bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hydrolysis and Availability of Pyrophosphate in Tropical Soils
Authors: Juo A. S. R. , Maduakor H. O. 
Published: July 2010

AbstractHydrolysis and retention of pyrophosphate were studied in selected Nigerian soils. Hydrolysis proceeded readily in the surface soils with half‐lives ranging from 4 to 14 days. Rate of hydrolysis was much slower in the subsoils when compared with their corresponding surface soils. The pyrophosphate halflives in these subsoil samples ranged from 16 to more than 64 days. It was also found that the subsoil samples retained more pyrophosphate resistant to hydrolysis than associated surface soil.Soils retained greater amounts of pyrophosphate than orthophosphate against 1N NH4Cl extraction although the relative amounts retained by the soils studied followed the same trend.A short‐term P uptake experiment showed that pyrophosphate could be considered as equally effective as orthophosphate as sources of P for plants.
Cotton Root Growth and Uptake of Nutrients: Relation of Phosphorus Uptake to Quantity, Intensity, and Buffering Capacity
Authors: Khasawneh F. E. , Copeland Jane P. 
Published: July 2010

AbstractCotton (Gossypium hirsutum var. ‘Stoneville 213’) was grown in greenhouse pots containing Hartsells fine sandy loam. Four rates of P were employed and the crop was harvested on three different dates. Dry matter yield of tops and uptake of P were measured. Roots were recovered and their length determined. These data were used to calculate a rate of P uptake per meter of roots which in turn was related to quantity and intensity of soil P. A parameter that combines the effects of quantity, intensity, and P buffering capacity was derived, and rate of P uptake was found to be related to this parameter. Rate of P uptake increased with rate of root growth.
A Method of Statistically Interpreting Soil Data for Agricultural and Engineering Land Use
Authors: Kloosterman B. , Lavkulich L. M. 
Published: July 2010

AbstractA methodology (model) was developed by which soils can be rated, inputs to improve the soil can be determined, and estimates of input costs can be calcuated. Routine soil survey data was used to make interpretations and to illustrate the characteristics of the methodology. Interpretations, including cost estimates, were made for suitability for cash cropping and suitability for roadbed construction. The quantitative soil interpretations were made by statistical procedures notably factor analysis, correlation and regression analysis. Various methods of using soil pedon data were compared and the methodology was evaluated with respect to assumptions and limitations. Recognized soils of the Lower Fraser Valley were quantitatively rated by comparison to the models constructed and hypothetical treatment costs to improve the soils were calculated. The methodology should allow the evaluation of the physical quality of a soil in terms of benefit/cost considerations among alternate land uses.
Steady‐State Seepage in a Hillside
Authors: Morin G. C. A. , Warrick A. W. 
Published: July 2010

AbstractThe complex potential function is obtained for two‐dimensional seepage of water through a hillside using conformal transformations. Two cases are considered: In the first a straight slope of finite length intersects an infinitely wide horizontal plane; in the second, a horizontal plane of finite width is between two symmetric hillsides. Flow nets and graphical relations characterize the flow patterns.
The Persistence of 2,4,5‐T in Greenhouse Lysimeter Studies
Authors: O'Connor G. A. , Wierenga P. J. 
Published: July 2010

AbstractThe persistence of 2,4,5‐T was evaluated in an agricultural soil under favorable microbial conditions in lysimeters. Degradation was most rapid in a soil previously treated with the herbicide if extended periods of time did not separate herbicide additions. The degradation of 2,4,5‐T was more rapid when the herbicide was applied at 40 ppm than when it was applied at 80 ppm. The time required for biological detoxification varied from 43 to 85 days depending upon pretreatment and concentration of the applied herbicide.
Foliar Chloride Levels in Some Eastern Australian Plantation Forests
Authors: Turner J. , Kelly J. 
Published: July 2010

AbstractVariation in foliar chloride concentrations in New South Wales, Australia, plantation forests were investigated as part of the forest tree nutrition program. Mean foliar chloride concentration was found to decrease with increasing distance from the Pacific Ocean (up to 82% variation accounted for depending on species) and to increase with increasing rainfall and/or number of wet days in the 12 months, covering the growing season, prior to sampling (up to 85% of variation accounted for). Consistencies between species differences were found in foliar chloride concentration. For example at a given location, Eucalyptus pilularis was always higher than both Pinus radiata and Pinus elliottii.
Soil Concretions: II. Mineralogical Analysis
Authors: Gallaher R. N. , Perkins H. F. , Tan K. H. , Radcliffe D. 
Published: July 2010

