bluuebunny/crossref_metadata_2025_split huggingface dataset:
Soil Water Evaporation: First Stage Drying as Influenced by Surface Residue and Evaporation Potential
Authors: Bond J. J. , Willis W. O. 
Published: July 2010

AbstractEvaporation with time was measured from wetted columns of fine sandy loam treated with seven rates of surface residue in six runs with different evaporation potentials. First stage (constant rate) evaporation rate decreased with either increasing residue rates or decreasing evaporation potentials. Total water loss during first stage drying decreased as the rate of first stage evaporation increased. Conversely, water loss for the first 25 days following first stage drying increased as first stage evaporation rate increased. A linear relationship was established by log‐log plotting the duration of first stage drying versus first stage evaporation rate.
Canfield Silt Loam, a Fragiudalf: I. Macromorphological, Physical, and Chemical Properties
Authors: Miller F. P. , Holowaychuk N. , Wilding L. P. 
Published: July 2010

AbstractMore than a half‐million hectares of the moderately well‐drained Canfield soil and its toposequence members occur in northeastern Ohio and northwestern Pennsylvania. These fragipan soils derived from low‐lime glacial till are intensively used for both agricultural and urban purposes. Because this soil is being used for a long‐term study of the disposition of strontium‐90 under natural conditions and because its classification was unconfirmed, 18 profiles from the Ohio Agricultural Research and Development Center at Wooster were described and characterized. The soil profile tended to be bisequal with a moderately well‐developed, loam fragipan occurring at an average depth of 45 cm. The bulk density of the fragipan centered on 1.7, with coarse fragments occupying about 12–16% by volume. The Canfield series was found to contain an argillic horizon above the fragipan and was classed as an Aquic Fragiudalf assigned to the fine‐loamy, mixed, mesic family. The fragipan controls the hydraulic conductivity of this soil, resulting in lateral movement of percolating water across the fragipan surface equivalent to about 30% of the total precipitation. The quantity of subsurface runoff which must accrue from the long slopes, which sometimes exceed 300 m, poses a major problem for the use and management of this soil.
Pyrophosphate Hydrolysis in Flooded Soil
Authors: Hossner L. R. , Phillips D. P. 
Published: July 2010

AbstractRate of hydrolysis of pyrophosphate, applied as (NH4)3‐HP2O7·H2O, was measured in four soils under flooded and ⅓ atm moisture content. Hydrolysis was faster under flooded conditions than at ⅓ atm moisture. Pyrophosphate hydrolysis was determined to be a first‐order reaction under flooded conditions but not at ⅓ atm moisture content. The first‐order rate constants under flooded conditions ranged from 2.09 × 10‐5 min‐1 to 1.43 × 10‐4 min‐1 depending upon the soil and temperature of incubation. Half‐life values for applied pyrophosphate varied from 0.6 to 3.9 days. The activation energy for pyrophosphate hydrolysis under flooded soil conditions was calculated to be 4,500 cal/mole for a Katy sl soil.
A Statistical Method for Analysis of Diffusion in Soils
Authors: Nakano Y. , Murrmann R. P. 
Published: July 2010

AbstractA special Monte Carlo method for use in investigating problems which involve random processes is developed. This approach differs from the usual Monte Carlo method for solution of differential equations in that the random process itself is constructed directly. The power of this approach is demonstrated by application of the method using two examples. In one case, the effect of thermal gradient on ionic diffusion through thin films of interfacial water in frozen clay is examined. The predicted ionic distribution is in agreement both with experimental data and with the result obtained by exact solution of the diffusion equation. In the second example, the distribution of acetone deposited in soil near the soil‐atmosphere interface is calculated for a two‐layer profile in which the adsorption coefficient and void‐porosity vary between horizons.
Calculation of the Leaching required to Reduce the Salinity of a Particular Soil Depth beneath a Specified Value
Authors: Terkeltoub Richard W. , Babcock K. L. 
Published: July 2010

AbstractSoil columns containing either Yolo silty clay loam or Hanford sandy loam were prepared with vertically nonuniform salt (Na+, Ca2+, Mg2+, Cl‐) and moisture distributions and with gypsum (CaSO4 · 2H2O) present in the surface soil. The columns were irrigated at both fast and slow rates of water application with a water containing Na+, Ca2+, Mg2+, and Cl‐. A simple method for calculating salt movement in soils successfully approximated the resultant salt profiles.A variation in the salt movement computation method was devised for calculating the leaching required to lower the salinity of a particular soil depth to less than a specified value. The method was experimentally verified on both a Yolo and a Hanford soil column, each with vertically nonuniform initial salt and moisture distributions.
Fungal Growth Responses to Osmotic as Compared to Matric Water Potential
Authors: Adebayo A. A. , Harris R. F. 
Published: July 2010

