bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optimizing Phosphorus Fertilization Rates for Soybeans Grown on Oxisols and Associated Entisols
Authors: Lins I. D. G. , Cox F. R. , Nicholaides J. J. 
Published: July 2010

AbstractAlthough soils vary considerably in their P sorption characteristics, this factor is often not considered in a soil test interpretation. One soil property closely related to P sorption is clay content. Residual P studies were conducted for 4 yr on three tropical soils of similar clay mineralogy, two Oxisols of 63 and 27% clay, and a Quartzipsamment of 12% clay. The Mehlich 1 (1:10) extractable P level was described as a function of time, initial soil P level, and P fertilization rate. One crop of soybeans [Glycine max (L.) Merr.] was grown each year and the yield related to extractable P, which, in turn, was related to the initial P soil level and P fertilization rate for a period of 1 yr. Based on a soybean price of $0.23/kg and a fertilizer P price of $1.23/kg, rates of P were calculated for each of the three soils that would maximize net returns for various initial levels of extractable P. As these rates differed markedly with clay content, a soil test interpretation was created by multiple regression based upon both Mehlich 1 extractable P concentration and clay percentage to predict a recommended rate of fertilizer phosphorus (R) as follows: R = 80 − 2.57(soil P) + 0.01386(clay)2 − 0.003281(soil P)(clay2). This function should be applicable to many soils with similar clay characteristics.
Effect of Clay Content in Soil on Boron Uptake and Yield of Wheat
Authors: Keren R. , Bingham F. T. , Rhoades J. D. 
Published: July 2010

AbstractThe effect of total B content in soil on B uptake by wheat (Triticum aestivum L.) and its effects on yield were studied for three soil‐sand mixtures at soil‐to‐soil + sand ratios of 1:3, 2:3, and 1. The results indicate that the higher the clay content of a soil, the lower is the B activity in solution for any given amount of B added. It was suggested that the soil adsorption sites act as a pool to which B can be stored or removed depending on the change in solution B concentration in soil. The B uptake by the plants is higher as the sand content increases, for any total amount of B added. However, the experimental results from all three soil‐sand mixtures lie on the same line when the B content in the shoot is plotted against B activity in soil solution (r2 = 0.9695). The dry matter of the plants was decreased with both an increase in total amount of B added and an increase in the sand content for any given amount of total B. As found for B uptake, the relative dry matter weight and the relative yield values lie on the same linear line when they are plotted against B activity in soil solution from all three soil systems. This indicates that the yield responds to B activity in soil solution only.
Late Season Heat Flux and Water Distribution in Summer‐fallowed Haploxerolls
Authors: Pikul J. L. , Allmaras R. R. , Waldman S.E. 
Published: July 2010

AbstractThe depth position and supply of water are especially critical soil management goals for fall‐sown crops in a semiarid climate such as the Pacific Northwest of the USA where precipitation during late summer and early fall is not a reliable source of water for germination. Soil heat flux and water distribution were measured from 1 August to 1 November in a summer‐fallowed soil which was cultivated several times with a rodweeder to create a loose soil mulch layer. Soil heat flux in the top 60 cm was measured using a combination of the temperature gradient method at 35 cm and calorimetry to obtain the flux at 1 cm. Daily soil heat energy at the 1‐cm depth ranged from 710 kJ/m2 on 2 August during clear weather (and with a dry soil mulch) to − 300 kJ/m2 on 3 October, a clear day following a 30 mm rain. An additional daily heat energy of about 1000 kJ/m2 was used on 2 August to evaporate 0.42 mm of water; on 3 October, the estimated additional daily heat energy to evaporate 0.98 mm of water was 2400 kJ/m2. Soil water evaporation was measured during a wet and dry late summer season when the 0‐ to 9‐cm mulch layer had respective average water contents of 0.15 and 0.05 cm3/cm3. Evaporation rates for comparable time periods during the dry year were generally one‐third of the evaporation rate measured during the wet year. Light rain during late summer and early fall did not add significantly to stored soil water, because recharge and evaporation occurred mainly above the seedzone depth. Soil water evaporation rate during the wet year did not change appreciably from early September to early October even though potential evaporation declined 40%; this comparison period had similar rainfall amounts and antecedent soil moisture. When there were no late season rains to consolidate the mulch layer, the evaporation rate during September and October ranged near 0.15 mm/d. Soil water conservation benefits of the soil mulch disappear following rains that consolidate the mulch layer.
Surface Soil Removal and Herbicide Treatment: Effects on Soil Properties and Loblolly Pine Early Growth
Authors: Tuttle C. L. , Golden M. S. , Meldahl R. S. 
Published: July 2010

