bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nutrient Losses from Timber Harvest in the Idaho Batholith
Authors: Clayton James L. , Kennedy Debora A. 
Published: July 2010

AbstractNutrient budgets for a mature ponderosa pine/Douglas‐fir [Pinus ponderosa Dougl./Pseudotsuga menziesii (Mirbel) Franco var. glauca (Beissn.) Franco] forest in the southwestern Idaho batholith are used to evaluate the potential for accelerated nutrient losses associated with timber harvesting. Soils formed from granitic rock in the Idaho batholith are commonly shallow, coarse textured, and highly erodible following disturbance. Cycling and annual budgets for K, Ca, Mg, S, P, and N are described for an undisturbed control watershed, and accelerated losses assoicated with clearcutting, helicopter yarding, and broadcast burning of slash are evaluated in an adjacent treated watershed. There were small but statistically significant increases in dissolved N losses of approximately 10 times preharvest rates for a 4‐yr period following treatment. Dissolved transport of other elements was not increased. Small but significant increases in sediment nutrient transport of all elements occurred 3 yr following harvest. The largest losses in nutrients were due to bole removal and ranged from 4% of total ecosystem N to 21% of ecosystem K. Rates of replacement from precipitation, primary mineral weathering, and N2 fixation would restore the ecosystem to the nutrient status prior to harvest in 50 yr. Based on these findings, logging systems that minimize erosion should not cause unacceptable nutrient loss over a normal timber stand rotation.
Titration Method for Determination of Clay‐Sized Carbonates
Authors: Bloom P. R. , Meter K. , Crum J. R. 
Published: July 2010

AbstractThe carbonate content of soil clay suspension samples obtained by the pipet method was determined by the titration of the excess acid after reaction with an acetic acid buffer. The clay samples were reacted with a pH 4.0 buffer and titrated after 30‐min of bubbling with air. Two variations of the method were evaluated. One was for use with an automatic titration and the other for manual titration. The accuracy of the two methods was demonstrated using a suspension of clay‐sized reagent grade CaCO3. The coefficient of variation for the determination of CaCO3 in soil clays by the automatic titration method was <0.15 for samples containing <4 mg of CaCO3. The precision was greater for samples with CaCO3 contents up to 26 mg. With greater quantities of CaCO3 the 30‐min reaction time was insufficient for complete dissolution because the rate of CaCO3 dissolution decreases with increasing suspension pH. The coefficient of variation for the manual titration method was <0.05 for all samples analyzed. The maximum quantity of CaCO3 that could be determined by the manual titration method was 55 mg.
Spatial and Spectral Relationships Between Field‐measured Denitrification Gas Fluxes and Soil Properties
Authors: Folorunso O. A. , Rolston D. E. 
Published: July 2010

AbstractThe relationship of the spatial variability of field‐measured denitrification gas fluxes to the variability of physical and chemical soil properties affecting denitrification were investigated in order to better understand the denitrification process in the field. The values of N2O, N2, and CO2 fluxes, soil‐water content, soil temperature, water soluble organic C, and NO‐3 were determined from four transects, each with 36 observations, in a Yolo loam (Typic Xerorthents) field site. Spectral analysis indicated the presence of spatial cycling of some parameters. Cospectra and coherency spectra were used to establish relationships between variables in the frequency domain. Spectra of N2O + N2 flux gave evidence that denitrification was cycling with a period of 4 to 5 m for some of the strips. Spectra of soil‐water content (0–0.15 m depth) showed that soil‐water content was also cycling at a period of about 5 m. Spectra of other variables showed less consistent cycling. Cospectra of N2O flux vs. most variables provided evidence of both positive and negative correlations over different frequency ranges. The cyclic nature of the soil‐water content in the surface soil appears to be the primary cause of cycling of the denitrification gas flux at a period of 4 to 5 m. Cycling of water soluble organic C at periods different from that of water content also caused some periodic behavior in denitrification gas fluxes. Without using spectral and coherency techniques, standard correlation or regression methods would have provided little evidence of significant causal effects on denitrification.
Potassium Exchange in Five Southern California Soils with High Potassium Fixation Capacity
Authors: Shaviv A. , Mattigod S. V. , Pratt P. F. , Joseph H. 
Published: July 2010

