bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cation‐Exchange Capacity of Plant Lignins and Soil Humic Colloids as Affected by pH and Hydrolysis Error
Authors: Wildung R. E. , Chesters G. , Thompson S. O. 
Published: July 2010

AbstractThe effect of the pH of the buffered saturating solution on the cation‐exchange capacity (CEC) of several plant lignins and soil humic colloids isolated by NaOH and 1,4‐dioxane was determined for the pH range 2.5 to 8.0. The CEC of lignins ranged from 0 to 38 meq/100 g at pH 2.5 and 33 to 130 meq/100 g at pH 8.0, whereas the CEC of soil humic colloids ranged from 40 to 117 meq/100 g at pH 2.5 and 163 to 367 meq/100 g at pH 8.0. For the same plant or soil material, NaOH‐extracted samples were invariably higher in CEC than were dioxane‐extracted samples. The CEC values of the root lignins were lower than those of the shoot lignins irrespective of extraction method. The extent of hydrolysis error throughout the pH range was measured using two comparable CEC methods in which a water‐wash step was included in one case and omitted in the other. Maximum percentage hydrolysis error occurred at pH 2.5. Dioxane lignins of prairie grass and dioxane extracts of the 0‐ to 12‐inch layer of the virgin and cultivated Prairie soils were found to be more susceptible to hydrolysis errors than their NaOH‐extracted analogs.
The Influence of Aggregate Size on Soil Moisture Content‐Capillary Conductivity Relations
Authors: Amemiya M. 
Published: July 2010

AbstractThe capillary conductivity of beds of 0.5‐ to 1‐, 1‐ to 2‐, 2‐ to 3‐, 3‐ to 5‐, and 5‐ to 9‐mm aggregates separated from Nicollet, Kranzburg, Aastad, and Miami soils was determined over a suction range of from 0.02 to 12 bars by using the pressure plate outflow technique. When moisture content‐moisture suction relations were essentially unaffected by aggregate size, capillary conductivity was a function of volumetric moisture content. However, if moisture content‐moisture suction relations were affected by aggregate size, then at any given moisture content, conductivity values for a given aggregate size were inversely related to the suction corresponding to said moisture content. For beds consisting of mixtures of aggregate sizes, changes in moisture content‐moisture suction brought about by mixing, affected capillary conductivity in much the same way as in the case of beds of single‐sized aggregates. Data from sand and uniformly porous ceramic “aggregates” indicate that capillary conductivity is a function of size only if size affects moisture content‐moisture suction relations. Other factors influencing moisture retention may be expected to influence capillary conductivity accordingly.
Desorption of Glycerol from Clays as a Function of Glycerol Vapor Pressure
Authors: Hajek B. F. , Dixon J. B. 
Published: July 2010

AbstractGlycerol desorption isotherms were developed for montmorillonite, vermiculite, kaolinite, and a mixture of montmorillonite and vermiculite at 95C and 80C. Application of the Langmuir equation to desorption data for montmorillonite indicated that 465 mg of glycerol was necessary for a complete monomolecular layer on all surfaces of 1 g of 2µ to 0.2µ clay. Although desorption data for vermiculite fitted the Langmuir equation, the adsorbed glycerol apparently was held at lower average density than for montmorillonite. Two intersecting straight lines fitted the desorption data for a montmorillonite and vermiculite mixture plotted according to the Langmuir equation, indicating that the two minerals could be distinguished quantitatively in the mixture. Multimolecular layers of glycerol appeared to be adsorbed on kaolinite at temperatures and pressures needed for duointerlayer (true monolayer) sorption by montmorillonite. Enthalpies of desorption from a Langmuir constant and from the Clausius‐Clapeyron equation compared favorably. Enthalpies ranged from 40 to 55 kcal/mole of glycerol desorbed from kaolinite and expansible minerals, respectively.
The Effects of Urea, Biuret, and Ammonia on Germination and Early Growth of Corn (Zea mays L.)
Authors: Hunter Albert S. , Rosenau William A. 
Published: July 2010

