bluuebunny/crossref_metadata_2025_split huggingface dataset:
Predicting Norway Spruce Growth From Soil and Topographic Properties in New York
Authors: Jokela E. J. , White E. H. , Berglund J. V. 
Published: July 2010

AbstractSoil‐site productivity relationships for Norway spruce (Picea abies (L.) Karst.) were studied on a single, but widespread soil catena (Bath‐Lordstown‐Mardin‐Volusia; ∼1.1 million ha) in central New York. Soils and vegetation data collected from 37 unthinned plantations (45‐55‐yr old) were used to develop multiple regression soilsite predictor equations and discriminant classification functions. Efforts were made through sampling procedures to reduce extraneous sources of variation inherent in many previous soil‐site studies (e.g., parent materials, geographic area, stand density, stand age, cultural practices, and seed sources). Results of regression analyses showed that three to seven independent variables could explain 53 to 82% of the variation in mean annual volume increment (MAI). Stratifying the data set by a common planting density (2990 stems ha−1) generally improved the precision of the regression equations. Independent tests of the soil‐site equations across diverse drainage conditions showed a significant correlation between predicted and measured values of MAI (r = 0.70). More accurate predictions resulted (r = 0.80) when the equations were restricted to moderately well‐ and well‐drained soils only. Discriminant functions correctly reclassified (jackknifed analysis) 81% of the 37 stands into two MAI productivity groups. In general, results from the discriminant analyses supported interpretations made from the regression analyses. Soil properties, such as textural components, coarse fragments, pH, exchangeable cations, organic C, and cation exchange capacity (CEC), were most consistently correlated with Norway spruce volume production. Topographic properties made little or no independent contribution to the predictive models developed for growth. Results should aid yield predictions and site classification decisions for Norway spruce in New York.
Volatilization and Foliar Recapture of Ammonia Following Spring and Fall Application of Nitrogen‐15 Urea to a Douglas‐fir Ecosystem
Authors: Nason G. E. , Pluth D. J. , McGill W. B. 
Published: July 2010

AbstractSeasonal effects on the volatilization and vegetal recapture of NH3 following application of pelleted 15N urea at 200 kg N ha−1 to a 40‐yr‐old Douglas‐fir [Pseudotsuga menziesii (Mirb.) Franco] ecosystem were investigated. Volatilization totalled 14 and 0.7% of applied N in spring and fall, respectively, and the difference appeared to be related to precipitation patterns following fertilization. Volatilization was generally enhanced by small spring rainfalls while depressed by larger fall rains. The isotopic abundance of evolved NH3 fluctuated from >90 to <10% of that of the fertilizer source. These fluctuations reflected the role of precipitation in the regulation of spatial heterogeneity of urea and urease in soil. Under spring conditions NH3 was recaptured by potted Douglas‐fir seedlings. Seedlings at 10 cm above the forest floor captured 16 times as much NH3 as seedlings positioned at the 150‐cm elevation. Labelled N was distributed among seedling tissues in the order: current foliage > 1‐year‐old foliage > roots which is consistent with anabolic incorporation and translocation. This mechanism may have a significant role in plant nutrition when conditions favorable to NH3 volatilization follow urea fertilization.
Vertical Distribution in Soil of Sprinkler‐applied Phosphorus
Authors: Lauer D. A. 
Published: July 2010

AbstractSoil‐immobile plant nutrients, such as P, accumulate near the soil surface in conservation cropping systems where tillage leaves crop residues on or near the soil surface and limits soil mixing. The objective was to determine, in field and laboratory experiments, the vertical distribution in soil of P applied in sprinkler irrigation water. Following P applications, distribution was determined from depth increment (1 or 2 cm) sampling on a Warden silt loam (coarse‐silty, mixed, mesic, Xerollic Camborthids) and a Quincy sand (mixed, mesic, Xeric Torripsamments). The fertilizer materials applied in 10‐mm irrigations were: monoammonium phosphate (227 g P kg−1), urea phosphate (192 g P kg−1), commercial white phosphoric acid (238 g P kg−1), and ammonium polyphosphate (149 g P kg−1) containing 61 g P kg−1 as polyphosphate. Application rates ranged from 50 to 400 kg P ha−1. Movement of P was about the same for all P fertilizer materials except ammonium polyphosphate, from which P moved only 60 to 70% of the depth of the other materials. Postapplication irrigation totals up to 160 mm at 10 mm d 1, which was applied without drying cycles, distributed P more uniformly with depth. The overall mean depths of P penetration across all treatments were 10.4 cm (SD = 4.04 cm) on the Quincy sand and 7.3 cm (SD = 4.93 cm) on the Warden silt loam. These depths of penetration and vertical distribution of sprinkler‐applied P are probably sufficient to supply the P needs of crop plants under sprinkler irrigation.
Determination of Organic and Carbonate Carbon in Calcareous Soils Using Dry Combustion
Authors: Rabenhorst M. C. 
Published: July 2010

