bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sodium Amalgam Reductive Degradation of Fungal and Model Phenolic Polymers, Soil Humic Acids, and Simple Phenolic Compounds
Authors: Martin J. P. , Haider K. , Saiz‐Jimenez C. 
Published: July 2010

AbstractReductive degradation of fungal humic acid‐type compounds and model phenolase phenolic polymers with 5% Na‐amalgam under N2 yielded 4 to 32% simple phenols which could be separated by two‐dimensional thin‐layer chromatography. Yields from soil and peat humic acids were 3 to 6%. Phenols recovered from all three types of polymers in greatest concentration were resorcinol, orcinol, 2,6‐dihydroxytoluene, phloroglucinol, p‐cresol or m‐cresol and p‐hydroxybenzoic, p‐hydroxycinnamic, ferulic, vanillic, 3,5‐dihydroxybenzoic, and protocatechuic acids. Vanillic and ferulic acids were found in the fungal polymers only when the organisms were cultured on plant residues or the phenols were placed under the fungus pads. Many other phenols incorporated into the model polymers were recovered in relatively low concentrations or not at all. In general, the phenols recovered in greatest concentrations from the polymers were those least affected by the Na‐amalgam reaction. Some of the hydroxybenzoic acids were partially or completely decarboxylated to form the corresponding phenols. Less than half the reacted phloroglucinol, caffeic acid and several other phenols were recovered. Hydroxynaphthalenic compounds were destroyed by the reaction. N‐linked phenylglycine was not recovered by the procedure. Over 16 phenols separated upon Na‐amalgam reduction of the soil humic acid fraction after incubation with 14C glucose or wheat straw were radioactive.
An Inexpensive But Durable Thermal Conductivity Probe for Field Use
Authors: Fritton D. D. , Busscher W. J. , Alpert J. E. 
Published: July 2010

AbstractA thermal conductivity probe is described which is constructed from heat‐shrinkable tubing, stainless steel tubing, and thermocouple wire. The probe requires about $3 worth of material and 0.5 hours of labor for construction. An example of data used to calculate the thermal conductivity of dry quartz sand is given. The probe is currently being used to acquire data in the field.
Diurnal Soil‐Water Evaporation: Comparison of Measured and Calculated Soil‐Water Fluxes
Authors: Jackson R. D. , Reginato R. J. , Kimball B. A. , Nakayama F. S. 
Published: July 2010

AbstractThe Philip and DeVries theory and the “isothermal” theory were used to predict diurnal soil water fluxes near the soil surface. The predicted values were compared with those obtained by measurements of soil‐water content, soil temperature, and evaporation. Previously measured soil‐water diffusivities were used in the theoretical calculations. The thermal vapor diffusivities were calculated using both the “simple” and the “complete” theory of Philip and DeVries. Comparison of measured and calculated fluxes indicated that the theory of Philip and DeVries predicts the measured values better at intermediate water contents, but the “isothermal” theory predicts values better at high and very low water contents.
Unsteady, Unsaturated, n‐Dimensional Moisture Flow in Soil: A Computer Simulation Program
Authors: Van der Ploeg R. R. , Benecke P. 
Published: July 2010

AbstractA computer simulation program for predicting n‐dimensional moisture flow in soils is simple to program and does not require extensive mathematical background. The programming was done with the computer program System/360 Continuous System Modeling Program (CSMP). For a number of selected problems the simulation results were compared with existing analytical and numerical solutions, and good agreement was found. Comparisons are made for 1‐dimensional adsorption, 3‐dimensional (spherical) absorption, 2‐dimensional infiltration from a line‐source, and 3‐dimensional infiltration from a point source.
A Method for Measuring First‐Stage Soil Water Evaporation in the Field
Authors: Arkin G. F. , Ritchie J. T. , Adams J. E. 
Published: July 2010

