bluuebunny/crossref_metadata_2025_split huggingface dataset:
Morphology and Water Regime of a Dothan Soil
Authors: Guthrie R. L. , Hajek B. F. 
Published: July 2010

AbstractThe water regime in a Dothan soil was characterized by installing piezometers at 137‐, 183‐, and 285‐cm depths. Monthly water table measurements differed for each piezometer throughout a 4‐year study period, indicating a perched water table. There was a water table at the greatest depth on only five occasions during the study period. On all but a few occasions, a water table was encountered at the two shallower depths. Morphological properties and seasonal precipitation were related to the water regime. The perched water table fluctuated in a continuous zone of saturation in the B horizon above the horizons containing appreciable amounts of plinthite. A discontinuous zone of saturation is bounded on the bottom by the B3 horizon. The piezometer that had perforations in the C horizon showed no water table, which indicated that a “dry” zone exists between the perched and regional ground‐water tables. Fluctuations in the depth to perched water corresponded to seasonal precipitation patterns.
A Lithosequence in Coastal Plain Sediments in Alabama
Authors: Hoyum R. A. , Hajek B. F. 
Published: July 2010

AbstractA lithosequence was used to explain the morphology and genesis of soils from the Tuscahoma Sand Formation in Crenshaw County, Alabama. Position‐slope‐geology computer displays were used for sampling and determining the distribution and extent of soils in the analysis area. The Tuscahoma Sand Formation has a locally distinctive topography and suite of soils that are closely related to the characteristics of three outcrop beds on 8–12% side‐slopes. The lower stratum, exposed farthest inland, is dominated by clayey soils. In argillic horizons the CEC ranges from 5.4 to 17.2 meq/100 g even though smectites dominate in one profile. Fine‐loamy soils with siliceous mineralogy dominate the middle stratum. The youngest sediments, superpositioned above the middle stratum, are clayey with mixed mineralogy. The pH of argillic horizons ranged from 4.9 to 5.2. All clayey soils were Hapludults while the fine‐loamy soils are now classified Paleudults; however, morphological properties suggest that all soils studied may be Hapludults. With all other soil‐forming factors relatively constant, the differences encountered in soils across the study area relate directly to parent material.
Rates of Weathering and Soil Formation on Granite in Rhodesia
Authors: Owens L. B. , Watson J. P. 
Published: July 2010

AbstractRates of weathering and soil formation on granite were studied in two areas of Rhodesia using small watersheds. The Juliasdale watershed of 0.91 km2 is hilly and has a mean annual rainfall of 1,220 mm. The Rusape watershed of 7.33 km2 is more nearly level and has a mean annual rainfall of 920 mm.Streamflow was measured in the two catchments over a period of at least 7 years. Streamwater, rainwater, soil, and rock samples were analyzed for Ca, Mg. K, Na, Si, and Al.The rate of granite weathering was calculated using Barth's equation which links the rate of weathering to the amount of an element removed in solution per unit time, its concentration in the rock and its concentration in the weathered product. Sodium and Ca were the elements used in the Barth equation. The weathering rates in the Juliasdale and Rusape watersheds were estimated at 400 and 150 kg/ha per year, respectively, or 15.4 and 5.8 mm/1000 years. The concepts of C. E. Marshall and J. F. Haseman as well as S. W. Buol include changes in bulk density during the weathering process and give soil formation rates more acceptable than those of Barth. Thus, the rate of soil formation was found to be 11.0 mm/1000 years in the Juliasdale watershed and 4.1 mm/1000 years in the Rusape watershed.
Aqueous Solubility Studies of Muscovite: Apparent Nonstoichiometric Solute Activities at Equilibrium
Authors: Mattigod S. V. , Kittrick J. A. 
Published: July 2010

AbstractSolubility studies were conducted on three different muscovites. The experiments were designed to conform with a number of well‐established criteria for studying the equilibrium solubility of sparingly soluble compounds. The compositions of the aqueous phase in contact with mixtures of muscovite and a synthetic gibbsite of known solubility, were monitored for over a period of 2 years. At the start of the experiments, the solid phases were characterized by various techniques such as chemical analysis, optical microscopy, X‐ray diffraction, infrared spectroscopy, and electron microscopy. The solids present at the end of the experiments were also examined. Free ion activities and activity ratios were computed from the measured total concentrations of various solutes. The attainment of equilibrium between the solid phases and the solution phase were established by rigorous chemical criteria. Analysis of the equilibrium solubility data indicated that the observed solute activity ratios were incompatible with the dissolution reaction based on the original chemical composition of muscovite. The stoichiometry of the muscovite phase was derived from solution equilibria and the standard free energy of formation of this phase was calculated to be −5501.1 kJ/mol.
Oxidation of Liquid Animal Wastes in Soil
Authors: Kowalik P. , Barnes C. J. , Smiles D. E. 
Published: July 2010

