bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Nomograph for Hydrometer Method of Particle Size Analysis
Authors: Sur Hardip. S. , Singh N. T. 
Published: July 2010

AbstractThe hydrometer method for particle size analysis in soils involves calculations of size of particle (d) settling in a suspension at a given time (t) from the hydrometer reading (R). A parabolic relation described by θ = m(a‐bR)1/2 exists between (θ) and R. A nomograph based on relationships between different parameters of the hydrometer method has been developed and its use is explained.
Influence of Hysteresis on Moisture Flow in an Undisturbed Soil Monolith
Authors: Beese F. , van der Ploeg R. R. 
Published: July 2010

AbstractThe moisture dynamics of an undisturbed soil monolith were studied during a lysimeter experiment. Daily measurements were made of the soil suction at 10 depths. Also daily measured were the precipitation, the seepage, and the evaporation from the monolith during a 3‐year period. For selected periods, a drying (desorption) curve and a wetting (sorption) curve of the soil moisture characteristic were determined from field data. Also the capillary conductivity was determined with use of daily monolith observations. With use of these hydraulic functions, the unsaturated soil moisture flow equation was solved numerically for one‐dimensional vertical flow. In order to determine the effect of hysteresis on the suction distribution in the monolith, calculations were performed either with the desorption curve or with the sorption curve without scanning between these curves. Neither of the two curves leads to complete agreement between observed and calculated soil suction values; the desorption curve usually gives too high values, the sorption curve too low values.
Response of Potted Slash Pine Seedlings on Imperfectly Drained Coastal Plain Soil to Additions of Zinc
Authors: McKee W. H. 
Published: July 2010

AbstractIn a greenhouse study, seedling dry weights and uptake of Zn, K, Mg, and Ca were increased by applying 1 ppm of Zn to Caddo silt loam soil fertilized with 123 ppm of N, 0.31 meq of K/100 g, and varying amounts of P and lime. Zinc interacted with P and lime to alter N uptake. Zinc uptake rose with increasing amounts of Zn and available P in the soil at harvest, but declined with increasing levels of exchangeable Mg, K, and Ca.
Long‐term Evaluation of Slow‐release Nitrogen Sources on Turfgrass
Authors: Waddington D. V. , Moberg E. L. , Duich J. M. , Watschke T. L. 
Published: July 2010

AbstractShort‐term studies with slow‐release nitrogen sources have not provided information on the changes in response that may occur with continued use of a given material. In this study eight nitrogen sources were used to fertilize ‘Merion’ Kentucky bluegrass (Poa pratensis L.) for 7 consecutive years to obtain long‐term results. Fertilizers used were urea, Uramite (ureaform), IBDU (isobutylidene diurea), Urex (urea‐paraffin matrix), ADM (plastic coated urea), Milorganite (activated sewage sludge), and two complete (NPK) fertilizers, with two‐thirds of the nitrogen from ureaform or IBDU and the remainder soluble. Urea was applied every other week and the other fertilizers were applied one, two, or three times per season to obtain total N of 1.46 or 2.44 kg/100 m2. Weekly clipping yields and color ratings were used to evaluate turfgrass response to the fertilizer treatments. Milorganite, Uramite, and IBDU produced more uniform growth than Urex, ADM, and the complete fertilizers. Response to Urex, ADM, and the complete fertilizer with IBDU was similar, and was often characterized by excessive growth after application. The greatest increase in response with continued use occurred with Uramite, which was the least efficient fertilizer in the first two years. At the end of the 7‐year period, determinations of yield, color, and total soil N indicated that Uramite had the greatest residual effect.
An Evaporation Chamber with Constant Suction
Authors: O'Connor G. A. , Cull C. 
Published: July 2010

AbstractLaboratory chambers to aid in the evaporation of water from soil surface have been described by numerous authors, but few units have been described which allow simultaneous collection of drainage water. This note describes the components and performance of an evaporation chamber enclosing a rotating turntable which allows the application of constant suction to multiple soil columns. The chamber will not be appropriate to all studies involving soil water evaporation, but offers certain advantages over conventially described units, particularly if suction needs to be applied to soil columns as they evaporate on a revolving turntable. Total cost of the chamber, including professional labor, was < $700.00.
An Electrical Conductivity Probe for Determining Soil Salinity
Authors: Rhoades J. D. , van Schilfgaarde J. 
Published: July 2010