AbstractThe K exchange with Ca and Mg in five southern California profiles with high K fixation capacity was studied. The objective was to obtain a correlative relationship between K selectivity with varying proportions of K, Ca, and Mg on the exchanger phase of the soils. A linear relationship between EP (the ratio of adsorbed K to adsorbed Ca and Mg) and potassium adsorption ratio (PAR = [K+]/([Ca2+]+[Mg2+])1/2) was found for all the soils investigated. A representative relationship EP = 0.134 + 0.026 (PAR), with high degree of correlation (r = 0.955), was found for the surface layers (0–30 cm) of all five soils studied. A sharp decrease in KG, the Gapon selectivity coefficient with EP increasing from 0 to 0.2 and ending with a levelling of KG values between 0.7 to 3.2 (mol−1 L)1/2 was observed for all the soil profiles. The KG relationship with potassium fixation showed a similar trend for all the soil profiles.
A Simple Microbial Bioassay for Plant Available Manganese
Authors: Germida J. J. , Karamanos R. E. , Stewart J. W. B. 
Published: July 2010

AbstractA bioassay using the soil bacteria Bacillus brevis or Ensifer adhaerens for determining plant‐available Mn in organic soils was developed. For this assay, a 1:10 soil‐agar plug was prepared in a nutrient agar plate and then overlaid with semisolid nutrient agar inoculated with either test organism. Manganese‐induced zones of growth stimulation were measured after 24‐h incubation at 27°C. There was a linear relationship between the logarithm of standard concentrations of Mn and the zone of growth stimulation. The enhanced growth was a specific response to Mn; Ca, Co, Cu, Fe, Mg, Mo, Ni, Sr, Zn, NO‐3, PO3‐4, and SO2‐4 did not stimulate growth of either organism. Addition of glucose as a C and energy source or yeast extract as a source of vitamins and growth factors had no effect on growth. Six organic, six Mn‐amended organic, and 17 mineral soils were tested with this assay. This new assay clearly identified five nonamended organic soils that were Mn‐deficient as determined by the growth of spring wheat (Triticum aestivum) in a growth chamber study. There was a statistically significant correlation between the zone of growth stimulation on bioassay plates and plant relative yields, Mn concentration, and Mn uptake. The DTPA extracts of these soils did not predict this Mn deficiency. Separation of responding from nonresponding soils was achieved using the E. adhaerens bioassay. This assay allows rapid and inexpensive identification of Mn‐deficient soils.
Effect of Temperature on Organic Carbon‐texture Relationships in Mollisols and Aridisols
Authors: McDaniel P. A. , Munn L. C. 
Published: July 2010

AbstractData from 143 grassland soils of Montana and Wyoming classified as Mollisols or Aridisols were analyzed to determine the effect of soil temperature regime on the relationship between organic carbon (C) and texture. Using existing data, average weighted organic C content to a 40‐cm depth was calculated for each soil and correlated with several variables, including elevation, weighted clay and sand contents to a 40‐cm depth, and sand/clay ratio. For all soils, organic C was significantly correlated with sand (r = − 0.27) but not with clay (r = 0.01). When soils were grouped by combinations of temperature regime and classification at the order level, organic C levels were highest in cryic soils (Cryoborolls) and lowest in mesic Aridisols. Correlations of organic C with sand and clay contents were highest for mesic Mollisols and mesic Aridisols and decreased as temperature regimes became colder. Sand/clay ratio was significantly correlated with organic C in mesic soils only, and therefore may not be useful in distinguishing between Typic and Borollic subgroups of frigid Aridisols in Soil Taxonomy. Results suggest that sand and clay contents have limited value in predicting organic matter levels in cold arid and semiarid grassland soils.
Effect of Physical and Chemical Profile Modification on Soybean and Corn Production
Authors: Hammel J. E. , Sumner M. E. , Shahandeh H. 
Published: July 2010

AbstractCrop production on highly weathered soils is frequently limited by poor root penetration into the subsoil as a result of highly acid conditions. This results in reduced water uptake from the subsoil and may subject the crop to drought stress. As a result, the possibility of ameliorating the subsoil of a Typic Hapludult, both chemically and physically, was investigated in a field experiment in which four subsoil treatments were compared, namely, control, subsoil mixed to 1 m, subsoil mixed to 1 m with sufficient lime incorporated to neutralize exchangeable Al3+, and gypsum incorporated into the surface soil. The crops grown were soybeans [Glycine max (L.) Merr.] and corn (Zea mays L.). Deep incorporation of lime increased yields. Surface‐applied gypsum increased yields only in the 2nd and 3rd yr. Yield improvement resulted from deeper root penetration into subsoils, which was confirmed by water‐depletion measurements. This improved root proliferation was accompanied by a reduction in exchangeable Al3+ and an increase in exchangeable Ca2+.
Soil Heat Flux, Thermal Conductivity, and the Null‐alignment Method
Authors: de Vries D. A. , Philip J. R. 
Published: July 2010

