bluuebunny/crossref_metadata_2025_split huggingface dataset:
Uptake, Translocation and Utilization of 15N‐Depleted Fertilizer in Irrigated Corn
Authors: Bigeriego Manuel , Hauck R. D. , Olson Robert A. 
Published: July 2010

AbstractThe objective of this study was to derive a better understanding of the manner in which N serves the nutritional needs of corn (Zea mays L.) and thereby afford a basis for improved fertilization practices. Measurements of uptake, translocation and utilization of tagged nitrogen (N) fertilizer in irrigated corn as influenced by time and rate of N application were made in a field experiment at the University of Nebraska Field Laboratory. Plant parts of root, crown, foliage, and eventually ear and grain were taken and analyzed for total N, NO3‐‐N and isotope ratio at eight growth stages.Application of N at planting resulted in greater vegetative production, but summer sidedressed N effected slightly larger grain production with a higher grain/stover ratio. Isotope ratio analyses revealed significantly greater utilization of fertilizer N in grain production with delayed application due to more active root uptake and translocation of the fertilizer source during the grain filling period.Following harvest, residual mineral N in soil from applied fertilizer was greater with summer sidedressing such that 24% more of the N applied could be accounted for in the crop and soil than with planting time application.
Characterization of the Thickness and Uniformity of the Coatings of Sulfur‐coated Urea
Authors: Jarrell W. M. , Pettygrove G. S. , Boersma L. 
Published: July 2010

AbstractThe objective of this study was to develop a test which can accurately predict the contribution of coating characteristics to the control of rates of release of urea from SCU granules. It was assumed that product quality is a function of average coating thickness and uniformity of coating thickness.To achieve the stated objective, concentric layers of coating were removed in successive increments by dipping granules in benzene and determining at each step the percentage of granules rendered available to water penetration due to exposure of cracks or pinholes. Five SCU materials were used with a range of coating characteristics. For materials which were coated with both sulfur and sealant, the results could be explained by postulating the existence of three classes of granules: Class I granules, which have unobstructed holes through the coating, Class II granules, with holes through the sulfur coating which are plugged with sealant, and Class III granules, which have sulfur coatings with no holes through them. Class I granules begin to release urea as soon as they are wetted, Class II granules begin to release urea as soon as the sealant is broken down or removed, and Class III granules begin to release urea as soon as the sulfur coating is penetrated by removal of parts of it.
Effect of H‐SPAN on Water Retained by Soils After Irrigation
Authors: Miller D. E. 
Published: July 2010

AbstractThe effect of hydrolyzed starch‐polyacrylonitrile graft polymers (H‐SPAN or super slurper) on the water retention proper ties of three soils to which it had been added was evaluated in soil columns. Its effect on water retention was negligible in medium‐textured soils but it markedly increased water retained by sand. H‐SPAN added at 0.5% by weight to the upper 60 cm of sand increased the available water retained to nearly the same levels as that of a loam and a silt loam soil. The H‐SPAN treatment was more effective after the second and subsequent irrigation than after the first one. H‐SPAN reduced infiltration rates in all soils.
Absorption of Water by Soil: The Constant Flux Boundary Condition
Authors: White I. , Smiles D. E. , Perroux K. M. 
Published: July 2010

AbstractAbsorption of water into soil as the result of a constant flux condition at the soil surface is examined.Experiments for a fine sand show that the surface water content, movement of the wetting front, and the water content profiles may be predicted from the soil water diffusivity function using the notion of the flux‐concentration relation of Philip (1973).Reduced space and time variables X = Vox and T = Vost are introduced. Use of these variables greatly simplifies treatment of the system and reveals that the surface water content and the reduced position of the wetting front are uniquely defined by T while the water content profiles at any value of T are unique in terms of X.
Nitrous Oxide Emission During Denitrification in a Flooded Field
Authors: Denmead O. T. , Freney J. R. , Simpson J. R. 
Published: July 2010