AbstractAn electrical conductivity probe for determining soil salinity is described with construction details. The probe's utility for measuring soil salinity within discrete soil depth intervals is illustrated with examples. Using the salinity probe, the Barnes method for estimating electrical conductivity profiles was shown to be accurate for soils that are reasonably homogeneous laterally.
Influence of Ionic Strength and Inorganic Complex Formation on the Sorption of Trace Amounts of Cd by Montmorillonite
Authors: Garcia‐Miragaya J. , Page A. L. 
Published: July 2010

AbstractCadmium sorption by montmorillonite from solutions in the 15 to 120 ppb range was studied in the presence of increasing concentrations of NaClO4, NaCl, and Na2SO4 solutions. The ionic strengths ranged from 0.01 to 1.00. Increasing ionic strengths decreased the amount of Cd sorbed on the clay surfaces. The percentage sorbed decreased from around 90% for I = 0.01 to about 50% for I = 1.00 in the ClO4 systems. The sorption of Cd in the chloride system was in the range between 25 to 50% less than the ClO4 systems for the same ionic strength. This was attributed to the presence of uncharged and negatively charged complexes of Cd with Cl ligands. This fact has some implications, especially in arid zone soils where high Cl concentrations in soil solutions are not unusual; there, Cd will behave mainly as a neutral species (CdCl20) and as an anion (CaCl3‐ and CdCl42‐), rather than as a cation (Cd2+).The SO4 systems showed a moderate decrease in the amount of Cd sorbed with respect to the ClO4 systems for the same salt concentrations. This observation was interpreted as due to the presence of a fraction of Cd in solution as the CdSO40 species.
Soil Elastic Constants: I. Calculations from Sound Velocities
Authors: Briones A. A. , Uehara G. 
Published: July 2010

AbstractCompressional and shear wave velocities were measured in remolded cylindrical‐shaped soil materials from a Vertisol and two Oxisols. The modulus of elasticity, shear modulus, and bulk modulus were computed from measured sound velocities. Compressional wave velocity increased with increasing water content, shear wave velocity decreased with increasing water content and both velocities increased with increasing soil density. The Vertisol with a high content of swelling clay underwent greater change in modulus of elasticity and shear modulus for a given change in water content than the Oxisols.
Soil Nitrate‐nitrogen Determined by Coring and Solution Extraction Techniques
Authors: Alberts E. E. , Burwell R. E. , Schuman G. E. 
Published: July 2010

AbstractSoil‐coring and solution‐extraction sampling techniques were compared for determining the content of NO3‐N in the soil profile of a Monona silt loam (Typic Hapludoll) in southwestern Iowa. The NO3‐N content of the 3.05‐m profile, determined by solution extraction, was 28% lower in 1972, 8% higher in 1973, and 13% lower in 1974 than that determined by soil coring. The profile difference in NO3‐N content between the two sampling techniques was insignificant in 1973 and 1974 but was highly significant (1%) in 1972.
A Perspective on Two Centuries of Progress in Soil Fertility and Plant Nutrition
Authors: Viets Frank G. 
Published: July 2010

