bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of Phosphorus Application Rate, Soil Properties, and Leaching Mode on 32P Movement in Soil Columns
Authors: Logan T. J. , McLean E. O. 
Published: July 2010

AbstractMovement of 32P‐labeled monocalcium phosphate was investigated in column experiments with P application rate, P‐fixation capacity, and mode and intensity of leaching as variables. Three soils of contrasting texture and P‐fixation capacity were studied. Leaching of P increased with P application rate and intensity of leaching. Constant head leaching resulted in greater movement of 32P out of the surface layer and greater accumulation in the leachate than intermittent leaching. In general, 32P recovered in the leachate was nonionic except in instances where maximum leaching occurred. Significant amounts of 32P were recovered in the leachate only with sandy loam soil and at the highest P application rate.
Complementary Ion Effects on Potassium, Sodium, and Calcium Displacement from Bi‐Ionic Bentonite and Illite Systems as Affected by pH‐Dependent Charges
Authors: McLean E. O. , Bittencourt V. C. 
Published: July 2010

AbstractBi‐ionic systems of bentonite and illite clay suspensions containing K‐Ca, K‐Na, and Na‐Ca were prepared in reciprocal saturation ratios at 100, 90, and 80% base saturations of bentonite and at 100, 80, and 60% saturations of illite. Each system was equilibrated with equal volumes of water, and then aliquots of each suspension were extracted with water, BaCl2, or HCl at 0.1 or 0.3 symmetry concentrations.Displacement of a given cation varied greatly depending on the accompanying cation adsorbed to the exchange sites of the clays. This complementary ion effect, although occurring on both types of charge, was much greater when the exchange was from pH‐dependent charges. Thus, maximum complementary ion effects on K and Na displacement were at low saturations of the clays with these cations, while these effects on Ca displacement were greatest at high Ca saturations. Since BaCl2 generally displaced more basic cations from pH‐dependent charges than did HCl, the combined effects of higher valency of Ba and higher pH of displacement in BaCl2 than in HCl evidently were greater than the single effect of preferential H‐bonding to pH‐dependent charges.
Influence of Simulated Fall and Spring Conditions on the Soil System: III. Effect of Method of Simulating Spring Temperatures on Ammonification, Nitrification, and Microbial Populations
Authors: Campbell C. A. , Biederbeck V. O. , Warder F. G. 
Published: July 2010

AbstractExperiments were carried out to determine (i) how different methods of simulating spring temperatures affect soil microbial activity, and (ii) the interactions between different types and amounts of added‐N and these temperature effects.In soil amended with mineral‐N, ammonification (change in NO3‐N + NH4‐N) was inversely proportional to the amount of added‐N when incubated at 8.5C, but ammonification was not affected by amount of N when incubated at fluctuating temperatures. When peptone‐N was added to soil, ammonification was unaffected by the method of simulating spring temperature conditions.In unamended soil and soil amended with 10 ppm NH4‐N, nitrification was greater at 8.5C than at square‐wave 14 to 3C. When peptone‐, NH4‐, or NO3‐N was added to soil, nitrification at 8.5C was generally equivalent to that at square‐wave 14 to 3C, but less than that at sine‐wave 14 to 3C. Where peptone‐N was added nitrification was > NH4‐N added > NO3‐N added.In unamended soil, fluctuating temperature cycles were deleterious to the three major groups of microorganisms but were particularly detrimental to the nonsporeforming, gramnegative bacteria. Square‐wave fluctuating temperature was more deleterious than sine‐wave; the constant temperature regime was not deleterious. The deleterious effect of fluctuating temperatures was partially alleviated by addition of 25 ppm NH4‐N.It was suggested that the protoplasmic materials released from the cells killed as a result of the fluctuating temperatures served as a ready source of N and energy substrate (much like the peptone amendment) for use by the surviving microbial populations.
Transformation of Propanil‐Derived 3,4‐Dichloroaniline in Soil to 3,3′,4,4′‐Tetrachloroazobenzene as Related to Soil Peroxidase Activity
Authors: Burge W. D. 
Published: July 2010