AbstractLittle field information is available on the amounts of nitrous oxide (N2O) released from soils during denitrification, or the proportion of the denitrification loss attributable to N2O production. The paper reports studies of N2O evolution and the simultaneous disappearance of nitrate (NO3) in a flooded rice field which initially contained 4 g NO3‐N m−2 in the top 0.08 m of soil.Measurements were made continuously for 18 days after the field was flooded. Nitrous oxide emission was calculated from the rate of increase of N2O in air circulating in a closed loop between a chamber installed in the field and an infrared gas analyzer. Emission rates as small as 1.8 ng N m−2 sec−1 could be measured. Nitrate disappearance was measured by chemical analysis of water samples.Nitrous oxide emission showed a diurnal cycle in phase with water temperature. Between the second and nineteenth day of flooding, 2.7 g NO3‐N m−2 disappeared from the water and 0.038 g N2O‐N m−2 were produced, only 1.4% of the apparent N loss. In a supplementary, small‐bay experiment in which sodium nitrate and glycerol were added to the water, N2O production accounted for only 0.8% of the NO3 disappearance. Even allowing for NO3 removal through other mechanisms, the production of N2O in both experiments was very much less than the 7% commonly assumed for denitrification in current models of the global N2O budget.
Characterization of Hysteresis in the Desorption of 2,4,5‐T from Soils
Authors: Koskinen W. C. , O'Connor G. A. , Cheng H. H. 
Published: July 2010

AbstractMethods for characterizing adsorption‐desorption of 2,4,5‐T (2,4,5‐trichlorophenoxyacetic acid) in the soil were investigated. Using the conventional method, the adsorption isotherms conformed to the linearized Freundlich equation for initial 2,4,5‐T concentrations of 2 to 176 µmol/liter. Desorption of 2,4,5‐T from soils exhibited significant hysteresis at all concentrations, with lower concentrations showing greater hysteresis. The longer the equilibration time for desorption, the greater was the observed hysteresis. Therefore, nonattainment of equilibrium was not evident as a major cause of the hysteresis effect. Using a modified method, biochemical degradation of 2,4,5‐T during the desorption process accounted for a significant amount of the hysteresis observed. In the Palouse soil, approximately 63% of the observed hysteresis was eliminated by taking into account the biochemical degradation. In the Glendale soil, approximately 35% of the hysteresis was attributed to biochemical degradation.
Transport of Inorganic Phosphorus in an Alfisol
Authors: de Camargo O. A. , Biggar J. W. , Nielsen D. R. 
Published: July 2010

AbstractAdsorption, desorption, and movement of phosphorus in an Alfisol soil were characterized by miscible‐displacement and batch‐type experiments. The influence of pore‐water velocity, aggregate size, and pretreatment of the soil with P was evaluated. A model which considers the interaction of P with soil as an equilibrium kinetic process was utilized to differentiate between instantaneous and time‐dependent reactions which appear to govern the adsorption‐desorption process during displacement.Pore‐water velocity has a greater influence on the adsorption rather than the desorption process which appeared to be more chemically controlled. Aggregate size affected the time‐dependent more than the instantaneous processes of soil‐P interaction. Instantaneous reactions between P and soil were shown to be mitigated by pretreatment of the soil with P in contrast to time‐dependent reactions. A pore model was hypothesized to explain the differential uptake and release of P during displacement.
Particle Size Analysis by Hydrometer: A Simplified Method for Routine Textural Analysis and a Sensitivity Test of Measurement Parameters
Authors: Gee G. W. , Bauder J. W. 
Published: July 2010

AbstractA simple modification of the Day (1965) hydrometer method is suggested for routine textural analysis. The simplified method requires no calibration, graphs or tables and uses a weighted average of the 1.5‐hour and 24‐hour readings to determine the 2µm clay fraction. The relationship is:
urn:x-wiley:03615995:saj2sssaj197903615995004300050038x:equation:saj2sssaj197903615995004300050038x-math-0001 whereP2µm = summation percentage for the 2µm clay fraction.P24, P1.5 = summation percentage for settling time of 24 hour and 1.5 hour, respectively.K = weighting factor, used to approximate the actual relation of the summation percentage curve over the clay percentage range of interest.This equation was found to be satisfactory in the range of 5% ⩽ P2µm ⩽60% by weight for over 70 North Dakota soil and subsoil materials when K=0.876.Sensitivity analyses were performed for the Day, Bouyoucos, and the Simplified Day hydrometer methods to determine which of several measured parameters contribute to the greatest possible error; hence which parameters should be controlled with the greatest precision. The hydrometer scale reading error contributes more error than any other single parameter.
Thermal Diffusivity and Conductivity of Moist Porous Media
Authors: Parikh R. J. , Havens J. A. , Scott H. D. 
Published: July 2010

