bluuebunny/crossref_metadata_2025_split huggingface dataset:
Phosphorus Fertility of Some Tropical Soils in Sierra Leone
Authors: McKenzie E. , Kurtz L. T. , Melsted S. W. 
Published: July 2010

AbstractChemical fractions and profile distributions of native phosphorus were determined in some soils of Sierra Leone, West Africa. Total P in the horizons of eight profiles ranged from 70 to 420 pp2m. Distributions within profiles were usually rather uniform, with concentrations tending to be somewhat greater in the surface and deepest horizons. Phosphorus fractions extracted by NH4F and NaOH were typically between 18 and 30 pp2m (6 to 12% of the total P), while the acid‐soluble fraction was virtually absent. On the average, 15% of the total P was in the reductant‐soluble form. Bray P‐1 values ranged from 5 to 25 pp2m P in the surface horizons, but were often < 3 pp2m at depths below 40 cm. A very low proportion of the native P in these soils would be expected to be readily utilized by crops.Estimates were also made of P retention capacities, P equilibrium concentrations in solution, and recovery with the Bray P‐1 extractant of added P after different periods of incubation. Behavior of P in Sierra Leone soils in these procedures was not greatly different from that in some Illinois soils where the management of P fertility has become routine. Attaining and maintaining adequate levels of P in Sierra Leone soils by fertilization would not appear to be difficult, assuming phosphate fertilizers can be obtained.
Pyrite and Pyritic Mill Tailing as a Source of Iron in a Calcareous Iron‐deficient Soil
Authors: Barrau E. M. , Berg W. A. 
Published: July 2010

AbstractMill wastes from ore processing, particularly acid‐forming pyrites, often pose disposal problems. This greenhouse study evaluated pyrite and a pyritic mill tailing as Fe sources on an Fe‐deficient calcareous soil.Pyrite and tailing < 0.1 mm in diameter were applied at rates of 45 and 135 metric ton/ha. Controls, 200 and 600 ppm Fe as Fe2(SO4)3 and 5 and 15 ppm Fe as FeEDDHA, were used as standards. The treatments were seeded with sudangrass (Sorghum vulgare sudanense) and six successive crops were harvested. Sudangrass yields increased 160 to 200% with pyrite and tailing treatments; these yields were significantly greater than the control and were comparable to yields from the other Fe sources. The 5 ppm FeEDDHA treatment, however, increased yield for only the first two crops.Plant‐available soil Fe measured by DTPA extraction increased with all Fe treatments, while the levels of DTPA‐extractable Zn and Mn remained the same or increased slightly. DTPA‐extractable Cu doubled with the high rate of pyrite addition. The concentration of Fe in the plants remained the same or increased slightly with the Fe treatments, while concentrations of Zn, Cu, and Mn all decreased.
Row Spacing and Direction Effects on Water Uptake Characteristics of Peanuts
Authors: Chin Choy E. W. , Stone J. F. , Garton J. E. 
Published: July 2010

AbstractPeanuts (Arachis hypogaea L.) grown in 30‐cm wide, north‐south rows, lost less water to evapotranspiraton than those grown in 90‐cm rows or than east‐west rows of these spacings. Plants grown in 90‐cm wide, north‐south rows tended to have the highest water losses. The reason for this phenomenon was not determined, although there is reason to believe net radiation is lower in narrow rows than wide.Yield of peanuts was enhanced by the narrow rows and no orientation effect on yield was noted. Thus, water‐use efficiency was increased by both yield effect and water conservation effect. Peanut quality was the same for all treatments.There is no reason to believe that the water conserving effect is unique to peanuts. Research on other crops in similar geometries is to be encouraged.
Fate of Urea Fertilizer Added to a Boreal Forest Pinus banksiana Lamb. Stand
Authors: Morrison I. K. , Foster N. W. 
Published: July 2010

AbstractDistribution of N in various components of a 45‐year‐old, relatively pure Pinus banksiana (jack pine) ecosystem on a sandy outwash site, was estimated at various times during the first three growing seasons following fertilization with 300‐kg urea‐N/ha. At the end of the third growing season, N, equivalent to that applied, was distributed as follows: in trees, 23%, in ground vegetation, 1%, in soil organic layers, 26%; and in mineral soil, 10%. An estimated 30% was lost into the atmosphere through volatilization, while the remaining 10% was unaccounted for. Negligible nitrification suggested little likelihood of ground‐water contamination following urea fertilization.
Automatic Feedback Control to Maintain Constant Soil Moisture Tension in the Study of Drought Tolerance in Rice
Authors: Alvarez E. I. , De Datta S. K. 
Published: July 2010

