bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spatial Variability and Soil Sampling for Salinity and Sodicity Appraisal in Surface‐irrigated Orchards
Authors: Miyamoto S. , Cruz I. 
Published: July 2010

AbstractLocalized salt accumulation and associated crop damage are common in surface‐irrigated orchards. This study examined salinity and sodicity variation at five pecan (Carya illinoensis K.) orchards in the El Paso Valley, Texas mainly to develop soil smapling schemes for salinity appraisal. The first orchard (13.6 ha) contained three mapping units, and the other orchard blocks (0.5‐3.3 ha), single mapping units or soil types. These fields had been irrigated by border or basin methods mostly with water of 1.1 dS m−1. Soil samples were collected in a systematic grid at 68 sites to a depth of 60 cm in the 13.6‐ha field, and 15 to 28 sites at three depths in the other orchard blocks. Salinity and sodicity of the saturation extract in the 13.6‐ha field ranged from 0.7 to 6.3 dS m−1 and 2.3 to 12.5 (mmol L−1)1/2, respectively. Even in the orchard blocks of <1 ha, salinity and sodicity readings varied two‐ to threefold. The semivariogram of soil salinity and sodicity along transects or within mapping units did not reveal spatial structure. Instead, salinity readings were closely related to the saturation water contents of the soils (r = 0.79), and their variation decreased several fold when stratified by mapping unit. The frequency distribution of soil salinity along transects followed a skew distribution, but when grouped by mapping unit and averaged over a depth, both salinity and sodicity readings followed a normal distribution. For routine salinity appraisal in comparatively small surface‐irrigated orchards, soil map‐based samplings may be more efficient than those based on arbitrary transects or grid. The number of samples required to obtain a mean value in an area consisting of a single mapping unit within 15% of the true mean at the 5% level ranged from 7 to 26 ha−1 for salinity, and 3 to 14 ha−1 for sodicity at a depth of 0 to 60 cm in these alluvial soils.
Blue Grama Response to Zinc Fertilization of Claypan Soil
Authors: White E. M. , Gartner F. R. 
Published: July 2010

AbstractClaypan soils with blue grama [Bouteloua gracilis (H.B.K.) Lagl plants, seeded to indigenous blue grama, or seeded to barley (Hordeum vulgare L.) if salinity might limit blue grama growth were fertilized with Hoagland's formulations in the greenhouse. The objective was to identify the micronutrient(s) that limits blue grama growth in western South Dakota. Growth was increased by the macronutrients N‐P‐K and further increased if all essential micronutrients were added. Zinc probably is the limiting element, and growth was usually reduced if other micronutrients were added with Zn to the claypan soil.
Ammonia Volatilization from Nitrogen Fertilizers Surface Applied to No‐till Corn
Authors: Keller Gary D. , Mengel David B. 
Published: July 2010

AbstractLow use efficiency has frequently been observed when N fertilizers, particularly those containing urea, are applied directly on the surface residue in no‐till corn (Zea mays L.) production systems. A portion of this low use efficiency has been attributed to volatilization of NH3. Field experiments were conducted at two locations in Indiana to make direct measurements of NH3 volatilization from granular urea, cogranulated urea‐urea phosphate (UUP), urea‐ammonium nitrate solutions (UAN) and prilled ammonium nitrate (AN). The fertilizers were applied directly on corn residue at a rate of 168 kg N ha−1. On a Lyles sandy loam soil (Typic Haplaquolls) 50.9 kg of the 168 kg N ha−1 applied as granular urea was lost in 120 h, with essentially all that loss occurring in the first 50 h after application. Peak loss rates of 3.0 kg N ha−1h−1 occurred 23 h after application. No significant volatilization loss occurred with AN, while 26.0 kg N were lost through volatilization with UUP and 14.6 kg N lost from UAN. Peak loss rates at 23 h after application were 1.83 and 0.37 kg N ha−1h−1 for UUP and UAN, respectively. A 25‐mm rain shower effectively stopped volatilization approximately 50 h after application. On a Bedford silt loam soil (Typic Fragiudalfs) volatilization losses were considerably lower than those found on the lower cation exchange capacity Lyles soil. Though overall losses were lower, relative losses from the different N fertilizers were similar to those found on the Lyles soil.
Mineralogy and Stability of Soil Evaporites in North Dakota
Authors: Keller L. P. , McCarthy G. J. , Richardson J. L. 
Published: July 2010