AbstractNeither soil removal nor herbicide treatment alone significantly increased loblolly pine (Pinus taeda L.) seedling height after 3 yr, although in combination they did increase height. Soil removal and herbicide treatments produced significantly higher 3‐yr volumes, apparently due to nonpine plant competition reduction. Removal of 2.54 or 7.62 cm of surface soil resulted in significant decreases in Ca, K, Mn, P, N, and organic matter in the surface 30 cm after three seasons. Mobile nutrients (Ca, Mg, and K) were also apparently leaching through the surface layers on the removal treatments. Surface soil bulk density was increased by soil removal. Soil nutrient concentrations decreased and bulk densities increased as the quantity of soil removed increased. The degree of nutrient and organic matter reductions imply that the total site potential may have been lowered, particularly on the heavy soil removal treatment.
Extractable Soil Nitrogen Following Clear‐cutting and Burning in a Beech Forest
Authors: Phillips M. J. , Goh K. M. 
Published: July 2010

AbstractNitrogen (N) mineralization was monitored in the humus layer and soil in an undisturbed and harvested beech (Nothofagus) spp. forest in the West Coast of the South Island of New Zealand. To assess the effects of different harvesting regimes and intensities of burning on N mineralization, treatments applied were (i) Podocarpus spp. clear‐cutting; (ii) Podocarpus spp. clear‐cutting and prescribed burning; (iii) harvesting to chipwood standard (10‐cm dbh); and (iv) chipwood logging and prescribed burning. Nitrate was found to be negligible in fresh and field‐incubated humus and soil samples in the undisturbed beech forest. Ammonium predominated in both the humus layer and soil. Clear‐cutting, and clear‐cutting and burning increased NH+4‐N. The burning effect was confined mainly to the humus layer.
Sampling Ports for An Instrumented Lysimeter System
Authors: Robbins C. W. 
Published: July 2010

AbstractAn improved method for mounting ceramic‐moisture sampling cups and soil‐atmosphere sampling tubes in lysimeters is described. The 0.31‐m diam by 1.18‐m deep lysimeters were constructed from low pressure polyvinyl chloride irrigation pipe (PVC) and contained soil 1.0‐m deep. Tensiometer tubes with attached cups, and open‐ended pyrex gas sampling tubes were installed at three depths, using sealing ports in the lysimeter walls. The sealing ports were constructed from half of a PVC pipe compression coupler. This system allows for inserting the sampling cups and tubes after the soil has been added and settled. The sampling equipment can also be removed before the soil is sampled and removed when studies are completed. Individual sampling units can also be removed for cleaning or repair during the study without disrupting lysimeter operation. This was not possible with earlier described lysimeter systems.
Calibrating Ground Penetrating Radar Data for Soil Applications
Authors: Zobeck T. M. , Lyon J. G. , Mapes D. R. , Ritchie A. 
Published: July 2010

AbstractA ground penetrating radar system (GPR) was tested in two soils to determine the accuracy of GPR measurements and to demonstrate a simple technique to calibrate the instrument. The GPR was used to identify a buried auger in a relatively dry loamy‐skeletal and a relatively moist fine‐silty soil. Radar measurements, on the average, were within 3 cm of the actual depths measured in adjacent soil pits.
Evaluation of a Field Method for Determining the Gas Diffusion Coefficient in Soils
Authors: Jellick G. J. , Schnabel R. R. 
Published: July 2010

AbstractAn in situ method, based on spherical diffusion of gas from an injection point, was evaluated for determining the diffusion coefficient of N2O in field soils. It was found that the analytical solution for spherical diffusion used previously with this method assumes unrealistic initial conditions to calculate concentration of gas at the injection point with time. A finite‐difference model was developed that incorporated initial conditions based on experimental data. Concentrations predicted by the model matched measured concentrations of N2O more closely than concentrations predicted by the analytical solution as determined by the mean absolute difference between predicted and measured concentrations. Mean absolute differences using the numerical model avg 2.4% as compared to 5.2% using the analytical model. Diffusion coefficients determined with the method were reproducible and compared well with those determined by a common laboratory core technique using sand and undisturbed soil cores. The in situ method is a rapid, nondistructive procedure for the determination of gas diffusion coefficients. The method gives reproducible results and is especially useful when many data are needed to determine the spatial or temporal variability of diffusion coefficients in the field.
Ammonia Volatilization from Nitrogen Sources Applied to Rice Fields: II. Floodwater Properties and Submerged Photosynthetic Biomass
Authors: Fillery I. R. P. , Roger P. A. , De Datta S. K. 
Published: July 2010

