c) were the controlling solid phase. Under flooded soil conditions, ZnS(c) was the only possible solid phase which could be controlling soil solution Zn activity, assuming that the H2S(g) pressure in the soil solution was similar to that of atmospheric air [pH2S(g) = 10.3] and that between 50 and 90% of solution Zn was complexed by organic species. Under laboratory conditions where H2S(g) levels were thought to be much lower than unpolluted air, both Zn2SiO4(c) and ZnCO3(c) appeared to be potential solid phases. Zinc phosphate, Zn3(PO4)2·4H2O,(c), was too soluble to control solution Zn in this soil.
The Microbiological Formation of Basic Ferric Sulfates: II. Crystallization in Presence of Potassium‐, Ammonium‐, and Sodium‐Salts
Authors: Ivarson K. C. , Ross G. J. , Miles N. M. 
Published: July 2010

AbstractSolutions of ferrous sulfate (pH 2.95) containing equivalent amounts of K+, NH4+, or Na+, either singly or in pairs, were inoculated with the iron‐oxidizing bacterium (Thiobacillus ferrooxidans) and allowed to incubate for 42 weeks. Successive quantitative analyses of the alkali cations in the single cation systems showed that after 3 to 4 weeks, virtually all of the K+ in solutions had reacted to form jarosite [KFe8(SO4)2(OH)6]. On the other hand, after 42 weeks, about 80% of the NH4+ and 60% of the Na+ had entered into their respective basic ferric sulfates—ammoniojarosite [NH4Fe3(SO4)2(OH)6] and natrojarosite [Na Fe3 (SO4)2(OH)6]. Progressive increases in peak intensities of the resultant X‐ray diffractograms and rates of acid production in solution agreed very well with rates of jarosite formation. In systems containing two alkali cations, solid solutions formed and the rate at which each cation disappeared from solution was similar to that in the single cation systems.The results are in accord with reported field analyses of acid sulfate soils, i.e., jarosite is the most abundant basic ferric sulfate in these soils and the soils invariably contain Fe2+ and T. ferrooxidans.
Effect of Moisture on the Survival of Rhizobium in Soil
Authors: Osa‐Afiana L. O. , Alexander M. 
Published: July 2010

AbstractRhizobium trifolii and Rhizobium japonicum survived in higher numbers in Collamer silt loam at 10% than at 22, 35, and 45% moisture levels. The rate of R. trifolii decline at the three higher moisture levels was initially rapid, but then the rate slowed. At 22, 35, and 45% moisture, fewer R. trifolii and R. japonicum survived in nonsterile than in sterile soil, and indigenous protozoa grew in response to addition of the root‐nodule bacteria to the nonsterile silt loam. The rate and extent of decline of both species in flooded soil were more marked if sucrose was added; in such soil, R. trifolii died more rapidly and its population reached lower numbers. Bdellovibrio was not detected as the rhizobial density declined. Butyric, acetic, propionic, and formic acids accumulated and the pH fell below 6.0 in the sugar‐amended flooded soil, but no marked accumulation of the first three microbial products and no comparable pH fall occurred in flooded soil receiving no sucrose. Liming the sugar‐amended flooded soil enhanced R. trifolii survival but still led to organc acid accumulation. The data suggest a role for protozoa at moderate moisture levels and for organic acids acting at low pH in flooded soils in the decline of Rhizobium populations.
Decomposition in Soil of Emodin, Chrysophanic Acid, and a Mixture of Anthraquinones Synthesized by an Aspergillus glaucus Isolate
Authors: Linhares L. F. , Martin J. P. 
Published: July 2010

AbstractA. glaucus synthesized 17 – 22 anthraquinones, and one to four phenolic compounds depending on cultural conditions and incubation time. The anthraquinones extracted from the culture media were equivalent to 10% or more of the total mycelium plus melanin polymers recovered. Based on two‐dimensional thin‐layer chromatography and cochromatography with reference compounds before and after separation on a silica gel column and on UV spectra, dominant anthraquinones included emodin, catenarin, physcion, erythroglaucin, endocrocin, and probably parietinic acid and questin. One of the phenols was orcinol. The anthraquinone mixtures, synthesized by A. glaucus under different cultural conditions, were only slowly degraded in soil. During a 12‐week incubation period the C losses ranged from 11 – 23%, while 69 and 47%, respectively, of emodin and chrysophanic acid C were evolved as CO2. Emodin when “linked” into peroxidase polymers was relatively stable to biodegradation during the earlier stages of incubation only. When in intimate physical association with a model humic acid‐type polymer, little protection was observed. The 14C‐labeled A. glaucus anthraquinone mixture when “linked” to phenolase polymer showed a biodegradability reduction from about 25 – 11% during 12 weeks.
Effect of Camping on Surface Soil Properties in the Boreal Forest Region of Northwestern Ontario, Canada
Authors: Monti P. W. , Mackintosh E. E. 
Published: July 2010

