bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison of Four Methods for Interpreting the Shoemaker‐McLean‐Pratt (SMP) Lime Requirement Test
Authors: Doerge T. A. , Gardner E. H. 
Published: July 2010

AbstractUsing a lime requirement (LR) test not calibrated under field conditions or on soils which differ greatly from those used to calibrate the procedure may lead to erroneous results. The objectives of this research were, (i) to compare under field conditions the accuracy of four methods of interpreting the SMP LR test, and (ii) to quantify the random, constant, and proportional error associated with each method. Lime applications ranging from 0 to 14.6 Mg ha−1 were made to field plots on two acid soils in northwest Oregon. Surface soil samples taken prior to liming were analyzed according to four methods of interpreting the SMP lime requirement test, namely the original SMP single buffer (SB), McLean's double buffer (DB) and two modified SMP procedures currently used in Oregon and Washington (Modified SB and Modified SB + initial pH, respectively). Statistical models from these four methods were algebraically solved to permit calculation of predicted pH values due to lime amendment which were compared to soil pH measured one and two years after liming. The proportional errors associated with the Original SB, DB, Modified SB and Modified SB + initial pH procedures were 1.2, 1.3, 0.19, and 0.06, respectively. The magnitudes of the constant and random errors associated with these same four methods were 7.8, 8.6, 0.64, and 0.26 pH units; and 0.83; 0.77, 0.19, and 0.25 pH units, respectively. All methods not calibrated under field conditions under‐predicted soil pH values resulting from applications of lime by an average of 0.5 to 0.7 pH units. These results emphasize the importance of employing field conditions and soils from similar geographical areas when calibrating LR tests.
Long‐term Tillage and Nitrogen Fertilization Effects on Organic Nitrogen and Carbon in a Semiarid Soil
Authors: Rasmussen P. E. , Rohde C. R. 
Published: July 2010

AbstractMaintaining or improving soil organic matter has high priority in agriculture because of its beneficial effect on soil physical, chemical, and biological properties. Soil organic N and C were measured 44 yr after establishment of a long‐term experiment to evaluate tillage and fertilizer effects in a winter wheat (Triticum aestivum L.)‐fallow rotation on a coarse‐silty mixed mesic Typic Haploxeroll. Main treatments consisted of three primary tillage systems, one conventional (moldboard plow) and two stubble mulch (offset disc, subsurface sweeps). Subplots consisted of six N treatments, 493, 728, 986, 1221, 1714, and 2207 kg N ha−1 applied over 44 yr. Organic N and C in the top 75 mm of soil were 26 and 32% higher, respectively, in the two stubble mulch systems than in conventional tillage, and equal below 75 mm. Stubble mulch plots contained 245 kg more N ha−1 than conventionally tilled plots, representing the conservation of 5.7 kg N ha−1 yr−1. Nitrogen fertilization increased soil N linearly in all tillage treatments, with 18% of the applied N incorporated into the soil organic fraction. Applied N also increased soil C linearly on plots with previous S application. Soil C was higher on plots with no previous S than on comparable plots with previous S, however, which suggests an S deficiency that altered S, but not N, transformations in soil. Identical N fertilization effects on soil organic N and C in both stubble mulch and conventional tillage suggests that N transformations were the same in both systems.
Spatial Variability of Wheat Yield and Soil Properties on Complex Hills
Authors: Miller Michelle P. , Singer Michael J. , Nielsen Donald R. 
Published: July 2010

AbstractSurface soil and wheat yield were sampled on a 400‐ by 250‐m grid to determine the relationship between wheat yield and soil properties influenced by erosion. The study, located in the Dunnigan Hills northwest of Sacramento, CA, began in October 1983. Five transects over complex slopes were made 50 m apart. Every 20 m, along each transect, depth to parent material, surface soil thickness, depth to carbonates, landscape position, and percent slope were recorded. In addition, soil samples were collected to determine particle size, percent organic C, water retention at 33 and 1500 kPa, and pH. One meter square plots of wheat were harvested at each of the 100 sites previously sampled. Subsoil samples were taken at select sites to determine organic C and particle size. Every meter along a 50‐m transect, surface soil thickness and percent sand in the surface soil were determined to assess the nugget effect of these variables. Standard regression analyses showed no correlation between percent slope and yield or soil properties. Semivariograms and cross‐semivariograms showed a strong spatial dependency between soil properties and wheat yield. Total above ground biomass increased from the knolls to the swales, while harvest index increased in the reverse direction. Particle size distribution varied by landscape position as a result of both mechanical and water erosion. Harvest index was shown to be positively correlated with percent clay <2 µm but not correlated with percent sand. Surface soil thickness was not found to be spatially correlated with crop growth.
Soil Sulfate‐Sulfur and Growth Responses of Nitrogen‐fertilized Douglas‐fir to Sulfur
Authors: Blake John , Webster S. R. , Gessel S. P. 
Published: July 2010