AbstractContrary to reports in the literature, no correlation was found between the peroxidase activity of five soils or the numbers of peroxidase‐producing microorganisms and the abilities of the soils to condense 3,4‐dichloroaniline (DCA) derived from the hydrolysis of N‐(3,4‐dichlorophenyl) propionamide (propanil) to 3,3′,4,4′‐tetrachloroazobenzene (TCAB). Amending the soils with an energy source increased the production of peroxidase extractable from the soil but decreased the amount of TCAB formed. It has been reported that a peroxidase‐producing fungus isolated from soil was capable of converting DCA to TCAB. However, peroxidase isolated directly from a soil of this study was incapable of converting DCA to TCAB. Apparently not all soil peroxidases catalyze the conversion.
Use of Physical Methods to Expand Soil Survey Interpretations of Soil Drainage Conditions
Authors: Bouma J. 
Published: July 2010

AbstractClassification systems of soil drainage conditions are used in the soil survey program to characterize hydrodynamics of soils in the field and these data are used for soil survey interpretations. Estimates of soil permeability and internal soil drainage, based mainly on inferences made from morphological features, and an estimate of runoff are used in the Soil Survey Manual to determine the placement of a soil in one of seven drainage classes. Different soil moisture regimes are defined in the new soil taxonomic system in terms of measurements made in situ. These methods do not provide the quantitative data needed for predicting what soil behavior will be under environmental conditions that have changed temporarily or permanently. Complex numerical procedures and simple approximate physical methods, both requiring hydraulic conductivity and moisture retention data, can be used to calculate hydrodynamic soil behavior for a variety of simplified boundary conditions. Two approximate methods were applied to four Wisconsin soils in which measurements of hydraulic conductivity had been made in situ. This work revealed that two soils that had been placed previously in different drainage classes on the basis of differences in soil mottling, actually had comparable hydrologic properties.
Coincidence and Interference Corrections for Dual‐Energy Gamma Ray Measurements of Soil Density and Water Content
Authors: Mansell R. S. , Hammond L. C. , McCurdy R. M. 
Published: July 2010

AbstractCoincidence and interference errors in the dual‐energy gamma ray attenuation method are discussed for simultaneous determination of water content and bulk density of soil columns. Collimated radiation from 300 mCi each of 241Am and 137Cs provides a high intensity beam comprised of 60 and 662 keV photons. Count rates measured by a single detector and a two‐channel gamma spectrometer were corrected for coincidence losses due to pulse‐resolving time. The lower energy channel counts were also corrected for Compton scattering of Cs radiation and for a counting loss attributable to a special coincidence interference.Mass attenuation coefficients were determined for glass beads, water, and eight soil materials. Errors in soil water content measurement by the dual‐energy gamma attenuation method appears to be restricted to standard deviations of approximately 1% due to practical limitations in measurement precision of 60 and 662 keV attenuation coefficients for soil and water.
Theory of a Rectangular Gravel Envelope in Drainage Design
Authors: Kirkham Don , Selim M. Sami 
Published: July 2010

AbstractA theory was developed to determine the radius of a circular drain which is equivalent to a square drain. A square drain is encountered in practice when a gravel envelope of square cross section is placed around a subsurface circular drain. The resistance of the gravel to flow was neglected. The square cross section of the envelope measured 4a2. The square drain tube was analyzed for two cases: (i) when an impermeable barrier was at great depth below the square drain tube center, and (ii) when the bottom edge of the square drain tube lay on a plane subsoil impermeable barrier. In both cases it was assumed that the length of 2a of the edge of the square drain tube was small compared with the distance from the drain's center to a water table over the drain and that the drain ran full. It is shown for Case 1 that an equivalent circular drain tube of radius 1.1772a may be used to replace the square drain tubes. If the square drains lie on the impervious layer, as in Case 2, the radius of the equivalent circular drain is 1.1037a.
A New Approach to Soil Testing: II. Ionic Equilibria Involving H, K, Ca, Mg, Mn, Fe, Cu, Zn, Na, P, and S
Authors: Baker Dale E. 
Published: July 2010

AbstractSeveral experiments were conducted in an effort to modify a new approach to soil testing in which the equilibrating or testing solution contains each element for which the soil is being tested. This report includes results for modification which caused 15 soils to differ more with respect to test levels of Mn, Fe, Zn, Cu, S, and P without substantially changing their rankings for K, Ca, and Mg. Modifications included the incorporation of a preservative, a flocculating agent, a pH buffer, DTPA, and several additional elements to maintain a relatively constant activity coefficient for each element in different soils.Results concluded that the adsorption equilibria soil test can be used successfully to test for several elements. The approach for calculating soil requirements is given for P. Although the test shows promise by indicating soil differences, additional calibration data will be required prior to routine use of the method.
Soil Characteristics of the Forest‐Prairie Ecotone in Northwestern Minnesota
Authors: Severson R. C. , Arneman H. F. 
Published: July 2010

