bluuebunny/crossref_metadata_2025_split huggingface dataset:
Interaction Between the Humic Acid Fraction of Soils and Certain Metallic Cations
Authors: Khan S. U. 
Published: July 2010

AbstractStudies were conducted to investigate the interaction between certain metallic cations and the humic acids isolated from one Black Chernozem and two Gray Wooded soils of Alberta. Potentiometric titrations of the humic acids in the presence of added cations showed the formation of metal‐humic acid complexes. The metallic cations released protons from functional groups of the humic acids and formed complexes. The order of magnitude of pH drop of the humic acids on addition of metallic cations was found to be Mn2+ < Co2+ < Ni2+ < Zn2+ < Cu2+ < Al3+ < Fe3+. The effectiveness of added cations in coagulating the humic acids followed the sequence Mn2+ < Co2+ < Ni2+ < Zn2+ < Cu2+ < Fe3+ < Al3+.
Effect of Acidity on Reactions of Organic Acids and Amines with Montmorillonitic Clay Surfaces
Authors: Harter Robert D. , Ahlrichs James L. 
Published: July 2010

AbstractThe effect of pH on the nature of 2,4‐D, Amiben, aniline, and urea adsorbed by montmorillonite has been characterized. In all cases the infrared spectra of air dry systems indicated a change of the compound to the acid or protonated form when the corresponding suspension pH was two to three pH units higher than the pKa of the molecule. This is consistent with previous studies which indicated that the clay surface in air dry systems is more acid than shown by electrometric pH readings of the suspension. At pH levels below the pKa the acids show evidence of adsorption by the clay. The amines acquire a positive charge and are capable of interacting with the clay exchange complex. Spectra of the aniline and urea adsorbed to acid clay were nearly identical to those of their hydrochlorides in the same environment, indicating reactions with the acid clay surfaces by protonated molecules.
Phosphatoiron (III) and Phosphatoaluminum Complexes in Dilute Solutions
Authors: Bohn H. L. , Peech Michael 
Published: July 2010

AbstractThe phosphate complexes of iron(III) and aluminum in dilute solutions were studied by ultraviolet spectrophotometry, voltammetry, and cation exchange resins. The stability constant of the FeH2PO42+ ion was found to be 4(± 0.8) × 103 at ionic strength of 0.1. Although phosphatoaluminum complexes were not directly detectable, their stability constants could be estimated as ≤ 103 for AlH2PO42+ and ≤ 107 for AlHPO4+. These results indicate that, over the range of ion concentrations likely to be found in soil solutions, phosphatoiron(III) complexes are the predominant phosphate species in solutions of pH < 1.3; phosphatoaluminum complexes are the predominant phosphate species in the range of pH 1.3–4.3; and aquated phosphate ions are the predominant species in the range of 4.3–7.2. Published equilibrium constants for phosphatocalcium and phosphatomagnesium complexes and ion pairs revealed that these species are the predominant phosphate species at pH > 7.2.
An Appraisal of the dai/dx Hypothesis
Authors: Olsen R. A. 
Published: July 2010

AbstractAn attempt was made to subject the dai/dx hypothesis to a more critical experimental appraisal than has been accomplished previously. A system was devised by the use of synthetic exchanger particles in which the suspension effect, as measured electrometrically, was exceptionally large; the value indicated an apparent difference in aRb + in the most extreme parts of the system of about one million. According to the dai/dx hypothesis, the rate of absorption of Rb+ by plant roots should have differed from these two parts of the system by a correspondingly large factor. The observed rates of absorption from all parts of the system, however, were within a factor of 1.2 of being identical. It is concluded that either: (i) electrometric methods do not provide a reliable estimation of ion activities in aqueous systems containing exchanger particles, (ii) the rate of absorption of an ion by plant roots is not a function of the activity gradient extending normal to the absorption surface, or (iii) both of these commonly accepted postulates are incorrect. The data are considered to be consistent with the alternative dμ̄i/dx hypothesis.
Retention of Zinc by Some Arid Zone Soil Materials Treated With Zinc Sulfate
Authors: Sharpless R. G. , Wallihan E. F. , Peterson F. F. 
Published: July 2010

AbstractSamples from six orchard soils and 17 type‐location soils were used for laboratory study. Results showed that addition of a concentrated solution of ZnSO4 to soil resulted in rapid adsorption of Zn, about 75% of the total being accounted for by cation exchange during the first minute. Subsequent rate of conversion from exchangeable to acid extractable form varied widely among soils. The main factors that accounted for the extent of Zn retention were CEC and pH; there appeared to be no significant relation to available P.
Variation in Potassium Available to Trees Within an Outwash Soil
Authors: Hart James B. , Leaf Albert L. , Stutzbach Stephen J. 
Published: July 2010

