bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Effect of Stabilized, Hydrophobic Aggregate Layer Properties on Soil Water Regime and Seedling Emergence
Authors: Rawitz E. , Hazan A. 
Published: July 2010

AbstractSoil crusts affect both the profile water regime and the fate of crop seedlings. The former is affected via modification of infiltration, evaporation, and redistribution, while mechanical crust impedance prevents or retards seedling emergence. Growers alleviate this problem by frequent, small irrigations which are costly in water, equipment, and labor. This study was conducted to determine whether surface soil properties could be modified by layers of stabilized, hydrophobic aggregates so as to render these irrigations unnecessary.Unstable aggregates of a clay‐loam soil were treated with 7% potassium siliconate and 1% polyvinyl acetate based on dry‐weight of soil and sprayed in water to wet the soil to 15% gravimetric water content. Layers of soil mixes with different aggregate‐size distribution were placed in transparent columns and given a simulated rainfall; then the progress of infiltration, redistribution, and drying was followed. The most promising mix was used in large outdoor tanks as a mulch for carrots (Daucus carotta L.), using 1‐ and 4‐cm mulch layers with 0, 25, 50, and 100% cover of the soil surface. The soil was given one post‐sowing sprinkler irrigation, and the soil moisture regime was monitored by microtensiometers and a two‐probe gamma gauge.A 100% cover of 4‐cm deep mulch of treated aggregates was the most effective for water conservation. It decreased water loss by 20% over a 14‐day period. Seedling emergence was close to 90% under a 1‐cm mulch and 50% under a 4‐cm layer, both of which were superior to the unmulched control treatment.
Juglone Inhibits Pine Growth Under Certain Moisture Regimes
Authors: Fisher R. F. 
Published: July 2010

AbstractBlack walnut (Juglans nigra L.) produces juglone (5‐OH‐1, 4‐napthoquinone), a phytotoxin that has allelopathic effects on certain plant species. Field studies were conducted in southwestern Ontario, Canada, in mixed plantations of red pine (Pinus resinosa Ait.), white pine (P. strobus L.) and walnut growing on the Brant‐Tuscola‐Colwood catena of fine sandy loam soils. On excessively drained Brant sites pine often suppressed the walnut while on imperfectly drained Tuscola and poorly drained Colwood sites, walnut suppressed or even killed the pine. In laboratory studies juglone and its inhibitory activity readily disappeared from Brant soil under a “dry moisture regime” but remained in Brant soil under a “wet moisture regime”. The field and laboratory studies suggest that edaphic conditions play an important role in the interactions between walnut and other species.
The Behavior of Nutrient Elements Added to a Forest Soil with Sewage Sludge
Authors: Riekerk H. 
Published: July 2010

AbstractSludge applications were made at a rate of 247 metric tons/ha dry weight to a cleared gravelly Douglas fir forest soil to test limits of nutrient conservation mechanisms. First year losses due to treatments were 8% of added N, 15% of Ca, 1% of K, and none of P. Predictably, NO3‐N was the dominant mobile anion significantly increasing the calcium nitrate level in the ground water. Differences between sludge treatments, including plowing, reflected the degree of aeration and decomposition of NO3‐N production and P‐fixation. These differences were more pronounced deeper in the soil, except for K which was more controlled by the stage of weathering. A very heavy sludge application rate (618 metric tons/ha) had less impact on soil nutrient behavior due to a high water absorption capability. Alternate ways of reducing NO3‐N leakage from the forest soil are being investigated.
Measurement of Furrow Infiltration Rates Made Easy
Authors: Miller D. E. , Rasmussen W. W. 
Published: July 2010

AbstractAn irrigation system was developed for infiltration studies that utilized overflow controls to maintain nearly constant inflow into irrigation furrows. Furrow outflow was measured with HS flumes equipped with water‐level recorders. Data were easily and rapidly converted to infiltration rates and cumulative infiltration by a computer.
A Universal Dimensionless Phosphate Adsorption Isotherm for Soil
Authors: Shayan A. , Davey B. G. 
Published: July 2010