AbstractA theory of oxygen diffusion in soil in which the oxygen consumption rates varies with time was applied to describe the oxidation of liquid animal wastes in a soil irrigated by a slurry of pig manure. Soil column experiments with a pig slurry of known biochemical oxygen demand (BOD) showed that the aerobic return of the soil atmosphere composition to that approaching air is described by analytical solutions of the diffusion equation with a time‐dependent sink term. The aerobic and anaerobic zones can be determined in the soil profile according to the solutions given for the transient state in two cases: (i) when uptake of oxygen is uniformly distributed over the soil profile; and (ii) when uptake of oxygen is limited to the upper part of the soil profile. These solutions may be used to determine maximum BOD loads for soils irrigated by waste water with relatively high organic content.
Phosphorus Response of Corn on an Oxisol as Influenced by Rates and Placement
Authors: Yost R. S. , Kamprath E. J. , Lobato E. , Naderman G. 
Published: July 2010

AbstractPhosphorus deficiency and high P sorbing capacities are a major limitation to intensive cropping of many soils in the Cerrado area of Central Brazil. A field study comparing rates and placement of P for corn (Zea may L.) was conducted to determine initial and long‐term P fertilization requirements. Rates of broadcast P were 70, 140, 280, and 560 kg P/ha and banded rates were 35, 70, and 140 kg P/ha. In addition, combination treatments of 140 or 35 kg P/ha broadcast and banded rates of 35 kg/ha per crop were used.Broadcast treatments gave greater yields than band treatments at the same rates for the first crop. At the end of four crops, however, total yields and P uptake were very similar for broadcast and band treatments in which the same total amount of P had been applied. Marked residual effects were observed with the higher rates of broadcast P.A greenhouse study was conducted in which a given amount of P was mixed with varying proportions of the total soil volume. Corn growth and P uptake were a function of both the concentration of P in the portion of the soil fertilized and the percent of the total soil volume that was fertilized. These results tend to explain the increase with time in relative yields of the banded treatments.The best method for applying P to these high adsorbing soils appears to be an initial broadcast application of 140 kg P/ha and a band application of 35 kg P/ha to each crop. This treatment maintained the available soil P at the critical soil test level and produced 80 to 85% of the maximum yield.
Estimating Animal Waste Applications to Supply Crop Nitrogen Requirements
Authors: Mathers A. C. , Goss D. W. 
Published: July 2010

AbstractAn equation was developed which estimates the amount of animal waste required to supply the desired amount of N for crops. This equation was based on annual mineralization rates which varied with time after application and with N content of the waste. When we calculated waste requirements to supply N needs using the equation, values were satisfactory for wastes containing 4% or less N. Residual N in soil fertilized with animal waste was closely correlated (r = 0.92) with values predicted by the equation.
An Aberrant Toposequence of Soils through a Titi Swamp
Authors: Coultas C. L. , Clewell A. F. , Taylor E. M. 
Published: July 2010

AbstractThree Great Groups of soil, Humaquepts, Haplaquods, and Psammaquents, were found on a traverse through a titi swamp in north Florida. The Humaquept occurred in the lowest, wettest position and plants of Cyrilla racemiflora L. and Nyssa biflora Walt, were largely restricted to these soils. These soils were extremely acid, low in extractable bases, well supplied with organic C, and highest in clay content. Haplaquods occurred in a higher position with better drainage. On these soils vegetation included Cliftonia monophylla (Lam.) Sarg., Magnolia virginiana L. and Myrica inodora Bartr. inside the titi swamp, and outside the swamp, species common to the pine flatwoods. These Haplaquods were acid and low in extractable bases. They contained less organic C and clay than the Humaquept. The Psammaquents were the best drained due to their high position and coarse texture. They contained the least organic C.Evidence is presented which indicates that the titi swamp has encroached into areas formerly vegetated with pine flatwoods. This was probably due to recent fire control and wetter soil conditions.
Water Use and Yields of Sugarbeets Over a Range from Excessive to Limited Irrigation
Authors: Ehlig C. F. , LeMert R. D. 
Published: July 2010