AbstractThe osmotic and matric water potential characteristics of Phytophthora cinnamomi and Alternaria tenuis, fungi of widely different tolerance to water stress, were evaluated using agar media of varying nutritional status and three texturally different soils. The water potential of the agar media was controlled osmotically with KCl or sucrose. For the osmotic soil system, soil water content was maintained approximately constant and the desired water potential range was achieved by adding KCl solutions of different concentrations to air‐dry soil samples at a level equivalent to the water content of the field moist soils; for the matric system, decreases in water potential were achieved by adding decreasing volumes of water to air‐dry soil according to the moisture retention characteristics of the soils. Fungal growth was determined by measuring changes in colony diameter with time.Osmotic water potentials for optimum fungal growth in agar and soil systems were similar to the water potentials for optimum growth in soils of matric‐controlled water potential. However, with decreasing water potential both fungi were much less tolerant to matric than to osmotic stress, emphasizing that fungal response to decreasing soil water cannot be explained solely on a water potential basis, but must include consideration also of changes in other water‐related soil properties such as solute transport. Fungal responses to matric and osmotic water potential differences were not related to soil texture.From a practical standpoint, the matric potentials at which growth extinction occurred were numerically one‐half to two‐thirds of the corresponding osmotic potentials at which growth ceased. If this relationship holds for other fungi and other soils, fungal growth responses to water potential obtained using simple agar systems of osmotic‐controlled water potential should provide useful approximations of the matric water potential relations of fungi in soil, thereby facilitating prediction of the maximum soil water potential range within which specific fungi may develop competitively in natural soils.
Nitrification Inhibition in Soil: I. A Comparison of 2‐Chloro‐6‐(trichloromethyl)pyridine and Potassium Azide Formulated with Anhydrous Ammonia
Authors: Parr J. F. , Carroll B. R. , Smith S. 
Published: July 2010

AbstractThe relative effectiveness of 2‐chloro‐6‐(trichloromethyl) pyridine and potassium azide as nitrification inhibitors, formulated and applied to soil with anhydrous NH3, was compared in laboratory and growth chamber experiments. At an inhibitor level of 10 ppm, and after 14 days, NH4+ concentrations 0 to 2.5 cm from the point of release of NH3, NH3 + KN3, and NH3 + N‐Serve were 695, 810, and 887 ppm N respectively, while after 56 days corresponding values had decreased to 129, 316, and 609 ppm N. After 14 and 56 days of incubation in unplanted pots, KN3 was 60 and 40%, respectively, as effective as N‐Serve in suppressing nitrification. N‐Serve was more effective than KN3 during longer incubation periods because of its greater residual activity.In general, yields of ryegrass (Lolium sp.) and cotton forage (Gossypium hirsutum L.) followed the order of NH3 = NH3 + KN3 > NH3 + N‐Serve. The greater residual activity of N‐Serve compared with KN3 and the absence of root development in the center of the NH3 + N‐Serve retention zone, as well as the stunted and flaccid appearance of roots, was indicative of potential phytotoxicity of N‐Serve in this particular mode of application.
Transition Matrix Approach to Numerical Classification of Soil Profiles
Authors: Norris J. M. , Dale M. B. 
Published: July 2010

AbstractIn conventional classification of soil profiles the relative positions of pedogenic horizons within the profile are usually considered. In this paper numerical classification methods are described which consider the relative positions of samples in the profile. The methods are applied to twenty profiles, each described by eight field properties and eight laboratory tests determined on samples taken from 10 fixed depths. Results of these two numerical classifications are compared using an ordination procedure. Advantages and pedological applications of the methods are discussed.
A Test of the Uniqueness of the Soil Moisture Characteristic During Transient, Nonhysteretic Flow of Water in a Rigid Soil
Authors: Smiles D. E. , Vachaud Georges , Vauclin Michel 
Published: July 2010

