bluuebunny/crossref_metadata_2025_split huggingface dataset:
Copper and Molybdenum Nutrition of Crops Grown on Acid Sphagnum Peat Soil
Authors: MacKay D. C. , Chipman E. W. , Gupta U. C. 
Published: July 2010

AbstractFive crops, carrot, onion, spinach, cauliflower and lettuce (Daucus carota L., var. sativa D. C.), (Allium cepa L.), (Spinacia oleracea L.), (Brassica oleracea, var. botrytis L.), (Lactuca sativa, var. capitata L.).] were grown successively in pails of virgin sphagnum peat soil receiving 6 rates of Cu and 5 of Mo in a replicated factorial experiment. The soil was limed to slightly above pH 5.0 and other nutrients were added as necessary.Significant yield responses to Cu applications were obtained with all crops, because of deficiencies on the untreatnts. soil and of toxicities on the plots receiving very high treatments. Molybdenum treatments also encompassed the range from deficiency to toxicity with all crops except spinach.Except for Cu in onion, analyses for Cu and Mo in aboveground plant tissue after harvests were closely related to treatments. The range in Mo content was 0.2–7, 0.4–42, 0.3–140, 1.8–1,140, and 0.5–280 ppm. for carrot, onion, spinach, cauliflower and lettuce, respectively. The range in Cu content for the same crops was 3.4–14, 6.5–11, 1.6–64, 2.2–17, and 3.1–13 ppm.A mutual antagonism between Cu and Mo was appaarent whereby the application of one element to the soil significantly affected the content of the other in the plant (except for onion). This was related to a significant yield interaction with cauliflower and to nonsignificant trends with the other crops. In general, the antagonism was exemplified in one or both of the following ways: (i) Toxicities of one nutrient were alleviated by applications of the other; and (ii) deficiencies of one nutrient were aggravated by excesses of the other.
Cambic and Certain Noncambic Horizons in Desert Soils of Southern New Mexico
Authors: Gile Leland H. 
Published: July 2010

AbstractIn a study area of southern New Mexico, horizons in the B position may be ordered in degrees of increasing development, and form an essentially continuous series closely related to age. No evidence of soil development is found in freshly deposited arroyo alluvium. Next in the developmental scale are horizons with some weak evidence of soil formation, but which are still too weakly developed to qualify as cambic horizons. With increasing age, cambic horizons and finally argillic horizons occur in the B position. The relationships of soil development to age are confounded in some older soils by such factors as soils truncation and soil mixing.Distinct cambic horizons have formed in soils that are less than about 5,000 years old. In various cambic horizons there has been sufficient alteration of the original parent material to destroy fine strata, form structure, develop redder color, redistribute carbonate, and accumulate slight amounts of silicate clay. Cambic horizons of old, polygenetic soils show evidence of profound change in the B position since deposition of the parent materials and the start of soil formation. Argillic horizons apparently formed in some soils and were later destroyed. Some soils once had much thicker B horizons than they now have.The present climate of this desert region is arid, but evidence of former glaciation and lakes indicates a climatic change. The present climate is apparently warmer and drier than the climates of Pleistocene pluvials. Soils formed mainly in the Pleistocene tend to have thicker, stronger horizons than do soils formed in the Recent; this is apparently caused in part by the Pleistocene pluvial climates.
Strength of Compacted Amarillo Fine Sandy Loam as Influenced by Moisture, Clay Content, and Exchangeable Cation
Authors: Mathers A. C. , Lotspeich F. B. , Laase G. R. , Wilson G. C. 
Published: July 2010

AbstractUnconfined compression strength of Amarillo fine sandy loam was affected by water content (at molding and at time of strength test) bulk density, clay content, and saturating cation. When dried after molding, briquettes of Amarillo fine sandy loam attained maximum strength at 3 to 6% water depending on clay content. Maximum strength was attained at approximately one monolayer of water on the total surface area suggesting that H‐bonding of water molecules contibutes to soil strength. As additional water was lost, strength decreased to a minimum at onehalf monolayer and increased again as complete dryness was approached. Shapes of the drying curves were similar regardless of the percent molding water, bulk density, clay content, or exchangeable cations.Na‐saturated soils had greater dry strength than Ca‐ or Al‐saturated soils.
The Occurrence of High Molecular Weight Organic Phosphorus Compounds in Soil
Authors: Thomas R. L. , Bowman B. T. 
Published: July 2010