AbstractWater use and sucrose yield of sugarbeets (Beta vulgaris L. cv. USH 10) as a function of decreasing water applications were investigated to determine if sucrose yield per unit of water use would increase with limited irrigation. The sugarbeets were fall‐planted in a silty clay soil and irrigated uniformly for 6 weeks to establish seedling stands and to wet soil to the 152‐cm depth. Thereafter, 102 mm water was applied whenever cumulative ET from sugarbeets growing in an adequately watered weighing lysimeter reached 91, 102, 112, 122, 133, or 143 mm water. Soil was sampled to the 152‐cm depth, in 30.5‐cm increments, before each irrigation after 12 November and at harvest. Water use was calculated from changes in soil water content between irrigations and applied water.Water applications, after the initial uniform applications, varied from 609 to 940 mm in six to nine irrigations plus 25 mm rainfall. Water use was linearly related to lysimeter ET. During differential treatment, water use varied from 11% above to 23% below the amount needed to replace lysimeter ET. Total seasonal water use varied from 900 to 1,195 mm. Lysimeter ET averaged 67% of pan evaporation after leaves completely covered the soil. Neither sucrose content nor yield was affected by irrigation treatments. Sucrose yields averaged 13 and 18 metric tons/ha on 14 May and 24 June, respectively. With limited irrigation, sucrose yield per unit of water use increased as much as 22% above the treatment that matched lysimeter ET. The soil salinity did not increase sufficiently to require immediate leaching for any of the treatments.
Factors Affecting Nitrate Nitrogen and Chloride Leaching Variability in a Field Plot
Authors: Cameron D. R. , Kowalenko C. G. , Campbell C. A. 
Published: July 2010

AbstractNitrate nitrogen and chloride concentrations were monitored in a 3‐year field study in order to examine factors affecting their variability. Fertilized and control plots, established each year, were sampled at least eight times throughout the year by removing about six‐replicate soil cores for individual analyses each sampling time. It was found that non‐uniform fertilization application accounted for 38 to 100% of the sampling variability immediately after fertilization. In fall and spring, differential rates of leaching of NO3‐N and Cl appeared to contribute significantly to variability increasing C.V.'s from about 40% to over 100%. Field and model results showed that differential leaching patterns could be attributed to two main factors: (i) variability of physical properties that determine water storage and transport, and (ii) point differences in redistribution of incoming rain (runoff) due to differences in surface microrelief.
Effects of Burning on Chaparral Soils: II. Soil Microbes and Nitrogen Mineralization
Authors: Dunn Paul H. , DeBano Leonard F. , Eberlein Gary E. 
Published: July 2010

AbstractUndisturbed moist and dry soil slabs collected from beneath two species of chaparral plants were burned at varying intensities in the laboratory. Treatment by intense burning over dry soil destroyed 67% of the total N and produced large amounts of NH4+. Treatment by intense and moderate burning over moist soil slabs removed only 25% of the total N, and a large portion of the remaining organic N was quickly ammonified after the fire by reinvading heterotrophic bacteria and later by fungi. All three burning treatments resulted in high levels of NH4+ in the soil after the fire. Nitrosomonas group bacteria did not respond to these high levels of available NH4+, and the nitrification that occurred was attributed to heterotrophic nitrification.
Tolerance of Rhizobia to Acidity, Aluminum, and Phosphate
Authors: Keyser H. H. , Munns D. N. 
Published: July 2010

AbstractLow levels of phosphorus and high levels of aluminum are important soil acidity factors for the growth of higher plants; however, very little is known about their effects on the soil rhizobia. The present study was conducted to determine the relative effects of acidity, P, and Al on rhizobia. Tolerance of low pH (4.5), low P (5–10 µM), and high Al (50 µM) was assessed for 10 strains of cowpea rhizobia by detailed growth studies in defined liquid media. Tolerances to these factors were determined for 65 strains of cowpea rhizobia and Rhizobium japonicum by a rapid method based on attainment of turbidity from a small inoculum. Strains varied in response. Low P (as compared with 1,000 µM) limited total attainable population density to 5 × 107 cells/ml, and slowed the growth of some strains. Acidity generally increased lag time or slowed growth of most strains, and stopped growth of about 50% of them. Tolerance of acidity did not necessarily entail tolerance of Al. Aluminum (50 µM) increased the lag time or slowed growth of almost all strains tolerant of low pH. It virtually stopped growth of 40% of the strains.With our system the rhizobia had to make 1,000‐fold growth in the stress media before they could significantly raise pH and precipitate Al. A valid rapid screening can be based on ability to attain visible turbidity in culture under acid or Alstress, so long as initial density is small (<<105 cells/ml). The cowpea rhizobia tended to have more tolerance to Al than R. japonicum and overall Al was a more severe stress than low pH or low P.
Growth, Water Relations, and Yield of Wheat Planted in Four Row Directions
Authors: Erickson P. I. , Kirkham M. B. , Stone J. F. 
Published: July 2010