AbstractQuick response water potential and nondestructive water content measurements indicate that during transient, nonhysteretic flow of water following a rapid change of water content at one end of a horizontal column of soil, the soil moisture characteristic curve is a unique function during sorption from a particular initial water content, but during desorption there is a multiplicity of curves. These transient curves depend on the magnitude of the imposed water content change and also on the speed with which static equilibrium is achieved after the change.The consequences of this behavior are discussed in terms of diffusion theory, and it is concluded that it would be unwise to apply this theory to desorption situations until the quantitative significance of this behavior is determined for other materials.
Effect of Liming on the Soil Test Level of Phosphorous as Determined By Three Methods
Authors: Griffin G. F. 
Published: July 2010

AbstractChanges in extractable P resulting from additions of Ca(OH)2 to samples of 13 acid Connecticut soils varied with soil type and soil extractant. The average pH increase from 5.3 to 7.7 resulted in the following average changes in extractable P: modified Morgan, +123%; North Carolina, +27%; Bray no. 1, −23%. Changes in Bray no. 1 extractable P were affected less by soil differences than changes in P extracted by the other two methods.
Nitrification Inhibition in Soil: II. Evaluation of Anhydrous Ammonia‐Potassium Azide Solutions in Eastern Washington
Authors: Papendick R. I. , Parr J. F. , Smith S. , Smiley R. W. 
Published: July 2010

AbstractThe effectiveness of potassium azide (KN3) as a nitrification inhibitor for field‐applied anhydrous NH3 was evaluated on a Naff silt loam in the winter wheat (Triticum aestivum L.) area of eastern Washington. Formulations of KN3 in liquid NH3 of 0, 2, and 6% (w/w) were applied to fallow soil in August 1969 at a rate of 112 kg N/ha (81‐cm spacing) with a special field applicator. The 2% formulation was also applied at a rate of 224 kg N/ha. The NH3 retention zone was sampled periodically through February 1970 and analyzed for NH4+‐N, NO2‐‐N, and NO3‐‐N. Both levels of KN3 were effective in reducing the nitrification rate during the early post injection period, but the higher level was more effective at later dates. Two months after application, the amounts of NO3‐‐N recovered from the retention zone as percent of total extractable N were 67, 48, and 36 for NH3 alone, NH3 + KN3 (2%), and NH3 + KN3 (6%), respectively. Percentage amounts of NO3‐‐N decreased with increase in N application rate. Nitrification inhibition due to KN3 was still evident 6 months after application, particularly at the high N rate. The inhibitory effect of low soil temperature during the winter months was also apparent. These results indicate that KN3 formulated with anhydrous NH3 was an effective nitrification inhibitor for this N source.
Rapid Analysis of Soil Nitrate with Chromotropic Acid
Authors: Sims James R. , Jackson Grant D. 
Published: July 2010

AbstractColorimetric analysis of nitrate in soil extracts using chromotropic acid (CTA) was studied and compared to the results obtained by the phenoldisulfonic acid (PDA) method. Extracting solutions of 0.5M MgSO4, saturated CaSO4, and a 0.2% Ca(OH)2 suspension were investigated. The three extractants were equally effective in recovering NO3‐; however, the clearest extracts were obtained with Ca(OH)2. Soil‐to‐extractant ratios of 1:2.5, 1:5, and 1:10 were studied. The 1:5 ratio effectively extracted NO3‐ and resulted in appropriate NO3‐ concentrations for color development. A shaking time of 15 min was adequate to extract a maximum of NO3‐. In a NO3‐‐N recovery study, equivalent amounts of NO3‐ were recovered by the CTA and PDA methods. Results of nitrate analyses by the two methods were significantly correlated (p = .01). Nitrate determined by the chromotropic acid procedure was positively correlated (p = .05) with the yield of winter wheat (Triticum aestivum L.) and was negatively correlated (p = .01) with response of winter wheat to N fertilizer additions. The new procedure has the advantages of rapidity, simplicity, sensitivity, and relative freedom from interference.
Domains and Quasi‐Crystalline Regions in Clay Systems
Authors: Quirk J. P. , Aylmore L. A. G. 
Published: July 2010