AbstractWe have developed a greenhouse technique by which a chosen soil moisture tension can be maintained continuously. The setup for supplying water at relatively constant soil moisture tension in pots includes five major components—water tank, W‐tube, water distribution system, soil moisture tension sensors, and pots. The W‐tube, which contains a predetermined amount of Hg, controls the soil moisture tension in the pots. Water can flow freely from the tank to the pots through the distribution system whenever the soil moisture tension exceeds that desired. Response to the sensors' demand for water is rapid.We have successfully used this setup to compare relative drought tolerance of rice (Oryza sativa L.) varieties and breeding lines. Another use of this setup might be to measure evapotranspiration (ET) almost instantaneously; the technique might be useful in some soil‐plant‐atmosphere‐water relationship studies.
A Possible Model for the Surface‐induced Hydrolysis of Organophosphorus Pesticides on Kaolinite Clays
Authors: Mingelgrin U. , Saltzman Sarina , Yaron B. 
Published: July 2010

AbstractA model for the hydrolysis of organophosphorus pesticides on clay surfaces is proposed; organophosphate ester molecules are susceptible to hydrolysis of the phosphate ester bond, whereby they are rapidly degraded on the kaolinite surfaces. It is suggested that the organophosphorus molecules undergo hydrolysis by the ligand water associated with the counter ions. Consequently, the degradation process is dependent on the nature of the saturating cation and its hydration status.
Evaluating Weathering Characteristics of Water‐harvesting Catchments from Rainfall‐runoff Analyses
Authors: Fink D. H. , Frasier G. W. 
Published: July 2010

AbstractBetter ways are needed to evaluate the weathering properties of water‐repellent and membrane‐covered water‐harvesting field catchments. Normally, only the ratio of runoff to precipitation from natural storms (percentage of runoff) is calculated, which provides useful information on treatment efficiency and durability, but little about why or how a treatment actually failed. We used linear regression analyses of precipitation vs. runoff‐yield data collected over several years (storms with no runoff omitted) to obtain (i) threshold values, i.e., the minimal rainfall needed to produce runoff, and (ii) the runoff‐efficiencies of treatments after threshold. These analyses showed that silicone and wax‐treated water‐repellent catchments weathered quite differently. The silicone treatment showed a uniform deterioration throughout the treated zone while the wax treatment showed a progressive deterioration beginning at the top of the treated profile. A gravel‐covered membrane catchment gradually increased runoff threshold from 1‐ to 2‐mm water, which was ascribed to a gradual accumulation of dust entrapped in the gravel. The weathering properties of several other common type catchments were evaluated using the technique. A brief discussion is included on the application of the technique to evaluate the accuracy of precipitation‐ and runoff‐measuring devices in water‐harvesting systems.
Biomass and Nutrient Accumulation in a Cottonwood Plantation—the First Growing Season
Authors: Baker James B. , Blackmon B. G. 
Published: July 2010

AbstractDuring their first growing season, eastern cottonwood (Populus deltoides Bartr.) planted at a 3 by 3 m spacing on a slackwater clay soil (Vertic Haplaquept) in western Mississippi produced 3,680 kg/ha of dry matter. Of this, 900 kg/ha was in leaves, 700 in branches, 820 in stems, and 1,260 in roots. Seventy‐six percent of the aboveground biomass was accumulated during August and September. At the end of September, just prior to leaf fall, the trees contained 43.5 kg/ha of N, 4.7 kg P, 34.7 kg K, 36.5 kg Ca, and 6.4 kg Mg. From 62 to 79% of these elements was accumulated in August and September.Foliar N and P concentrations peaked in early summer, then steadily decreased until leaf fall in November. Branch and stem N and P decreased from a maximum in early summer to a low in September, then increased during October and November. Seasonal patterns of Ca and Mg were similar to those of N and P, except that foliar concentrations steadily increased throughout the summer to a maximum at time of leaf fall. Trends in foliar K were similar to those of N and P; however, K concentrations in branches and stems declined through the summer to a low at time of leaf fall.Of the total quantity of N, P, K, Ca, and Mg in the foliage in September, 26% of the N, 33% of the P, 28% of the K, 62% of the Ca, and 51% of the Mg fell with abscised leaves in November. Sixty‐one percent of the foliar N and 53% of the foliar P were translocated to other tissue prior to leaf fall. Potassium, calcium, and magnesium were not involved in internal nutrient cycles since they were not translocated and retained in support tissue. A large portion of the foliar K was apparently leached or lost through root exudation or other means.
Surface Morphology of Quartz and Age of Soils
Authors: Douglas Lowell A. , Platt David W. 
Published: July 2010