AbstractThe evaporite mineralogy of 106 samples of salt efflorescence collected from throughout North Dakota was determined by x‐ray powder diffraction. The mineralogies of these efflorescences are dominated by sulfate salts of Na, Mg, and Ca. The evaporite minerals were mirabilite, thenardite, gypsum, epsomite, hexahydrite, konyaite, bloedite, burkeite, and tychite. Konyaite is the most frequently and widely occurring mineral identified. Efflorescences dominated by Na‐ and MgSO4 minerals account for >90% of the observed mineralogies. The mineral assemblages dominated by Na2SO4 minerals were evenly distributed across the state. The MgSO4‐rich efflorescences were confined to the glaciated part of the state. Many of the observed minerals are labile with respect to temperature and water vapor pressure. Dissociation vapor pressure curves from the literature are used to describe the field stability relations of epsomite/hexahydrite and mirabilite/thenardite.
Statistical and Autoregressive Analysis of Soil Physical Properties of Portsmouth Sandy Loam
Authors: Anderson S. H. , Cassel D. K. 
Published: July 2010

AbstractReliable estimates of soil physical and hydraulic properties are needed for designing drainage systems for soils with limited natural drainage. The objective of the study was to determine the autocor‐relation structure of soil physical properties in a poorly drained soil. Saturated hydraulic conductivity, soil‐water characteristic, soil‐water diffusivity, texture, and bulk density were measured on undisturbed soil cores sampled from the A, Btg, and Bg soil horizons at 150 points on two transects in a field of Portsmouth sandy loam (Typic Umbraquults). Unsaturated hydraulic conductivity for each of the 450 cores was computed using a quasi‐analytical expression utilizing measured soil‐water diffusivity data and the derivative of the inverse of the van Genuchten equation for the measured water characteristic. Hydraulic conductivity values at a given soil‐water pressure had a high coefficient of variation, ranging from 130 to 3300%, and were lognormally distributed. Evidence of significant short‐range autocorrelation, usually ≤2 m, was found for hydraulic conductivity, soil‐water characteristic, texture, and bulk density. First‐order coefficients for autoregressive equations indicated a decrease in predictability of the observed variation with increasing soil depth. The number of measurements required to estimate the mean of a soil property of the A horizon to within ±10%, ranged from four for sand content to 1985 for saturated hydraulic conductivity. The means for most soil properties in the A horizon, however, can be estimated to within ±10% with 35 observations.
Chemical Modeling of Arsenate Adsorption on Aluminum and Iron Oxide Minerals
Authors: Goldberg Sabine 
Published: July 2010

AbstractThe constant capacitance model was used to describe arsenate adsorption on goethite, gibbsite, and amorphous Al hydroxide. Because the model assumes a ligand exchange mechanism it is appropriate for describing the specific adsorption of arsenate anions. Arsenate surface complexation constants were fitted to the experimental data using a nonlinear least squares optimization technique. The constant capacitance model was able to represent arsenate adsorption over the pH range 4.5 to 9 on each oxide using the same set of surface complexation constants. However, the values of the surface complexation constants varied with the mineral considered. The model was able to describe arsenate‐phosphate competition on gibbsite quantitatively over the pH range 4.5 to 9 using the same set of anion surface complexation constants. A set of surface complexation constants obtained for one ternary system could be used to predict competitive phosphate and arsenate adsorption on the same material for other ternary systems containing different amounts of total anions in solution.
Response of Irrigated Soybeans to Rate and Placement of Fertilizer Phosphorus
Authors: Rehm G. W. 
Published: July 2010

AbstractThis study was conducted to measure the response of irrigated soybeans [Glycine max (L.) Merr.] to rate and placement of fertilizer P and to develop critical values for P in this crop. Five rates of P (0, 11, 22, 33, 44 kg ha−1) were either broadcast and incorporated before planting or applied to the side of and below the seed at planting (starter) at 10 irrigated sites over 3 yr. Tissue samples consisting of the most recently matured trifoliates (petiole excluded) were collected at early bloom and analyzed for P. Use of fertilizer P increased soybean yields at three of 10 sites and higher yields at these sites were recorded each year when the fertilizer P was broadcast and incorporated before planting. Fertilizer P increased yields when the soil test P level (0‐20 cm) measured by the Bray and Kurtz no. 1 procedure was <3.1 mg kg−1. There was no response to fertilizer P when the P level measured by this method was 9.6 mg kg−1 or higher. Soil P measured by the Na HCO3 method was as satisfactory as the Bray and Kurtz no. 1 procedure for separating responsive from nonresponsive sites when subsoil P was considered. The P concentration of leaf tissue at responsive sites was increased with application of fertilizer P. At 95% of maximum yield, P concentration in leaf tissue was 3.35 g kg−1.
Achieving Desired Moisture Conditions in Potentially Mineralizable Nitrogen Incubation Studies
Authors: Lueking M. A. , Schepers J. S. 
Published: July 2010