AbstractTwo studies were conducted to determine the growth response of N‐fertilized Douglas‐fir [Pseudotsuga menziesii (Mirb.) Franco] to S supplements. The relationship between response and soil SO4‐S extracted with Morgan's solution, 1.22 M NaOAc + 0.53 M HOAc (pH 4.8), was used to establish critical levels for S. Douglas‐fir seedlings were grown in the greenhouse in the surface mineral layer (0 to 0.15 m) of 20 forest soils from western Washington and Oregon. On the average, significant increases in total dry weight (17.5%), stem diameter (10.1%), and height (6.9%) occurred when soils were fertilized with N and S in comparison to N alone. Using the Cate‐Nelson procedure, growth responses to N and S were most likely to occur when soil SO4‐S was below 14 mg S kg−1. Twenty eight installations were established in the field containing five N treatments, three rates of N as urea, and one plot of 336 kg N ha−1 with P, K, Ca, and S. Differences in percent basal area growth between N alone and N with P, K, Ca, and S were significantly related to soil SO4‐S. Over the initial 5‐yr period, response over N alone was improved by 74% when soil SO4‐S was <20 mg S kg−1. When the N with P, K, Ca, and S plots were retreated with only N and S, response over the next 3 yr was more than doubled compared with N alone. Identification of S responsive stands was improved by the inclusion of stand age weighted subsoil SO4‐S concentrations.
Potential for Buffering of Acidic Precipitation by Mineral Weathering in a Forested Entisol
Authors: Bockheim J. G. , Leide J. E. , Li C.S. , Wentz D. A. 
Published: July 2010

AbstractBulk precipitation, soil‐water, and groundwater chemistry were monitored at Round Lake, a small, forested catchment receiving acidic precipitation (pH 4.6) in northwestern Wisconsin. The groundwater basin retained H ion and released nonhydrolyzable cations (NHC = Ca, Mg, Na, K) and Si. The percentages of plagioclase feldspar, hornblende, olivine, and augite increased with depth in soils from the catchment; quartz, orthoclase feldspar, and weathered mica decreased with depth. Thermodynamic stability indices estimated from water‐quality and mineralogic data, and from the WATEQF chemical speciation model indicate that the soil‐water and groundwater are undersaturated with respect to hornblende, chlorite, olivine, augite, plagioclase, and orthoclase feldspars and that these minerals may be undergoing dissolution. Minimally disturbed soil cores were leached with dilute H2SO4 and distilled water (pH 3.0 to 5.7). When the pH of the extracting solution was ≥4.5, Ca was released in the greatest amounts, followed by Si, Mg, K, Na, and Al. This ranking is similar to that for cations in groundwater. Leaching with a pH 3.0 solution released Si in the greatest amounts from the C horizon, followed by the Bw2, Bw1, and A + B/E horizons. This trend parallels the depth distribution of weatherable minerals in the very fine sand fraction. Results from the laboratory leaching study confirm the chemical modeling studies, indicating that mineral weathering (hydrolysis) can contribute to buffering within the groundwater basin at Round Lake.
Effects of Soil Physical Structure on Solute Transport in a Weathered Tropical Soil
Authors: Sollins P. , Radulovich R. 
Published: July 2010