AbstractAn economical, automated method was developed for measuring soil water evaporation during first‐stage drying simultaneously at several locations in a field to evaluate the effectiveness of mulches and crop canopies in reducing soil water evaporation. The method also provides a reasonable procedure for separating soil water evaporation during first‐stage drying from transpiration, when the total evapotranspiration rate is accurately measured.Water flow through a thin evaporation plate with a known surface area is measured and used as a direct indicator of the evaporation rate. Flow rates can be recorded manually or automatically.Field tests of evaporation indicated that the resolution of the system was equal to that of a precision weighing lysimeter and that the system gave reasonable accuracy on an hourly basis. Mulch rates of 1,000, 4,000, and 10,000 kg ha‐1 reduced daily soil water evaporation measured with this method by 26, 59, and 78% of the bare soil evaporation. Cumulative daily soil water evaporation was reduced by 57 and 71% under plant canopies with 100‐ and 50‐cm row spacings and similar leaf area indices (3.0 and 2.7, respectively).
Biomass Production and Nitrogen Recovery after Fertilization of Young Loblolly Pines
Authors: Baker J. B. , Switzer G. L. , Nelson L. E. 
Published: July 2010

AbstractAmmonium nitrate applied at rates of 112 and 224 kg of N/ha in successive years to different areas of a young loblolly pine (Pinus taeda L.) plantation increased aboveground biomass by 25% and N accumulation by 30%. Fertilization at plantation age 3 resulted in significantly greater biomass and N accumulations in the pine; fertilization at age 4 caused greater accumulations of biomass and N in the herbaceous fraction. These differences are related to changes in the composition of the herbaceous species. Fertilization had little effect on distribution of biomass or N within the pine component of the system. Comparable but generally small proportions of applied N were recovered in the aboveground vegetation in spite of two‐fold differences in quantities of applied N and threefold differences in biomass development. Nitrogen recovery was influenced only by the frequency of N application.
Comparative Efficiency of Soluble and Controlled‐Release Sulfur‐Coated Urea Nitrogen for Corn in Tropics
Authors: Dalal R. C. 
Published: July 2010

AbstractThe efficiency of the soluble‐N sources, ammonium sulphate (AS), urea‐ammonium phosphate (UAP) and urea and controlled‐release‐N sources, sulfur‐coated urea (SCU‐8.9, SCU‐1.1 and SCU‐0.9) of differing N‐release rates (applied at 50, 100, and 200 kg/ha of N to an acidic soil) were compared in terms of N uptake and grain yield of corn (Zea mays L.). The apparent N recovery of added N, calculated by uptake differences from the control plots, was evaluated from N uptake by the two successive crops, one in the wet season and the other in the following dry season. In general, N uptake, grain yield, and apparant N recovery were increased by added N in this order: SCU‐0.9 = SCU‐1.1>SCU‐8.9 = Urea>UAP = AS; which was opposite to the nitrification of these N sources except that the performance of urea was better than the other soluble‐N sources, primarily because it had a smaller effect on soil pH and exchangeable Al. The inclusion of microbicide in the S‐coatings of SCU had no influence on N efficiency or grain yield. More N was recovered from SCU with slower N‐release characteristics irrespective of coating weight. Apparent recovery of added N was almost complete from urea, SCU‐8.9, SCU‐1.1 and SCU‐0.9 when appplied at the rate of 50 kg/ha of N, although the recovery at 200 kg/ha of N was about 50%. The “priming effect” of soluble‐N sources on soil N was observed. It appeared that release of fixed NH4+‐N was primarily responsible for the priming effect on soil N.
Boron Availability as Influenced by Application of Fly Ash to Soil
Authors: Plank C. O. , Martens D. C. 
Published: July 2010

AbstractThe relationships between fly ash application to soil and B availability under field conditions were studied over a 3‐year period. The two fly ash samples studied contained 232 and 370 ppm of total B. Incorporation of one application in 1971 of either fly ash sample into a Tatum silt loam increased alfalfa (Medicago sativa L.) yield over a 3‐year period. Yield increases were attributed to an alleviation of B deficiency. Boron uptake data indicated that B in the fly ash samples was readily available initially but decreased with time. Results of correlation and regression analyses suggested that hot‐water‐soluble B extractions could be used to predict plant availability of B in fly ash‐soil mixtures.
Soil‐Water Pressure During Intermittent Simulated Rain Application Measured with a New Rapid‐Response Tensiometric Technique
Authors: Sloneker L. L. , Olson T. C. , Moldenhauer W. C. 
Published: July 2010