AbstractCorn seeds were germinated near bands of fertilizer containing urea, biuret, cyanuric acid, ammonium, and certain other materials in sand‐solution cultures varying in urea and biuret, in closed systems containing gaseous NH3, and in soils with varying amounts of exchangeable NH4. Seeds were also soaked, before germination, in solutions of urea, biuret, (NH4)2SO4, or NH4OH. Germination was greatly inhibited by gaseous NH3 in closed systems, by more than 32% NH4‐saturation of the soil, and by soaking seeds in NH4OH; seeds that did germinate produced normal plants. In the field, germination was not affected but seedlings were injured by 1.5 lb or more of biuret‐N per acre (38‐inch rows); up to 1.5 lb cyanuric acid per acre had no harmful effects. Seed injury by NH3 released from urea is dependent upon hydrolytic activity, soil aeration, rate of nitrification, exchange capacity, and volume of soil between fertilizer and seed. Germination is affected by NH3; biuret principally affects seedling development after germination.
Inorganic Nitrogen Transformations Through the Oxidation and Reduction of Iron
Authors: Chao Tyng‐Tsair , Kroontje Wybe 
Published: July 2010

AbstractIn acid solution nitrate can be reduced by ferrous iron to N2 through such intermediates as nitrogen tetraoxide, nitrous acid, hyponitrous acid and nitrous oxide or through nitrogen tetraoxide, nitrous acid, nitric oxide, and nitrous oxide. These sequences show similarities to those occurring in the denitrification process. In a basic solution the reduction of nitrite to N2 may go through nitric oxide, N2O22‐, and nitrous oxide, or it may be reduced to ammonia through hydroxylamine, and hydrazine. Hydrazine and hydroxylamine are very unstable in the presence of iron in solution. In acid solution both hydrazine and hydroxylamine are oxidized by ferric iron to N2 and N2O. The amount of N2O formed is proportional to the ferric iron concentration.
The Dependence of Soil Water Uptake and Release Upon the Applied Pressure Increment
Authors: Davidson J. M. , Nielsen D. R. , Biggar J. W. 
Published: July 2010

AbstractTwo independent methods and three porous materials were used to ascertain whether or not the soil water content‐capillary pressure relation (soil water characteristic) depends on the rate at which soil water redistributes with applied capillary pressure increment. In one method small, uniform samples were subjected to known capillary pressures by means of a porous plate. The other method involved rotating 100‐cm long samples end‐to‐end at different rates and measuring the water content and capillary pressure distributions at equilibrium when the samples were vertical. The data from two soils, a silt loam and a sand, and a sandstone support the conclusion that the equilibrium water content depends on the size of the applied capillary pressure increment.
Influence of Added Aluminum on Carbon Dioxide Production in Tropical Soils
Authors: Mutatkar V. K. , Pritchett W. L. 
Published: July 2010

AbstractAluminum added to a yellow‐brown Latosol, as Al2(SO4)3, at rates of 6.6, 16.5, and 33.0 meg /100 g of soil decreased soil pH from 5.9 to 4.6, 4.0 and 3.8, respectively. Carbon dioxide production during 35 days of incubation decreased with increases in H‐ion concentration. In an attempt to separate the effects of H‐ion displacement from that of Al‐ion hydrolysis on microbial activity, Al‐treated soils were left unadjusted, or adjusted to pH 4.0, 5.5 or 6.5 before incubation.Carbon dioxide production decreased with increases in added Al when the soil pH was maintained below about 4.0. Aluminum precipitated rather rapidly in soils with a higher pH and the Al had little influence on CO2 production. Less than 1 ppm of Al was extracted by 1n KCl when the final pH of the soil was above approximately 4.0 (as determined in neutral salt). Below this range, exchangeable Al increased with increases in amounts of Al initially added to the soil.In a second experiment, a highly significant negative linear relationship was found between CO2 production and increasing percentages of Al in mixtures of Al‐ and Ca‐saturated Everglades muck. Furthermore, when Ca‐saturated muck was adjusted to pH 4.0 with HCl, and incubated, the production of CO2 was significantly greater than in Al‐saturated muck adjusted to pH 4.0. Since exchangeable Al did not increase when the Ca‐saturated muck was adjusted to a lower pH, but did increase when the pH of the Al‐saturated muck was lowered, it appeared that Al had an influence on CO2 production in these acid soils.
Survival and Reproduction of Two Species of Earthworm and a Rotifer Following Herbicide Treatments
Authors: Caseley John C. , Eno Charles F. 
Published: July 2010

