bluuebunny/crossref_metadata_2025_split huggingface dataset:
Variation of Selected Properties across a Soil Boundary
Authors: Campbell James B. 
Published: July 2010

AbstractThis study is a statistical analysis of the changes in the distributions of soil properties at the contact between two soil series. Samples were collected at 10‐m intervals on an 18 by 40 grid positioned over the mapped boundary between two contrasting soil series in eastern Kansas. Samples collected from the B2 horizons of both soils were analyzed for gravel, sand, and silt content, for pH, and for Munsell color. These measurements were used to calculate a discriminant function which was used to define the boundary between the two soils. The variations of sand, silt, and pH measurements were compared with each of three models describing changes within the study area. The first model is a random distribution of the measurements. Simple trend surfaces were calculated for each of the three sets of measurements as a second model. A third model consisted of two uniform categories separated by an abrupt boundary. The fit of each model was tested against the distributions of the three sets of measurements using autocorrelation functions to examine the distributions of the residuals. The simplest model having random variation in the residuals was selected as the most efficient descriptor for each variable. Trend models were selected for the pH and silt measurements; and the two‐category model was selected for the sand data. This indicates that measurements of pH and silt change slowly within the study area, whereas the sand measurements exhibit a very sharp change at the contact between the two soils.
Effects of Beef Cattle Manure on Water‐stability of Soil Aggregates
Authors: Mazurak A. P. , Chesnin Leon , Thueel A. Amir 
Published: July 2010

AbstractA field experiment was established to determine the effect of applying varying large amounts of manure on (i) the size distribution of water‐stable aggregates and (ii) their resistance to dispersion during prolonged periods of shaking in water. It was hypothesized that the formation of highly water‐stable aggregates as a result of organic matter amendments to the soil took a relatively long period of time to occur.Beef cattle manure was applied at rates of 0, 180, and 360 metric tons/ha for 3 consecutive years to a Sharpsburg silty clay loam soil in eastern Nebraska. One year after the third manure application, soil samples were collected from the 0 to 10 cm depth of soil and air dried. Aggregates of 4,760–9,440 µm in diameter were wetted under vacuum and then shaken in water for 2, 20, and 200 min. The size distribution of aggregates in water was measured using pipette, elutriators, and sieves.Increased rates of manure application increased the percentage of water‐stable aggregates >295 µm in diameter and decreased the percentage in size groups 18.5–295 µm and <18.5 µm in diameter after 2‐ and 20‐min shaking periods. Distribution of aggregates present after 200 minutes of shaking was not affected by levels of manure application to the field plots.
Effect of Irrigation Systems on the Water Requirements of Sweet Corn
Authors: Wendt C. W. , Onken A. B. , Wilke O. C. , Hargrove R. , Bausch W. , Barnes L. 
Published: July 2010

AbstractA field study was conducted to determine the influence of sprinkler irrigation (Sp), furrow irrigation (F), subirrigation (Su), and automated subirrigation (ASu) on the water requirements of sweet corn (Zea mays L.). Irrigation water was applied to the SP, F, and Su plots when the soil water potential at the 30‐cm depth in the row reached −40 cbars potential. The time and amount of water applied was based on a combination of leaf area index (LAI) and potential evapotranspiration (ETp). Water application to the ASu plots was controlled by a switching tensiometer 30 cm deep set at −40 cbars potential. Soil water content changes were determined by gravimetrically sampling the surface 15 cm and obtaining neutron probe measurements of water in the deeper depths.Significant differences existed in the irrigation water requirement of the sweet corn irrigated by the different systems (F = 351 mm, SP = 248 mm, Su = 248 mm, ASu = 142 mm). However, little difference in consumptive use occurred between systems (F = 361 mm, Sp = 346 mm, Su = 346 mm, ASu = 310 mm) due to differences in soil water utilization. Automation of irrigation systems offers the possibility of significantly enhancing irrigation water use efficiency in supplementally irrigated areas.
Determination of Terrestrial Albedo from Landsat I Satellite Imagery in Photographic Form
Authors: Ben‐Asher J. 
Published: July 2010