AbstractAn unsteady‐state method was used to determine thermal diffusivities and conductivities of nominally 250 µm glass beads and a silt loam soil over a range of moisture contents. The thermal diffusivity of the beads was found to increase from 0.0013 cm2/sec for dry beads to 0.003 cm2/sec at 5% volumetric moisture content, but is only weakly affected by moisture contents > 5%. The thermal diffusivity of the silt loam soil increases from 0.0022 cm2/sec for dry soil to 0.0042 cm2/sec at 30% volumetric moisture content, above which it remains essentially constant with increasing moisture content. The thermal conductivities of both porous media increase with moisture content over the entire wetness range, the thermal conductivity of the glass beads increasing from 0.53 mcal °C−1 cm−1 sec−1 to 1.97 mcal °C−1 cm−1 sec−1, and that of the silt loam soil from 0.57 mcal °C−1 cm−1 sec−1 to 2.79 mcal °C−1 cm−1 sec−1. Measured thermal conductivities of the glass bead media were in excellent agreement with values calculated using deVries' method.
Comparison of Various Methods of Sampling Soil Water for Determining Ionic Salts, Sodium, and Calcium Content in Soil Columns
Authors: Barbarick K. A. , Sabey B. R. , Klute A. 
Published: July 2010

AbstractAt the end of a column experiment studying the flux of ionic salts and Na+ from applied sewage effluent, the salt, Na+, and Ca2+ contents were compared in extracts from porous cups, from the soils around the cups, and saturated paste extracts after the column soils were air‐dried. The salt level in the porous cup samples and in the moist soil samples obtained directly at the end of the experiment, and the Na+ content in the porous cup and in saturated paste extracts that were equilibrated for 48 hours were highly correlated.
Infiltration of Soils as Affected by the Pressure and Water Content at the Time of Compaction
Authors: Akram Mohd. , Kemper W. D. 
Published: July 2010

AbstractInfiltration rates, volume reduction, and bulk densities of soils were determined on soils as a function of compacting pressures and water content at the time of compaction.Maximum compaction generally occurred when the soils were packed at water contents near field capacity.When compacting loads were < 1 kg/cm2 the minimum bulk densities occurred when soils had water contents of about one half field capacity, indicating that surface tension of water films in the soils plays a major role in cohesiveness and stabilization against compaction under these conditions.Compacting loads of 3.46 kg/cm2, at field capacity on sandy loams and finer textured soils, reduced infiltration rates to < 0.1% of values obtained after these soils had been compacted when they were air dry. In a loamy sand soil this reduction was to about 1%.The low infiltration rates following compaction were increased by wetting and drying, although several cycles of wetting and drying did not raise the infiltration rate to the level observed before packing.Freezing and thawing cycles also increased the infiltration rates of previously compacted soils. Most of the change took place in the first freezing and thawing cycle.The large changes in infiltration rates using achievable levels of compaction at the “optimum” water contents indicate that compaction can play a major role in the management of water in ditches, reservoirs, furrows, and watersheds.
An Analytical Solution to Solute Transport Near Root Surfaces for Low Initial Concentration: I. Equations Development
Authors: Cushman John H. 
Published: July 2010

AbstractIn Part I of this two part paper the governing differential equation for radial flow to a root with constant moisture properties, is transformed into a nondimensional and more useful form. An analytical solution to the differential equation with two appropriate sets of boundary conditions is developed. The solution can be expressed as an infinite series of Bessel functions, powers of nondimensional distance and an exponential.Equations for total and diffusive nutrient uptake are developed for both growing and nongrowing roots. Nondimensional equations are also presented for the various components of the nutrient flux (diffusive, convective, and total).The equation for total nutrient uptake for a root growing at a rate f(t) such that f(o) = Lo (initial length), is examined in detail when f(t) is an exponential.
Soybean Plant Growth, Nodulation, and Nitrogen Fixation as Affected by Root Temperature
Authors: Lindemann W. C. , Ham G. E. 
Published: July 2010