AbstractThe null‐alignment method of estimating soil heat flux density(q) and thermal conductivity (λ) depends on calorimetry, and ignores convection of sensible heat by mass flow and processes involving latent heat. Study of the energy balance of drying bare soils indicates that the major errors of null‐point calorimetry are likely to arise from net evaporation in upper soil layers. A net evaporation rate of at least 1 mm/d probably occurred in the example used to introduce null‐alignment. This small evaporation rate changes the q profile so radically that null‐alignment may give λ‐values averaging about 52% of the correct ones. Diurnal variations of latent heat sink strengths, null‐points, and temperature gradients, combine to produce diurnal variation of the error in null‐aligned λ's, thereby explaining the reported diurnal variation of null‐aligned λ. Since errors tend to be large and negative in daytime, and small and positive at night, 24h avg are likely to be too small. Null‐alignment does not provide the precise measures of q and λ its exponents supposed, so that various null‐alignment‐based critiques of the Philip‐De Vries theory of heat and moisture transfer in soils, and of the De Vries model of λ, cannot be sustained. Of course there is much scope for improving both through incisive theory and precise experiment. All calorimetric methods of estimating q that ignore latent heat, not only null‐alignment, must involve serious errors in the presence of significant net evaporation in the soil.
Transformations of Inorganic Phosphorus During the Flooding and Draining Cycles of Soil
Authors: Sah R. N. , Mikkelsen D. S. 
Published: July 2010

AbstractPhosphorus transformations that occur after anoxic soils are drained have been associated with acute P deficiencies in rotation crops following rice. Flooded rice may not respond to P fertilization while rotation crops respond markedly to P fertilization on similar soils. The changes that occur among the inorganic P forms during flooding and after drainage in four soils were investigated. Significant changes in the inorganic P fractions—aluminum‐P (Al‐P), iron‐P (Fe‐P), calcium‐P (Ca‐P), and reductant soluble‐P (RS‐P) occurred in soils during their flooding and draining cycles. Typically, the Fe‐P fractions increased and Al‐P fractions decreased when soils were flooded. The Ca‐P fraction increased during flooding in two soils that had initially high levels of Ca‐P but was almost unchanged in two other soils of lower Ca‐P content. The RS‐P fraction decreased during flooding in the soils subjected to annual flooding. During the drainage period, Fe‐P and Al‐P fractions decreased and the RS‐P fraction increased in flooded rice‐cropped (Oryza sativa L.) soils, probably due to occlusion of Fe‐P and Al‐P by hydrated Fe and Al oxides. The RS‐P fraction in Willows clay, a soil that had not been flooded recently, decreased during the drainage period. Phosphorus added as Ca(H2PO4)2. H2O was recovered mainly in the Fe‐P and Al‐P fractions. The recovery of Fe‐P was greater in flooded‐drained soils and Al‐P was greater in unflooded soils.
Decomposition of Methyl Nitrite in Solutions and Soils
Authors: Magalhães A. M. T. , Chalk P. M. 
Published: July 2010

AbstractThe role of hydrolysis as a process affecting the concentration of CH3ONO in the soil atmosphere was investigated by measuring the sorption of CH3ONO and the formation of NO‐2 and NO‐3 in two soils (−33‐kPa soil water potential) and three solutions in the dark at 20°C for 10 h. Soil pH and the pH of distilled H2O decreased on absorption of CH3ONO. In acidic solutions (distilled H2O and 0.1 M H2SO4), > 90% of CH3ONO was recovered as NO‐3, whereas to an alkaline soil and 0.2 M NaOH, > 80% was recovered as NO‐2. Only 0 to 7% of CH3ONO remained in the atmosphere. In an acid soil only 50% of CH3ONO was recovered as [CH3ONO + NO‐2 + NO‐3]‐N. Recoveries of N in γ‐irradiated and nonirradiated soils did not differ significantly. The data indicate that CH3ONO was rapidly hydrolysed in solutions and in soils [CH3ONO + H2O ⇌ CH3OH + HNO2], and that NO‐3 formed via the self‐decomposition of HNO2. The low recovery of N in the acid soil may have been due to the participation of HNO2 in chemodenitrification reactions. The rapid hydrolysis of CH3ONO is likely to inhibit the emission of CH3ONO formed in soils, and to cause the sorption of CH3ONO evolved from soils in closed systems.
Organic Matter Inputs to Soil After Growth of Carbon‐14‐Nitrogen‐15 Labeled Maize
Authors: Hétier J. M. , Andreux F. , Schouller E. , Marol C. 
Published: July 2010