AbstractA technique was developed to determine soil‐to‐sand mixing ratios to achieve desired soil moisture conditions during incubation in potentially mineralizable N studies. Five soils were selected to represent a range of soil textures. Segmented plastic leaching tubes were used to determine gravimetric water content, bulk density, and percent water‐filled pore space (WFP) for two portions of soils used within the incubation tubes. Vacuum leaching resulted in greater water content of soil near the bottom of the incubation tubes compared to the top of the tubes. The proportion of soil‐to‐sand used in the incubation tubes, which was necessary to attain a given WFP status, was different for each soil type and was a function of original sand and organic C contents. The technique is an inexpensive and time‐efficient means to standardize and document soil moisture conditions within incubation tubes used to determine potentially mineralizable N.
Irrigation Management for Soil Salinity Control: Theories and Tests
Authors: Bresler Eshel , Hoffman Glenn J. 
Published: July 2010

AbstractThe steady‐state leaching theory and related concepts regarding soil salinity control were evaluated in view of the transient‐state theories presented and recent experimental results. Data from small plot experiments to establish the leaching requirement of nine crops and from a rhizotron study on the influence of irrigation frequency on soil salinity control agreed with theoretical, transient‐state predictions that consider water flow, salt transport, and water uptake by crop roots, simultaneously. Root water uptake was assumed to depend on matric (water content) and osmotic (soil salinity) potentials, and on a critical root‐water potential of about −0.3 MPa. The assumption that the major effect of soil salinity is a reduction in plant water uptake was substantiated. Results show water balance components (for nine crops irrigated several times each day and for grass irrigated with various combinations of quantity, quality, and frequency) deviated significantly from predictions based on the steady‐state leaching fraction equation. The deviation was attributed to an increase in soil‐water content and transpiration as irrigation applications increased; or conversely, an increase in soil‐water content as transpiration decreased because of increased soil salinity. The practical limitations of salinity control in irrigated agriculture based on the steady‐state leaching equation were evident even for high frequency irrigation where steady‐state conditions should be approached. Measured commercial yields and aboveground dry matter production compared well with yields computed on the assumption that relative crop yield is equivalent to relative transpiration. Both measured and computed results indicated that irrigation water quality and quantity, rather than irrigation frequency, influenced dry matter production of grass.
Soil Acidity in Loblolly Pine Stands with Interval Burning
Authors: Binkley Dan 
Published: July 2010

AbstractPrescribed burning of loblolly pine (Pinus taeda L.) stands every 2 yr for 24 yr increased soil pH by 0.3 to 0.9 units. Measurements of total acidity (titratable to pH 8.2) in the forest floor showed about a 14 to 21 kmol H+ ha−1 decrease in burned plots. Burning increased the acid neutralizing capacity per gram of forest floor material, but the reduction in forest floor biomass largely offset the difference. Titration curves indicated that the burned forest floor would require only about 0.6 kmol H+ ha−1 to lower its pH to the level of the control plots. Total acidity in the 0 to 10 cm mineral soil was more variable; one burned plot showed no decrease relative to controls, but a more intensely burned plot decreased by about 95 kmol H+ ha−1. Despite this large reduction in total acidity, titration curves indicated that only 25 kmol H+ ha−1 would lower the pH to the control level. This increase in acid neutralizing capacity is about 50 times the current annual H+ input in rain. However, other major components of the ecosystem's H+ budget would need to be quantified to assess the importance of fire in relation to acid deposition impacts.
Errors in Analyses for Ammonium and Nitrate Caused by Contamination from Filter Papers
Authors: Sparrow S. D. , Masiak Darleen T. 
Published: July 2010