AbstractThe survival and reproduction of Lumbricus terrestris Linné (Red Wiggler) and Eudrilus eugeniae Grinsburg, 1866 (African Giant) earthworms were followed in Everglades muck and Arredondo loamy fine sand treated with 11 herbicides at five rates.Generally, E. eugeniae were more susceptible to the herbicides than L. terrestris and both suffered greater damage in Arredondo fine sand than in Everglades muck. Eggs and young were found in all treatments in the muck while none were observed in the fine sand. Several of the compounds had no effect, even at 64 ppm. Apart from dalapon, which had a significant effect on E. eugeniae at 8 ppm, the other compounds were ineffective below 16 ppm in Arredondo fine sand, and 32 ppm in Everglades muck. These levels are much in excess of the recommended rates for field applications.Rotifers appear under moist conditions in most soils, and their diet includes soil algae. In solution culture, no direct toxic effects could be attributed to any one of the seven herbicides tested, but significant reductions in numbers of rotifers resulted from treatments which adversely affected the growth of unicellular algae. This demonstrated the indirect effect which some herbicides may have on an organism by way of a given food chain.
Effect of Soil Moisture on Ammonification and Nitrification in Two Northern Plains Soils
Authors: Reichman G. A. , Grunes D. L. , Viets F. G. 
Published: July 2010

AbstractSamples of a Chestnut and Chernozem soil, with and without additions of (NH4)SO4 and K2HPO4, were incubated at constant water contents ranging from suctions of 0.2 to about 100 bars, and the exchangeable NH4‐ and soluble NO2‐N measured periodically. NO2‐N in excess of 1/3 ppm was never detected. Addition of P had no effect on N transformations. Ammonification and nitrification of soil N were almost directly proportional to soil water content at suctions between 0.2 and 15 bars. Measurable ammonification and nitrification occurred at a suction of 15 bars.
Evidence Indicating the Presence of Loosely‐Bound Phenolic Groupings in Soil Organic Matter Extracts
Authors: Keefer R. F. , Himes F. L. , Mortensen J. L. 
Published: July 2010

AbstractPurified low molecular weight material from a sodium hydroxide extract of a peat soil was separated by paper chromatography into at least 8 components which coupled with diazotized spray reagents suggesting the presence of phenols, aromatic or aliphatic amines, β‐diketo groups, imidazoles, or other highly reactive compounds. The color reactions with the diazonium sprays indicate the presence of derivatives of catechol and resorcinol. Aromaticity is further suggested by infrared spectra of fractions of the fulvic acid. Two components appear to be of the flavonoid type.
Sulfur Requirements for Decomposition of Cellulose and Glucose in Soil
Authors: Stewart B. A. , Porter L. K. , Viets F. G. 
Published: July 2010

AbstractThe rates of glucose and cellulose decomposition in soils treated with adequate N and P were dependent on the S level More S was required for a maximum decomposition rate of cellulose than for glucose. A minimum of 1 part S to 300 parts C was required for maximum cellulose decomposition, whereas 1 part S to 600–900 parts C was sufficient for maximum decomposition of glucose. One factor for the higher S requirement for cellulose decomposition may be that more S is required in the production of extracellular enzymes essential for cellulose decomposition.
Wind Erosion as Influenced by Row Spacing, Row Direction, and Grain Sorghum Population
Authors: Skidmore E. L. , Nossaman N. L. , Woodruff N. P. 
Published: July 2010

AbstractReplicated plots of grain sorghum (Sorghum vulgare) with 21‐ and 42‐inch row spacings and three plant spacings within each row spacing were established on Dalhart sandy loam in 1963 and yield data were obtained. In March 1964, four wind tunnel tests were conducted one ach plot, two with wind blowing parallel to row direction and two perpendicular. Sorghum stubble residue was sampled and analyzed The results were interpreted in terms of natural wind conditions for sample locations in the Great Plains by applying previously developed procedures to determine prevailing wind erosion direction and preponderance of wind erosion forces in the prevailing wind erosion direction.Soil loss was reduced by narrow row spacing, high plant population, and rows perpendicular to wind direction. Nearly three times as much erosion occurred with wind blowing parallel as perpendicular to row direction.The combined advantage of narrow row spacing (21‐inch) and rows perpendicular to prevailing wind erosion direction reduced soil loss from 29 to 55%. Greater reductions result when a larger proportion of wind erosion forces occur in the prevailing wind erosion direction.Plant residue and grain yield increased significantly with higher plant population. Grain yield was not significantly affected by row spacing.Based on the results of this study and for similar conditions, for decreased wind erosion and maintenance of grain yields one should (i) plant high plant populations within the recommended range, (ii) plant in narrow row spacings, and (iii) where field layout permits, plant perpendicular to prevailing wind erosion direction.
Surface Chemistry of Hematite: Anion Penetration Effect on Water Adsorption
Authors: Jurinak J. J. 
Published: July 2010