AbstractThe surface morphology of quartz sand grains from soils developed from Wisconsin, Illinoian, and Kansan age glacial material and on residual parent materials were studied using scanning electron microscopy. Both solution and precipitation surfaces were observed. Quartz surfaces showed an amount of chemical alteration proportional to the water holding capacity and the age of the parent material. More alteration was found in the A horizons than in the B horizons of the youngest soils studied, while little difference between A and B horizons of very old soils was observed. The surface morphology of quartz sand grains may be used to estimate the age of a soil relative to the glacial periods within the Quaternary.
Programmable Pocket Calculator vs. Computer: A Comparison of Relative Efficiency for Small Jobs in the Soil Characterization Laboratory
Authors: Parker J. C. , Amos D. F. 
Published: July 2010

AbstractA time and cost comparison was made for three methods of performing computations for pipette particle size distribution, clod bulk density, Atterberg limits, and potential volume change (FHA‐PVC Meter). The programmable calculator was more efficient than either a nonprogrammable calculator or a computer using Fortran with card input. The nonprogrammable calculator costs were 1.6 to 5.3 times those using the programmable machine. The computer costs were 2.8 to 10.4 times those of the programmable calculator. In this particular lab, $200 per year was saved using a programmable calculator on these four analyses alone.
Assessing Phosphorus Fertilizer Needs Based on Intensity‐Capacity Relationships
Authors: Lee Yong S. , Bartlett R. J. 
Published: July 2010

AbstractPhosphorus in a pH 4.8 NH4OAc soil extract, through crop response correlation work, may indicate the degree to which a level of P in a given soil is optimum. But, being an intensity measurement, this NH4OAc‐P value does not indicate the amount of P fertilizer needed to bring a soil, which has a particular P sorption capacity, to its optimum level.The relationship between added P and the square root of the NH4OAc‐P, measured after incubation of a given acid or limed soil, was a straight line with a characteristic slope for that soil. The value of this slope, termed the Phosphorus Fertilizer Index (PFI), showed a high correlation with the amount of Al extracted by pH 4.8 NH4OAc (r2=0.94). Inclusion of soil chemical characteristics other than Al in the calculation did not improve the P intensity‐capacity relationships significantly.The usefulness of these relationships in determining P fertilizer needs was verified in an incubation study with 50 acid Ap horizon samples of Vermont soils. This study showed excellent correlations (r2=0.90 and 0.92 for unlimed and limed soils, respectively) between NH4OAc‐P measured in the soils after fertilizer addition and the NH4OAc‐P calculated from the PFI slopes estimated from the Al measured in the same NH4OAc extract.
Microbial Epimerization of Myo‐inositol to Chiro‐inositol in Soil
Authors: L'Annunziata Michael F. , I. Juan Gonzalez , Olivares O. Luis A. 
Published: July 2010

Abstract14Carbon‐(1,2,3,5/4,6)‐inositol (14C‐myo‐inositol) was incorporated into an Andosol sandy loam soil and incubated for a 12‐day period at 70% field moisture capacity under sterile and nonsterile soil conditions. Comparison by thin‐layer chromatography of an isolated metabolite with an authentic standard and infrared spectrometry were used to identify the metabolite as 14C‐(1,2,4/3,5,6)‐inositol (14C‐chiroinositol) of unknown optical activity. The 14C‐chiro‐inositol was identified in the biologically active soil. No epimerization of 14C‐chiroinositol was observed in sterile soil. The abundance of the 14C‐chiroinositol was approximately 4% relative to that of the parent compound, as determined by liquid scintillation counting of the two chromatographically separated compounds.
A Survey of the Fertility Status of Surface Soils Under “Cerrado” Vegetation in Brazil
Authors: Lopes A. S. , Cox F. R. 
Published: July 2010