AbstractChanges in surface soil properties along a gradient of increasing intensity of recreational use was investigated for two vegetation units, Pinus banksiana and Populus tremuloides, in the Boreal Forest Region of northwestern Ontario. The initial changes involve the compression and loss of surface leaf litter followed by formation of a thin, compacted mineral layer at the soil surface. Porosity photograms show that the content of macropores in the size range 300 to >3,000 µm were reduced by up to 60% in this layer, and pores >2,000 µm were almost entirely eliminated. Infiltration rates were correspondingly reduced to 0.1 cm/hour.The importance of processes operating at the leaf litter‐mineral soil interface in this environment are emphasized and discussed in relation to development of campsite rehabilitation programs.
A Thermal Conductivity Probe Designed for Easy Installation and Recovery from Shallow Depths
Authors: Sophocleous Marios 
Published: July 2010

AbstractExisting designs of thermal conductivity probes were modified in order to build a probe suitable for easy installation and recovery from shallow depths above or below the water table in unconsolidated deposits. The performance of the thermal conductivity probe described here was compared to a recent probe design with satisfactory results; it was also successfully tested in the field.
An Analytical Solution to Solute Transport Near Root Surfaces for Low Initial Concentration: II. Applications
Authors: Cushman John H. 
Published: July 2010

AbstractExamples are presented to illustrate the affects of changing the outer radius (r1), and the ratio of root absorbing power to inward flux of water (k/vo) on nondimensional concentration as a function of nondimensional time and distance. The examples presented are based on the analytical solution to two flow situations (see Part I). A method is also presented to show how simple solutions can be constructed for the flow problem involving only trigonometric functions.
Effect of Montmorillonite and Trace Elements on the Growth of Penicillium frequentans: I. Ammonium Nitrogen Source
Authors: McCormick R. W. , Wolf D. C. 
Published: July 2010

AbstractIn laboratory studies, the addition of clay to culture media has been shown to increase microbial growth and metabolic activity. The objective of this study was to determine the influence of montmorillonite clay and three trace element treatments on the growth of Penicillium frequentans with NH4‐N as the N source.The fungus was grown in 100 ml of a defined basal medium with glucose as the carbon‐energy source and NH4Cl as the N source. The trace element treatments were (i) no trace elements, (ii) trace‐element solution 1 which contained the following final concentration of trace elements (µg/ml): FeSO4·7H2O, 0.20; ZnSO4·7H2O, 5.0; CuSO4·5H2O, 0.02; CoSO4·7H2O, 0.02; Na2MoO4·2H2O, 0.02; and H3BO3, 0.10; and (iii) trace element solution 2 which contained a 0.1M pH 6.0 phosphate buffer plus the following final concentration of trace elements (µg/ml): Fe2(SO4)3·nH2O, 10.0; ZnSO4·7H2O, 2.5; CuSO4·5H2O, 0.5; CoCl2·6H2O, 1.5; Na2MoO4·2H2O, 2.5; H3BO3, 0.5; MnSO4·H2O, 1.0; and CaCl2, 10.0. Either clay, at a concentration of approximately 500 mg/100 ml, or distilled water (controls) was added in dialysis tubing to the trace‐element treatments.In the no trace element treatment, the biomass of the control was increased from 624 to 1,211 mg with the addition of clay. In the trace‐element solution 1, biomass was increased from 1,084 to 1,197 mg with the addition of clay. In both treatments, the addition of clay increased CO2 evolution, glucose and N utilization, and the economic coefficient of cell synthesis. Neither biomass nor metabolic activity was increased in the trace element‐solution 2 with clay addition. There were no significant differences in biomass production among the no trace element treatment with clay, the trace‐element solution 1 with clay, and the trace‐element solution 2 with or without clay. Except for the trace‐element solution 2, which contained a phosphate buffer, the addition of clay resulted in a decrease in the pH of the medium. In all three treatments, the addition of clay increased the Cu and Fe content of the fungus. With the addition of clay, the Zn content of the fungus increased in all treatments except the trace element solution 1. After fungal growth, the structural Zn and Cu contents of the clay, in the no trace‐element treatment, were reduced from 51 to 21 µg/g and 37 to 21 µg/g, respectively.It appeared that P. frequentans removed trace elements from the clay for growth which accounted for a large portion of the stimulation in growth due to clay.