AbstractFilter papers were tested for NH4 and NO3 contamination by eluting them with 2 M KCl solution and analyzing the leachate. Significant amounts of NH4 or NO3‐N were found in many filters. Variability between grades and kinds of filters, among lots within a grade, and within packages was high. For cellulose papers, quantitative grades were usually relatively high in NH4 and low in NO3. The reverse was true for qualitative grades. Glass fiber filters contained low but usually significant amounts of both ions. Most of the NH4‐ and NO3‐N was removed from cellulose filters by prewashing with water or 2 M KCl solution. Water successfully removed NO‐3 but not NH+4 from glass filters.
Comparison of a Forced‐draft Technique to Nitrogen‐15 Recovery for Measuring Ammonia Volatilization Under Field Conditions
Authors: Hargrove W. L. , Bock B. R. , Raunikar R. A. , Urban W. J. 
Published: July 2010

AbstractReliable field measurements of NH3 volatilization are necessary for evaluating N‐fertilizer efficiency for sod crops and conservation crop production systems. This study was conducted to compare NH3 loss measurements under field conditions using a forced‐draft technique and recovery of urea‐15N. Measurements were made from urea solution applied at a rate of 100 kg N ha−1 to a bare or mulched Cecil sandy loam soil (Typic Hapludult). In an adjacent area, microplots were established to which urea enriched with 15N was added. Ammonia losses from the bare and mulched soil were 49 and 72% of the applied N by the forced‐draft technique, and 14 and 46% of the applied N by 15N recovery. The air flow rate with the forced‐draft technique was shown to exceed the actual wind speed near the soil surface 10 and 50% of the time for bare and mulched soil, respectively. These results raise serious questions about the validity and accuracy of the forced‐draft technique. The usefulness of the forced‐draft technique may be limited to relative comparisons of N sources, N rates, and various management practices.
The Influence of Eolian Dust on the Genesis of Alpine Soils in the Front Range, Colorado
Authors: Litaor M. Iggy 
Published: July 2010

AbstractThe chemical and mineralogical properties of the soils in an alpine watershed, Front Range, CO, were studied to assess the sensitivity of the soil environment to acid deposition. Field and laboratory analyses indicated that properties of surface horizons were heavily influenced by eolian dust accumulation whereas the subsurface horizons were mainly derived from local bedrock. Surface and subsurface horizons differed in texture, bulk density, pH, CEC, exchangeable cations, and clay and silt mineralogy. A discriminant analysis based on these parameters proved useful for confirming lithologic differences between the surface (alpine loess) and subsurface horizons (bedrock residua). The alpine environment in the Front Range, which is naturally acidic and therefore very susceptible to acid deposition, has been affected by wind‐blown calcite that has raised the pH of surface horizons. Such natural liming presumably increases the ability of the alpine soils to buffer acid deposition.
Estimating Air Porosity and Available Water Capacity from Soil Morphology
Authors: McKeague J. A. 
Published: July 2010

AbstractField guidelines based on soil morphology and calibrated against measured values were developed for estimating air porosity (AP, volume percent air‐filled pores at 5 kPa) and available water capacity (AWC, volume percent water retained between 5 and 1500 kPa). The guidelines were tested by estimating and subsequently measuring these properties of 24 soil horizons. The mean of the absolute differences between estimated and measured AP and AWC were 3.7 and 4.5% respectively. AP for the 24 horizons ranged from 3 to 30% and AWC from 14 to 39%. In view of the magnitude of local soil variability, the discrepancies in measured values of AP and AWC by different methods and the lack of standard methods, the estimates are shown to be useful. Estimation of air‐water regime properties of soils from well‐calibrated morphological guidelines is recommended for use in soil survey and in research on effects of management on soil physical properties.
Effects of Soybean and Corn Residue Decomposition on Soil Strength and Splash Detachment
Authors: Gantzer C. J. , Buyanovsky G. A. , Alberts E. E. , Remley P. A. 
Published: July 2010

AbstractAlthough field experiments have documented increased soil and water losses after soybeans (Glycine max L.) as compared with corn (Zea mays L.), a “soil effect” appears to be nondetectable by regular laboratory means. Because significant differences in quantity and quality of post‐harvest residues occur between soybean and corn, a laboratory incubation experiment was designed to assess the effect of the plant materials on soil properties. Analysis shows that laboratory incubation of disturbed soil with and without corn and soybean residues at 20°C, with optimal water contents of 25% v/v, decreases splash detachment, increases shear strength and aggregate size after 7 to 14 d. Additions of corn or soybean residues increase soil strength and decrease soil splash in a log‐linear fashion. The most pronounced effects were observed after 14 d. This corresponds to peak microbiological activity, indicating changes in stability are probably related to biological processes. Corn residue at typical field rates (20 Mg/ha) reduced soil splash by about one‐third and increased strength about two times as compared to the check after 14 d of incubation. Incubation with soybean residue for a similar time caused slightly greater soil splash than incubation with the same amount of corn residue, suggesting that small changes in stability are related to residue quality. No difference in soil strength relative to residue quality was detected after 14 d of incubation, indicating a subtle difference between splash and strength as measures of surface‐soil stability. Aggregate size measurements were less sensitive to plant residue treatment and time of incubation than splash or strength.
Distribution and Recovery of Nitrogen‐15‐labeled Liquid Anhydrous Ammonia Among Various Soil Fractions
Authors: Norman R. J. , Kurtz L. T. , Stevenson F. J. 
Published: July 2010