AbstractSatellite imagery taken from Landsat I were used to determine terrestrial albedo and its changes with location and season in the basin of Sonoita Creek (31°45′N 110°43′W). A simple linear equation was derived to link the albedo with the optical density of the imagery. The modeling approach was based on the cyclic nature of the energy exchange between earth and space on the one hand and on the local density on the developed film as an output on the other hand. The results showed acceptable agreement between photographic and radiometric method for albedo determination.
Water Movement in Bare and Cropped Soil Under Isolated Trickle Emitters: I. Analysis of Bare Soil Experiments
Authors: Jury W. A. , Earl K. D. 
Published: July 2010

AbstractA field experiment on a Buren sandy loam with a low (0.5 cm/hr) saturated hydraulic conductivity is reported in which water movement in soil irrigated from a single isolated trickle emitter was observed. Water was introduced at a uniform rate of 4 liters/hr and a weekly volume of 84 liters at frequencies of 3 irrigations/day and 1 irrigation/week. During a 41‐day experiment, soil water movement was followed by tensiometers and gravimetric water content sampling, and surface ponding was recorded by photography. It was found that more water moved laterally in the weekly irrigation plots than in the daily ones, a result which was not consistent with predictions of simplified theoretical models which did not consider surface ponding. Observation of the wetted radius at the surface indicated that substantial amounts of water were running off laterally during the weekly irrigation, which could account for the storage changes seen at large radial distances from the emitter.
The Effect of Split Nitrogen Applications on Nitrogen Uptake by Pensacola Bahiagrass from an Aeric Haplaquod
Authors: Blue W. G. , Graetz D. A. 
Published: July 2010

AbstractAn experiment was initiated with an established ‘Pensacola’ bahiagrass (Paspalum notatum Flugge) sod on Myakka fine sand (sandy, siliceous, hyperthermic Aeric Haplaquod) that had been used in a 10‐year experiment with N fertilizers. Five lime treatments were used in the previous experiment as main plots, with three N rates (0, 112, and 224 kg of N/ha/year) as subplots, and five N sources (calcium nitrate, ammonium nitrate, ammonium sulfate, urea and ureaform) as subsubplots.The current experiment was established to determine the effect of the number of N applications on N uptake efficiency in Pensacola bahiagrass forage with particular emphasis on rainfall amounts and distribution. The original experimental design was used except that treatments which had 1, 2, 4, 8, and 16 N applications/year replaced the N source variable on the sub‐subplots. Nitrogen rates were retained as in the original experiment. The experiment was conducted for 3 years.Nitrogen uptake in forage was relatively efficient ranging from 64 to 79%. There was little difference among treatments involving number of N applications. Generally, 1 or 16 applications were slightly superior to treatments involving two, four, or eight applications. Nitrate‐ and NH4+‐N concentrations in soil solutions higher than those from the control treatment were found only in March and April 1973 when initial N applications were followed by 202 mm of rainfall within a 12‐day period. This coincided with low N recovery in forage, particularly from treatments involving one or two N applications since all or one‐half of the annual N supply for these two treatments had been applied prior to this relatively intense rainfall.
Micronutrient Concentrations in Soil Solution After Ammonium Phosphate Applications
Authors: Mortvedt J. J. , Osborn G. 
Published: July 2010

AbstractTwo fluid ammonium polyphosphates, 11‐17‐0 (11‐37‐0 oxide basis), a commercial 10‐15‐0 (10‐34‐0), and an equimolar mixture of mono‐ and diammonium phosphate (MAP‐DAP), each with a solution pH of about 6.2, were well mixed with 1‐kg lots of several soils to supply 2,000 ppm of P, which approximates the P concentration in soil near a fertilizer band at a P rate of 50 kg/ha. Each soil was then moistened to 0.2 or 0.3 atm and stored in plastic bags. After periods up to 28 days, soil samples were placed in a lucite cell and a portion of the soil solution was expressed by N2 gas. These solutions were analyzed for Cu, Fe, Mn, Zn, organic C, and total and orthophosphate P.Micronutrient concentrations in solutions of acid soils were temporarily increased by both ortho‐ and polyphosphates. Increases were related in part to the amount of soil organic matter solubilized by these fertilizers. Organic C in solutions of treated soils increased in the order: MAP‐DAP, 10‐15‐0, and 11‐17‐0, which was related to the original percentage of the total P in polyphosphate form (0, 50, and 78, respectively). Micronutrient concentrations in solutions of acid soils were highest during the first week and decreased to those in untreated soil by 28 days. Soluble micronutrient concentrations in neutral and calcareous soils were not affected by phosphate applications even after 1 day. Thus, solubilization of soil micronutrients by polyphosphates does not appear to play an important role in micronutrient nutrition of crops, especially in calcareous soils.Phosphorus concentrations in soil solution generally were higher in soils treated with ortho‐ than with polyphosphates. Decreasing polyphosphate concentrations in solutions of polyphosphate‐treated soils with time indicated hydrolysis and precipitation of water‐soluble polyphosphates; less than 25% of the soluble P was in polyphosphate form after 2 weeks, with higher polyphosphate concentrations found in 11‐17‐0 than in 10‐15‐0 treated soils during the first 2 weeks after application.
Acidic Properties of Kaolinite in Water and Acetonitrile
Authors: Loeppert R. H. , Zelazny L. W. , Volk B. G. 
Published: July 2010