AbstractEffects of soil structure on solute transport were studied in a clayey, well‐aggregated Oxic Dystropept under grass and secondary forest at La Selva, Costa Rica. Both fine pores (<0.1 µm) and coarse pores (>30 µm) are abundant, as indicated by a water content of 0.37 m3 m−3 at −1500 kPa matric potential, the shape of the moisture release curve, and an initial infiltration rate (at field capacity) averaging 3900 mm hr−1. Field application of Rhodamine B dye without ponding (simulating heavy rainfall) showed preferential flow along decayed‐root channels, animal burrows, cracks, and other macropores. Dye application to intact cores under conditions of ponded steady‐state flow gave a good correlation between flow rate and total stained area (p <0.01 under forest; p < 0.05 under grass). Solute (CaCl2) breakthrough occurred very rapidly, often after < 0.1 pore volumes had percolated; however, relative concentration of the effluent did not exceed 0.95 even after five pore volumes had percolated. These results indicate that most water flows between aggregates or through macropores (as preferential or channelized flow), even when the fine pores are not fully saturated, and in effect bypasses the fine pore space. When solution inflow was interrupted after ∼1.8 pore volumes, then resumed after 10 min pause, relative concentration of the effluent dropped by 10 to 40%, then rose again. This indicates that solute diffused slowly into the aggregates. Taken together the results suggest that this soil strongly resists leaching. Preferential water flow may serve to prevent nutrient loss from the matrix of all highly aggregated soils and of all noncultivated soils in which animal activity and turnover of woody roots create abundant macropores.
Experimental Validation of the Monophase Structure Model for Montmorillonite Solubility
Authors: Kittrick J. A. , Peryea F. J. 
Published: July 2010

AbstractPreviously published solubility data for Belle Fourche montmorillonite were plotted on pH or pH‐pK+ vs. pSi(OH)4 axes, in order to determine the proper model for representing smectite formulas in hydrolysis reactions. The resulting line slopes did not agree with predictions based upon a model where smectite and exchangeable ions are considered to be separate phases. A model where exchanger and exchangeable ions form a single macroscopic phase (monophase) generated a line slope that agreed with the data within experimental error. Agreement between the monophase model and the data suggests that the experimental requirements for phase meta‐equilibrium and K saturation were sufficiently met to show that smectite solid solutions behave as thermodynamic phases over the time span of the experiments.
Measurement of Nitrous Oxide Dissolved in Soil Solution
Authors: Davidson E. A. , Firestone M. K. 
Published: July 2010

AbstractDegassing of soil solution as soil water enters springs and streams may be a significant pathway of N2O release into the atmosphere. A simple method is presented to sample soil solution to include gases dissolved in solution. Small porous cup lysimeters connected to narrow diameter nylon tubing were flushed with N2 gas; a vacuum was applied with an evacuated serum bottle; and solution and gases were captured in the bottle. Concentrations of N2O in soil solution of a grassland in central California varied from below ambient to 13 times ambient. At a wet riparian zone site, N2O in soil solution appeared to be related to NO‐3 concentration, which can be determined from the same soil solution sample.
Distribution of Selenium in Soils of Agricultural Fields, Western San Joaquin Valley, California
Authors: Fujii Roger , Deverel S.J. , Hatfield D.B. 
Published: July 2010

AbstractSoils from three agricultural fields in the Panoche Creek alluvial fan area in the western San Joaquin Valley, California, were analyzed for soluble, adsorbed, and total concentrations of selenium (Se) to assess the distribution and forms of Se in relation to the leaching of Se from soils. This assessment is needed to evaluate the importance of soil Se in affecting ground water concentrations. Soil samples were collected from three fields with drainage systems of different ages (6, 15, 1.5 yr) and different Se concentrations in drain water (58, 430, 3700 µg L−1, respectively). Concentrations of soluble Se and salinity were highest in soils from the field drained for 1.5 yr and lowest in the field drained for 6 yr. Of the total concentration of soil Se from all three fields, the proportion of adsorbed and soluble Se ranged from 1 to 11% and <1 to 63%, respectively. Most of the soluble Se was present as selenate and most of the adsorbed Se was found to be selenite. Consistent with a model of evaporative concentration of Se and salinity in soils and shallow ground water in this area, most of the variance in soluble Se is explained by salinity (r2 > 0.68) in saturation extracts of soils sampled from below the water table. In contrast, most soluble salts and Se apparently have been leached from the unsaturated soils in the fields drained for 6 and 15 yr. For the leached soils, dissolution and precipitation of evaporite minerals containing Se may no longer control concentrations of soluble Se.
Survival of Rhizobium in an Oxisol Subjected to Incremental Simulated Erosion
Authors: Habte M. , El‐Swaify S.A. 
Published: July 2010