AbstractThirteen deep soil pits were sampled by strata, 40 forest floor samples were collected, and tube samples were taken at 119 locations of the surface 15‐cm layer and at 30‐cm intervals to a soil depth of 2.1 m. The sampling was done on an 0.8‐ha area supporting good and poor growing 37‐year‐old red pine (Pinus resinosa Ait.) separated by an old fenceline. The soil has formed in slanted and discontinuous strata of different physical and chemical properties. Acid‐extractable K data from the 13 pits indicate the magnitude but not the pattern of variability. Data from the pit samples were used to predict acid‐extractable K for the tube samples. Regression techniques were used on the 0‐ to 15‐ and 15‐ to 45‐cm layers. An ocular textural classification technique was employed for deeper soil layers. Results indicate K variability is pronounced in the soil volume studied and is associated with the occurrence of discontinuous finer‐textured strata at differing depths. K variability as measured by these techniques was found to be only partly related to red pine growth.
Increased Availability of Nitrogen and Phosphorus in the Root Zone of Conifers
Authors: Fisher R. F. , Stone E. L. 
Published: July 2010

AbstractThe N and P contents of herbaceous vegetation and soil across the interface between pine or larch plantations and the open, abandoned fields in which they were planted were investigated. Herbaceous plants growing beneath or near the conifers had significantly higher N and P concentrations as well as greater dry weight. NO3‐N, NH3‐N, and readily soluble P were also significantly higher beneath or near the conifers. Although the total N of the forested and open soils was not different, significantly higher percentages of the organic N could be extracted with hydrofluoric acid from the soil beneath 10‐ to 14‐year‐old plantations. However, the proportion extracted from soils beneath 32‐ to 33‐year‐old plantations was not different from that extracted from adjacent old‐field soils. All lines of evidence are consistent with a hypothesis that the conifer rhizosphere mineralizes or otherwise extracts some fraction of the soil nitrogen that had been resistant to microbial action under the previous vegetation.
Nitrate Content of the Upper Rio Grande as Influenced by Nitrogen Fertilization of Adjacent Irrigated Lands
Authors: Bower C. A. , Wilcox L. V. 
Published: July 2010

AbstractOver a 30‐year period, when the application of N fertilizer to three irrigated areas adjacent to the Upper Rio Grande increased from a very low to a high level, the overall NO3‐N concentration of the river did not increase, indicating no significant stream pollution by NO3‐N from applied N fertilizer.
Soil Water Evaporation as Affected by Wetting Methods and Crust Formation
Authors: Bresler E. , Kemper W. D. 
Published: July 2010

AbstractLaboratory studies showed that evaporation from soil columns which were wetted by flooding was 25–30% higher than soil wetted by rain and 30–40% higher than from soil to which NaCl was applied prior to wetting by simulated rain. About 25–35% more water evaporated from soil which was exposed to evaporation immediately following infiltration compared to soil which exposed to evaporation 4 days after infiltration ceased. The crust which was formed at the soil surface by the raindrop action and dispersion due to sodium ion caused the wetting rate to decrease from 23 cm/hour in the flooded treatment to 1.1 in the rain and 0.06 cm/hour in the rain on NaCl treatment. Higher water content profile and shallower wetting zone resulted when rates of wetting were faster, and caused the total water loss to be higher. The total water loss was also affected by the type of crust which formed at the soil surface. After from 1 to 4 hours of evaporation, the highest resistance to water flow was estimated in the region immediately below the crust. This high resistance region hastened the formation of a surface dry layer in the rain‐wetted treatments which reduced evaporation.
Conductometric and Potentiometric Titration of Exchangeable Aluminum
Authors: Rich C. I. 
Published: July 2010

AbstractConductometric and potentiometric titrations of an AlCl3 solution and AlCl3‐treated Dowex‐50, trioctahedral vermiculite, and two montmorillonites were compared with the Al and acidity removed from these systems with neutral chloride salts. The endpoints of potentiometric titrations of AlCl3 or AlCl3‐treated exchangers in neutral salt solution were lowered by these salts and adsorption of partially neutralized hydroxy‐Al groups on the exchangers. Titrations of solutions to pH 8.0 gave better estimates of the acidity present than did inflection points. Hydrolysis of Al on the exchanger during exchange may produce H+ ions not originally present. Conductometric titrations with Na2B4O7 and NaOH were confounded by incomplete exchange and reaction with Al. The formation of aluminate in the titration with NaOH and Ba(OH)2 decreased the conductivity and caused “high” results. It is proposed that conductometric titrations should be continued until the change in conductivity with added base approaches that of a blank. A method for correcting for aluminate formation is proposed.
Titration of Acid Soils
Authors: Dewan H. C. , Rich C. I. 
Published: July 2010