AbstractAgriculture is becoming more intensive in central Brazil, but there is little information available on the fertility status of most of the soils. To determine this status a total of 518 topsoil samples were collected from a 600,000‐km2 area in central Brazil. Laboratory characterization included pH, exchangeable Al, cation exchange capacity, nutrient levels (including micronutrients), organic matter, texture, and color. The results, presented as frequency distributions, indicate the following general conditions: a pH of 4.8 to 5.2, an organic matter level of 1.5 to 3.0%, extremely low levels of effective CEC and extractable Ca, Mg, P, and Zn, a high level of Fe, a high degree of Al saturation, and a broad range in textural class. Organic matter was the most important soil fraction in relation to effective CEC in these soils. The data suggest that problems associated with fertilizer inputs needed to bring these soils under more intensive agriculture are generally similar, but may vary in degree.
Effect of Soil Shear Strength on Soil Detachment due to Raindrop Impact
Authors: Cruse R. M. , Larson W. E. 
Published: July 2010

AbstractSoil strength was altered in three different ways to test the hypothesis that soil splash from raindrop impact is related to soil strength parameters. Bulk density changes were used to alter direct solid particle‐to‐particle contact; changes in matric potential were used to change contact relationships between solid particles and liquid films; and additions of polyvinyl alcohol (PVA) provided a direct bonding mechanism between solid particles. The amount of soil detached by a single simulated 4.8‐mm raindrop falling from a height of 177 cm was closely correlated with the shearing strength as measured by a triaxial compression test.
Field‐measured Spectroradiometric Reflectances of Disked and Nondisked Soil With and Without Wheat Straw
Authors: Gausman H. W. , Leamer R. W. , Noriega J. R. , Rodriguez R. R. , Wiegand C. L. 
Published: July 2010

AbstractOur objective was to compare field‐measured spectroradiometric reflectances of nondisked bare soil with or without littered wheat (Triticum aestivum L.) straw and bare soil that was disked directly or after littering with wheat straw. This information is needed to develop a procedure for predicting potential soil erosion using aircraft or satellite multispectral scanner reflectance measurements.A ground‐based spectroradiometer was used to measure reflected radiation from six soil‐tillage‐wheat straw treatments: disked and nondisked soil with and without two wheat straw rates—equivalent to 2.24 and 4.48 metric tons/ha, respectively.The near‐infrared region (0.75 to 1.3 µm), exemplified by the 1.05‐µm wavelength, seemed to be better than the visible region (0.45 to 0.75 µm) or water absorption wavebands (1.5 to 1.8 µm and 2.0 to 2.5 µm) for distinguishing among reflectances of the soil‐tillage‐straw treatments.Results indicated that LANDSAT multispectral scanner's band 7 (0.8 to 1.1 µm) might be used to distinguish nondisked bare soils from those with different amounts of straw on their surface, but not to distinguish reflectance of nondisked bare soils, disked bare soils, and disked soils with small amounts of straw incorporated in them.Further research is needed on the interacting effects on reflectance of other soils, soil moisture contents, kinds and amounts of plant residue, tillage operations, and their interactions on reflectance.
Chiseling Influences on Soil Hydraulic Properties
Authors: Allmaras R. R. , Rickman R. W. , Ekin L. G. , Kimball B. A. 
Published: July 2010

AbstractChiseling is now more frequently used for primary tillage in the drylands of eastern Oregon and Washington. Improved measures of chiseling effects on soil water relations are needed to evaluate water intake and infiltration benefits, especially as related to depth of chiseling. Hydraulic conductivity (K) and soil water desorption characteristic (SWDC) were field measured in the 120‐cm soil profile of a Walla Walla (mesic typic Haploxeroll) silt loam before and after chiseling 43‐cm deep.The test Walla Walla soil is layered. Cation exchange capacity, exchangeable Ca2+, clay content, and organic matter all changed at the 30‐cm depth; dry bulk density decreased with depth above 45 cm and was constant below 45 cm; K was 10 to 1,000‐fold lower in depths above 30 cm; water contents in the SWDC (−50 to −200 mbar range) were lower in upper 30‐cm layer.Chiseling affected both the SWDC and K in the upper 30 cm, especially at 10 and 20‐cm depths, but had no influence on these measurements at 40 cm. Both water potential at constant water content in the SWDC and K were increased especially in the −50 to −300 mbar range. Failure of chiseling to improve water relations in the mild duripan extending from 30 to 45 cm suggests the need for addition of plant residue or chemical amendments into the chisel slots.Water contents and hydraulic heads during drainage showed that chiseling could reduce evaporation by reducing water content and diffusivity. Overall soil profile hydraulic resistances showed relative average K up to 15 times greater as a result of chiseling 43 cm deep, but nearly similar accelerated internal drainages were projected for simulated chiseling to 25‐cm depth vs. chiseling to 43 cm.
Response of Yellow‐Poplar and Red Oak to Fertilization in West Virginia
Authors: Auchmoody L. R. , Smith H. Clay 
Published: July 2010