AbstractA number of terms have been used by different authors to describe regions of near‐parallel alignment of the plate‐shaped crystals in clay materials. This has resulted in some confusion through inadequate definition and misconceptions in the usage of these terms. Use of the term quasi‐crystal to describe the regions of parallel alignment of individual alumino‐silicate lamellae in montmorillonite and of the term domain to describe the regions of parallel alignment of crystals for illite and other fixed lattice clays is recommended in preference to terms such as tactoid or crystal of montmorillonite.The similarity in behavior of a domain of illite crystals and a montmorillonite quasi‐crystal is illustrated. These regions show a marked difference in swelling behaviour between sodium and calcium systems.
Nuclear Magnetic Resonance Spectra of Acetate Derivatives of Soil and Plant Inositol Phosphates
Authors: L'Annunziata Michael F. , Fuller Wallace H. 
Published: July 2010

AbstractAcetate derivatives of inositols found in soils and plants were prepared subsequent to the extraction of the inositols as phosphates. Yields as high as 88% were obtained with the acetylation of samples as small as 20 mg of the inositol. The increase in molecular weight of the inositol upon acetylation was advantageous due to the small amounts of inositols usually available from soils and plants. The nuclear magnetic resonance spectra (NMR) of these acetate derivatives permitted the observation of the number of axial and equatorial acetoxy groups. The axial or equatorial position of an alkyl substituent on one of the oxygen atoms was easily observed by means of the NMR spectra of the acetate derivative. Improved NMR spectroscopic techniques can permit the analysis of the stereochemistry of soil and plant inositol phosphates without the requirement of an authentic sample as a standard for comparison.
Illite Solubility
Authors: Routson R. C. , Kittrick J. A. 
Published: July 2010

AbstractEquilibrium solubilities of the 0.2–2.0µ size fraction of three K+‐saturated illites were determined in high‐pH aqueous solutions. Beavers Bend, Fithian, and Goose Lake illites were selected for the study. Solubility products were found to be 10‐77.6±0.1 for Beavers Bend, 10‐76.6±0.3 for Fithian, and 10‐76.7±0.2 for Goose Lake illites, based on mean calculated formulae of K0.53 (Al1.66, Fe0.20, Mg0.13) (Si3.62, Al0.39) O10 (OH)2, K0.64 (Al1.54, Fe0.29, Mg0.19) (Si3.51, Al0.49) O10 (OH)2, and K0.59 (Al1.58, Fe0.24, Mg0.15) (Si3.65, Al0.35) O10 (OH)2, respectively. From the solubility product and known thermodynamic relationships, the standard free energy of formation (ΔG) was calculated for each illite. ΔG's were −1267.6±0.9 for Beavers Bend, −1270.6±1.0 for Fithian, and −1265.3±1.0 kcal/gram formula weight for Goose Lake illities.
Pesticide Mobility in Soils I. Parameters of Thin‐Layer Chromatography
Authors: Helling Charles S. 
Published: July 2010

AbstractPesticide movement was studied using the recently developed soil thin‐layer chromatographic (TLC) method (Science 162:562, 1968). Thin layers of soil, the adsorbent phase, are developed with water using techniques analogous to conventional TLC.Mobility, expressed as RF values for frontal movement, was insensitive to these parameters: removal of coarse or medium sand, movement distance, soil layer thickness, temperature, and sample size (0.3 to 50 µg). Water flux was modified by physical, soil amendment (inorganic and organic additives), and solvent amendment methods. Increased flux may slightly increase mobility of pesticides. The mobilities of 2,4‐D and atrazine decreased markedly in > 0.5M NaCl solution, whereas some movement of paraquat then occurred. Distance to the wetting front on soil TLC plates was linearly related to the square root of time.Three methods of visualizing radioactive pesticide movement were compared: autoradiography, radiochromatogram scanning, and zonal extraction.
Pesticide Mobility in Soils II. Applications of Soil Thin‐Layer Chromatography
Authors: Helling Charles S. 
Published: July 2010

AbstractForty pesticides were grouped into five categories based on relative mobilities on Hagerstown silty clay loam plates, using soil thin‐layer chromatography. Diffusion was also examined in moist and air‐dry soils. Methyl esterification greatly reduced mobility of herbicides while increasing diffusion and volatility. The surfactant Tween 20 (1% in solution) increased 2,4‐D movement, but 0.5% solutions of five surfactants were relatively ineffective with several herbicides. Metabolites of atrazine, propanil, and 2,4‐D were less mobile than their parent compounds. Two chlorinated dibenzo‐p‐dioxins, potential 2,4,5‐T impurities, were immobile. Movement of components in chlorpropham/propham/p‐chlorophenyl methylcarbamate and atrazine/propachlor combinations were mutually independent.Dicamba and fenac RF values were directly related to soil pH in the range of pH 5.0 to 6.5–6.7. Other soil modifications included in situ oxidation of soil organic matter and the use of model clays. Chlorpropham and propham mobilities were increased by removal of organic matter. Diphenamid was less mobile in oxidized soil, immobile in Ca‐montmorillonite, and moderately mobile in kaolinite.
Pesticide Mobility in Soils III. Influence of Soil Properties
Authors: Helling Charles S. 
Published: July 2010