AbstractIn the American colonial period soil fertility management depended on the empirical practices learned on similar soils in Western Europe, many of them known since Roman times. There were no experiment stations, colleges of agriculture, or known principles on which to build better practices. Advances in chemistry, physics and plant physiology starting very late in the 18th century catalyzed the beginnings of soil science in the late 1890's and early 1900's.The most rapid advances in discovery of principles and putting them into practice have occurred since World War II aided by new electronic instrumentation, development of statistical theory and designs for field research, and new fertilizer and pest control materials. Among the developments put to practical use have been extension of the list of essential elements, soil and plant tissue testing for better guidance of fertilizer useage, and theories on ion transport from the solid phase to the root surface, which help to explain fertilizer placement effects, “fixation,” residual availability, and fertilizer efficiency.Our present high‐yielding agriculture depended on the development of systems with the timely combination of the best cultivars; soil, water and plant management alternatives; and plant protection. Soil fertility specialists have had a leading role in the development of these systems.Although progress in development of soil fertility theory appears to have slowed, great challenges exist for making further progress using modern developments from engineering and other sciences. Among the problems are an ever‐growing need for more food and natural fiber. This need involves further intensification for higher yields and the expansion of agriculture onto kinds of soils having unprecedented soil fertility problems. The conservation of fossil fuel energy; the management of nitrogen to improve efficiency of uptake, and to minimize denitrification and ground water pollution; and finally the development of cultivars that tolerate adverse soil conditions uncorrectable economically with traditional fertilizers and amendments are also necessary developments. To apply with selectivity all of the knowledge now available from diverse sciences will require broader training of individuals and more refined field measurements of significant variables affecting plant growth during the season.
History and Challenges in Soil and Water Conservation and Management
Authors: Browning George M. 
Published: July 2010

AbstractSoil and crop management practices have been used for centuries in some parts of the world, but in the United States it was not until the 1930's that the public became concerned over the abuse of land. In response a series of emergency and long‐range programs were initiated on the conservation and wise use of natural resources. Information generated by the publicly supported agricultural research system undergirded these programs. The net effect has been major improvements in how our natural resources are used. The job is far from done. Among the challenges and opportunities for additional research in the future are: (i) refine the universal soil loss equation and extend the data base to those areas where it is not available now, (ii) complete soil survey as soon as possible, (iii) strengthen our present effort to assure greater efficiency of water use for agricultural purposes, (iv) develop extensive quantitative information on the relationship between weather variables in a growing season and the yield of different crops, (v) assemble, summarize, and evaluate existing information and develop new information when needed relative to specific sets of conditions for use by all concerned in the development of realistic and practical land use plans, (vi) generate additional data essential in developing sound programs to improve the environment and at the same time maintain our capacity to meet future food requirements, (vi) improve existing tillage systems and develop new ones tailored to meet a wide range of soils, crops, and climatic conditions, and (viii) develop knowledge and plans whereby strip‐mining operations can be carried out without permanent damage to the environment and soil productivity.
Assessing Two Diagnostic Methods for Enumeration of Nitrate Reducing and Denitrifying Bacteria in Soil‐plant Root Associations
Authors: Volz M. G. 
Published: July 2010

AbstractMost probable number (MPN) determinations were made of NO3‐ reducing‐ and denitrifying bacteria in soil samples taken at time of crop harvest from fallow sites and from root zones of fertilized field plots of tomato (Lycopersicon esculentum L.), soybean (Glycine max L. Merr.), or corn (Zea mays L.) plants cultivated in pure stand or in association with nutsedge (Cyperus esculentus L.), a competitive weed. Diagnostic methods utilized were inoculated Difco NO3‐ broth and Giltay's medium (citrate‐nitrate‐asparagine + mineral salts), incubated with and without the exclusion of atmospheric O2, respectively.The NO3‐ broth method usually yielded both numerically larger and significantly different (5% level) MPNs for NO3‐ reducers (5 of 7 cases larger, 3 significant) and denitrifiers (6 of 7 cases larger, 3 significant) from a given soil inoculum when compared with identical enumerations performed with Giltay's medium.When selected soil inocula were incubated anaerobically in Giltay's medium, MPNs of neither NO3‐ reducers nor denitrifiers were increased significantly as compared with the aerobic procedure. Therefore, larger MPNs of soil NO3‐ reducers and denitrifiers observed when NO3‐ broth is utilized are probably more due to improved nutritional environs than to ambient oxygen status. As a result, a more complete estimate of these soil bacterial populations, especially those from the vicinity of plant roots is thought to be obtained using the NO3‐ broth procedure.
Growth Rate‐Nutrient Concentration Relationships During Early Growth of Corn as Affected by Applied N, P, and K
Authors: Terman G. L. , Noggle J. C. , Hunt C. M. 
Published: July 2010