AbstractSeven acid soils containing varied cation exchange materials were studied by means of conductometric and potentiometric titrations with Ba(OH)2, NaOH, Na2B4O7, and NaOAc, and extractions with KCl, NH4OAc (pH 4.8), and BaCl2‐triethanolamine (pH 8.3).Generally consistent results were obtained when the aluminate reaction was considered for titrations with strong bases. The extent of the aluminate reaction for exchangeable interlayer Al3+ apparently depends on the exchange of Al3+ by the base. Thus, the low values in conductometric titrations with NaOH compared to Ba(OH)2 are explained on the basis of the poorer exchange of Al3+ by Na+.Titrations with NaOAc indicate that only a cat clay soil contained strong acid type exchangeable H+, although four of the other soils contained about 20 meq/100g of Al3+ exchangeable by KCl.
Michaelis Constant of Soil Urease
Authors: Paulson K. N. , Kurtz L. T. 
Published: July 2010

AbstractApplication of the Michaelis‐Menten equation to urease activity of soil showed that the Michaelis constant (Km) changed with fluctuation in microbial population and thus with changes in the proportion of microbial and adsorbed urease. Regression of urease activity on number of ureolytic microorganisms permitted division of total urease activity into portions caused by microbial and adsorbed forms, respectively. Computations using the partitioned urease activities gave Km's for the microbial and adsorbed forms of 0.057 and 0.252M, respectively. These values are similar in order of magnitude to those reported in the literature and thus further support the hypothesis that urease is active in both microbial and adsorbed forms in soil.
Early Effects of Forest Vegetation and Topographic Position on Dark‐Colored, Prairie‐Derived Soils
Authors: Geis J. W. , Boggess W. R. , Alexander J. D. 
Published: July 2010

AbstractA complete development range of soils from the Humic Gley (Haplaquolls) and Brunizem (Argiudolls) soils of the original tall grass prairie to well‐developed Brunizem‐Gray‐Brown Podzolic Intergrade (Mollic and Aquollic Hapludalfs) soils was studied in a recently forested “Prairie Grove” remnant in eastcentral Illinois. The first measurable changes occur in organic carbon, cation exchange capacity, and base saturation. Alterations in color and structural development which distinguish a minimal A2 horizon are followed by accelerated movement of clay from the A to B horizons. Differences in soil development in an area of uniform forest occupancy are related to the physiographic position of the soil units and the subsequent retarding of normal forest soil development by conditions of excessive soil moisture.
Losses of Wheat Straw Residue Under Simulated Field Conditions
Authors: Brown Paul L. , Dickey David D. 
Published: July 2010

AbstractWheat (Triticum aestivum L.) straw residues contained in fiberglass screen envelopes were exposed to field conditions at Bozeman and Huntley, Mont. Samples from above‐soil, on‐soil, and buried exposures were taken periodically during an 18‐month period to measure weight losses and changes in N and P contents of the residues. Decomposition was more rapid at Huntley than at Bozeman, probably because air temperatures averaged 2.3C warmer at Huntley. Percentage losses were inversely related to residue amounts. After 18 months, on‐soil residue losses averaged 31% at Bozeman and 40% at Huntley. The 50% decomposition stage for buried straw occurred in 3 months at Huntley and 6 months at Bozeman, and after 18 months, losses of buried straw averaged 93% at Bozeman and 98% at Huntley. Compared to the original straw, both N and P percentages increased as much as sixfold in the buried samples during decomposition. For buried straw, maximum percent N was 1.18 at Bozeman and 1.46 at Huntley. Similar values for maximum percent P were 0.132 at Bozeman and 0.147 at Huntley.For buried straw, N and P immobilization was maximum after 3 months at both locations. At that time, N contents at the two locations exceeded original content by an average of 1.6, 2.9, 2.8, 2.9, and 5.3 kg/ha for straw rates of 1,121, 2,242, 3,363, 4,484, and 6,732 kg/ha. P contents exceeded original content by an average of 0.3, 0.5, 0.7, 1.0, and 1.7 kg/ha for the same straw rates.
Fertilizer Release from Packets and its Effect on Tree Growth
Authors: Attoe O. J. , Rasson F. L. , Dahnke W. C. , Boyle J. R. 
Published: July 2010