AbstractWheat (Triticum aestivum L. em. Thell. ‘Osage’) was planted in north‐south, northwest‐southeast, east‐west, and southwest‐northeast directions, using a wheel layout, to determine the effect of row orientation on height, leaf water potential, stomatal resistance, and yield of winter wheat exposed to the normally strong north and south winds of central Oklahoma.Before plants started to grow rapidly in the spring, wheat in north‐south rows was about 1 cm taller than wheat in the other row directions. After plants started to grow rapidly, wheat in north‐south rows was 2‐ to 6‐cm taller than wheat in the other rows. Leaf water potentials of wheat oriented in north‐south rows were, on an average throughout the spring of the experiment, 2.8, 2.9, and 2.1 bars higher (less negative) than potentials of leaves oriented in other rows for 1000‐, 1300‐, and 1600‐hour readings, respectively. Stomatal resistances of leaves of wheat oriented in north‐south rows were, on an average throughout the spring of the experiment, 0.2, 0.7, and 0.2 sec/cm lower than those of leaves oriented in other row directions for the 1000‐, 1300‐, and 1600‐hour readings, respectively. The east‐west plantings had about a 10% higher yield than the north‐south rows.
An Error Analysis of the Photographic Technique for Measuring Percent Vegetative Cover
Authors: Lee Williams T. H. 
Published: July 2010

AbstractA vertical overhead ground photographic technique was developed to determine percent vegetative ground cover. Acquisition of the photographs is rapid and simple and the technique is well suited to situations where simplicity and speed in the field are necessary. A vegetative canopy model was used to derive a measure of the errors inherent in the technique. The degree of error is related to the canopy structure and is at a minimum in dense canopies.
Comparative Performance of Nitrogen Sources on Smooth Bromegrass and Tall Fescue
Authors: Lamond R. E. , Murphy L. S. , Swallow C. W. , Kelley K. W. 
Published: July 2010

AbstractStudies were initiated in 1973 at two locations in eastern Kansas to evaluate the performance of five N carriers as sources of N for bromegrass (Bromus inermis L.) and tall fescue (Festuca arundinacea Schred.). Late winter applications of ammonium nitrate, urea, urea‐ammonium nitrate solution (UAN), sulfur‐coated urea (SCU), and urea‐ammonium sulfate (UAS) were compared at rates of 67, 134, and 201 kg N/ha.Excellent visual responses to applied N were evident in both years. Total yields of forage generally increased with N applications up to 201 kg N/ha. The response to N decreased as the rate was raised from 134 to 201 kg N/ha. Maximum economic return from the application of N occurred at a level of about 134 kg N/ha. No clear‐cut superiority was established for any N carrier. Sulfur‐coated urea performed well on tall fescue but less effectively on bromegrass. Although there was evidence of delayed release of N from SCU, its efficiency as measured by total yield was similar to conventional N sources. The effectiveness of a carrier was influenced by location, environmental conditions, and grass species.
Chemisorption and Precipitation of Mn2+ at CaCO3 Surfaces
Authors: McBride M. B. 
Published: July 2010

AbstractThe adsorption of Mn2+ on two samples of powdered calcite with different surface areas has been studied using atomic absorption and electron spin resonance spectroscopy to investigate the solution and mineral phases. Chemisorption of Mn2+ on CaCO3 surfaces lowered the solubility of Mn2+ below the level expected for MnCO3 precipitation. At high levels of Mn2+ in solution, after saturation of surface sites, nucleation at CaCO3 surfaces seemed to occur, followed by slow precipitation of separate phase MnCO3. The preference of calcite for Mn2+ relative to Ca2+ decreased with increasing Mn2+ absorption. The results indicate the importance of the surface area of the solid phase in determining the quantity of Mn2+ adsorbed and the final solution concentration.
Methods for the Production and Use of Nitrogen‐13 In Studies of Denitrification
Authors: Tiedje J. M. , Firestone R. B. , Firestone M. K. , Betlach M. R. , Smith M. S. , Caskey W. H. 
Published: July 2010