AbstractPotentiometric titration of weakly acidic sites on soil clays is limited in aqueous media by the acidic property of water which prevents sharp endpoints. Generally, it is not possible to obtain sharp endpoints in aqueous systems for acids with pKa > 8. In this study, kaolinite with K, H, or Al as the saturating cation was successfully titrated in water and acetonitrile using the glass‐calomel electrode system for potentiometric determination. Sharper endpoints and wider working potential ranges were obtained in acetonitrile than in the aqueous system. Titer of base needed to reach the final endpoint was greater in acetonitrile than in water; for example, K‐saturated clay required a negligible titer in water (0.4 meq/100 g clay) in contrast to acetonitrile, in which a significant titer (7.4 meq/100 g clay) was required. The larger titer in acetonitrile was attributed to (i) pH‐dependent sites for which a quantitative endpoint was not obtained in water due to the acid‐base properties of this solvent, and (ii) an increased surface acidity in acetonitrile. A comparable difference in total titers at the final endpoint was observed for the titration of H‐ of Al‐saturated kaolinite in water and acetonitrile.
Winter Wheat Recropping on Dryland as Affected by Stubble Height and Nitrogen Fertilization
Authors: Black A. L. , Siddoway F. H. 
Published: July 2010

AbstractAlthough crop‐fallow systems stabilize production in the semiarid northern Great Plains, fallow often wastes water, minimally controls water and wind erosion, and contributes to the saline‐seep problem. Developing alternate cropping systems which rely less on fallow requires additional crop residue and more specific soil fertility management guidelines. To optimize the potential of a spring wheat‐winter wheat‐fallow rotation for the northern Great Plains, we examined the effects of spring wheat (Triticum aestivum L. ‘Norana’) stubble management (conventional‐till vs. no‐till stubble at heights of 15, 28, and 38 cm) and N fertilization (rate, timing, and source) on winter wheat yields. Grain yields were significantly higher for ammonium nitrate (NH4NO3) than for urea applied at 67 kg N/ha early (1 May) or late (23 May). Maximum grain yields were 2,620 and 2,540 kg/ha for winter wheat seeded directly (no‐tillage) into 15‐ and 28‐cm stubble heights, respectively, with 67 kg/ha of N applied in early May as NH4NO3. With 22 or 45 kg/ha of N applied early (1 May), grain yield increases for NH4NO3 and urea were similar. With a later application at the same rates, NH4NO3 was significantly superior. Nitrogen topdressing of winter wheat in a recropping system must be completed early, either before or soon after spring growth begins and definitely before the end of tillering.
A Mechanically Controlled Variable Rate Leaching Device
Authors: Holmgren George G. S. , Juve Robert L. , Geschwender Robert C. 
Published: July 2010

AbstractTwenty‐four leaching tubes attached to 60‐ml plastic syringes are mounted on the periphery of three vertically aligned slotted discs 45 cm in diameter. The plungers are withdrawn at a controlled rate by a variable speed screw jack that separates the two lower discs holding the plungers and syringe barrels, respectively. Leaching time can be varied from 15 min to 12 hours or more. The final volume of extract is determined by weighing the syringes. Precision of ammonium acetate CEC and extractable cations by this procedure with 2.5 g of soil and 50‐ml extract matches that of a comparable manual method using vacuum extraction with 5 g soil and 100 ml of extract. This apparatus has also cut required operator time in half.
Transient‐ and Steady‐flow Experiments Testing Theory of Water Flow in Saturated Bentonite
Authors: Smiles D. E. 
Published: July 2010