AbstractPhysical, morphological, and chemical properties of a continuum of soil pedons expressing the developmental range from Haploboroll (Chernozem) to Eutroboralf (Grey Wooded) were studied in northwestern Minnesota. The abrupt nature of the forest‐prairie boundary and the abrupt change in physical, chemical, and morphologic properties of the soil pedons associated with this boundary do not reflect the gradual nature of the climatic or topographic gradients which occur across this area. The postglacial vegetation history for the area is documented and changes in soil development are related to this history.
Infiltration, Hydraulic Conductivity, and Resistance to Water‐Drop Impact of Clod Beds as Affected by Chemical Treatment
Authors: Gabriels D. M. , Moldenhauer W. C. , Kirkham Don 
Published: July 2010

AbstractChemicals were sprayed on large dry surface clods (8 to 20 mm) and small surface clods (2 to 8 mm) of a Clarion loam to test their effectiveness in preventing erosion during rainfall. The small clods were initially wetted with 15% water on a soil weight basis and mixed with bitumen emulsions. The large and small clods were subjected to a 6.35‐cm‐per‐hour simulated rainfall under controlled conditions in the laboratory. Simultaneously with the measurements of infiltration rate, determinations were made of (i) the starting time for initial runoff, (ii) energy needed to initiate runoff, (iii) runoff rate, (iv) total soil loss, and (v) final soil loss rate.Surface applications of most of the soil conditioners on large clods applied at high enough rates kept the infiltration rate high and prevented runoff on a 9% slope. Polyvinyl alcohol and polyacrylamide prevented any soil loss during 90 min.Surface applications with bitumen emulsions were also highly effective in preventing erosion of large clods but were less effective for small clods. When the bitumen emulsions were mixed with the small clods, the saturated hydraulic conductivity was very high. The infiltration rate was low because water would not enter the clod bed and stable clods were carried in the runoff water.
Priming Effect of 15N‐Labeled Fertilizers on Soil Nitrogen in Field Experiments
Authors: Westerman R. L. , Kurtz L. T. 
Published: July 2010

AbstractEvidence of the “priming effect” on the uptake of soil N by additions of rather conservative amounts of fertilizer N was examined in data from two recently reported field experiments. In these experiments, urea and oxamide each labeled with 15N were compared on adjacent locations in successive years with ‘Sudax SX11’ Sorghum‐sudan hybrid (Sorghum sudanense) as the test crop. The priming effect in the first experiment was calculated from data from four cuttings during the first year and from a residual cutting during the second year. For the second experiment, data were used from the three cuttings harvested during the year the fertilizers were applied.Additions of N fertilizer increased the uptake of soil N by 17 to 45% in the first experiment in 1966 and by 8 to 27% in the second experiment in 1967. In the residual cutting of the first experiment, increases in uptake of soil N ranged from less than 0 to 29%. The increase in uptake of soil N by the crops was speculated to be due to stimulation of microbial activity by N fertilizers which increased mineralization of soil N, thus making more soil N available for use by plants.
Effect of Forest Cover Removal on Depth of Soil Freezing and Overland Flow
Authors: Sartz Richard S. 
Published: July 2010

AbstractDepth of soil freezing and overland flow were measured under four hardwood forest conditions in southwestern Wisconsin: woody vegetation cut and removed; all vegetation cut and removed; uncut forest with litter removed; and undisturbed forest. Removing only the litter and removing all the vegetation increased both soil freezing depth and overland flow. Removing only the woody vegetation decreased both. Frost‐depth means in a year of deep frost were 6 and 11 cm on the woody vegetation removed and undisturbed plots, and 19 and 35 cm on the all vegetation‐removed and litter‐removed plots. Overland flow values ranged from less than 1 cm on the woody vegetation‐removed plots to more than 7 cm on the all vegetation‐removed and litter‐removed plots. The increases in frost depth and overland flow appeared to be related to changes in soil bulk density and porosity.
Forest Windthrows and Their Influence on Soil Morphology
Authors: Armson K. A. , Fessenden R. J. 
Published: July 2010