AbstractAn extraction procedure using the chelating resin Dowex A‐1 after an HF‐HCl pretreatment is described for the extraction of high molecular weight organic phosphorus compounds. This procedure appears to reduce the degradation of high molecular weight compounds that occur with more drastic extraction techniques now in use
Soluble Silica in Soil
Authors: Miller Raymond W. 
Published: July 2010

AbstractSilica, as dissolved Na2SiO3, was added to soil samples or to soil cores; the silica was measured as the molybdenum blue complex of mono‐ and disilicic acid. The concentration of silica in a soil solution is determined by the soil's properties. Solubility is both temperature and pH sensitive. When large quantities are added to soil as a solution of NaSiO3 and then dried, only a smaller concentration of soluble silica characteristic of the soil will remain in simple soluble forms. The fate of the bulk of the added silica is believed to be some reaction with disorganized or amorphous surfaces of silicate particles in the soil. This alteration of soluble silica is rapid and results in a lower silica concentration in the soil extract than would be expected if no reaction occurred. The change in concentration of soluble silica can occur in the time required for water to percolate through the soil profile. The change can also occur either during drying or while the soil is maintained in a moist condition.Addition of CaCO3 to soil reduced the “equilibrium” silica concentration of a soil extract. This is believed to result mostly because of a change in pH of the soil. Higher temperatures increased the concentration of soluble silica obtained.The presence of soil pans containing cementation by silica might be at least partly explained by changes in pH of profile layers, temperature alterations with depth, and loss of water by soil dehydration. Aging and drying would aid the development of deposits of a nonreversible nature.
Humification of Carbon‐14 Labeled Glucose in Soils of Sanborn Field
Authors: Mutatker V. K. , Wagner G. H. 
Published: July 2010

AbstractDuing the incubation of C14‐labeled glucose in soil for 3 months, 25% of the radioactive carbon was incorporated in the soil organic matter while the remainder was evolved as CO2. Fellowing incubation, the soil organic matter was extracted by 0.5N NaOH and fractionated. Humin, humic, and fulvic fractions were similarly labeled in a given soil. Generally, soil organic matter resulting from glucose was rather uniform in character for the several soils studied, whereas, that present prior to adding glucose may have differed among soils as a result of humification of diverse substrates. Selective combustion of aliphatic material in each fraction by heating at 170C for 25 days indicated that about 50% of the total carbon in humin and fulvic material and 66% of that in humic acid were aromatic. Aromatic and aliphatic components of the fulvic fraction were about equally labeled in all soils. Humic acid and humin showed less C14 incorporation into the aromatic than the aliphatic component.
A Rapid Citrate‐Dithionite Extractable Iron Procedure
Authors: Holmgren George G. S. 
Published: July 2010

AbstractA procedure for obtaining iron which is both convenient and reliable is described. The procedure involves shaking the samples overnight in a citrate‐dithionite buffer. This is followed by a colorimetric iron determination using orthophenanthroline. The use of an automatic pipette, a flocculating agent, and noncritical quantities of dry reagents facilitates the determination. The results show increased effectiveness and reliability over Kilmer's porcedure for high‐iron Oxisols and Ultisols from Puerto Rico.
Potassium Nutrition Effects on Net Photosynthesis and Morphology of Alfalfa
Authors: Cooper R. B. , Blaser R. E. , Brown R. H. 
Published: July 2010

AbstractGreenhouse experiments were conducted to study the influence of K on CO2 assimilation, growth, and morphological characteristics of alfalfa (Medicago sativa L.). Yield increases were consistently obtained with high K. Added K increased plant height. The rate of leaf accumulation, leaf size, and weight per unit area also increased as did stomatal number and aperture. More and larger epidermal cells per leaf were observed with high K nutrition. Net photosynthesis rates of excised leaves increased with K application. Leaves from plants with added K had lower CO2 compensation points, indicating higher efficiency of CO2 assimilation under limiting CO2 conditions.
Sampling for Pedographic Modal Analysis of an Argillic Horizon
Authors: Milfred C. J. , Hole F. D. , Torrie J. H. 
Published: July 2010