AbstractThe effects of (NH4)2SO4, urea, and urea amended with the urease inhibitor, phenyl phosphorodiamidate (PPD), on floodwater properties were studied concurrently as part of a field NH3 volatilization study. In the (NH4)2SO4 treatment the maximum concentration of ammoniacal‐N in the floodwater (≃ 50 g N m−3) occurred immediately after its application to the floodwater. Thereafter, floodwater ammoniacal‐N concentrations declined rapidly and were negligible 6 d after the application of (NH4)2SO4. Ammoniacal‐N concentrations in the urea treatment reached maxima of ≃ 12 g N m−3, 3 to 5 d after urea was applied and then declined steadily to negligible concentrations in 7 d. Application of PPD (1% wt/wt) along with urea delayed the buildup of ammoniacal‐N in floodwater until 5 to 7 d after N was applied although the maximum ammoniacal‐N concentration in the floodwater was comparable to that obtained in the urea treatment. Floodwater pH displayed a marked diurnal pattern throughout the experiment in the urea‐amended and background fields. In contrast, pH in the floodwater in the (NH4)2SO4‐amended field was buffered at ≃ 8.00 for the first 2 d, probably because high concentrations of NH4HCO3 formed in floodwater. Diurnal fluctuations in pH prevailed after 3 d when ammoniacal‐N concentrations had declined substantially. The partial pressures of NH3 (pNH3) in the floodwater in all treatments were synchronized with diurnal temperature and pH changes in the floodwater. The maximum pNH3 in floodwater was similar in both the (NH4)2SO4‐ and urea‐amended fields even though ammoniacal‐N concentrations were initially significantly higher in the former. Total titratable alkalinity in floodwater increased after urea and urea/PPD were applied but declined following the application of (NH4)2SO4. The initial levels of alkalinity in floodwater were double the content of alkalinity in irrigation water, and it is surmised that evaporation and/or respiration contributed significantly to alkalinity in the floodwater. Enumerations of algae present in the flooded soil showed the biomass to be small and dominated by non‐N2‐fixing blue‐green algae (Syanophyceae). This biomass, however, was associated with marked diurnal fluctuations in floodwater pH, which coupled with the accumulated alkalinity, were the major factors contributing to the rapid NH3 loss following the application of (NH4)2SO4 and urea to the floodwater.
Nitrogen Release from Urea and Sulfur‐coated Urea in Jack Pine Forest Humus
Authors: Foster N. W. , Beauchamp E. G. 
Published: July 2010

AbstractUrea and sulfur‐coated urea (SU) were each applied in the spring at a rate equivalent to 200 kg N ha−1 to a separate set of replicated 1‐m2 plots in a 50‐yr‐old boreal jack pine (Pinus banksiana Lamb.) forest. Fertilizer N recovery in L, F, and H horizons was determined periodically over 4 yr. Urea was completely hydrolyzed in soil within 10 d, whereas incompletely dissolved SU pellets, containing N equivalent to approximately 10% of the amount added, were recovered from the humus horizons 447 d after fertilization. In urea‐treated humus, NH+4‐N concentrations significantly greater than those in controls were observed for 57 d. In SU‐treated humus, NH+4‐N concentrations significantly greater than those in a control were maintained for 477, 336, and 115 d in L, F, and H horizons, respectively. Initial (3 d) NH3 volatilization from SU‐treated soil was only 17% of that observed in the urea treatment, presumably because slower release from SU granules resulted in lowere initial pH increases in L and F horizons.
Laboratory Apparatus for Preparing and Dispensing Nitrogen‐15‐labeled Anhydrous Ammonia
Authors: Norman R. J. , Kurtz L. T. 
Published: July 2010