AbstractThree greenhouse pot experiments with corn (Zea mays L.) were conducted to study effects of multiple rates of applied N, P, and K on growth and yield—nutrient concentration trends. Harvests were made each 4 or 6 days from 15 to 56 days after plant emergence. Growth and plant nutrient concentrations and uptake increased with rate of each applied nutrient at adequate levels of other nutrients. Applied N also increased both P concentrations and uptake in young corn plants. Yield response to applied K resulted only in dilution of N and P concentrations at even the earliest harvest. Concentrations of all nutrients were soon diluted to lower levels with increase in dry matter and/or age of plants, so that comparative results varied with time of harvest. Growth rates increased with adequacy of nutrient supply and more favorable growth conditions; they declined greatly soon after depletion of applied N. The limited soil volume in pot experiments, rate of growth, and time of harvest all greatly influence the effects of one nutrient on plant concentrations of other nutrients.
Diurnal Soil Water Regime in the Tilled Plow Layer of a Warm Humid Climate
Authors: Bruce R. R. , Thomas A. W. , Harper L. A. , Leonard R. A. 
Published: July 2010

AbstractThe soil water content in 10 depth intervals in the surface 15 cm of soil was determined hourly for 9 days in June at 83° 25′W, 33° 52′N. Over the same period at 15‐min intervals soil temperatures were measured at eight depths, windspeed and air temperatures at six elevations, atmospheric water vapor pressures at three elevations, incident solar and net radiation at one meter. From the microclimate data, flux of water vapor at the soil surface was calculated, which was then used to compute soil water flux at several depths by using soil water content data. The diurnal soil water content and soil water flux patterns are compared for a dry period before a rainfall event and afterward. Dramatic diurnal variation of the soil water content at depths < 2 cm was observed. This variation during periods of no rain is related to daily radiation inputs at the soil surface, which generated the observed temperature and soil water gradients responsible for soil water redistribution. Occurrence of rainfall and infiltration events during the measurement period show additional dynamics of the field system. Description of the diurnal soil water dynamics in the plowlayer provide a basis for examining soil processes dependent upon soil water regime.
Measurement of Soil Gaseous Diffusion Coefficients by a Transient‐State Method with a Time‐dependent Surface Condition
Authors: Rolston D. E. , Brown B. D. 
Published: July 2010

AbstractPrecise measurement of the gaseous diffusion coefficient in soils is necessary for calculating the flux of gas resulting from soil respiration, denitrification, or fumigation. Gaseous diffusion coefficients of soil columns and a field soil were determined by fitting a solution of the transient‐state diffusion equation for a time‐dependent surface condition to measured N2 concentration profiles. The time‐dependent surface condition was experimentally imposed by pumping argon at a constant rate into a chamber placed within the soil and on the soil surface. The argon and air mixture exited the chamber through several exit ports. The N2 concentration at the soil surface and within the soil profile was determined several times within a 5‐hour period after initiation of the argon flow. A solution of the diffusion equation for a non‐constant initial condition can also be used for determining the diffusion coefficient for cases where the initial gas concentration is not constant with depth. Diffusion coefficients for a field soil determined from the transient‐state solutions compared favorably with those determined from laboratory measurements on undisturbed soil cores and field measurements of CO2 flux.
Denitrifying Bacteria can be Enumerated in Nitrite Broth
Authors: Volz M. G. 
Published: July 2010

AbstractDenitrifying‐ and NO3‐ reducing bacteria in air dry, moist, and organic matter amended Yalesville fsl (Typic Dystrochrept), lake water, and in both effluent and drainage field soil from a septic tank system were enumerated using Difco nutrient broth, which contained either or both NO3‐ and NO2‐ and was incubated anaerobically. Most probable numbers (MPN) of denitrifiers (1.3 × 103 to 1.1 × 107/g) were always less than those of NO3‐ reducers (1.5 × 106 to 8.1 × 107/g) in the same sample, and constituted from 0.02% to 70% of bacteria capable of aerobic growth on yeast extract agar. Further, for a given sample, denitrifier populations as estimated in nutrient broth + NO2‐ (NO2‐ broth) were always statistically equivalent to or larger than those determined using nutrient broth + NO3‐ (NO3‐ broth). Therefore, NO2‐ broth may be preferable to NO3‐ broth for estimating denitrifier populations in soil and water samples. Nitrite broth retains the nutritional advantages of nutrient broth but also represses competitive growth effects of NO3‐ reducing bacteria. Further, in order to determine when in vitro denitrification has occurred, one needs only to assess colorimetrically the presence of NO2‐ following culture tube incubation.
Corn and Alfalfa Production as Influenced by Irrigation and Salinity
Authors: Hanks R. J. , Sullivan T. E. , Hunsaker V. E. 
Published: July 2010