AbstractA procedures is proposed which utilizes dry combustion and gravimetric determination of evolved CO2 for the determination of both organic and carbonate C in soil samples. A series of experiments was designed to determine the optimum temperature and duration of combustion that would be consistent with efficiency of analysis. Heating at 575 °C for 900 s using an O2 flow rate of 3.3 mL/s allows for determination of organic carbon (OC). Carbonate C from CaCO3 and dolomite is then determined by subsequently heating the same sample at 1000 °C for 600 s using the same O2 flow rate. This method gives quantitative recovery of organic and carbonate C from standard materials. Values for organic and carbonate C from 14 soil samples are in good agreement with existing procedures. The method is simple, requires a minimum of equipment, and has the benefit of using essentially the same procedure for both organic and carbonate C.
Flourescence Spectroscopy of Humic Substances
Authors: Miano T. M. , Martin J. P. , Sposito Garrison 
Published: July 2010

AbstractFluorescence spectroscopy has been underutilized as a method to investigate the nature of humic substances. This study was conducted to obtain fluorescence excitation and emission spectra systematically for a variety of humic and fulvic acids of diverse origin. Solutions containing 50 g m−3 humic or fulvic acid at pH values between 4 and 10 were investigated with excitation, emission, and synchronous‐scan excitation modes of fluorescence spectroscopy. The excitation spectra were markedly different for humic vs. fulvic acid and could be used to distinguish unambiguously between the two kinds of humic substance in aqueous solution. The fulvic acid excitation spectra also differed as a function of provenance. The fluorescence emission spectra, although broad, showed maximum‐intensity wavelengths that were lower for humic than for fulvic acids, indicating a greater degree of condensed, aromatic character in humic acids. Synchronous‐scan excitation spectra of the humic substances showed complex lineshapes that depended sensitively on the type of humic substance as well as on the pH value. These spectra, which are unique for fluorescence processes, may have important potential in resolving condensed aromatic structures in humic and fulvic acids.
Effects of Simulated Acid Rain on Soil Solution Composition and Orchardgrass Seedling Viability
Authors: Haun G. Wesley , Wolt Jeff , Reynolds John H. 
Published: July 2010

AbstractAcid, low cation exchange capacity (CEC) surface soils in low intensity management forage ecosystems may be sensitive to acid rain. Alteration of surface soil chemical properties by acid rain may influence establishment of small seeded forage grasses. Viability of orchardgrass (Dactylis glomerata L.) seedlings was monitored concurrently with simulated acid rainfall applications (pH 4.3‐2.5) on Etowah (Typic Paleudults) and Statler (Humic Hapludults) surface soils sampled from established sod which had been unfertilized in the prior 2 yr. Simulated rainfall of pH 3.1 tended to result in increased seedling viability in comparison to other rainfall pH, but the effect of rainfall pH was significant in only six of 16 counting dates. Maximum seedling numbers and days to maximum were unaffected. Increased rainfall acidity (pH 4.3‐3.1) increased total seedling dry weight. Soil solutions from the surface 1.5 cm obtained by vacuum displacement were analyzed for pH, electrical conductivity (EC), and total concentrations of Ca, Mg, K, Na, Al, NH4, Cl, NO3, and SO4. Soil solution pH decreased and EC increased with increasing acidity of simulated rainfall. Generally, increasingly acid rainfall resulted in linear (sometimes quadratic) increases in cation and anion components of soil solution with the exception of Al, Na, and NH4. The rainfall pH × soil interaction was not significant for any solution component. Calcium ion activity was unaffected, while Al3+ activity increased from 5.62 × 10−8 to 3.16 × 10−6 with increased rainfall acidity (rainfall pH 4.3‐2.5). The Ca/Al activity ratio decreased 64‐fold with increasing acidity of simulated rainfall. No association between orchardgrass seedling responses and soil solution composition was apparent.
Subsoil Blocky Structure Formation in Some North Carolina Paleudults and Paleaquults
Authors: Southard R. J. , Buol S. W. 
Published: July 2010