AbstractThe objective of this study was to investigate the influence of root temperature, Rhizobium japonicum strain, host variety, and plant age on soybean growth, nodulation, and N2 fixation.Soybean plants were grown in sand‐filled Leonard jars and watered with N‐free nutrient solution. Soybean root temperatures were held constant at 15, 20, 25, and 30°C in a growth chamber environment. At harvest, plant height and weight, nodule number and weight, and acetylene reduction activity were measured.Interactions between root temperature, R. japonicum strain, and soybean variety were complex and changed with plant age. Temperature by strain interactions were more common than temperature by variety, variety by strain, or temperature by variety by strain interactions. Plant height was solely dependent on root temperature, but nodulation and acetylene reduction activity parameters depended on temperature, strain, and variety. Such interactions were more complex at later growth stages.Maximum plant dry weight and nodule number occurred at 25°C. Nodule weight and acetylene reduction activity were greater at 25°C than at the other root temperatures early in plant growth (3–4 weeks after planting.) However, 5–6 weeks after planting, these parameters were greater at 20° than at 25°C. Apparently more nodules were formed at 25°C, but eventual nodule development, size and acetylene reduction activity was greater at 20°C. Nodules also degenerated sooner at 25°C. Nitrogen fixation significantly increased plant growth over that of the uninoculated controls except at 15°C. The confined root environment of the Leonard jar may have restricted further nodulation after 5 weeks from planting and may have influenced nodule weight and acetylene reduction activities as well as nodule numbers.
The Influence of Nitrate, Nitrite, and Oxygen on the Composition of the Gaseous Products of Denitrification in Soil
Authors: Firestone M. K. , Smith M. S. , Firestone R. B. , Tiedje J. M. 
Published: July 2010

Abstract[18N]‐N2O produced by denitrification of 18NO‐3 in soil slurries readily exchanged with nonlabeled pools of added N2O. This supports the role of N2O as a free, obligate intermediate of denitrification in soils. The observation that N2O diffuses freely from the site of active denitrification in soils means that any factor which produces a change in the relative rate of N2O reduction compared to the rate of N2O production can alter the proportion of N2O and N2 resulting. Increased concentration of NO3‐ and NO2‐ resulted in increased production of N2O relative to N2 as the product of denitrification. The influence of NO2‐ was much stronger than that of NO3‐, with low concentrations of NO2‐ causing N2O to become a significant product of denitrification. This suggests that NO2‐, not NO3‐, may be the influential species. Additions of small quantities of O2 (0.02 atm) caused a large decrease in denitrification activity and resulted in a significant increase in the N2O/N2 ratio.
Effect of Depth of Lime Incorporation on the Growth of Corn on an Oxisol of Central Brazil
Authors: Gonzalez‐Erico E. , Kamprath E. J. , Naderman G. C. , Soares W. V. 
Published: July 2010

AbstractHigh Al saturation is one of the limiting factors to intensive cropping of many soils in the Cerrado of Brazil. A field study on the effect of lime rate and depth of incorporation on growth of corn (Zea mays L.) was conducted on an Oxisol (Typic Haplustox) at Brasilia. Lime rates used were 0, 1, 2, 4, and 8 tons CaCO3/ha and depths of incorporation were 15 and 30 cm. Incorporation of 4 tons of CaCO3 to a depth of 30 cm reduced Al saturation from 72% to < 5% on a soil which initially had 1.1 meq Al/100 cm3. Concentrations of soil solution Al decreased to very low levels at pH 5.5.Grain yields of three successive corn crops were increased by liming. Incorporation of lime to a depth of 30 cm resulted in higher yields than incorporation to a depth of 15 cm. Application of MgSO4 to the acid soil increased yields above the nonlimed treatment.Yield responses to liming were due to improved Mg nutrition and neutralization of toxic Al. Root length was increased considerably in the 0‐ to 15‐cm depth and doubled in the 15‐ to 30‐cm depth when Al was neutralized by liming. Increased root development in the 15‐ to 30‐cm depth of the deep lime treatments resulted in greater water utilization from this depth and decreased the detrimental effects of moisture stress at tasseling on corn yields.
Jack Pine Biomass Accretion on Shallow and Deep Soils in Minnesota
Authors: Green D. C. , Grigal D. F. 
Published: July 2010