AbstractA unique dimensionless phosphate adsorption isotherm, covering the solution concentration range 10−6 to 10−1M P, which has been found to fit 17 materials including 15 soils, pure kaolinite and amorphous Al(OH)3, is derived. The soils shown to fit the isotherm include chromic luvisols, pellic vertisols, calcic luvisols, a tropeptic eutrorthox, a volcanic ash soil from New Zealand, and a number of English soils.The necessary parameters to derive, a complete adsorption isotherm for a particular soil, from the universal isotherm, requires three adsorption experiments in the high concentration range (10−4 to 10−1M P) to define the linear portion of the isotherm and the critical concentration. Three other determinations in the range 10−6 to 10−4M P are needed to obtain the Freundlich isotherm from the data after correction for the effect of the linear region of the isotherm at high concentration. The Freundlich constant a was shown to be a capacity factor, and the constant b to be related to the chemical potential of the phosphate in solution. For the soils studied the variation in the magnitude of b was found to be smaller (0.11 to 0.37) than in a (1.60 to 9.66).The advantage of this universal isotherm over conventional isotherms, is that it requires less experimental work to define and is applicable over a wide range of P concentrations such as might be found surrounding a fertilizer granule.
Exchange Adsorption of Trace Quantities of Cadmium in Soils Treated with Calcium and Sodium: A Reappraisal
Authors: Milberg R. P. , Brower D. L. , Lagerwerff J. V. 
Published: July 2010

AbstractCadmium was selectively adsorbed over Ca in Cecil, Winsum, and Yolo soils with up to 1.7% of the total cation exchange capacity occupied by Cd. Selectivity was greatest in Yolo and least in Cecil. Effects of undissociated Cd in solution were minor. Separation factors (Ks) decreased with increasing exchangeable Cd. Reexamination of Cd‐Na exchange revealed that anomalous earlier results were due to the dispersion of organic matter during treatment with Na2CO3 in the preparation of Na‐saturated soils. Na‐Cd exchange was normal where organic matter loss was prevented.
Predicting Site Productivity of Mixed Conifer Stands in Northern Idaho from Soil and Topographic Variables
Authors: Brown H. G. , Loewenstein H. 
Published: July 2010

AbstractCharacteristics of 32 soils, consisting of an upper sequum influenced by volcanic ash over a buried sequum, and topographic variables were used to develop prediction equations for site index, height, and total volume of mixed coniferous stands in northern Idaho. Soil and topographic variables explained 70% of the variation in site index. Ninety‐four percent of the variation in height of the site trees, and 86% of the variation in total volume of the stand were explained by soil and topographic properties and age. Depth of volcanic ash influence, bulk density, P content, and elevation were important soil and topographic variables.Site index was negatively correlated with elevation, and positively correlated with extractable Ca, exchange acidity, cation exchange capacity, organic matter, total N, soil to rock ratio of the buried soils, and clay of the ash derived soils.
Effect of pH and Redox on Predicted Heavy Metal‐Chelate Equilibria in Soils
Authors: Sommers L. E. , Lindsay W. L. 
Published: July 2010

AbstractMetal‐chelate stability diagrams were developed as a function of pH and redox to predict the behavior of DTPA, EDTA, CDTA, EGTA, and HEDTA in soils. The metals evaluated include H+, Fe3+, Fe2+, Al3+, Mn2+, Ca2+, Mg2+, Zn3+, Cu2+, Cd2+, Pb2+, and Ni2+. In acid systems, Ni2+ at 10−5 to 10−7M was the predominant ligand species for all chelating agents. Similar results were obtained in alkaline systems when NiCO3 controlled Ni2+ solubility. In the absence of Ni2+, either Cd2+ or Pb2+ ligand species dominated at alkaline pH for all chelating agents. In acid systems, Cu, Pb, Fe, and Zn are the major chelated species.In acid soils, the chelating agents EDTA, EGTA, and HEDTA deserve further study as extractants for metals and as reagents for determining metal ion activities through competitive equilibria. The results identify ligands which may be useful in determining various metal ion activities in soils. The DTPA soil test appears to have a sound theoretical basis for evaluating plant available Pb, Cd, and Ni in soils.
Copper(II) Complexation by Fulvic Acid Extracted From Sewage Sludge as Influenced by Nitrate Versus Perchlorate Background Ionic Media
Authors: Sposito Garrison , Holtzclaw Kenneth M. 
Published: July 2010