AbstractThe relationships among subsoil blocky structure, soil drainage class and landscape position were studied on nine Ultisol pedons from the Middle Coastal Plain of North Carolina. The pedons represented fine‐loamy, fine‐silty, and clayey families of Typic and Aquic Paleudults and Typic Paleaquults. The grade of blocky structure was strongest in poorly drained soils and in moderately well‐drained soils below the seasonal high water table. Soils of fine‐silty families had the strongest blocky structure. Weighted mean ped diameter (WMPD), which was interpreted as a combination of ped size plus grade of structure, was highly and positively correlated with percent silt; WMPD decreased with increasing clay or sand content. Within a given particle‐size family, WMPD increased in more poorly drained soils. There was no consistent trend of WMPD with depth. Stronger grades of structure observed in the field were associated with the presence of thicker and more abundant clay films on peds and with thick oriented pore argillans in thin section. Plotting the location of the pedons relative to the edge of the Coastal Plain surface and to the location of the water table revealed that the subsoil zone with the strongest grade of structure coincided with the region of the subsoil that is saturated about 75% of the time. Poorly drained soils become better drained as the Coastal Plain is dissected by stream downcutting and saturation‐desiccation cycles occur less frequently. Blocky peds that formed when the soils were poorly drained are degraded by other soil forming processes such as eluviation and bioturbation.
Effects of Cultivation on Soils in Northern Great Plains Rangeland
Authors: Aguilar R. , Kelly E. F. , Heil R. D. 
Published: July 2010

AbstractPaired rangeland and cultivated soils were characterized along toposequences formed in sandstone, siltstone, and shale parent materials in southwestern North Dakota to evaluate changes in organic constituents and total P resulting from 44 yr of cultivation. Cultivated and virgin grassland soils were compared on adjacent landscape segments in order to quantify losses or gains of organic C, N, P, and total P. Losses were generally greatest from the upper landscape segments where erosion resulted in significant reductions in solum thickness. Sediment accumulation through erosional processes and redistribution during tillage operations resulted in accretion on selected landscape segments along the cultivated fields. Soils derived from sandstone and siltstone appear to have lost larger proportions of organic C, N, and P through mineralization than the soils formed in shale. Mineralization losses of organic constituents were countered by accretion on depositional segments. Regression analyses indicated that losses of organic C, N, and P were more closely linked to erosion in the finer‐textured soils formed in shale. Changes in total P were closely linked to redistribution and sorting of soil particles because the total quantity of P in soils is independent of mineralization transformation.
Bulk Density Values Diagnostic of Restricted Root Growth in Coarse‐textured Soils
Authors: Vepraskas M. J. 
Published: July 2010

AbstractBulk density values diagnostic of both moderate and excessive levels of soil compaction have not been conclusively identified. This study estimated diagnostic bulk density values related to conditions where root elongation was virtually stopped due to high mechanical impedance, and also to the less compact condition where root growth was occurring but where subsoiling could be used to increase root growth and yield. Undisturbed cores were collected from Ap, E‐B, and B horizons of 24 Paleudults and Hapludults. Each core was equilibrated to a soil water potential of −0.1 MPa and mechanical impedance was determined and expressed as a cone index (CI). Bulk density and particle size distribution were also measured. A model was developed to estimate CI from bulk density (ρb) and percentages of sand, clay, and very fine sand (0.125‐0.050 mm diam). Using the CI model and previously published soil, tobacco (Nicotiana tabacum L.) root, and tobacco yield data, diagnostic CI values related to zero root growth and significant subsoiling effects on both root growth and yield were estimated. The combinations of ρb and texture that produced the diagnostic CI values were then computed for four textural classes having very fine sand percentages of 0, 10, and 20%. The minimum bulk density values associated with where subsoiling increased both root number and yield over that of a moldboard plow/disk treatment were 1.66, 1.61, 1.60, and 1.58 Mg m−3 for the sand, loamy sand, sandy loam and sandy clay loam textural classes, respectively, having 10% very fine sand. It was estimated that root concentration would be zero at bulk densities of 1.85, 1.82, 1.81, and 1.80 Mg m−3 for these same textural classes.
Planting Depth and Tillage Interactions on Corn Emergence
Authors: Gupta S. C. , Swan J. B. , Schneider E. C. 
Published: July 2010