AbstractThe survival of four strains of Rhizobium was monitored as a function of time at constant moisture potential and temperature in soils from sites subjected to incremental simulated erosion. Populations of two of the strains were either stimulated or unaffected by simulated erosion representing up to 37.5 cm of surface soil removal. Populations of the remaining two strains were also stimulated or unaffected by simulated erosion not exceeding 15 cm of surface soil removal. Simulated erosion in excess of this level, however, significantly decreased the survival of these strains. Strain tolerance to erosional losses of soil closely paralleled tolerance to soil acidity. Declines in the populations of the erosion‐intolerant strains were accompanied by declines in soil pH, organic C, total N, extractable P, and extractable Ca, Mg, and K. The adverse effects of simulated erosion on the sensitive rhizobia was eliminated, however, by liming the eroded soil samples to pH 6.0. Liming improved the survival of the bacteria in these soil samples largely by improving the supply of Ca. Our results demonstrate that the adverse effect of erosional soil losses on the survival of Rhizobium in the Wahiawa soil could be overcome either by increasing the supply of Ca or by selecting rhizobial strains that are insensitive to erosion.
Evaluation of Nitrogen‐15 Tracer Techniques for Direct Measurement of Denitrification in Soil: III. Laboratory Studies
Authors: Mulvaney R. L. 
Published: July 2010

AbstractLaboratory studies were conducted to evaluate the assumption of isotopic uniformity that underlies mass spectrometric determination of dinitrogen (N2) and nitrous oxide (N2O) evolved during denitrification in soil treated with 15N‐labeled fertilizer. In these studies, a gas chromatograph (GC) and mass spectrometer (MS) were used to analyze replicate atmospheric samples containing N2O generated through oxidation of 15N‐labeled NH2OH, evolved from 15N‐treated soil slurries incubated at constant moisture content (1 kg H2O kg−1), or evolved from 15N‐treated soil subjected to wetting and drying cycles. Both instruments gave almost identical values in analysis of N2O derived from a single pool of 15N‐labeled NH2OH or from two pools having similar, but not necessarily the same, enrichments. The MS gave lower values for N2O derived from two pools differing markedly in their enrichment of 15N. The values measured by GC and MS differed significantly (0.05 level) for about 50% of the soil atmospheric samples analyzed; however, the differences usually did not exceed 10% and probably resulted from analytical error rather than lack of isotopic uniformity in the NO−3 denitrified, because in about half of these cases, the greater value was obtained by MS.
Mineralization of Carbon and Nitrogen from Freeze‐ and Oven‐Dried Plant Material Added to Soil
Authors: Moorhead K. K. , Graetz D. A. , Reddy K. R. 
Published: July 2010

AbstractDrying organic material before soil incorporation is a common procedure used in mineralization or decomposition studies. A laboratory study was conducted to determine the effect of drying methods on plant C and N and associated mineralization patterns in soil. Freeze‐ and oven‐dried water hyacinth (Eichhornia crassipes [Mart] Solms) was added to a Kendrick soil (loamy, siliceous, hyperthermic Arenic Paleudults) at a rate of 5 g kg−1 and incubated in the dark at 27 °C for 90 d. Oven drying in paper bags significantly increased the lignin content and decreased the mineral content of the plant material compared to freeze drying. The total C and N was not significantly different for the two materials. The mineralization of C from freeze‐dried plant material was more rapid during the initial stage of decomposition and remained significantly higher throughout the incubation. At 90 d, 50 and 41% of the plant C had evolved as CO2 for the freeze‐ and oven‐dried plant material, respectively. Mineralization of 15N from the plant material accounted for 33% of the applied N of the freeze‐dried material and 23% of the applied N of the oven‐dried material. Nitrogen mineralization and CO2 evolution were linearly correlated (r = 0.998) for the oven‐dried plant material, but less correlated (r = 0.770) for the freeze‐dried material.
Effects of Soil Properties on Plant‐Available Phosphorus Determined by the Isotopic Dilution Phosphorus‐32 Method
Authors: Sen Tran T. , Giroux M. , Fardeau J. C. 
Published: July 2010