AbstractSoil parameters influencing pesticide movement were isolated using simple correlation and multiple linear regression analyses. Mobilities of 12 pesticides on 14 soils were first characterized by soil thin‐layer chromatography. Mobility of nonionic compounds was inversely related to adsorption of similar compounds, field moisture capacity, organic matter and clay contents, and cation‐exchange capacity. Mobility of acidic compounds (dicamba, picloram, fenac, and 2,4‐D) was directly correlated with soil pH and inversely with picloram adsorption. Pesticide mobility tended to be directly related to increased water flux.When soils were grouped according to their clay mineralogy, there was a tendency for movement of acidic pesticides to be directly related to montmorillonitic clay content and inversely related to nonmontmorillonitic clay content.Regression equations usually contained field moisture capacity, water flux, and often simazine or chlorpropham adsorption terms for predicting movement. These parameters are highly correlated with soil organic‐matter content, which does not itself appear in the regression equations. The average deviation of predicted from observed mobility, across all soils and pesticides, was 0.04 RF units.
Electron Scanning Studies of the Fabric of Fracture Surfaces
Authors: Eswaran H. 
Published: July 2010

AbstractFracture surfaces of soil peds were studied with the scanning electron microscope (SEM). An attempt was made to correlate such studies with the classical petrographical study of the soil. Cambic, spodic, argillic and oxic horizons were examined and some of the more significant properties were evaluated. A brief discussion has been included regarding the problems involved in using SEM technique in soil micromorphology.
Movement and Persistence of Dieldrin and Lindane in Soil as Influenced by Placement and Irrigation
Authors: Cliath M. M. , Spencer W. F. 
Published: July 2010

AbstractRedistribution and recovery of dieldrin and lindane were measured in two calcareous, low organic‐matter soils with and without irrigation. The insecticides were uniformly mixed within the 0–7.5 or 7.5–15 cm depths by excavating the soil, mixing the soil and insecticide in a cement mixer, and placing the treated soil back in the excavation.Dieldrin was highly stable and persistent, although volatilization apparently was a significant pathway for loss of dieldrin when the surface soil was wet and dieldrin was placed in the surface layer of soil. Dieldrin apparently did not move significantly with the water and moved very little by diffusion, either upward or downward from its zone of application. No evidence was found that catalytic breakdown of dieldrin occurred in the hot, dry soil.The movement and the dissipation of lindane from both soils were markedly greater than for dieldrin. Lindane moved downward with water application, especially in the sandy loam soil. Lindane was lost by volatilization and also by degradation, as considerable quantities of gamma‐pentachlorocyclohexene (PCCH) were found in the soil extracts.The results suggest that volatilization losses can be reduced or prevented by keeping the soil surface dry or by incorporating or injecting insecticides into the soil.
Apparent Nitrogen Fixation in Soil Influenced by Prescribed Burning
Authors: Jorgensen J. R. , Wells C. G. 
Published: July 2010

AbstractNitrogen increases of 23 kg/ha/year were associated with annually burned loblolly pine (Pinus taeda L.) in the lower Coastal Plain of South Carolina. Unburned areas showed no increase of N. Nitrogen fixation in cores from the forest floor and at depths of 0–1 and 3–4 cm was assayed using the acetylene‐ethylene technique, with the ethylene produced related to N fixation. In the 0–4 cm of mineral soil on burned plots more than 4 g/ha of N were fixed in 24 hours, but only 0.2 g/ha were fixed on unburned areas. Up to 61 g/ha of N were fixed in 24 hours in individual samples from burned areas. Most fixation in the burned areas took place in 14% of the samples; half the samples fixed no N or an insignificant amount, regardless of burning treatment. Fixation rate increased as moisture content increased from below to above field capacity and as temperature increased from 25 to 35C. However, the rate of increase related to temperature and moisture was usually associated with samples which had fixed N under less favorable conditions, rather than with the initiation of fixation in more samples.