AbstractThe theory of water flow in a saturated, swelling clay has recently been criticized. This criticism concerns possible effects on the material characteristics of particle re‐orientation during transient flow, as well as suggestions that the flux equation (Darcy's law) may be inappropriate to such systems.This paper examines these problems by comparing data from transient‐ and steady‐flow experiments with bentonite.The data from all experiments are mutually consistent within the experimental error. It is concluded that Darcy's law is valid for this material and that the conductivity/water content, and water content/suction relationships are well defined.
Retention of Cu2+, Ca2+, Mg2+, and Mn2+ by Amorphous Alumina
Authors: McBride Murray B. 
Published: July 2010

AbstractThe adsorption of Cu2+ at low pH on amorphous alumina gels was studied using electron spin resonance and specific ion electrode techniques. The results, when compared with the inability of alumina to retain Mn2+, Ca2+, and Mg2+, indicated that Cu2+ demonstrated a specific preference for alumina. Both Cu2+ and Mg2+ were found to coprecipitate readily with alumina; however, these ions opened the structure, increasing the noncrystallinity and adsorptive capacity of the alumina. The data indicated that the sites of adsorbed and coprecipitated Cu2+ in alumina were similar, suggesting that adsorption of metals capable of occupying octahedral sites in the structure involves the same mechanism as substitution of the metals into the structure during coprecipitation. In both cases, the Cu2+ ions appeared to be nonexchangeable and immobile as they entered structural positions.
Transport of Microorganisms in Sand Columns
Authors: Wollum A. G. , Cassel D. K. 
Published: July 2010

AbstractTransport of streptomycete conidia through saturated columns of uniformly packed sand was studied using miscible displacement techniques. Autoclaved sand was uniformly packed to give sand columns 20.3 and 152 cm high. Mean pore water velocities ranged from 14.4 to 131 cm/hour. A pulse of sterile water containing from 104 to 106 conidia and tagged with 36Cl was displaced through each column with sterile water. Column effluent was collected and analyzed for conidia by serial dllution techniques utilizing starch‐casein agar. At the termination of each run, the column was sampled and analyzed for conidia distribution. For 20.3‐cm long columns, increasing the mean pore water velocity increased the maximum conidia concentration of the effluent and decreased the volume of effluent at which maximum conidia concentration was observed. Decreasing the mean pore water velocities also resulted in a broadening of the breakthrough peak and a greater volume of effluent was collected before the maximum conidia concentration was attained. Longer columns behaved as the shorter columns with the slower pore water velocities. Considerably more effluent was collected before maximum conidia concentration occurred and substantially fewer conidia were recovered from the effluent. A majority of the organisms recovered were present in the sand and a preponderance of organisms were retained near the soil surface.
Liming of Latosols and the Effect on Phosphorus Response
Authors: Mendez Jose , Kamprath E. J. 
Published: July 2010

AbstractStudies were conducted with six Latosols from Panama to evaluate exchangeable Al as the criterion for determining lime rate and the effect of liming on P availability. Liming rates equivalent to exchangeable Al × 1.5 neutralized most of the exchangeable Al and adjusted pH to levels satisfactory for plant growth. Such liming rates were considerably less than those required to adjust the pH to 7.At low rates of applied P, liming to neutralize Al significantly increased growth of millet (Pennisetum typhoides, var. Gahi 1), but had no beneficial effect if high rates of P were applied at < 60% Al saturation. However, liming significantly increased growth at all P rates if the Al saturation is > 60%.
An Evaluation of Mechanical Impedance for Three Tillage Treatments on Norfolk Sandy Loam
Authors: Cassel D. K. , Bowen H. D. , Nelson L. A. 
Published: July 2010