AbstractMineralogy of soil concretions, collected from Henry, Iredell, Tifton, and Decatur soils of the southeastern USA, were studied by DTA, X‐ray diffraction, and electron microprobe analysis. The results indicated the presence of considerable differences in mineralogical composition of concretions formed under different conditions. Although they were basically composed of 1:1 and 2:1 lattice type of clay minerals, quartz, and feldspars, Iredell soil concretions appeared to contain in addition appreciable amounts of amphibole and goethite compared to concretions of Henry soil. On the other hand Tifton soil concretions were made up of predominantly quartz, some 1:1 lattice type of clay mineral, and sesquioxides including gibbsite and hematite. Concretions from Decatur soil appeared to consist partly of amorphous minerals in addition to material, which exhibited X‐ray diffractions characteristic of the mineral psilomelane. It was concluded that Fe‐Mn concretions from Henry and Iredell soils had more complex mineralogy than those found in Tifton and Decatur soils. Mineralogy of Fe‐Mn concretions of Henry and Iredell soils also revealed less intense soil weathering than was indicated by concretions in Tifton soil that contained plinthite.
A Digital Programmer for the Heinrich Miniature Probe Attachment for an X‐Ray Emission Spectrograph
Authors: Barnhisel R. I. , Stapp I. P. 
Published: July 2010

AbstractA solid‐state digital programmer was developed to drive a Heinrich miniature probe attachment for an X‐ray emission spectrograph. This allowed the automated operation of the X‐ray emission spectrograph during analysis of transects in a variety of studies such as: clay films associated with ionic diffusion, ionic distribution in plant tissue, etc.
Residual Soil Phosphorus Under Sustained Cropping in the Humid Tropics
Authors: Brams E. 
Published: July 2010

AbstractResidual P in river terrace soils of the West African humid uplands sustained satisfactory yields of Funk G‐901 maize (Zea mays L.), Anethoda rice (Oryza sativa L.), and Mares groundnut (Arachis hypogaea) under a sequence of continuous cropping for 3 consecutive years. Up to 90 kg/ha soluble P applied at the inception of the cropping sequence failed to elicit a yield increase when other cultural parameters were maintained at levels recommended as adequate for satisfactory yields under these conditions.At the start of the experiment the soil had already attained a residual P level of 55 kg/ha, the Ca + Mg concentration averaged 0.5 meq/100 g soil, and fresh crop and cover residues contributed 18 metric tons/ha of organic matter to the 15‐cm soil depth each year.Lime applied in the last year raised soil pH from 4.8 to 5.1, reduced Al base‐saturation from 30% to 9%, and probably contributed to the increase in groundnut yield, although this effect was not experimentally tested. In the 3rd year a second application of the P treatments after liming did not induce a significant increase in yield over the check (0‐P) or in those plots which had received only the P treatment initially.In soils where exchangeable Al comprised 30% or less of the base saturation, the conversion of soluble P into insoluble Al and Fe phosphates apparently was not a yield‐limiting reaction. Phosphorus fixation, particularly as Al phosphates, is a recalcitrant problem for soils in the humid tropics, but this is not true for soils under sustained cropping. By using the same crop varieties and soils similar to those used in this study, subsistence farmers could intensify their operations on selected sites utilizing residual P for extended periods without soil P becoming a yield‐limiting factor.
Effect of Exchangeable Cations on Lateral Movement of Sulfate in Excised Roots
Authors: Franklin R. E. 
Published: July 2010

AbstractAutoradiographs of histologic sections from excised corn (Zea mays) roots exposed to 35S labeled SO42‐ after pretreatment with K+, Ca2+, or Al3+ are shown. The autoradiographs indicate that the permeability of the epidermal layer to sulfate is severely restricted when pretreated with K+ but not when pretreated with Ca2+ or Al3+. Apparently this effect is associated with the cation exchange sites located in or near the epidermal layer and results from the electrostatic repulsive forces opposing anions which approach the epidermis, where the negatively charged sites are first encountered. The repulsive force would be an inverse function of the degree neutralization of the exchange sites by adsorbed cations which is in the order Al3+ > Ca2+ > K+.
Slick Spots in Southeastern Nebraska—Patterns and Genesis
Authors: Lewis David T. , Drew James V. 
Published: July 2010