AbstractThe variability in thickness of the O and A2 horizons was studied on a sandy loam forest soil in the Great Lakes‐St. Lawrence Region of southern Ontario. Horizon thicknesses were recorded in 1.3 cm (0.5 inch) classes for each 10.2 cm (4 inches) of horizontal distance on the faces of each soilpit. Soilpits were located both subjectively on windthrows and randomly in the study area. Thickness frequency distributions for O horizons were normal and for the A2 horizons Poisson‐like. Both were independent of recent fire history and sampling method. It may be inferred that the disturbance by windthrow is infrequent in relation to O horizon formation, but frequent relative to A2 horizon development. Microtopographic position had a slight effect; thicknesses in top positions being somewhat less than for bottom positions. Horizon distortions related to windthrow disturbance were recorded for only 19% of the soil profiles sampled.
The Simultaneous Effect of pH and Chloride Concentrations upon Mercury(II) as a Pollutant
Authors: Hahne H. C. H. , Kroontje W. 
Published: July 2010

AbstractThe mercuric ion, compared to other heavy metal pollutants, hydrolyzes at low pH values and forms soluble chloride complexes at low chloride concentrations. To evaluate the possible implications of such behavior in natural aquatic systems, Hg(II) hydroxy and chloride species distributions were calculated using pH and chloride ion concentrations as variables simultaneously. Range in pH values selected was from 2 to 9 to cover conditions encountered in acid mine drainages, rivers, all types of soil solution extracts, and sea‐water. In addition, a study was performed in which montmorillonite, illite, and kaolinite were equilibrated with different HgCl2 solutions. The range of HgCl2 concentrations in equilibrium solutions was 1.25 × 10‐4M to 0.005M.Results of the calculations show that chloride complexes compete effectively with the hydroxy complexes of Hg(II). The chloride and hydroxy complexes may contribute appreciably to the mobilization of Hg(II). The mobility of Hg(II)‐hydroxide is limited by the intrinsic solubility of Hg(OH)2. At pH 4 and 5, chloride ion concentrations of 3.5 and 14 ppm, respectively, are sufficient for all Hg(II) to be in the HgCl2° form. At higher pH values, partial to complete mobilization is possible depending on the prevailing chloride and Hg(II) concentrations. The equilibria study with the clay minerals revealed that little or no Hg(II) was adsorbed. The chloride ion concentrations of the equilibrium solutions varied between 1.4 and 14 ppm and pH values ranged from 3.68 to 4.90.
Effect of Rainfall and Subsequent Drying on Nitrogen and Phosphorus Changes in a Dryland Fallow Loam
Authors: Campbell C. A. , Biederbeck V. O. , Warder F. G. , Robertson G. W. 
Published: July 2010

Abstract36Chloride placed at 15‐ or 30‐cm depth in 15‐cm diameter cylinders of fallow loam was leached to at least 50 cm during and immediately following rainfall > 1.75 cm. As the soil dried following rainfall 36Cl moved upwards. Nitrate content of leachates from a lysimeter experiment corroborated the leaching aspects of the 36Cl expcriment.In the 0‐ to 2.5‐cm segment of a second‐year fallow loam which was sheltered from rainfall, moisture was below the wilting percentage and NO3−N and bacterial numbers declined as the soil gradually dried out. In the 2.5‐ to 15‐cm segment, moisture was in the available range, yet moisture and NO3‐N changes were small.In unsheltered fallow loam, NO3‐N production in the 0‐ to 2.5‐cm depth was primarily a function of soil moisture change: ΔNO3−N = −0.55 − 1.11 ΔM, (r = −0.94**), and ΔNO3‐N = −0.45 ‐ 0.56 ΔM, (r = −0.81*) in the second‐ and first‐year fallow, respectively; (M = % moisture and Δ = daily change). The increase in NO3‐N during drying seemed to be more a result of upward movement than of nitrification. There was a negative linear relationship between ΔNO3‐N and Δ bacteria in the 0‐ to 2.5‐cm soil segment. Sodium bicarbonate soluble inorganic P (IP) generally exceeded NaHCO3 soluble organic P (OP). In second‐year fallow, P was unaffected by environmental conditions. In first‐year fallow ΔIP in the 0‐ to 2.5‐cm segment was directly related to rainfall (r = 0.98**), to ΔM (r = 0.97**), and to Δ bacteria (r = 0.88**), and inversely related to ΔNO3‐N (r = −0.76*).
The Effect of Exclusion Volume on Potentiometric Nitrate Measurement
Authors: Gilmour J. T. , Scott H. Don 
Published: July 2010