AbstractSince liquid anhydrous ammonia (LAA) is a major N fertilizer, information was sought about the proportions of LAA that enter into various combinations in soils. Liquid anhydrous NH3, labeled with 15N was injected into three soils (Drummer, Typic Haplaquoll; Blount, Aeric Ochraqualf; Cisne, Mollic Albaqualf) in the laboratory at a rate equivalent to a field application of 206 kg N ha−1 in 76.2 cm knife‐spacings. At 1, 7, 14, 28, 56, and 112 d after application, fertilizer N present in different soil fractions was determined in five concentric zones with radii of 0 to 1.5, 1.5 to 3.0, 3.0 to 4.5, 4.5 to 6.0, and 6.0 to 7.0 cm around the point of application. Depending on the soil, from 68 to 83% of the applied 15N was accounted for as (exchangeable NH+4 + NO‐3 + NO‐2)‐N by the 112th day following application, the remainder being accounted for as clay‐fixed NH+4 (1.9‐4.9%), organic matter‐fixed NH3 (4.0‐6.0%), and biologically immobilized organic N (3.9‐9.3%). From 50 to 70% of the organic matter‐fixed NH3‐N was released by hydrolysis with dilute KOH solution as compared to 10 to 15% for the immobilized N. Total recovery of 15N at 112 d ranged from 77% for the Cisne soil to about 97% for the Drummer and Blount soils. Lateral distributions and transformations of NH+4 and NO‐3 and pH trends after LAA applications were similar to those reported by previous investigators.
Evaluation of Urea‐Urea Phosphate as a Nitrogen Source for No‐tillage Production
Authors: Urban W. J. , Hargrove W. L. , Bock B.R. , Raunikar R.A. 
Published: July 2010

AbstractUrea‐urea phosphate (UUP), a combination of urea and phosphoric acid, has properties which reduce the potential for NH3 volatilization but has not been evaluated extensively under field conditions. The objective of this study was to evaluate UUP (34‐17‐0) under laboratory and field conditions. All experiments were conducted on acid sandy soils typical of the predominant Ultisols found in the southeastern USA. A forced‐draft technique was used to make direct measurements of NH3 losses in a growth chamber and also in the field. In addition, UUP and six other N sources were compared for no‐till grain sorghum (Sorghum bicolor L. Moench) production. Direct measurement of NH3 losses in the growth chamber resulted in small losses from UUP on both mulched and bare soils, while NH3 losses from urea ranged from 15 to 32% of the applied N on a bare soil and 68 to 82% on a mulched soil. Direct field measurement of NH3 losses from urea, UUP, and ammonium nitrate applied at 200 kg N/ha were 19, 5, and 2% of the applied N, respectively. In the field plot studies, UUP compared favorably with ammonium nitrate and calcium nitrate with respect to crop response. The mechanism of NH3 loss prevention appears to be pH buffering by the phosphoric acid component of UUP. It is concluded that UUP is an effective N source for surface application to noncalcareous soils under no‐tillage management.
Soil Air Carbon Dioxide Concentrations in a New England Spruce‐Fir Forest
Authors: Fernandez Ivan J. , Kosian Patricia A. 
Published: July 2010

AbstractResearch and modeling efforts to evaluate soil‐soil solution chemical interactions must take into account solution equilibria with soil air CO2. Measurements of soil air CO2 and soil temperature were made in the major horizons of a forest soil in eastern Maine through the 1985 growing season. Soil air CO2 concentration ranged from 0.10 to 0.35%, 0.10 to 1.25%, and 0.20 to 1.20% in the O, B, and C horizons respectively. Peak soil air CO2 concentration occurred in July and early October which coincided with high points in soil temperature during the growing season.