AbstractA procedure using 32P isotopic exchange kinetics was suggested to characterize the availability of soil P. The ratio of the radioactivity remaining in the solution over the total radioactivity (r1/R) was closely and inversely proportional to the maximum P‐fixation capacity (M) estimated by the Langmuir isotherm (r = 0.82**, significant at the 0.01 probability level) and to the P‐buffering capacity (Mb) (r = 0.71**). The 1/r1/R) ratio was also correlated with oxalate‐Al (r = 0.69**) and oxalate‐Fe (r = 0.35**). The kinetic parameter, n, described as the decrease of radioactivity remaining in the solution with time, was related to the soil pH (r = −0.52**), the prevailing form of soil P (Mehlich ratio Q, r = −0.50**), the P‐fixation capacity (r = 0.44**), and organic matter (r = 0.44**). The isotopically exchangeable P (E1 value) was closely related to the plant P uptake on soils having low P‐adsorption capacity (Group III, r = 0.90**). However, E1 value may overestimate the available P on high P‐fixing soils especially for acid Spodosols (Group I, r = 0.47**). The water soluble P (M1) or the labile P pool (M1 + M2) showed a curvilinear (logarithmic) relationship with plant P uptake and the correlation coefficient was higher than that obtained from E1 when grouping all soils together. The effect of soil properties on the relation between plant P uptake and E1, log M1, or log (M1 + M2) was confirmed by the increase of the coefficient of determination (R2) of the multiple regression including soil parameters as second variable. An exponential relationship was observed between relative yield (%) and E1, M1, (M1 + M2); the R2 value was 50.4, 65.1, and 68.1%, respectively. The three classes of soil P fertility (poor, medium, rich) were established for E1, M1, and (M1 + M2) according to the Cate and Nelson procedure.
Physical Properties of Constructed and Undisturbed Soils
Authors: Potter K. N. , Carter F. S. , Doll E. C. 
Published: July 2010

AbstractThere is a growing impetus to use soil properties to determine if reclamation efforts are adequate to restore productivity. Constructed mine soils were studied 4 and 11 yr after reclamation to determine physical and hydrological properties. Soils constructed using similar methods and with similar vegetation histories were compared to each other and to an equivalent undisturbed soil. Bulk density was greater in the topsoil and subsoil materials of the constructed soils than in the undisturbed A and B soil horizons. Macropore volume (pore radii > 15 µm) was greater in the topsoil and subsoil materials at the 11‐yr site relative to the 4‐yr site but was significantly lower than that in the undisturbed soil. Small pore volume (pore radii from 4.5 to 0.1 µm) in the reclaimed topsoil materials was similar to the undisturbed A horizon soil but was larger in reclaimed subsoil materials than in the undisturbed B horizon. Saturated hydraulic conductivity (Ks) of the reclaimed topsoil was about 25% that of the undisturbed A horizons and the reclaimed subsoil Ks was less than 10% that of the undisturbed B horizon. The reduction in Ks was attributed to the increase in bulk density and disruption of soil structural units and associated interpedal pore spaces during mining and soil construction. No significant differences in Ks were found between constructed minesoils 4 and 11 yr after reclamation. The results of this study show that soil properties may be useful for evaluating reclamation success after soil construction.
Nitrogen Fertilization of Young Yellow Poplar and Loblolly Pine Plantations at Differing Frequencies
Authors: Johnson Dale W. , Todd D. E. 
Published: July 2010

AbstractLoblolly pine (Pinus taeda L.) and yellow poplar (Liriodendron tulipifera L.) seedlings from 1–10 seedling stock were established in the Tennessee Valley near Oak Ridge and fertilized with 300 kg ha−1 of urea‐N over a period of 3 yr according to two regimes: annually in one spring application (100 kg ha−1) and quarterly (25 kg ha−1 quarter−1). Two plantation blocks for each species, one consisting of seedlings preinoculated with mycorrhizae and one without preinoculation, contained three replicate plots per treatment. Annual fertilization produced greater growth and N recovery in both loblolly pine plantations than did quarterly fertilization, the latter not being significantly different from the controls. Growth responses in yellow‐poplar plantations were less certain and not statistically significant, probably due to moisture stress for this species on this site. There was no evidence of prolonged (> 2 yr) enhancement of soil available N following either quarterly or annual fertilization. Quarterly fertilization produced the earliest and generally the most pronounced increases in soil solution NO−3 concentrations in all cases, followed by annual fertilization and control, respectively. These results, combined with laboratory incubations, indicated that quarterly fertilization benefited the nitrifying bacteria more than the trees on this site, particularly in the case of loblolly pine.