AbstractAfter growth of doubly labeled (14C and 15N) maize (Zea mays L.), two loamy soils were labeled by root exudation and rhizodeposition, and by direct microbial immobilization of N. Fresh roots were then carefully separated and washed, eliminating organic and organomineral cementing agents by acid and alkaline solubilizing reagents, and the remaining insoluble humin was water dispersed in order to separate coarse, medium, and fine fractions. At harvest time, fresh roots represented 85% of the total C input, and rhizodeposition 15%. Sixty to 70% of the N input was still in living roots at this time, and other organic forms of N were more a result of microbial activity than of rhizodeposition. The largest and most homogeneous organic fraction was the finest insoluble fraction, in which about half of the label for both C and N was found.
Effect of Irrigation Method and Acetylene Exposure on Field Denitrification Measurements
Authors: Terry R. E. , Jellen E. N. , Breakwell D. P. 
Published: July 2010

AbstractAn increased understanding of denitrification in situ may contribute to the development of agricultural practices that minimize denitrification losses from cropland. The objectives of this study were to: (i) observe the effects of sprinkle and flood irrigation on denitrification losses; and (ii) to evaluate the effects of acetylene (C2H2) exposure on inhibition of nitrification and C2H2 decomposition. Acetylene was introduced into the soil atmosphere of field plots either by flood irrigation with C2H2‐treated water or by continuous diffusion of C2H2 from dispersion tubes placed in the soil to a depth of 25 cm. Some plots received C2H2 through dispersion tubes continuously for 42 d, while rotated plots received the gas for 7 d and were then abandoned in favor of fresh plots. Denitrification losses from the fallow, clay loam soil were approximately 16‐kg N when the soil was flood‐irrigated and approximately 3‐kg N when the soil was sprinkle‐irrigated. Soil environmental conditions within the disintegrated structure of the flood‐irrigated soil promoted denitrification losses. Nitrification rates in C2H2‐treated soils were only 30 and 87% of control rates, but nitrification rates recovered within 4 d after removal of the gas. The complications of nitrification inhibition by acetylene in field denitrification studies may be minimized by intermittent exposure of soil to acetylene or by rotation of experimental sites. Soil microorganisms began to metabolize C2H2 after 7 d of continuous exposure. The problems of C2H2 decomposition and decreased C2H2 partial pressures were overcome by rotating field plots every 7 d.
Identification of Some Trace Metal Minerals in a Mine‐waste Contaminated Soil
Authors: Mattigod S. V. , Page A. L. , Thornton I. 
Published: July 2010

AbstractA scheme involving the use of particle and density separations was used to isolate and identify by x‐ray diffraction (XRD) and scanning electron microscopy/energy dispersive x‐ray analysis (SEM/EDX), several trace metal minerals in a mine‐waste contaminated soil from Shipham, England. The heavy density (> 3.3 Mg m−3) fraction of this soil contained smithsonite, leadhillite, barite, rutile, goethite, and hematite. The scheme of particle separations appears effective in that the mineral fractions which constitute a minor fraction of a soil matrix can be isolated and identified directly.
Distribution of Nitrogen Forms and Availability Indices in Profiles of Differently Managed Soil Types
Authors: Hadas Aviva , Feigenbaum Sala , Feigin A. , Portnoy Rita 
Published: July 2010