AbstractThe adsorption of water by αFe2O3 (hematite), using high vacuum techniques, was studied. The surface of hematite was treated with phosphate, sulfate, or molybdate and activated at various temperatures prior to adsorption studies. The anion treatment had no apparent effect on the physical adsorption of water. The hematite surface was found to adsorb one water molecule/23‐24A2 whereas an OH group on the hematite surface was found to occupy an effective area of 22–23A2. Water adsorption on OH sites is inferred. About 45 to 47% of the oxide surface was found to physically adsorb water. Chemisorbed or OH water was influenced by anion treatment and was related to both the density of the OH population and the mobility of the associated proton. Both water and anion reaction with the surface is discussed.
Distribution of Nitrogen Fixed in Desert Algal‐Crusts
Authors: Mayland H. F. , McIntosh T. H. 
Published: July 2010

AbstractFixation of isotopically labeled N2 by desert algal crust organisms was very rapid after initial wetting of crusts. After 8 days of incubation, a steady rate of fixation was reached which continued for 152 days.The initial distribution of N was 4% extracellular NH4, 16% acid‐hydrolyzable NH4 (included extracellular NH4), 41% α amino acid, 4% hexosamine, 29% acid‐hydrolyzable but unidentified, and 11% non‐hydrolyzable. After 21 days of incubation the distribution of total N was 2, 18, 42, 2, 29 and 11%, respectively. The distribution of excess N15 after 21 days of incubation was trace, 12, 51, 2, 29 and 7% for the respective fractions. Continued incubation had little effect on the relative distribution of N in the several fractions.
Influence of Natural Drainage on the Distribution and Forms of Phosphorus in Some Iowa Prairie Soils
Authors: Runge E. C. A. , Riecken F. F. 
Published: July 2010

AbstractTotal, inorganic, organic, and available P were determined for 12 loess‐derived prairie soil profiles. The amount of total phosphorus (TP) is high near the surface, has minimum values from 1 to 3 ft, has maximum values from 3 to 6 ft, and has nearly uniform values below 6 to 7 ft. The higher amounts near the surface are due to organic phosphorus (OP). The amount of OP in the poorly drained soils is about one‐half that in the better drained members of the topo‐sequence.Differences in organic carbon (OC)/OP ratios between the poorly and better drained soils are appreciable, with the poorly drained soils having the higher ratios.Difference in extractable or available phosphorus (AP) within and between profiles may be interpreted when pH, extractable Fe and Al, rooting depth of plants, TP and OC/OP ratios are considered. Phosphorus differences between soils of southeast and southwest Iowa are appreciable. The role of P in soil genesis studies is discussed.
Crop Response From Tile and Surface Drainage
Authors: Schwab Glenn O. , Taylor George S. , Fouss James L. , Stibbe Ehud 
Published: July 2010

AbstractThe effects of various drainage systems and different levels of N treatments on corn (Zea mays) yields were evaluated for a fine‐textured lakebed soil during a period of 3 years. The drainage treatments consisted of undrained plots, surface drained, the drained, and a surface and tile drained combination. Excess wetness was provided each year by sprinkling all plots in June and July. The three drained treatments gave significantly higher yields than the undrained treatment, and N increased corn yields significantly at all drainage levels.An economic evaluation of the drainage systems with a N application of 100 lb/acre showed that the benefit/cost ratio for surface drains was 10:1; tile drains 6:1; and the combination tile‐surface drainage system 4:1, when compared to the un drained treatment. The study indicated that the surface drainage system gave the greatest benefit per dollar invested in the drainage system.
Effects of Stones on Runoff, Erosion, and Soil Moisture
Authors: Epstein E. , Grant W. J. , Struchtemeyer R. A. 
Published: July 2010

AbstractStudies on a caribou silt loam at Presque Isle, Maine were conducted to determine the effect of stones on runoff, erosion and soil moisture. The three treatments consisted of a control, stones over 3.81 cm in diameter removed, and stones over 3.81 cm removed, crushed and reincorporated into the soil. Removing the stones increased soil and water losses over a 4‐yr period. Infiltration and soil moisture was decreased as a result of stone removal. Crushing and returning the stones resulted in soil losses similar to that obtained under normal soil conditions. During 1961–1964, 20 storms produced 75% of the total soil loss and about 55% of the total runoff.
Zinc Availability for Corn as Related to Source and Concentration in Macronutrient Carriers
Authors: Giordano P. M. , Mortvedt J. J. 
Published: July 2010