AbstractPedographic modal analysis expresses soil composition in terms of the relative amounts of constituents observed in thin sections. Data are presented on the sampling density necessary for pedographic modal analysis of an argillic horizon. Thirty‐one randomly selected samples (100cc cores) were obtained from a 61 cm by 61 cm vertical exposure of the horizon. Four thin sections were made from each core. Six constituents were counted in each thin section by the point count method of modal analysis. Constituents less than 50 µ in diameter were classified as matrix, while those larger than 50 µ were classified as glaebules, pores, papules, argillans, or skeleton grains.Results indicate that a sample adequate to measure these constituents in an argillic horizon with a standard error 10% of the mean would involve taking 21 cores, making 2 thin sections per core, and counting 1,000 points per thin section.
Determination and Isotope‐Ratio Analysis of Different Forms of Nitrogen in Soils: 7. Urea
Authors: Keeney D. R. , Bremner J. M. 
Published: July 2010

AbstractTwo methods of determining urea in soils are described. In one (extraction‐distillation method), the soil sample is extracted with 2M KCl (10 ml/g of soil) for 5 min, and an aliquot of the extract is treated with potassium phosphate buffer (pH 8.0) and urease for 2 hours at 30C to convert urea N to ammonium N. In the other (direct‐distillation method), the soil sample is treated directly with pH 8.0 potassium phosphate buffer and urease for 1 hour at 30C. In both, the ammonium released by the urease treatment is separated by steam distillation of the treated sample for 3.3 min and determined by titration of the distillate with standard acid. The extraction‐distillation method is useful when analyses for nitrate and nitrite as well as urea are required, but it does not give completely quantitative recovery of urea added to some soils. The methods are rapid, specific and precise, and they permit isotope‐ratio analysis of urea N in N15‐tracer studies of urea transformations in soils.
Salt Displacement and Titration of AlCl3‐Treated Trioctahedral Vermiculites
Authors: Kaddah Malek T. , Coleman N. T. 
Published: July 2010

AbstractFreshly prepared and 45‐day‐aged Al‐saturated trioctahedral vermiculites from Libby, Montana, and northeastern Transvaal, South Africa, were: (i) leached with 1N and 0.05N solutions of NaCl, KCl, and CaCl2, (ii) subjected to repeated cycles of 1N NaCl leaching and Al saturation, and (iii) potentiometrically titrated in H2O or N NaCl. In the leaching experiments, the exchange acidity, exchangeable H, Al, and Mg, and the CEC after leaching were determined.Salt solutions displaced only part of the adsorbed Al, with less from South African than from Libby samples. Also displaced were H3O and small amounts of Mg ions. The exchange acidity (H3O + Al), the ratio of H3O to Al, the displaced Mg, and the apparent CEC after Al saturation and displacement varied with the kind and concentration of the displacing solution, the source of vermiculite, the aging period, and the number of cycles of Al saturation and displacement.With freshly prepared Libby samples, the exchange acidity varied from about 60 to 80% of the CEC, with Al constituting 60 to 90%. The corresponding ranges for South African samples were 35 to 50% and 30 to 85%. Of the three salts, KCl solutions gave the smallest exchange acidity and the lowest values for Al/exchange acidity; CaCl2 effected the highest values, with NaCl in between. Dilution of displacing solutions generally increased the H3O ion component of exchange actidity. Repeated Al saturation and displacement resulted in decreased exchange acidity.Potentiometric titration curves of Al‐vermiculites in H2O did not suggest the presence of appreciable amounts of exchangeable H3O. Titration curves in NaCl had buffer ranges interpreted as suggesting the presence of H3O, Al, and another component presumed to be mostly monohydroxy‐Al ions.The two Al‐vermiculites manifested by X‐ray analysis different collapsibility on K saturation and heat treatment. The X‐ray data support the conclusion that Al hydrolysis occurs between vermiculite plates, with general correspondence between the amount of nonexchangeable Al and the failure of the minerals to collapse to 10A upon K saturation and drying.
Desorption of Phosphate from Kaolinite
Authors: Kafkafi U. , Posner A. M. , Quirk J. P. 
Published: July 2010