AbstractAn apparatus and a procedure are described for preparing liquid anhydrous NH3 (LAA) of a desired 15N concentration and a cold‐jacketed syringe for dispensing the LAA. Preparation of LAA was accomplished by reacting 15N‐labeled (NH4)2SO4 (30‐50 atom % 15N) with a 2 M NaOH solution and allowing the resultant 15N‐labeled NH3 gas to mix with reagent grade anhydrous NH3 gas dispensed from a lecture bottle (38.5‐ by 5.1‐cm cylinder). The resulting gas mixture was condensed and drained into a collection vessel from which it could be withdrawn, measured, and dispensed with specially built cold‐jacketed syringes. With the apparatus and procedure described here, 10 mL of LAA containing 0.7 to 2.0 atom % 15N can be prepared and applied quantitatively in amounts ranging from 25 (15.21 mg NH3‐N) to 500 µL (296.98 mg NH3‐N). A detailed description of how to construct and operate the 15N‐labeled LAA preparation apparatus and dispensing syringes are discussed.
A Stainless‐Steel Soil Solution Sampler for Monitoring Pesticides in the Vadose Zone
Authors: Smith C. N. , Carsel R. F. 
Published: July 2010

AbstractA design for an in situ soil solution sampler (suction lysimeter), consisting of a stainless steel tube with a 0.1 MPa (−1.0 bar), high‐flow, porous ceramic cup, is presented for use in monitoring pesticide or other dissolved chemical leaching in the vadose (unsaturated) zone. The sampler is of one piece construction with the porous ceramic cup attached by epoxy adhesive. The design permits collection of a total volume of up to 0.5 L of soil solution per sample. Laboratory studies indicated that pesticide sorption on the sampler was insignificant and no analytical interference problems were observed. The samplers were designed to monitor leaching of pesticides and inorganic tracers in an on‐going field study in southwest Georgia. Successful field performance of 60 installed samplers (depths of 1.5, 2.1, and 2.7 m) was demonstrated during the 1984 cropping year. Soil solution sample volumes of 10 to 500 mL were obtained during one 24‐h sampling period with vacuums of 0.015 and 0.020 MPa.
Characterization of Compacted Soil Using Sorptivity Measurements
Authors: Walker Jon , Chong S. K. 
Published: July 2010

AbstractResearch was conducted on reconstructed soil cores compacted at varying levels of water content and static pressure. The pressure levels were chosen in an effort to simulate the static conditions that might occur during field cultivation and forest logging operations. Sorptivity, So, and void ratio, e, were measured from the soil cores. The statistical analysis showed that both sorptivity and void ratio showed similar responses to different degrees of soil compaction and there was a correlation coefficient of 0.89 between So and e. The result also showed that sorptivity was more sensitive to the change in soil structure than in soil‐water content.
Models for Predicting Potentially Mineralizable Nitrogen and Decomposition Rate Constants
Authors: Deans J. R. , Molina J. A. E. , Clapp C. E. 
Published: July 2010

AbstractTwo equations, a single exponential: Nt = No (1 − e‐kt) and a double exponential: Nt = No S (1 − e‐kt) + No (1 − S)(1 − e‐kt), were used to compare mineralization potentials of soils, where Nt is the N mineralized in time (t), No is the potentially mineralizable N, and S and (1 − S) are the fractions of the labile and recalcitrant organic N compounds decomposing at specific rates h and k, respectively. Data were obtained from the published and unpublished incubation studies of Stanford and Smith (MD), Smith et al. (WA), Deans et al. (MN), El‐Haris et al. (US), and Griffin and Laine (CT). The double exponential equation provided the “best fit” of the N mineralization‐time (Nt/t) curve as determined by the estimated mean square error (MSE). With long‐term (>84 d) incubations, Nt/t curves for the double exponential equation resulted in an avg MSE of 6 compared with the single exponential equation (avg MSE of 79) for CT, MN, and MD data sets (n = 20). For short‐term (≤84 d) incubations, Nt/t curves were better estimated by the double exponential (avg MSE = 4, n = 21) than by the single exponential (avg MSE = 12, n = 13) for WA, US, and MN data.
Soil Sorting by Forty‐five Years of Wind Erosion on a Southern New Mexico Range
Authors: Hennessy J. T. , Kies B. , Gibbens R. P. , Tromble J. M. 
Published: July 2010

AbstractThis paper presents the fractional composition of soil lost from wind erosion for a 45‐yr period on mesquite sand dune rangeland in south‐central New Mexico. In addition, an equation was developed for defining the soil loss by particle size. Three arbitrarily chosen groups (deposition, noneroded, and eroded) were used to categorize the sampling locations. Net soil loss was in excess of 4.6 cm/ha. Maximum deposition was 78.6 cm and maximum erosion was in excess of 61.9 cm. The sand fraction was divided into three particle size classes. There was a significantly greater amount of the 0.5‐ to 0.05‐mm sand fraction in the deposition site than in either the eroded or non‐eroded sites. No net loss of sand from the experimental site was measured. The silt fraction was significantly greater in the noneroded and eroded sites than in the deposition site, indicating removal of the silt fraction by wind erosion. Wind erosion occurring on the site is resulting in a more sandy textured soil.
Development of Particle‐size Distributions in Some Alfisols of Southeastern Australia
Authors: Walker P. H. , Chittleborough D. J. 
Published: July 2010