AbstractThe possible adverse effect of CuNO3+ ion pairs on studies of the complexes formed between Cu(II) and fulvic acid extracted from sewage sludge was investigated by potentiometric titration of 2 × 10−3M K/H fulvate with Cu(NO3)2 and Cu(C104)2, at pH 5 and 25°C, in ionic media of 0.1M KNO3 or KC104, respectively. It was shown that the degree of complexation of Cu2+ in the NO3 medium was always significantly greater than that in the C104 medium for total Cu concentrations in the range 10−4M to 10−2M. This result was interpreted as evidence for significant concentrations of CuNO3+ ion pairs and mixed CuNO3‐fulvate complexes in the NO3 medium. Further support for the existence of CuNO3+ in the NO3 medium was obtained through a successful calculation of the thermodynamic stability constant for this ion pair that employed data from blank titrations with Cu(NO3)2 and Cu(ClO4)2. It was concluded that ClO4 ionic media should be used instead of NO3 ionic media in studies of Cu(II) complexation with the functional groups of fulvic acid.
Exchangeable Cation Hydrolysis and Soil Weathering as Affected by Exchangeable Sodium
Authors: Oster J. D. , Shainberg I. 
Published: July 2010

AbstractThe specific conductance and chemical composition of aqueous soil suspensions were measured as a function of time on suspensions prepared from three arid soils pretreated with acidified salt solutions to remove lime. The release of Ca2+, Mg2+, and K+ from silicate minerals and the hydrolysis of exchangeable Na+ occurred rapidly and prevented the preparation of homoionic Na soils. Crystalline ion release and hydrolysis of exchangeable Na+ and Ca2+ continued after the soils were suspended in distilled water. The rate was enhanced by increasing exchangeable NA+. The combination of Ca2+ hydrolysis and its release from silicate minerals was sufficient, when coupled with Na+ hydrolysis, to cause the solution phase of the suspension to be supersaturated with lime for one soil.Separate experiments with untreated soil and its silt fraction indicated that silt weathers rapidly and contributes significantly to the increase in soil conductance. Silt weathering was enhanced by increasing exchangeable Na+.
Dissolution of Selected Rocks and Minerals in a Dilute Salt Solution as Influenced by Temperature Regime
Authors: Lanyon L. E. , Hall G. F. 
Published: July 2010

AbstractSoil environments are generally characterized by temperatures that vary diurnally and/or seasonally, but mean temperatures are often reported to describe these environments. This study was designed to monitor the dissolution of ground samples of olivine (OL), microcline (M), a sandstone (SD) and a shale (SH) in 0.01N AlCl3 when subjected to an alternating temperature regime (mean 25°C with range 3 to 47°C) and constant temperature regimes of 3, 25, and 47°C for periods of up to 90 days. The concentration of a structural cation (Mg for OL and K for M, SD and SH) in the suspending medium was employed as an indicator of the extent of dissolution. Dissolution increased approximately linearly with increasing constant temperature in the order OL > M > SD > SH. The effect of the alternating temperature regime was to increase dissolution relative to a constant temperature of 25°C; the magnitude of the increased varied with the material. An “effective temperature” was calculated to quantify the relative effect of the alternating temperature to the constant temperature regimes. The ranking of the effective temperatures was OL > SH > SD > M. The concepts developed from this laboratory study may be related to reported observations of soil development/aspect relationships in the field where it appears that variables that describe factors such as the interaction of the nature of the parent material and the magnitude of environmental differences may need to be included.
Volatility of Mercury from Soils Amended with Various Mercury Compounds
Authors: Rogers Robert D. 
Published: July 2010

AbstractA study was conducted to determine the rate of mercury volatilization from soils freshly amended with mercury compounds. Mercuric nitrate, mercuric chloride, mercuric acetate, mercuric oxide, and mercuric sulfide were used in conjunction with three soils; a loamy sand, a sandy loam, and a clay loam. Mercury was evolved from all combinations and was shown to be dependent upon the solubility of the mercury compound and possibly the texture of the soil.
Adsorption of Magnesium and Calcium by a Soil with Variable Charge
Authors: Chan K. Y. , Davey B. G. , Geering H. R. 
Published: July 2010

AbstractThe subsoil of a xanthic ferralsol was used to determine the effect of varying ionic strength and pH on the cation exchange capacity and the amounts of Na, K, Ca, and Mg in exchangeable form.The cation exchange capacity increased with both pH and ionic strength from 2.6 meq/100 g at pH 2.5 and 0.01M ionic strength to 6.9 meq/100 g at pH 9.5 and 1.0M ionic strength.Sodium and K remained completely exchangeable over all the ionic strengths (0.01 to 1.0M) and pH range 2.5 to 9.5. By contrast Mg became fixed in nonexchangeable forms as the pH increased so that 62% of Mg originally exchangeable at pH 4.0 was fixed at pH 9.5 and 1.0M ionic strength. Calcium also appeared to become fixed in nonexchangeable form as the pH increased, but to a much lesser extent than Mg.
Carbohydrate Content of Fungal Humic Acid‐type Polymers (Melanins)
Authors: Linhares L. F. , Martin J. P. 
Published: July 2010