AbstractA study was made of various factors affecting the release of fertilizer from polyethylene packets. Movement of water from the soil into the packets was almost entirely in the form of vapor and was closely related to both the area and perimeter of the pinholes in the packets. Absorption of water vapor by saturated salt solutions from air maintained near 100% relative humidity was directly related to both the solubility of the salts used and to their vapor pressure lowering values. The length of time required to release the fertilizer was directly related to the size of packet and inversely related to the number of pinholes. The more soluble fertilizer constituents were released faster than the less soluble ones. The use of packets of 19‐5‐17 (N, P, K) fertilizer in the field generally increased by 10 to more than 100% the rates of growth in height and diameter of cottonwood (Populus deltoides Marsh.), silver maple (Acer saccharinum L.), sugar maple (Acer saccharum Marsh.), and white ash (Fraxinus americana L.).
Temperature Stabilization of Gamma Ray Transmission Equipment
Authors: Reginato Robert J. , Stout Karl 
Published: July 2010

AbstractAccurate measurements of water content of soil in situ can now be made using an improved gamma ray transmission method. Prior to this development, existing equipment tried in the field responded to temperature fluctuations as well as density and water content changes. With the new method, the nuclear counting system is stabilized on a reference 60Co gamma ray source attached to the detector assembly. Density changes are then measured with a 137Cs gamma ray source about 30 cm away from the detector. In laboratory tests, similar attenuated count rates were obtained for 137Cs gamma rays through a standard absorber while the temperature was varied from 5 to 33C.
Salt Accumulation at the Soybean (Glycine Max. (L.) Merr.) Root‐Soil Interface
Authors: Riley D. , Barber S. A. 
Published: July 2010

AbstractWater soluble salts accumulated at the soybean (Glycine max L.) root‐soil interface and in the rhizosphere soil when salts, dissolved in the soil solution, moved to the root surface at a greater rate than they were absorbed by the roots. Salt accumulation increased with increase of salt concentration in the soil solution and transpiration rate. The average salt accumulation decreased with increase in the average age of the roots.
Prediction of Interlayer Swelling of Clays in Mixed‐Salt Solutions
Authors: McNeal B. L. 
Published: July 2010

AbstractA comparison has been made of the relative interlayer swelling values predicted from two different ion‐distribution models for mixed Na‐, Ca‐clays. When interlayer swelling predicted from a demixed‐ion model is plotted as a function of exchangeable‐sodium‐percentage (ESP) at constant salt concentration, a series of straight lines having increasing slopes and decreasing ESP‐axis intercepts with decreasing salt concentration is obtained. Similar plots involving a diffuse double‐layer (mixed‐ion) model produce a series of hyperbolas having concentration‐dependent intercepts on the swelling, rather than the ESP, axis. Most of the limited data available from the literature on soil and clay swelling in mixed‐salt solutions agree more closely with predictions from the demixed‐ion model, though neither model is fit exactly. Implications and limitations of each swelling model are discussed.
Arylsulfatase Activity of Soils
Authors: Tabatabai M. A. , Bremner J. M. 
Published: July 2010

AbstractThe detection of arylsulfatases (enzymes that hydrolyze aryl sulfates) in soils is reported, and a simple method of assaying soil arylsulfatase activity is described. This method involves colorimetric estimation of the p‐nitrophenol released by arylsulfatase activity when soil is incubated with buffered (pH 5.8) potassium p‐nitrophenyl sulfate solution and toluene at 37C for 1 hour, and it is rapid, sensitive, and precise. The procedure used to extract p‐nitrophenol stops arylsulfatase activity, develops the yellow color used to estimate p‐nitrophenol, and gives quantitative recovery of this compound. Studies of the properties of the arylsulfatases in soils are reported.
Exchangeable Aluminum As a Criterion for Liming Leached Mineral Soils
Authors: Kamprath E. J. 
Published: July 2010

AbstractLime rates equivalent to the amount of exchangeable Al reacted primarily with the exchangeable Al and reduced the Al saturation of the effective CEC to less than 30%. Lime rates greater than the equivalent amount of exchangeable Al resulted in appreciable amounts of nonexcharigeable acidity being neutralized. Below pH 5.4 the buffer capacity of the soils was primarily due to exchangeable Al. Lime applications based on the exchangeable Al extracted with a neutral unbuffered salt appear to be a realistic approach for Ultisols and Oxisols.
Infrared Analysis of Partially Deuterated Water Adsorbed on Clay
Authors: Leonard Ralph A. 
Published: July 2010