AbstractSlick spots formed in Peoria loess near the crests of interfluves in southeastern Nebraska were studied in relation to their distribution and genesis. Peoria loess forms a discontinuous mantel over a maturely dissected plain of Kansan till. Soils within the slick spots are low in chroma, contain some soluble salts, and have more extractable sodium than associated soils formed in Peoria loess. Calculations indicate that clay formed per unit of nonclay lost was greater in a slick spot soil profile than in an adjacent soil profile. Subsurface data indicate that the configuration of an erosion surface cut into Kansan till underlying the slick spot and the differential permeability of Illinoian sediments above the till contribute to the occurrence of a perched ephemeral water table in the loess beneath the slick spot. The evidence suggests that soluble products of weathering, including Na and Ca, are added to the slick spot by capillary rise from a perched water table following periods of above average precipitation and accumulate in the slick spot during subsequent periods of intense evapotranspiration.
Effects of Drainage and Organic Amendments on the Reclamation of a Sodic Soil Cropped with Rice
Authors: Puttaswamygowda B. S. , Wallihan E. F. , Pratt P. F. 
Published: July 2010

AbstractIn a greenhouse pot culture study, effects of drainage and organic amendments on the reclamation of a saline sodic soil material under submerged conditions were studied with and without the presence of a rice crop (Oryza sativa L.). In drained soils, application of dairy manure, sugar, straw or straw + CaCl2 increased the rate of drainage and decreased the electric conductivity (EC) and exchangeable sodium percentage (ESP). Without drainage, treatments were less effective. Crop growth hastened the reclamation process by increasing the volume of water drained and the concentration of Ca + Mg in the drainage water.Drainage had a significant effect on the vegetative growth of rice, percentage of earbearing tillers, and straw and grain yield. In the undrained condition, organic soil amendments, except dairy manure, adversely affected the straw and grain yield.
Characterization of the Forest Floor in Stands along a Moisture Gradient in Southern New Mexico
Authors: Wollum A. G. 
Published: July 2010

AbstractForest floor properties of stands along a moisture gradient from dry, represented by a piñon‐juniper stand (Pinus edulis Engelm—Juniperus scopulorum Sarg.), to wet, represented by a white fir stand (Abies concolor [Gordon & Glend.] Lindl.), were studied. Dry weights and amounts of nutrients were directly related to the moisture gradient. For example, dry weights of the forest floor increased from 9.4 to 80.8 metric tons/ha from the dry to the wet end of the moisture gradient, respectively. Nutrient concentrations were not related to the moisture gradient with the exception of K. In the more mesic stands sufficient water appears to have been present to allow substantial leaching of K from the forest floor.
Growth and Wood Properties of Loblolly Pine on a Piedmont Subsoil as Influenced by Early Fertilization
Authors: Van Lear D. H. , Saucier J. R. , Goebel N. B. 
Published: July 2010

AbstractA field study was conducted on an impoverished “borrow” area in the South Carolina Piedmont to determine the response of loblolly pine (Pinus taeda L.) seedlings to various fertilizer treatments. Treatments were applied for 4 consecutive years to individual seedlings outplanted for 2 years. At the end of the fertilization period, seedlings receiving N, either alone or in combination with P and/or K, were significantly taller than seedlings in other treatments. Ten years after the last fertilizer application, trees treated with N, with or without other nutrients, averaged 0.6–1.6 m taller and 23–30% larger in diameter than control trees. Merchantable tree volume was at least doubled by N application. Phosphorus and potassium, at the rates used, had no effect on growth. Percentage latewood and wood specific gravity were not altered by fertilization.
Spheroidal Halloysite in a Guatemalan Soil
Authors: Askenasy P. E. , Dixon J. B. , McKee T. R. 
Published: July 2010