AbstractYields of corn and alfalfa were determined where both salinity and water stress were imposed. Yields of corn (Zea mays L.) at Logan, Utah in 1975 were decreased by salinity or water stress (caused by low irrigation levels) in direct relation to the decrease in evapotranspiration. The decrease in evapotranspiration was caused by a decrease in soil water depletion, indicating that salinity influenced soil water availability. Corn yields at Vernal, Utah in 1974 were decreased by salinity, but to a considerably lesser extent by low irrigation, probably because of water flow upward into the root zone from a water table. Alfalfa (Medicago sativa L.) yields at Vernal in 1974 were not decreased by salinity or by low irrigation rates, because of water supplied by a water table and used by roots below the zone of salinity.
Fall Soil Water: Effect on Summer Soil Temperature
Authors: Willis W. O. , Wierenga P. J. , Vredenburg R. T. 
Published: July 2010

AbstractSoil temperature with depth (to 150‐cm) and time (April through September) was measured in field plots in North Dakota to determine the effect of three depths of wetting in late fall before freezing on the growing season soil temperature the following year. All plots were planted with spring wheat [Triticum aestivum, ssp. vulgare (Vill., Host) MacKey var. Selkirk] and received identical treatment during the growing season. The data indicate that a high soil water content in the fall may cause soil temperature in the 30‐ to 120‐cm depth to be 1 to 2°C lower than normal during the next year's growing season, particularly if that season has lower‐than‐normal precipitation. By using soil temperature values from the 15‐cm and 120‐cm depths as the upper and lower boundaries, calculated soil temperatures agreed better with measured values than when 0.2‐cm and 120‐cm depths were used as boundaries.
Enzymatic Activities Related to the Decomposition of Coniferous Leaf Litter
Authors: Spalding Brian P. 
Published: July 2010

AbstractThe rate of CO2 evolution at 23°C and 75% moisture content for a diverse group of coniferous leaf litter samples from Oregon was measured. Significant correlations (1% level) were observed between the rate of CO2 evolution and the activity of amylase, cellulase, and xylanase (r = 0.71, 0.58, and 0.44, respectively) in 0.05M potassium acetate, pH 5.0 extracts of the litter. The amounts of extractable hexose, phenolics, and reducing substances were also correlated with the rate of CO2 evolution (r = 0.74, 0.53, and 0.73 respectively). Peroxidase and invertase activities were not correlated with the rate of CO2 evolution. Litter extracts showed zero‐order kinetics for the hydrolysis of carboxymethylcellulose, xylan, starch, and sucrose. All carbohydrase activities were destroyed by a 15 min exposure to a boiling water bath.
Drainage Flux in Permeable Soil Underlain by a Coarse‐Textured Layer
Authors: Clothier B. E. , Scotter D. R. , Kerr J. P. 
Published: July 2010

AbstractDrainage from a permeable soil underlain by a coarse‐textured layer is investigated. Simplified theory is used to develop a model relating the drainage flux at the base of the soil to the water storage in the soil. Despite significant hysteresis in the water retentivity curve of the overlying soil and in the hydraulic conductivity‐pressure potential relationship of the coarse layer, hysteresis had little effect on the storage‐flux relation. The model fairly successfully simulated field drainage as measured by a lysimeter and field profile water storage as found by neutron moisture probe measurements. The decline in the drainage flux after the profile has been wetted depends on the depth and retentivity of the soil and the hydraulic conductivity of the underlying coarse layer. To use the model only simple field measurements to find the storage‐flux relationship are needed.