AbstractVarious chemical methods have been used to predict the N mineralization potential of soils, but studies have been restricted mainly to surface soil layers, to which most N mineralization is attributed. In this study, the distribution of N forms, extracted from soil by different chemical methods, and the relationship between them were determined within the profiles of several soil types. All N parameters tested were significantly correlated with total N. The fractions of several N parameters of total N changed with soil depth: oxidative release of NH4+ by acid KMnO4, N extracted by NaHCO3, and NH4+ and hexosamine in soil acid hydrolyzate all increased, whereas amino acids and amidase activity decreased with soil depth. Soil type also influenced some N parameters: acid KMnO4 extracted relatively more NH4+ from calcareous than noncalcareous soils; a smaller fraction of total N was acid hydrolyzable in soils with a greater surface area; and amidase activity was considerably higher in cultivated clay soils.
Soil Respiration in a Winter Wheat Ecosystem
Authors: Buyanovsky G. A. , Wagner G. H. , Gantzer C. J. 
Published: July 2010

AbstractRespiration of a silt loam soil (Udollic Ochraqualfs) was studied under cultivation of winter wheat (Triticum aestivum L.) over a 3‐yr period. Evolved CO2 was measured by the alkali absorption method during 24‐h periods at intervals of usually two weeks. Extended estimates of CO2 evolution were made after extrapolating the measured results, in accord with abiotic influences, to include the longer time intervals. Among the abiotic factors examined in relation to evolution of CO2 during the annual agricultural cycle, the most significant was temperature and second, soil water content (R2 = 0.67 for two factors combined). Better models were obtained when the annual cycle was split into two periods, that with predominating plant activity from October through June, and that when CO2 arose solely from the activity of heterotrophs from harvest to planting. Although factors affecting CO2 evolution were the same, predictability increased, and up to 88% of changes in soil respiration during the first period were related to soil temperature and moisture content of the 0‐to 10‐cm layer. For the second period, air or soil temperature plus moisture of the soil at 20 to 30 cm accounted for 76% of the variability. Using models developed for both periods, average annual respiratory loss of C under wheat in Missouri was approximated at 640 g m−2. Maximum soil respiration, presumably from decomposition activity on freshly incorporated residues, occurred during a 56‐d period after harvest, and accounted for 40% of the total annual amount of CO2 evolved from soil. Differences in seasonal patterns of soil respiration and photosynthetic uptake of CO2, indicate that no more than one‐fifth of the photosynthesis requirement for CO2 by winter wheat is produced by soil respiration during the growing season.
Effect of Sequence in Extraction of Trace Metals from Soils
Authors: Miller W. P. , Martens D. C. , Zelazny L. W. 
Published: July 2010

AbstractWhile many workers have utilized various reagents for sequential extraction of soil trace metals, few studies have examined the order of extraction for key steps in the sequential procedure. In this study, several sequences involving both adsorbed and structural (occluded) metal extractants were evaluated to determine the most appropriate sequential methodology for extracting different forms of Cu, Fe, and Mn. For “specifically adsorbed” metals, Pb(NO3)2 and CH3COOH were used. The results showed that the former reagent extracted less Cu, Mn, and Fe and was probably more specific in replacing metals covalently bound to adsorption sites. Lead nitrate was therefore placed before CH3COOH extraction in the sequence. Chao's NH2OH·HCl reagent and K4P2O7, used for Mn oxide and organic metal removal, respectively, were found to solubilize significantly different amounts of Cu and Mn depending on sequence, with K4P2O7 extracting more metal when used first. As NH2OH·HCl has little effect on organic metals, it should be used before K4P2O7. Noncrystalline and crystalline Fe compounds are solubilized next, using a variety of reagents, and residual (silicate lattice) metals are dissolved in the final step. A nine‐step sequential method is proposed to characterize trace metals in agricultural, polluted, and waste‐amended soils.
Influence of Tannic Acid on Retention of Copper and Zinc by Aluminum Precipitation Products
Authors: Goh Tee Boon , Violante A. , Huang P. M. 
Published: July 2010

AbstractThe influence of pH on the adsorption of Cu and Zn from solution by precipitation products of Al formed both in the absence and presence of tannic acid was studied. The results show that well crystallized Al hydroxides formed in the absence of tannic acid have low specific surface and thus adsorbed the least amounts of these trace metals per unit weight basis. The presence of tannic acid during the precipitation reaction of Al significantly modifies the adsorption behavior of the hydrolytic products by increasing the specific surface and adsorption capacity. This result is attributable to the structural distortion of the Al precipitation products by tannate ligands and the exposed edges, carboxylate and phenolic groups on the surfaces. The adsorption processes of the Al oxides for Cu and Zn were influenced by the presence of ionized organic functional groups of tannic acid coprecipitated with the poorly ordered Al oxides. The infrared spectra establish the presence of carboxylate COO‐ ions in the oxides prepared.