AbstractThe carbohydrate contents of a variety of fungal humic acid‐type melanins ranged from 1.1 to 5.9%. Values were 1.7 to 2.6% for soil humic acids and 0.4% for Leonardite peat humic acid. Fungal culture medium polymers not precipitated by acid and fungal cells contained from 12 to 55% carbohydrates. The uronic acid content of all products was very low, ranging from essentially zero (not detected) to 1.1%. Stachybotrys atra was the only fungus where uronic acids were detected in all samples. Uronic acids were, however, present in all soils, the values ranging from 0.3 to 0.4%. Recovery of uronic acids after acid hydrolysis using galacturonic acid as a check gave low values. The necessity of eliminating interferring substances before the colorimetric determination of sugars and uronic acids in soil and fungal polysaccharide hydrolysates was demonstrated. Thin‐layer chromatography of concentrated hydrolysates from the humic acid‐type fungal melanins and soil humic acids showed the presence of glucose, galactose, mannose, and xylose in most of the samples. A mass spectrum of the pyrolysis fragments of Aspergillus glaucus sp. humic acid‐type polymer showed definite series peaks related to polysaccharides, the most prominent, however, were related to proteins and phenolic substances.
Variation in Surface Charge Characteristics in a Soil Chronosequence
Authors: Hendershot W. H. , Singleton G. A. , Lavkulich L. M. 
Published: July 2010

AbstractThe surface charge characteristics of the B horizons of seven soils in a chronosequence developed on sandy beach material were studied. The soils range in age from 127 to 550 years and exhibit morphological and chemical characteristics ranging from Typic Udipsamment to Aquic Haplorthod. The difference between the zero point of charge (ZPC) and the pH of the soil decreased as the age of the soils increased, from a maximum value at the youngest site of 0.72 to a minimum value at the oldest site of 0.11. The decrease in this ΔpHzpc value is interpreted as indicating that the soils are approaching a steady‐state with time. The ΔpHzpc value is presented as a measure of pedogenic development.
Thermal Conductivity of Soils as a Function of Temperature and Water Content
Authors: Sepaskhah A. R. , Boersma L. 
Published: July 2010

AbstractApparent thermal conductivities of loamy sand, loam, and silty clay loam soils were measured with a cylindrical heat probe at several water contents and temperatures. Values of λ were also calculated with the de Vries model. Results show that the model may be used satisfactorily to calculate λ. However, improvements may be needed to account for the enhancement of vapor transfer at high temperatures (45° C) in medium to fine textured soils. The heat probe method of measuring the thermal conductivity requires a correction factor to allow for errors due to the entrapment of air at the surface of the heat probe, when used at water contents ranging from 0 to about 30% of saturation.The contribution of vapor distillation to thermal conductivity was analyzed by comparing λ at 25 and 45° C. The ratios λ45/λ25 were nearly equal to unity when < 5% of total pore space was filled with water. The ratios increased, due to vapor distillation, as water filled the pores and reached maximum values of 2.17, 2.71, and 2.96 when 22, 27, and 35% of total pore space was filled with water, corresponding to soil water potentials of −0.8, −9.0, and −8.0 bars for loamy sand, loam, and silty clay loam, respectively. As the water content increased further, the ratios decreased and approached unity when > 50% of total space was filled with water.The apparent thermal conductivity was independent of water content at very low water contents. The water molecules are in layers only a few molecules thick. The water content below which the apparent thermal conductivity is not affected by water content is a function of the soil temperature and the clay content. In our experiments these water contents were 0.03 and 0.05 cm3/cm3 at 45° C and 0.13 and 0.18 cm3/cm3 at 25° C for the loam and silty clay loam respectively.
Infiltration as Influenced by Irrigation Water Quality
Authors: Oster J. D. , Schroer Fred W. 
Published: July 2010