AbstractSurface crop residues lower soil temperatures delaying emergence of corn (Zea mays L.) under no‐till tillage systems in the northern Corn Belt. This study evaluates the use of planting depth as a management tool to overcome the disadvantages of cool temperature under residue covered soils. Growth chamber experiments evaluated the effects of planting depths, ranges of soil temperatures, and soil matric potentials on corn emergence. The seeding medium was aggregates of Webster clay loam (fine‐loamy, mixed, mesic Typic Haplaquolls). Deep planting (75 mm) delayed emergence from 2.8 to 18 d as the soil temperatures decreased from ranges of 15 to 25 °C and 5 to 15 ° C. Seed zone growing degree days (GDD) needed to achieve 75% emergence increased with an increase in planting depth and a decrease in soil matric potential. Relationships of corn emergence vs. seed zone GDD needed to achieve 75% corn emergence at various planting depths were tested in the field for three planting depths, three tillage and three surface residue conditions during 1984 and 1985. Predicted time to 75% corn emergence was within 2 d of the field‐measured values for three planting depths, and seven tillage and surface residue conditions, over two seasons. Simulation studies were conducted to predict the effects of tillage, planting depth, and planting date on the probability of obtaining 75% corn emergence within 14 d of planting. Input data for simulation studies included 10 to 20 yr of daily maximum and minimum air temperatures from Morris, MN and Lexington, KY. Tillage treatments included moldboard plow, no surface residue, and no‐till surface residues. Reducing the planting depth from 50 to 25 mm advanced the planting date from 2 d to several weeks, depending on the weather, soil matric potential, and tillage‐surface residue conditions. When soil water is nonlimiting, the effect of cooler temperatures on corn emergence under a no‐till tillage system (with surface residues) can be compensated for by reducing the planting depth by 25 mm or less from that of average planting depth under conventional tillage systems.
Effect of the Sampling Network on Estimates of the Covariance Function of Stationary Fields
Authors: Russo David , Jury William A. 
Published: July 2010

AbstractThe covariance function of the stochastic component of various soil properties plays an essential role in the estimation and interpolation of spatial phenomena using kriging techniques and in the solution of transport problems in heterogeneous media using stochastic continuum transport modeling. In this study the effect of the sampling network on the estimates of covariance functions of two‐dimensional, isotropic, second‐order stationary processes, characterized by different underlying correlation scales, was analyzed. Estimates of the covariance function based on a standard systematic sampling network were compared with estimates of the covariance functions based on a modified sampling network. Results of these comparisons showed that the modified sampling network was better suited than the systematic network to resolving the statistical properties of the underlying stochastic process at small separation distances. This may result in an improvement in structure identification. Analyses of the effect of the sampling network used for estimating the covariance function on the results of conditional inference procedures such as kriging showed that the kriging estimates were essentially insensitive to the geometric configuration of the sampling network. Uncertainties about these estimates were reduced when using the modified sampling network, however. In the case of unconditional inferences, such as with stochastic analyses of transport problems in heterogeneous media, predictions of the head variance provided by using estimates of the parameters of the covariance function of the log saturated hydraulic conductivity based on the modified sampling network fit the theoretical head variance better than those based on the systematic sampling network. The effect of the sampling network used for estimating the covariance function on the predicted head variance was significant, particularly when the underlying correlation scale was relatively small, when the porous medium texture became finer, and when the hydraulic conductivity variations were treated as being three‐dimensional.
Spectroscopic Evidence for a Copper‐Picloram Complex on Cu(II)‐Saturated and Cu(II)‐Hydrous Oxide Coated Montmorillonite
Authors: Aochi Y. , Farmer W. J. 
Published: July 2010