AbstractData are presented which show that large anion exclusion volumes can occur when montmorillonitic soils, low in total salt, are extracted with water. Nitrate measurements on such extracts with the nitrate specific ion electrode reflect this exclusion volume induced error. A possible solution to the problem is suggested.
Evaluation of Water Flux Above A Deep Water Table Using Thermocouple Psychrometers
Authors: Enfield C. G. , Hsieh J. J. C. , Warrick A. W. 
Published: July 2010

AbstractDeep water flow was evaluated in a Washington desert environment using hydraulic conductivity and potential gradients. Thermocouple psychrometers and temperature transducers were installed to depths of 94 m in the soil profile and used to measure the potential gradients. The hydraulic conductivity was calculated using a modified Millington and Quirk equation and the soil moisture characteristic curve. The thermal fluid diffusivity was calculated and used to estimate flow induced by thermal gradients. Under the conditions studied, a more refined analysis of the thermally induced flow is required to give a definite answer as to the direction of flow. It was concluded, however, if flow existed at this location, it was less than 1 cm/year.
Estimates of Potentially Mineralizable Soil Nitrogen Based on Short‐Term Incubations
Authors: Stanford George , Carter J. N. , Smith S. J. 
Published: July 2010

AbstractNitrogen mineralization potentials were determined for a large number of soils by a method involving determination of N mineralized after several consecutive incubations at 35C under optimum soil water conditions. The determination of N mineralization potential, No, based on the first‐order equation, log (No − Nt) = log No − kt/2.303, is laborious and usually requires incubation periods of 8 weeks or more. From the present study, involving soils from major agricultural areas throughout the United States, it was demonstrated that No could be estimated reliably from the amounts of N mineralized during 2‐week incubations following preliminary incubations of 1 to 2 weeks. From the above first‐order equation, No = Nt/(1–10‐kt/2.303). Hence, for a 2‐week incubation (t = 2), No = 9.77Nt (Nt = N mineralized in 2 weeks and k is the rate constant, weeks‐1). Estimates of No from short‐term incubations were similar to those derived after extensive periods of incubation. Preincubation of soils is required in order to decompose plant residues and for other possible reasons noted. Estimates of No from preliminary incubations are meaningless. The implications of No as a basis for predicting amounts of soil N mineralized under fluctuating temperature and soil water conditions are discussed.
Isotopic and Nonisotopic Estimations of Fertilizer Nitrogen Uptake by Sudangrass in Field Experiments
Authors: Westerman R. L. , Kurtz L. T. 
Published: July 2010

AbstractRecoveries of fertilizer N in above‐ground portions of crops grown in field experiments were estimated by: (i) difference method; (ii) linear regression of total N in crops on rates of applied N; (iii) 15N isotopic tracer method; and (iv) linear regression of labeled fertilizer N uptake on rates of labeled fertilizer N. In order to evaluate the use of the isotope, these four methods were applied to data from previously reported experiments (Westerman, Kurtz, and Hauck, 1972) which involved two 15N‐labeled fertilizers (urea and oxamide) at rates of 0, 56, 112, and 168 kg N/ha. The test crop was Sudax (SX11) sorghum‐sudangrass hybrid (Sorghum sudanense) and harvests were made at approximately 30‐day intervals during the cropping seasons.The difference method overestimated recovery of urea and oxamide nitrogen in sudangrass 35 and 31%, respectively, in 1966 and 23 and 35% in 1967 when compared to the isotopic tracer method. Similarly, linear regression of total N in crops on rates of N overestimated recoveries of urea and oxamide nitrogen 32 and 17%, respectively, in 1966 and 17 and 21% in 1967 when compared to linear regressions of fertilizer N in crops on rates of 15N labeled nitrogen. Isotopically‐labeled fertilizers are almost a necessity for estimating N recovery in many agronomic experiments.