AbstractMethods were developed for use of the radioactive isotope of nitrogen, 13N, for short‐term studies of denitrification. 13N was generated by irradiation of water with 12 to 15 MeV proton beams from a sector‐focused cyclotron. Under typical operating conditions of 0.7 to 3 µA beam currents for 10 min, the 13N ionic species produced were NO3‐, 75–90%; NO2‐, 5–10% and NH4+, 0.5–25%. Traces of [13N] N2O and [13N] N2 were also produced. The measured yield varied from 2 to 16 mCi/10 min irradiation depending on beam current. Vacuum evaporation at high pH was used to obtain 13NO3‐ + 13NO2‐ at > 99.8% purity, and high performance liquid chromatography (HPLC) was used to obtain 13NO3‐ or 13NO2‐ at > 99% purity. The HPLC system used a Partisil SAX anion exchange column eluted with phosphate buffer at pH 3.0 and was coupled to a coincidence NaI(T1) detector for counting 13N species in the effluent. Separation of NH4+, NO2‐, and NO3‐ was achieved within 5 min. This system was used to monitor purity of 13N substrates and for studies of dissimilatory nitrate reduction to ammonia. A gas chromatograph‐proportional counter detector system was developed to separate and measure [13N] N2, [13N] N2O and 13NO. Separation was by Poropak Q and Molecular Sieve 5A columns and was achieved in 5 min. Denitrification rates and products of soils and bacterial cultures incubated in sealed flasks were monitored with this system. Continuous rates of [13N] N2 and [13N] N2O production were monitored using a differential trapping, gas stripping system. Soil slurries amended with 13NO3‐ or 13NO2‐ were stripped of gases by continuously sparging with helium. N2O was collected in a liquid nitrogen trap. Nitrogen gas passed through this trap but was retained in a Molecular Sieve trap immersed in liquid nitrogen. 13N gases collected in each trap were continuously counted by NaI (T1) detectors. Linear rates of gas production were typically observed from 15 min after addition of the 13N substrate to termination of the experiment after 1 to 1.5 hours. 13N has the advantage in denitrification studies of allowing direct measurement of N2, very sensitive short‐term rate measurements, and isotope exchange experiments at low substrate concentrations.
Asynchronous Activity of Ammonium Oxidizer Clusters in Soil
Authors: Molina J. A. E. , Gerard G. , Mignolet R. 
Published: July 2010

AbstractAmmonium oxidation by 468 large (0.49 mg) and 416 small (0.12 mg) soil aggregates from an Ochric Epipedon was determined by the Winogradsky silica gel‐CaCO3 plate technique. Activity was spread over 8 weeks. The histogram for the percentage of active soil aggregates presented a maximum after 3 to 4 weeks of incubation. Only 48 and 22% of the large and small aggregates oxidized ammonium, which corresponded to an average of 0.65 and 0.34 clusters of activity per large and small aggregates, respectively. On the average, each cluster in the large and small aggregates harbored 31 and 14 ammonium oxidizer cells, as computed from the MPN values for the ammonium oxidizer cells per g of soil. Enrichment of the soil by preincubation for 8 weeks after the addition of 100 ppm NH4+ induced for the large and small aggregates a 1.5‐ and 1.4‐fold increase in the number of clusters but a 4.6‐ and 4.8‐fold increase in the number of ammonium oxidizer cells per cluster.The results indicate that the kinetics of ammonium oxidation in soil, for the nonsteady state situation, represents the resultant average of pulses of activity from small isolated and asynchronous ammonium oxidizer clusters, in contrast with present models which assume one homogenous, synchronous population of ammonium oxidizer cells in soil.
Mössbauer Studies of Synthetic and Soil‐Occurring Aluminum‐Substituted Goethites
Authors: Golden D. C. , Bowen L. H. , Weed S. B. , Bigham J. M. 
Published: July 2010

AbstractMössbauer spectroscopy of partially Al‐substituted synthetic goethites shows marked variation of the internal magnetic field (H) with Al substitution. Empirical relations are reported which allow using observed H values to estimate % Al in the oxides present in soil clay. Relaxation effects due to small particle size and substitution of Al3+ for Fe3+ complicate the spectra, and in many cases liquid nitrogen or liquid helium temperatures are necessary to resolve the components. However, the relaxation effects observed may be related qualitatively to particle size of the Fe oxides present. The utility of the Mössbauer technique was tested with a number of soil samples containing Al‐substituted goethite.