AbstractDeuteration and deconvolution techniques were applied to infrared investigations of bonding between the herbicide picloram (4‐amino‐3,5,6‐trichloropicolinic acid) and mineral surfaces. Self‐supporting clay films for infrared analysis were prepared from aqueous suspensions of picloram with Cu‐treated montmorillonite or with montmorillonite coated with Cu hydrous oxides. The spectral data show clear evidence for a coordination type bonding between picloram and the Cu‐treated mineral surfaces. Additional evidence is presented from infrared data confirming the presence of the monomeric acid on Al‐ and Fe‐treated montmorillonite. Deuteration of the picloram‐Cu‐montmorillonite and of the picloram‐Cu hydrous oxide‐montmorillonite systems were both extremely slow, requiring several weeks to complete compared to a few hours for the Al‐ and Fe‐systems.
Fluorescence Quenching and Aluminum Complexation by a Chestnut Leaf Litter Extract
Authors: Shotyk William , Sposito Garrison 
Published: July 2010

AbstractFluorescence quenching (FQ) on addition of Al (III) to aqueous solutions of chestnut (Castanea sativa L.) leaf litter extract (LLE) has been interpreted previously as a parameter directly proportional to the mole fraction of Al‐complexed organic ligands in the LLE. To provide independent confirmation of this interpretation, FQ and labile Al (defined by a 15‐s reaction with 8‐hydroxyquinoline) were measured simultaneously in mixtures of Al(ClO4)3 with the LLE. Solutions containing about 0.3 kg m−3 organic matter with total Al concentrations in the range 0 to 60 mmol m−3 were investigated at pH 4.0, 4.5, and 5.0. The total concentration of inorganic Al in the solutions (Alin) at each pH value was calculated as the sum of labile Al and the concentrations of the species Al(OH)+2 and Al(OH)−4 as estimated with thermodynamic hydrolysis constants. The independently‐measured parameters, FQ and Alin, then were used to calculate an overall stability coefficient for Al complexation by the leaf litter extract at each pH value. The values obtained were in good agreement with previous determinations of the stability coefficient based on fluorescence quenching alone. The conditional stability constant cβ0/0 for the quasiparticle species AlL (L = organic ligands) was found to have the value 108.7 ± 0.5 in agreement with a previous estimate of 108.6 ± 0.1 derived from FQ data only. These results confirmed the hypothesis that fluorescence quenching is proportional to Al complexation by the ligands in the LLE.
Boron Sorption on Composted Organic Matter
Authors: Yermiyaho U. , Keren R. , Chen Y. 
Published: July 2010

AbstractBoron (B) sorption on composted organic matter at various pH levels and ionic strengths was determined. The compost contained 158 g kg−1 of humic acid and 56 g kg−1 of fulvic acid fractions, totaling 21.4% of the organic matter. At pH 8, the amount of sorbed B increased by about 57% with an ionic strength increase from 0 to 0.15 M. For solutions of CaCl2 at concentrations lower than 5 × 10−3 M, the effect of CaCl2 on B sorption was negligible. Sorption isotherms of B on organic matter were determined at pH levels of 7.0, 7.9, and 8.9. The sorption increased with increasing B concentration in solution and pH.A comparison with literature data for clays shows that sorption of B on organic matter at similar pH levels and total B concentration is significantly higher than on clays. A modified Langmuir equation was fitted to the measured data. Based on the isotherms, sorption coefficients were derived and used to calculate the predicted dependence on pH of B sorption on organic matter at various total B levels. Desorption studies of B from organic matter at pH 8 and increasing levels of sorbed B exhibited strong hysteresis effects and the sorbed B was removed to a partial extent only. The formation of dihydroxy and/or hydroxy‐carboxy binding of borate to humic substances and/or carbohydrates is proposed to be the sorption mechanism. These bonds may explain the limited irreversibility of the process.