AbstractParticle‐size distributions of 20 soils in southeastern Australia were studied to determine whether Alfisols had consistent characteristics, and to examine the changes in clay and nonclay fractions with soil age. Particle‐size intervals, based on the logarithmic phiscale, were chosen to give adequate details of size distributions. The A horizons of three Alfisols with strong textural contrast from erosional and depositional landscapes (group I) had essentially one size mode in the nonclay range. The Bt horizons had bimodal particlesize distributions with a strong mode in the 0.06‐ to 0.12‐ or 0.12‐ to 0.24‐µm size classes and another in the nonclay range. Other subsoil horizons were less clearly bimodal. Seventeen soils from four river terrace sequences (group II) ranged from unmodified alluvium of valley floors (Fluvents) to soils with strong textural contrast (Us‐talfs) on Pleistocene terraces. The A horizons of these soils generally had one particle‐size mode in the nonclay range. With increasing soil age and textural differentiation, the particle‐size distributions of B horizons were more strongly bimodal with clay‐size populations similar to the Bt horizons of soils in group I. Only one clay‐size population occurred in Bt horizons with an upper size limit close to 2 µm. Although enriched, the fine clay fraction (<0.2 µm) was not identified as a size population separate from coarse clay (0.2‐2 µm). Development of Bt horizons is envisaged here as progressing from an initial translocation of the clay inherited from parent materials to intensive weathering and size reduction of clay particles in response to strong seasonal fluctuations in soil moisture.
Wheat Residue Loss for Chemical and Stubble‐mulch Fallow
Authors: Tanaka D. L. 
Published: July 2010

AbstractSurface placement of wheat (Triticum aestivum L.) residue can be an effective practical method for erosion control in the semiarid Plains. Therefore, a study was conducted to determine the effect of chemical and stubble‐mulch fallow on residue orientation and decomposition, N and P concentrations, C/N ratios, and to compare straw weight per unit length and stalk population of standing winter wheat residue on chemical fallow plots to that of spring wheat. the study was conducted on a Williams loam (fine‐loamy, mixed Typic Argiborolls) in eastern Montana. Chemical fallow plots were sprayed four times, whereas stubble‐mulch fallow plots were tilled with sweeps, followed by three additional tillage operations with a rod weeder to control weeds. Residue samples were collected and analyzed periodically during 426‐d (14 months) winter wheat fallow and 638‐d (21 months) spring wheat fallow periods. Quantities of winter and spring wheat surface residue on stubble mulch plots decreased 70% from May through July of the year following harvest, while on chemical fallow plots, standing residue decreased and flat residue increased at constant rates. Chemical fallow plots had three times more surface residue for erosion control after 426‐ and 638‐d of fallow than stubble‐mulch fallow plots. About 27 and 8% of the initial winter and spring wheat total residue, respectively, were standing at the end of fallow on chemically fallowed plots. Nitrogen concentration was about 1.3 times greater, and P concentration two times greater for flat residue, than for standing residue.
Debris Avalanching in the Southern Appalachians: An Influence on Forest Soil Formation
Authors: Neary D. G. , Swift L. W. , Manning D. M. , Burns R. G. 
Published: July 2010

AbstractIn early November 1977, a storm system that formed in the Gulf of Mexico moved northeast into the Appalachian Mountains of North Carolina. It produced intense (30–120 mm h−1), heavy rainfall (200–320 mm), which triggered debris avalanching in steep terrain of the Pisgah National Forest. Soil material displaced by the mass wasting was in the order of 2 to 3 × 103 ha−1 along avalanche tracks, which exceeded 1 km in length. Peak stormflows had recurrence intervals ranging from 20 to >100 yr. Factors prominent in development of the storm were evaluated using infrared satellite imagery and rain gauge data. Most debris avalanches on one well‐documented basin originated in shallow Umbric and Typic Dystrochrepts soils on upper slopes and ran out onto Typic Haplumbrepts, Typic Hapludults, and Typic Fluvaquentic Dystrochrepts soils in lower gradient deposition zones. Although debris avalanching in the Appalachian Mountains is a rare phenomenon in human history (100–1000+ yr return period), it is a major and frequent geomorphic process influencing soil formation.