AbstractInitially all the phosphate adsorbed onto kaolinite is isotopically exchangeable. On washing some of the phosphate ceases to be exchangeable, but if the amount that remains labile is plotted against the solution concentration the original isotherm is preserved. Thus, some of the total phosphate goes into a nonexchangeable “fixed” sink.If phosphate is adsorbed in very small increments some of it is converted directly into the fixed form. In the presence of large concentrations of phosphate, all the adsorbed phosphate becomes exchangeable.
Soil Temperature Patterns in Surface‐Insulated Containers in Water Baths Related to Maize Behavior
Authors: Walker John M. 
Published: July 2010

AbstractDifferent soil surface insulators did not establish isothermal conditions in soil in metal containers placed in constant temperature water baths. The water temperatures were 15, 25, and 35C, with the air temperature about 25C. The behavior of maize (Zea mays L.) seedlings, which were grown in these soils, was related to the degree of temperature control by the various insulators. Differences in growth and ion uptake were statistically significant when the water bath temperatures were not optimum at 15 and 35C.
Contributions of Fixed Charge and Mobile Complexing Agents to the Diffusion of Zinc
Authors: Hodgson J. F. , Lindsay W. L. , Kemper W. D. 
Published: July 2010

AbstractZinc was allowed to diffuse from a ZnCO3 precipitate through an agar‐agar gel to a stream of continuously flowing water. In one treatment, part of the agar‐agar was replaced by Ca‐poly‐galacturonate to incorporate fixed negative charges in the gel in the form of carboxyl groups. In a second treatment, Cacitrate was introduced into the flowing stream of water. In every case, all phases of the system were kept in equilibrium with CaCO3.Both fixed charges and the mobile complexing agent increased the transport of Zn in the system, but the latter was considerably more effective than the former. One percent polygalacturonic acid increased the transport of Zn by 13%, whereas 2 × 10‐3 M citrate increased the transport of Zn 100‐fold.Results compare favorably with a theoretical treatment for the contribution of the mobile complexing agents to Zn transport.
Ant (Formica cinerea) Pedoturbation in a Prairie Soil
Authors: Baxter F. Paul , Hole Francis D. 
Published: July 2010

AbstractActive and recently active mounds made by the ant (Formica cinerea montana Emery) number 1,531 ha and occupy 1.7% of the area of the surface of Tama silt loam in a prairie remnant in southwestern Wisconsin. The average volume of an ant mound is 0.02 m3, of which about 12% is occupied by channels and chambers. The mineral soil in the upper half to two‐thirds of a representative mound consists about 85% of B horizon material, judging by soil color, content of clay, and oriented argillans. Unusually high contents of available K and P in the mound are probably a result of concentration by the ants of organic materials, particularly those derived from plant sap from aphids; of rapid mineralization of organic matter; and by addition by the ants of B horizon material. Upward movement of soil material by ants could account for the relatively high clay content of the A horizon of Tama silt loam in southwestern Wisconsin, as contrasted with that of the A horizon of the comparable nearby forest soil.
The Movement of Phytic Acid in Soil Cores
Authors: Bowman B. T. , Thomas R. L. , Elrick D. E. 
Published: July 2010

AbstractThe movement of phytic acid‐phosphorus in a vertical soil core was studied under controlled conditions using a miscible displacement technique. Experiments were conducted on a sandy loam soil with gamma irradiation at 20C and without irradiation at 5C and 20C. Phytic acid appeared to be quickly bound by the soil, accumulating near the top of the soil core. Phytic acid apparently displaced native inorganic phosphorus. The movement of phytic acid increased and its rate of mineralization decreased at 5C as compared to 20C. Gamma irradiation reduced, but did not completely eliminate, mineralization of phytic acid at 20C. Changes in free iron concentration within the core were noted and related to the movement of phytic acid‐phosphorus.
Gamma Irradiation and the Microbial Population of Soils at Two Water Contents
Authors: Jackson N. E. , Corey John C. , Frederick L. R. , Picken J. C. 
Published: July 2010