AbstractAfter 19 months of irrigation with waters of different quality, columns of Heimdal loam cropped to alfalfa had infiltration rates that were correlated better with irrigation water sodicity and salinity than with soil surface (0–76 mm) or column average (0–530 mm) exchangeable sodium and soil salinity. Two sets of irrigation water parameters were tested: (i) total cation concentration (Cc) in molc m‐a (meq liter−1) and sodium adsorption ratio (SARc) of the irrigation water in equilibrium with solid phase CaCO3 at a PCO2 of 0.07% based on ion activities corrected for ion pairing; and, (ii) total cation concentration of the irrigation water as prepared and the adjusted sodium adsorption ratio based on the calculated pH of the water in equilibrium with CaCO3. On the basis of multiple linear regression analyses, the best correlation was obtained with the lime‐equilibrated water parameters (R2 = 0.87). The corresponding relationship between infiltration rate (I) in mm hour−1 and the chemical parameters was I = 6.80 − 1.10 SARc + 0.79 Cc. Cation concentration greatly affected infiltration rates even at low SAR levels (2<SAR<5). Apparently, the mechanical action of the applied water greatly enhances the effects of exchangeable sodium and soil solution concentration on swelling and dispersion at the soil surface which, in turn, has a large effect on infiltration rates.
Aluminum Organic Matter in Acid Soils: Buffering and Solution Aluminum Activity
Authors: Bloom P. R. , McBride M. B. , Weaver R. M. 
Published: July 2010

AbstractThe variation of solution Al3+ activity with pH, the effect of suspending salt solution cation on Al3+ activity, and the buffering intensity were determined for salt solution suspensions of three soil samples and an Al substituted peat that contained one equivalent of Al3+ for each equivalent of carboxyl groups. The soil samples used were a surface and a subsurface horizon of an Inceptisol from New York and a surface horizon of an Oxisol from Brazil. The soils were equilibrated for periods of up to 35 days in 0.02N solutions of the chlorides of K+, Na+, Ca2+, Mg2+, Cu2+ and La3+ with the addition of acid or base. In the pH range 3.9 to 4.9, plots of pH vs. pAl were linear with ΔpAl/ΔpH<2.5, significantly different from the value of 3 predicted by Al(OH)3 solubility. At a given pH, Al3+ activity was a function of the solution cation. The Al substituted peat in 0.02N CaCl2 gave a pH vs. pAl plot very similar to that of the surface horizon of the Inceptisol. Also, the addition of partially rotted leaf humus to the Inceptisol subsoil caused a reduction of Al3+ activity at any given pH even after 35 days of equilibration.It was concluded that hydrolysis of organically bound Al is a major source of buffering in the pH range of 4 to 5 for dilute salt suspensions of acid soils and that exchange of Al ions from organic matter exchange sites controls the relationship between pH and Al3+ activity in acid soils that have a low amount of permanent charge CEC relative to the quantity of organic matter.
Effects of Burning on Chaparral Soils: I. Soil Nitrogen
Authors: DeBano Leonard F. , Eberlein Gary E. , Dunn Paul H. 
Published: July 2010

AbstractUndisturbed moist or dry soil slabs collected from beneath chaparral plants were burned at different intensities in the laboratory. Inorganic and organic nitrogen levels were measured before and after burning. An intense burn over dry soil slabs decreased KCl‐extractable NH4+‐N in the litter but increased it in the underlying soil. In contrast, NO3‐‐N was decreased in both soil and litter during an intense burn over dry soil. Little change in NO3‐‐ and NH4+‐N occurred when litter and soil were moist. About 67% of the total N in the litter and soil was lost during the intense burn over dry soil, but less than 25% was lost when the soil and litter were moist. Amino acids were particularly sensitive to heating and were almost destroyed in dry litter during the intense burn. Almost 75% of the hexosamines in the litter and soil were also destroyed by the intense burn over dry soil.
Efficiency of Phosphorus Utilization by Alfalfa from Manure and Superphosphate
Authors: Goss D. W. , Stewart B. A. 
Published: July 2010

AbstractEfficiencies of phosphorus utilization by alfalfa (Medicago sativa L.) from feedlot manure and superphosphate were examined in greenhouse and field studies. Alfalfa grown in soil treated with superphosphate removed a higher percentage of the added P than alfalfa grown in soil treated with manure. However, alfalfa grown in manured soil had the higher P utilization efficiency, as measured as yield increase per unit increase in P removed. This was due in part to more luxury consumption of P by the early cuttings on the superphosphate treatment. The P in feedlot manure was released more slowly for plant uptake and the P level remained adequate for a longer period. Apparently, microbial activity is important in the slow release of manure P. This was thought to be due to the increase in microbial activity as a result of the added energy source. Field studies indicated that P from feedlot manure carries over from year to year and becomes available with time.