AbstractPartially deuterated water (HDO) adsorbed on Na+, K+, Mg2+, and Ca2+ saturated montmorillonite clays was studied by use of infrared spectroscopy. Positions of the primary O‐D absorption band of adsorbed HDO were 2533, 2530, 2506, and 2526 cm‐1, respectively. In addition, a small secondary band was found at 2670 cm‐1. This band may arise from an O‐D group very weakly H‐bonded to a surface oxygen, or to water isolated in hexagonal cavities in the surface. No evidence of strong H‐bonding to the mineral surface was evident. Findings indicate that at low water contents, the exchangeable cation exerts the dominate force affecting the structure of the adsorbed water.
Separation of Clay Minerals and Soil Clays Using Isopycnic Zonal Centrifugation
Authors: Francis C. W. , Tamura Tsuneo , Bonner W. P. , Amburgey J. W. 
Published: July 2010

AbstractThe technique of isopycnic‐zonal centrifugation in a continuous nonaqueous density gradient was used in the purification and separation of standard clay minerals and soil clays. A suspending agent (polyvinylpyrrolidone) compatible with tetrabromoethane and ethanol stabilized clay suspensions produced multiple banding of systems which otherwise flocculated into one band. Data from x‐ray diffraction analyses revealed the technique is useful in purification of clay minerals and identification of clay minerals in soil clays; however the banding obtained from the clay fraction of a Dodge silt loam did not represent discrete bands of specific clay minerals.
Measurement of the Total Suction of Soils by a Thermistor Psychrometer
Authors: Kay B. D. , Low Philip F. 
Published: July 2010

AbstractA detailed description of a thermistor psychrometer is presented. The psychrometer depends on differential cooling due to unequal evaporation rates of water droplets suspended from matched thermistors which are located above the sample and reference. The resulting difference in resistance between the thermistors is measured by a Wheatstone bridge and referred to a calibration curve for the determination of the total suction of the sample.Results obtained by the psychrometer on a Brookston silt loam are shown to agree with those obtained by a pressure plate. However, results obtained by the psychrometer on a pure clay‐water system are shown to differ from those obtained by a tensiometer. A possible reason for this difference is given.
Zinc Adsorption by Calcareous Soils
Authors: Udo E. J. , Bohn H. L. , Tucker T. C. 
Published: July 2010

AbstractZinc adsorption was studied in suspensions of 10 calcareous Arizona soils in dilute ZnSO4 solutions. At low concentrations, Zn2+ adsorption was described by the Langmuir adsorption equation. The calculated Langmuir adsorption maxima were related to the carbonate and organic matter contents of the soils. When the added Zn2+ exceeded the adsorption maximum, the value of the (Zn)(OH)2 ion concentration product in solution corresponded to the solubility of zinc hydroxide or carbonate so long as soil carbonates were present. At lower amounts of adsorbed Zn2+ and/or when the soil carbonates had dissolved, the (Zn)(OH)2 product was about one hundred‐fold less indicating that the soils then retained Zn2+ about as strongly as zinc silicate, and more strongly than zinc hydroxide or carbonate.
Effect of Dyrene and Maneb on Nitrification and Ammonification, and Their Degradation in Tropical Soils
Authors: Dubey H. D. , Rodriguez Rita L. 
Published: July 2010

AbstractThe effect of 2,4‐dichloro‐6‐(o‐chloroanilino)‐s‐triazine (dyrene) and manganese ethylene bisdithiocarbamate (maneb) at 0, 15, 60, 240, and 960 ppm on nitrification of 100 ppm applied NH4‐N, and on ammonification of soil nitrogen, and the degradation of these fungicides, were studied in a lateritic clay and a fertile loam incubated at 24C for 16 weeks.Inhibition of nitrification by the fungicides was lesser and of shorter duration in the rapidly nitrifying loam than in the slow nitrifying lateritic soil. The chemicals inhibited the ammonia oxidizing bacteria but not the nitrite oxidizing bacteria. Maneb was several times more toxic to the nitrifying organisms than dyrene, and its effect lasted even after the chemical was degraded. Ammonification was inhibited only at 960 ppm of the fungicides. There was no synergistic effect with regard to inhibition of nitrification or ammonification when the soil received both the fungicides. The fungicides were degraded faster in the rapidly nitrifying soil than in the slow nitrifying soil. Maneb was decomposed earlier than dyrene.