AbstractFertilization tests with small sawlog‐size yellow‐poplar (Liriodendron tulipifera L.) and red oak (Quercus rubra L.) were begun in the northern mountain section of West Virginia in the spring of 1970. Treatments were made with N, P, N‐P, and N‐P‐K. During the first year, N was broadcast at 336 kg/ha, P at 97 kg/ha, and K at 93 kg/ha. Second season application included 112 kg/ha of N and 97 kg/ha of P. Basal‐area response to N over a 3‐year period amounted to a 47% increase for yellow‐poplar and a 29% increase for red oak. There was no response to P, either alone or in combination with N. Negative effects on basal‐area growth were observed where KCl was applied. Foliar response in leaf weight and color was attributed mostly to N, although P in combination with N produced slightly heavier and darker green leaves than N only. Foliar N in yellow‐poplar corresponding to the best basal‐area growth was about 3.0% N.
A New Approach to Determination of Cation Exchange Capacity
Authors: Fernando M. J. , Burau R. G. , Arulanandan K. 
Published: July 2010

AbstractThe dielectric dispersion (Δε0), defined as the difference in the dielectric constant of a sample measured at 3 × 106 Hz and at 75 × 106 Hz, was linearly related to CEC of the sample. One linear relationship between Δε0 and CEC was obtained for clay‐silica flour mixtures where CEC was varied by changing the proportion of clay in the sample as well as by using clays with different CEC (kaolinite, illite, montmorillonite). A second linear relationship, with somewhat different slope, was obtained between the Δε0 and the CEC of natural soil samples.
A Field Procedure for Base Saturation Using KCl‐Triethanolamine, pH 8.
Authors: Holmgren George G. S. , Nelson Reuben E. 
Published: July 2010

AbstractBase saturation as determined by BaCl2‐triethanolamine acidity (pH 8.1) and NH4OAc‐extractable bases is closely approximated by analysis of acidity and bases extracted by KCl‐triethanolamine (0.0375N triethanolamine in 1N KCl, pH 8.1). One gram of soil is extracted with 20 ml of this reagent and titrated sequentially for acidity and calcium plus magnesium. Sodium and potassium are not included in the analysis.The extraction apparatus is constructed from two 20‐cm3 syringes, one acting as extraction tube and the other providing vacuum and volumetric measurement of the extractant. Titration is conveniently performed by calibrated syringes mounted in the caps of reagent bottles.
Soil Thermal Diffusivity Determination from Overspecification of Boundary Data
Authors: Singh S. R. , Sinha B. K. 
Published: July 2010

AbstractThe heat conduction equation has been solved for evaluating thermal diffusivity of soils by overspecifying the usual boundary conditions in terms of the thermal gradient at the boundary surface. Solutions have been obtained for different Dirichlet‐type boundary conditions describing the boundary temperature. These were (i) linearly rising/falling, (ii) exponentially rising, (iii) exponentially falling, and (iv) sinusoidal. The thermal gradient in the soil profile was evaluated using a cubic spline. Field data were analyzed firstly by representing the surface temperature as linearly rising and secondly as sinusoidal. More consistent results were obtained with the help of the first approximation which represented the boundary data closely. This shows that a close approximation of boundary condition by an appropriate function is essential to get reliable values of the thermal diffusivity.
Flow from a Line Source above a Shallow Water Table
Authors: Warrick A. W. , Lomen D. O. 
Published: July 2010

AbstractAn analytical solution is developed for a buried line source with an underlying constant potential surface. The geometry is appropriate to describe flow from a trickle or subsurface irrigation system of porous pipe or emitters spaced closely in a line above a shallow water table or in a lysimeter. Assumptions include steady‐state conditions and a hydraulic conductivity exponentially related to the pressure head.The soil water pressure head distribution is calculated for two geometries, one for which the water table dominates over the line source throughout the flow medium, and a second for which most of the flow region is as if the source were above an infinitely deep lower boundary.