AbstractZinc oxide, ZnSO4, and ZnS were tested as sources of Zn at rates of 1, 2, and 4 ppm Zn for two successive crops of corn (Zea mays) grown on Nolichucky sandy clay loam (pH 7.3). Each source was mixed throughout the soil as finely ground material, incorporated into granules of ammonium nitrate (AN) or ammonium polyphosphate (APP) by pressure granulation, and into granules of concentrated superphosphate (CSP) during the granulation stage of the manufacturing process. When mixed with the soil ZnO and ZnSO4 were more effective than when incorporated with a macronutrient carrier. Both ZnO and ZnSO4 were markedly superior to ZnS. Ammonium nitrate and APP were comparable carriers when ZnSO4 was the source, but APP was superior to AN when ZnO was used. A higher concentration of Zn in the CSP granules resulted in poorer response to this carrier. Zinc oxide was pressure granulated with CSP, AN, APP, or Nolichucky soil to contain 0.5, 2.0, or 8.0% Zn. Soil granules and CSP were applied at 1, 2, and 4 ppm Zn while AN and APP were applied at 2 ppm only. Forage yields and Zn uptake varied inversely with concentration of Zn in all carriers.
A Comparison of Clay Contents Determined by Hydrometer and Pipette Methods Using Reduced Major Axis Analysis
Authors: Liu T. K. , Odell R. T. , Etter W. C. , Thornburn T. H. 
Published: July 2010

AbstractTest results on the amount of <0.002 mm clay determined by hydrometer and pipette methods have been obtained from 155 duplicate soil samples, of which 48 are from Illinois and the remaining 107 are from soil survey reports published by the Soil Conservation Service in cooperation with 10 other states. Correlation analysis of the data yielded a highly significant coefficient of 0.965. The best‐fit line between the clay contents determined by these two procedures was obtained by the reduced major axis method of statistical analysis. In this statistical method, neither one of the two variables is considered as the dependent variable and the reduced major axis is determined by mininizing the sum of the areas of triangles formed by lines drawn from each point to the best‐fit line and paralle with the X and Y axes. The relationship between the clay contents is expressed by the equation Y = 0.63 + 1.008 X, in which X and Y represent the pipette and hydrometer clay content, respectively. Clay contents determined by these two methods are quite similar, although there is a tendency for hydrometer analyses to be slightly higher. Relationships between data from Illinois and other states are very similar. The slightly poorer correlation between clay contents of A horizons as compared to other horizons may have been caused by organic matter which was not removed in hydrometer analysis.
Soxhlet Extraction of Simazine from Soils
Authors: Adams Russell S. 
Published: July 2010

AbstractSimazine was quantitatively extracted from soils and clays in 2 to 24 hours using 95% ethanol as a solvent in a Soxhlet extractor. Absorption of ultraviolet light by the extracts was measured at 220 and 240 m µ and quantities of simazine and hydroxysimazine calculated from simultaneous equations. Plotting recovery of simazine vs. time of extraction as a first‐order reaction gave straight lines that varied in slope with each soil or clay sample. From the slope of the line a release constant (KRC) was calculated. Relating these constants to clay and organic matter contents and the cation‐exchange capacity (CEC) of the soils indicated that the ease of extraction was inversely related to the clay contents and CEC. However, bioassays demonstrated that the organic matter contents of the soils exerted the greatest influence upon the bioactivity of simazine in these soils. The organic matter‐simazine complex was presumed to be soluble in the alcohol and the KRC values were considered to represent a measure of the affinity of the clay for simazine.
Characterization of Mineralizable Nitrogen in Soils
Authors: Keeney D. R. , Bremner J. M. 
Published: July 2010

AbstractA study of the changes in total N, fixed ammonium N, and hydrolyzable and nonhydrolyzable forms of N that occurred when soils were incubated under conditions which promoted mineralization of soil N showed that prolonged incubation led to a marked decrease in all forms of N determined excepting fixed ammonium N and indicated that native fixed ammonium is practically unavailable to soil microorganisms. It also showed that there are marked differences among soils with regard to the nature of the N that is most readily mineralized and made available for plant growth and indicated that any chemical method of obtaining an index of soil N availability based solely on determination of a hydrolyzable or nonhydrolyzable form of soil N will prove unsatisfactory.