AbstractBiomass accretion and standing biomass of jack pine (Pinus banksiana Lamb.) were studied on sballow soils over three different bedrock types; granite, greenstone, and gabbro; and on deep till in northeastern Minnesota. The shallow soils were either Lithic Udorthents or Lithic Dystrochrepts and the deep soils were Typic Dystrochrepts. Individual tree biomass accretion was described by combining diameter‐age and biomass‐diameter relationships. At age 50, the mass of an average surviving tree on till would be 117 kg, and of trees growing on shallow soil over greenstone, granite, and gabbro would be 88, 68, and 57 kg, respectively. As an index of productivity, this ranking agrees with that of rock types based on site index (14.3, 11.2, 10.2, and 9.3 m at 50 years, respectively). Although these results imply differences in yield, the average overstory biomass did not differ between shallow soils, with an average of 81,000 kg/ha, compared to a significantly greater 147,000 kg/ha on the deep till. Stand biomass accretion was estimated by adjusting the relationship between stocking and age, and diameter and age, from a normal yield table to fit the present status of the sampled stands on each rock type. These data were then combined with a tree biomass‐diameter function, yielding a relationship between stand biomass and age for each rock type. The estimated biomass accretion was similar on shallow soils but greater mass occurs at any age on deep soils.
Kinetics of Dissolution of Phosphate Rocks in Soils
Authors: Chien S. H. , Clayton W. R. , McClellan G. H. 
Published: July 2010

AbstractA modified Elovich equation in the form of Ct = C0 − (1/β)ln (αβ) − (1/β) ln t was derived to describe the kinetics of dissolution of three phosphate rocks (North Carolina, central Florida, and Tennessee) in three soils (one soil from Florida and two Nigerian soils). The equation fitted the experimental data the best among various models of kinetics. Comparisons of dissolution rates of various phosphate rocks in a given soil or a given phosphate rock in various soils can be made by comparing the values of three parameters—C0, α, and β—in the equation where C0 is the maximum P concentration in the soil solution that a phosphate rock can provide in a soil (Ct is the P concentration at time t), and α and β are constants. It was found that C0 increased as α increased and/or β decreased in a given system.Temperature was found to have no significant effect on the dissolution of phosphate rock in the soil. This implies that phosphorus retention by the tropical soils treated with phospate rock may be much less affected by temperature as compared with water‐soluble P fertilizers such as concentrated superphosphate.
Gaseous Nitrogen Evolution During Nitrification of Ammonia Fertilizer and Nitrite Transformations in Soils
Authors: Smith C. J. , Chalk P. M. 
Published: July 2010

AbstractThe biological oxidation of NO2‐ is inhibited when alkaline‐hydrolyzing N fertilizers are band‐applied to soils, and NO2‐ may accumulate. Nitrogenous gases can be evolved with NO2‐ is added to soil. The aim of the work described here was to determine if gaseous‐N losses could occur via chemical transformations of NO2‐ during nitrification in soils treated with NH3 fertilizer.Evolution of N2, N2O, and NO + NO2 occurred during nitrification in three soils treated with aqueous NH3. Losses occurred when measured soil pH was > 7.5. The highest gaseous‐N loss amounted to 16.5% of applied‐N (1156 µg N applied/g of soil) in a calcareous soil incubated for 28 days at 30°C. Nitrogen was the major gaseous form of N evolved in all soils. In two soils, NO2‐ did not accumulate to more than 13 µg N/g of soil, but substantial N2 emission was measured. Addition of the nitrification inhibitor, nitrapyrin, with the fertilizer, prevented NO2‐ accumulation without preventing nitrification. This treatment prevented N2O evolution and markedly reduced loss of N2 and NO + NO2.Evolution of N2, N2O, and NO + NO2 occurred in the three soils following NO2‐ addition. Loss of N2 was very sensitive to soil pH, and markedly increased with increasing acidity. However, N2 was readily evolved when soil pH was slightly alkaline. Evolution of NO + NO2 was inversely related to pH, but N2O loss was highest in the most alkaline soil (pH 8.4). The marked similarities within individual soils of the patterns of gaseous‐N losses obtained for NH3 and NO2‐ treatments, strongly suggest that similar processes were operating. Gaseous‐N evolution was similar in γ‐irradiated and nonirradiated soils treated with NO2‐. These results, together with the effect of nitrapyrin, suggest that gaseous‐N losses can occur via chemical transformations of NO2‐, when the competitive biological oxidation of NO2‐ by Nitrobacter is inhibited.