AbstractThirty‐gram soil samples, in plastic tissue culture dishes (60 × 15 mm), were irradiated with gamma rays (8000 curie Co‐60 source) at doses ranging from 0 to 3 million rads. Fungal and bacterial plus actinomycetal counts were made by plating soil suspensions on rose bengal‐streptomycin agar and egg albumin agar, respectively. Plates were incubated for 4 to 8 days before counting. The numbers of fungal and bacterial units reflected differences in survival among the microbial populations from soil samples taken at three horizons within field profiles. Microbial counts in the soils at 30% water content (by weight) were generally reduced to zero at lower radiation doses than those in the air‐dry soils. One million rads were required to kill all fungi, but 2 to 3 million rads were required to kill all bacteria in a 30‐g soil sample. At a given water content, samples with the higher initial microbial populations required greater radiation doses for sterilization than samples with lower populations. For small soil samples, exposure to gamma radiation proved a rapid and efficient method of sterilization.
Responses of the Soil Microflora to Volatile Components in Plant Residues
Authors: Menzies J. D. , Gilbert R. G. 
Published: July 2010

AbstractExposure of soil to volatile substances from alfalfa (Medicago sativa L.) hay, corn (Zea mays L.) leaves, and other plant residues induces an immediate rise in the respiration rate of the soil microflora. This if followed by an increase in bacteria numbers and by vegetative growth of fungus mycelia over the soil surface. These volatiles, active at a distance from the plant residue, may function as respiratory and growth stimulants for soil microorganisms in the initial stages of colonization of residue.
Plow‐Layer Porosity and Surface Roughness from Tillage as Affected by Initial Porosity and Soil Moisture at Tillage Time
Authors: Allmaras R. R. , Burwell R. E. , Holt R. F. 
Published: July 2010

AbstractTotal porosity increase and random roughness due to plowing were each significantly affected by the moisture content at tillage time. Their magnitudes were greatest at low moisture contents, decreased approximately linearly as soil moisture increased to the lower plastic limit (LPL), and then increased at moisture contents greater than LPL. The porosity before plowing more significantly affected tillage‐induced random roughness than total porosity increase. There were significant deviations from these generalities within each of the three soil associations: Barnes‐Aastad, Kranzburg‐Poinsett, and Nicollet‐Webster.In all three associations, the porosity decrease by subsqeuent disking and harrowing was more pronounced where plowing gave the greatest porosity increase. Only in the Kranzburg‐Poinsett association (high in silt content) were porosity increases observed from disking and harrowing near and above the LPL. Disking and harrowing nearly always reduced random roughness, and the reduction increased linearly as the random roughness of the plow treatment increased.
Effect of Straw Mulch Rates on Soil Water Storage during Summer Fallow in the Great Plains
Authors: Greb B. W. , Smika D. E. , Black A. L. 
Published: July 2010

AbstractNet gains in soil water storage during fallow due to increased quantities of wheat (Triticum aestivum L.) straw mulch varied from 1.0 to 4.3 cm at Sidney, Mont., from 2.1 to 4.1 cm at Akron, Colo., and from 1.3 to 3.3 cm at North Platte, Nebr. These gains were made primarily during the spring months of the 14‐month fallow season. More than 70% of the net gains in soil water under heavier amounts of mulch was found below the surface 61 cm of the soil profile at all experimental locations, thereby minimizing potential evaporation losses. Storage of water tended to increase with the delayed date of straw burial in Nebraska. Additional soil water was conserved at Akron, Colo. during the first fall by subtillage of wheat stubble at harvest when compared with spring subtillage; however, by the end of the fallow there was no significant difference between treatments. Fallow efficiencies averaged 22, 30, and 32% for all treatments at the Montana, Colorado, and Nebraska locations respectively.
The Chemical Composition of Sphagnum Species and the Influence of Drainage on its Location
Authors: Maas E. F. 
Published: July 2010

AbstractDrainage of a sedge swamp containing islands of Sphagnum species resulted in a shift of new sph gnum growth on to the sedge around the perimeter of the islands. The new sphagnum deposit developed on a substratum of sedge peat was higher in exchangeable Ca and Mg, total N, percent ash and pH than that produced in its original location on the lower nutritional substratum of sphagnum peat.
Osmotic Effects on Water Flow Through a Ceramic Filter
Authors: Jackson Ray D. 
Published: July 2010

AbstractNon‐Darcy type flow of water through a porous ceramic filter of 0.1µ pore diameter was shown to be caused by osmotic effects. When osmotic effects were accounted for, the flow rate through the filter was proportional to the pressure gradient, indicating that water flow was viscous and not plastic as has been previously reported. Threshold effects, if present, were small. The permeability, calculated by using the viscosity‐density ratio for bulk water, was invariant with temperature.