AbstractMineralogical analyses of clays from two Alotenango soil horizons were made by utilizing transmission and scanning electron microscopy, infrared, X‐ray diffraction, and chemical methods. This report of spheroidal halloysite demonstrates the presence of this mineral form in an area of important volcanic ash‐derived soils where it has not been previously identified. The presence of spheroidal halloysite in Central American volcanic soil and its presence in volcanic soils of Hawaii, Japan, and New Zealand indicate its wide geographic occurrence in soils of volcanic origin. Oblate halloysite spheroids tend to settle preferentially, offering an end‐view along the axis of some particles and correspondingly, reduced 00l X‐ray reflections from portions of layers not parallel to the plane of the powder mount. Halloysite spheroids appear to be composed of roughly concentric layers with occasional interlayer separations. The interior structure suggests inclusion of amorphous cores and interlayers which appear to be removed by 0.5N NaOH. The exterior layers often retain a shell‐like appearance after NaOH treatment. The apparent association of spheroidal halloysite and allophane interlayers suggests that the crystalline component forms alternately with the amorphous one. The crystalline exterior may protect amorphous interior material from rapid alteration and cause allophane to persist in a soil where minerals representing more advanced stages of weathering have accumulated.
Temperature Regimes and Classification of Some Well‐Drained Alpine Soils in Alaska
Authors: Rieger Samuel 
Published: July 2010

AbstractTemperatures at a depth of 50 cm were taken in four well‐drained alpine soils of interior and south‐central Alaska over a 3‐year period. The soils of the interior, under a strongly continental climate, have a pergelic temperature regime, but those of coastal mountains under a cool maritime climate do not.
Soil Urease: Paucity in the Presence of the Fairy Ring Fungus Marasmius oreades (Bolt.) Fr.
Authors: Norstadt Fred A. , Frey C. R. , Sigg Harold 
Published: July 2010

AbstractTurf infection by Marasmius oreades (Bolt.) Fr. produced concentric rings of affected soil or fairy ring phenomena. Urease activity of soil invaded by the fungus ranged from 0.86 to 15.4 mg NH4+‐N/100 g per 3 hours, or about 10 to 40% that in unaffected soil. Normal soil from outside the fairy rings had activity ranging from 8.9 to 36.2 mg NH4+‐N/100 g per 3 hours. Urease activity of soil was determined by distillation of NH4+, radioactivity of 14CO2, and respirometry of CO2. In determining urease activity, the quantity of NH4+‐N produced by hydrolysis of added urea was correlated (r = 0.84) with released 14CO2, but was twice as large. The results from respirometry of CO2 agreed with that from distillation of NH4+‐N. The numbers of microbes and urease activity were correlated for fresh soil with coefficients (r) ranging from 0.62 to 0.77. Extractable NH4+‐N was about 40 times larger in affected than in normal soil, although NO3‐‐N was unchanged. Soil pH was reduced about one unit. Urease activity was restored in affected soil by three successive incubations. The decrease in soil urease caused by the fungus likely was concomitant with humus destruction.
Leaching Requirement Studies: Sensitivity of Alfalfa to Salinity of Irrigation and Drainage Waters
Authors: Bernstein Leon , Francois L. E. 
Published: July 2010