AbstractThe variability of in situ mechanical impedance in field soils hinders evaluation of impedance differences stemming from various tillage and soil management practices. Use of the penetrometer cone index (CI) is one method to measure mechanical impedance and many CI data have been treated statistically. This study was conducted to evaluate the mechanical impedance as measured by CI for Norfolk sandy loam for the following tillage treatments: (i) moldboard plowing to 22 to 25 cm followed by disking, (ii) chisel plowing to 27 cm, and (iii) subsoiling at 91‐cm intervals to a depth of 45 cm followed by bedding. Mechanical impedance was continuously recorded to a depth of 41 cm with a tractor mounted, hydraulically driven, constant rate descent penetrometer at seven positions spaced 15 cm apart on a transect normal to the soybean row. Measurements were taken four times during the year, representing a wide range in soil water content; replicated gravimetric water content measurements were taken as a function of depth at two of the seven positions at the time penetrometer readings were taken.Analysis of variance showed significant differences in CI for tillage treatment, soil depth, position, and all two‐way interactions. Chisel plowing reduced impedance at all seven positions to values less than those measured for the moldboard plowing. Of the three treatments, the subsoiled plots generally had the lowest impedance only in or near the subsoil slit, but had the highest impedance in the trafficked interrow.We recommend that future characterizations of mechanical impedance (and other soil physical properties which are induced or modified by tillage practices which introduce nonhomogeneity of these properties, i.e., mechanical impedance, water movement, etc.) include sufficient measurements to isolate not only tillage effects, but also position and depth effects.
A Mechanism of Phosphate Adsorption on Soil and Anion Exchange Resin Surfaces
Authors: Taylor Robert W. , Ellis Boyd G. 
Published: July 2010

AbstractLangmuir plots of P adsorption isotherms of four soils were shown to fit two intersecting lines. The adsorption data were also found to fit the BET equation. The monolayer capacities computed from the BET equation corresponded closely with the adsorption maxima computed from the initial slopes of the Langmuir plots.Studies of P adsorption on the energetically homogeneous sites of the anion exchange resins Dowex 1 − X8 and Dowex 2 − X4 (Cl − forms) at 25°C, gave results similar to those obtained with soils. Measurements of Cl‐ released during adsorption indicated that initially 2 mmole of Cl‐ were released per mmole of P adsorbed, and this value decreased at higher equilibrium P concentrations approaching 1 mmole of Cl‐. Measurements of pH of the equilibrium P solutions suggested that there was deprotonation of the H2PO4‐ ion during the initial stages of adsorption. Similar results were obtained when the Dowex 1 − X8 was saturated with the IO3‐ ion and P adsorption on the resin studied.The differential isosteric heat of adsorption, ­ΔH, of P adsorption on Dowex 1 − X8 was computed between 11°C and 25°C. ­ΔH decreased sharply over the first region of the isotherm and became almost constant over the second.It was concluded that at low concentrations P was bonded by two points of attachment after deprotonation of the H2PO4‐ ion, followed by one point of attachment at higher P concentrations during adsorption on the resin surface. This resulted in the deviation from linearity predicted by the Langmuir equation. This hypothesis for the mechanism of adsorption is presented to explain the deviation observed on soil and pure soil mineral surfaces.
An Exotic Source of Extractable Potassium in Some Soils of Northern Utah
Authors: Southard Alvin R. , Kolesar Peter T. 
Published: July 2010

AbstractHigh values of extractable potassium are characteristic of some soils formed on the tuffaceous member of the Salt Lake Formation in northern Utah. The apparent source of the K is a zeolite, clinoptilolite. The Blackrock soil, mapped on part of the Salt Lake Formation, is noncalcareous in the upper part as opposed to the strongly calcareous Wheelon soil mapped on other parts of the formation. No attempt was made to delineate the exact extent of the zeolite‐bearing strata.
An Inexpensive Precipitation Gauge
Authors: Buchanan B. A. , DeVelice R. L. , Urquhart N. S. 
Published: July 2010

AbstractAn inexpensive, yet accurate, precipitation gauge was developed from readily available materials. The gauge accurately estimated precipitation as measured by a standard Weather Bureau gauge for 35 precipitation events in a one‐year period. This inexpensive gauge has been used successfully int he field for two years.
Steady Infiltration from Single and Periodic Strip Sources
Authors: Batu Vedat 
Published: July 2010

AbstractThe matric flux potential and horizontal and vertical flux distributions were obtained using Fourier analysis techniques for single and periodic strip sources located on the soil surface. The theory is based on the assumption that the hydraulic conductivity is an exponential function of the soil water potential. The matric flux potential distributions were compared with the results obtained by Warrick and Lomen (1976) who used different mathematical techniques.