AbstractAlfalfa (Medicago sativa L. cv. Sonora) was grown in 0.6 by 1.5 m greenhouse lysimeters and irrigated with two waters of EC 1 and 2 mmho/cm prepared by adding equivalent amounts of NaCl and CaCl2 to a 0.4 mmho/cm tap water. Yields showed relatively little effect of leaching fraction (LF) within the limits consistent with steady‐state salt balance for suction‐drained lysimeters but decreased 26% at the lowest LF for gravity‐drained lysimeters. Yields with the 2 mmho/cm irrigation water treatments were consistently about 10% less than those with the 1 mmho/cm water. Cessation of leaching or reduction of LF to levels requiring drainage water salinities for salt balance at steady state to exceed 35 mmho/cm, the maximum salinity achievable by alfalfa roots, eventually reduced yields. Yields were significantly higher (by 9%) when leaching was done every third or sixth irrigation than in every irrigation while maintaining the same average LF of 1/32 and 1/16 for the 1 and 2 mmho/cm irrigation waters, respectively. Since alfalfa yield was affected as much by a 1 mmho/cm difference in salinity of the irrigation water as by a ca. 20 mmho/cm difference in salinity of the drainage water, alfalfa yields obviously were not responding to the soil water salinity averaged by depth. Yield response appears to be related rather to the calculated mean salinity against which water was absorbed, which is influenced more by the salinity of the irrigation water than by the salinity of the drainage water.Steady‐state salinity profiles were achieved after 4 to 8 irrigations when LF was equal to or greater than 1/8, but at lower LF's of 1/16 and 1/32, steady‐state profiles were achieved only after 20 and 55 irrigations, or 1 and 2 years, respectively. Increasing the degree of water depletion caused major salt accumulation at lower depths corresponding to the increased depths at which major water depletion occurred. LF in the broad range that permitted nearly maximum growth had essentially no effect on water requirement (grams water evapotranspired per gram dry matter produced) or on Na and Cl contents of the harvested alfalfa. Increasing irrigation water salinity in the range 0.4 to 2 mmho/cm consistently increased plant Na and Cl contents, but had no effect on water requirement.Implications of the demonstrated lower leaching requirements for irrigation management and drainage and for water quality assessment are discussed.
An Evaluation of Kinetic and Equilibrium Equations for the Prediction of Pesticide Movement Through Porous Media
Authors: van Genuchten M. Th. , Davidson J. M. , Wierenga P. J. 
Published: July 2010

AbstractMiscible displacement techniques were used to study the movement of picloram (4‐amino‐3,5,6‐trichloropicolinic acid) through a water‐saturated Norge loam soil. The equilibrium adsorption and desorption isotherms for picloram and Norge loam soil were not single‐valued relations. Picloram mobility was reduced significantly when the average pore‐water velocity was decreased from 145 to 14.2 cm/day. Observed and predicted effluent concentration distributions were compared. Predictions were made with a S/360 CSMP simulation model, using two kinetic rate equations and an equilibrium Freundlich equation. The two kinetic models and the equilibrium model each satisfactorily described the observed effluent concentration distributions at low pore‐water velocities provided the nonsingle‐valued character of the adsorption‐desorption process was included in the calculations. At high pore‐water velocities, the kinetic adsorption models were found inadequate to predict the picloram movement. An empirical model was then developed, based on the assumption that equilibrium existed during displacement and that only a fraction of the soil participated in the adsorption process. This fraction was found to be a function of the average pore‐water velocity. With the empirical model, a reasonable fit between data and calculated effluent curves was obtained for all pore‐water velocities.
Nitrate Adsorption by Some Volcanic‐ash Soils of Southern Chile
Authors: Schalscha E. B. , Pratt P. F. , Domecq T. C. 
Published: July 2010

AbstractNitrate adsorption by several soils was determined as the difference between the NO3‐ added and that remaining in the supernatant liquid. A nitrate ion electrode method, which was checked against a phenoldisulfonic method, was used to determine the NO3‐ remaining in the supernatant liquid.The time required for equilibrations was 16 hours. The amount of NO3‐ adsorbed varied from 1.2 to 7.5 meq/100 g of soil from a 0.05M NO3‐ solution for soils of pH values ranging from 5.3 to 6.1. The amount adsorbed increased with decreasing pH.
Nitric Oxide Sorption by Calcareous Soils: II. Effect of Moisture on Capacity, Rate, and Sorption Products
Authors: Miyamoto S. , Prather R. J. , Bohn H. L. 
Published: July 2010

AbstractAt room temperature, the nitric oxide (NO) sorption capacity of calcareous soils increased with the presence of moisture in an air + NO stream (1.5% NO by volume) and/or in the soils. The largest increase, up to 10‐fold or approximately to the acid‐titratable basicity of soils, occurred when NO and H2O were sorbed simultaneously by initially dry soils from a moist air (humidity > 95%) + NO stream. The sorption rates were proportional to the unused portion of the capacity with the rate constants ranging from 0.02 to 0.03 min‐1 for NO and 0.01 to 0.015 min‐1 for H2O under simultaneous sorption. Initially moist soils sorbed NO from a dry air (humidity < 5%) + NO stream until the soils dried. The rate of NO sorption slowed at initial soil water suctions less than approximately 1 bar. Sorbed NO was recovered as nitrate and reacted with the basicity in moist soils. Less than 20% of the sorbed nitrogen was lost upon heating at 105C for 24 hours.