AbstractA method is described for measuring instantaneous changes in soil‐water pressure in soil beds during intermittent application of simulated rainfall. Differences in soil‐water pressure do occur in soil beds, depending on nozzle off time. Intermittent off periods between nozzle on times affected soil‐water pressure which influenced the accumulated rainfall energy required to initiate runoff.
Supersaturation Phenomena and the Formation of Fluorapatite in Aqueous Suspensions of Phosphate Rock
Authors: Chien S. H. , Wier D. R. , Black C. A. 
Published: July 2010

AbstractDilute HCl solutions equilibrated with Florida phosphate rock and Tennessee brown phosphate rock in the presence of solid fluorite (CaF2) developed a condition of supersaturation with respect to fluorapatite at 25C. In suspensions boiled before equilibration at 25C, however, the solutions were in equilibrium with fluorapatite, as evidenced by ion‐activity products for fluorapatite in the solutions. The pH and concentrations of calcium and phosphorus in solution decreased due to boiling a suspension of Florida phosphate rock, as expected if fluorapatite had been precipitated. A condition of supersaturation with respect to fluorapatite redeveloped upon long‐continued equilibration of boiled suspensions of Florida and Tennessee phosphate rocks at 25C. Dilute HCl solutions equilibrated with phosphate rock or with phosphate rock plus solid fluorite became supersaturated with respect to fluorite at low pH values (about pH 3) where considerable calcium and fluoride were released from the phosphate rock, and the supersaturation persisted until the end of the equilibration period of 47 days at 25C. At pH values above about 4, the solutions became saturated with fluorite if solid fluorite was present but remained unsaturated where only phosphate rock was present as the solid phase.
Kinetics of Fixation of Iron and Zinc Applied as FeEDTA, FeHDDHA and ZnEDTA in the Soil
Authors: Lahav N. , Hochberg M. 
Published: July 2010

AbstractThe disappearance of zinc and iron from soil solution after their addition as soluble metal chelates is attributed to adsorption and fixation. The value of the adsorption coefficient, Kd, was estimated from a batch experiment but because of the inaccuracy involved they were evaluated from the breakthrough curves of column experiments using Rehovot sand. FeEDDHA was neither adsorbed nor was its iron fixed by the soil to any significant extent.The fixation of iron applied as FeEDTA was found to be a first order reaction. Assuming that the fixation reaction kinetics is similar in both the solution and the solid phase, then the reaction rate constant can be expressed as k = (k1θ + k2ρKd)/(θ + ρKd), where k1 and k2 are the reaction rate constants in the liquid and solid phases, respectively. θ is the volumetric water content and ρ is the bulk density. By using 5 different soil/water ratios, the values of k1 and k2 were found to be 0.0096 h‐1 and 0.087 h‐1, respectively. The value of k was also estimated from the breakthrough curve in a column experiment by using the relative effluent concentration under steady state condition (C/Co)s.The adsorption of ZnEDTA was negligible under the present experimental conditions. Thus k = k1 and is independent of the water content and bulk density. This was shown by comparing the results of the two experimental techniques. The value of k1 thus found was 0.084 h‐1. The first order model of the fixation reaction of zinc applied as ZnEDTA is applicable for time periods up to 8 to 10 hours.
Landform‐Soil‐Vegetation‐Water Chemistry Relationships, Wrigley Area, N.W.T.: II. Chemical, Physical, and Mineralogical Determinations and Relationships
Authors: Walmsley M. E. , Lavkulich L. M. 
Published: July 2010

AbstractThe relationship among five landforms in terms of chemical, physical, mineralogical, and water chemistry of lakes and the through flowing streams is presented. The landforms occur as a catenary sequence (toposequence) in the intermittent permafrost region of the Mackenzie Valley, N.W.T., Canada. The five landforms are identified as an alpine meadow, an area of stone stripe and stone ring formation, a colluvial slope, an area of coalescing fans and an area of polygonal bog formation. Information collected on the chemical quality of a stream flowing through the area included pH, O2, Ca, Mg, Na, K, Cl, F and NO3. Chemical, physical, and mineralogical analyses of the soils occurring on these landforms illustrated the effect of climate on soil genesis. Cryoturbic action is the dominant process occurring in the stone stripe area while ice segregation is predominant in the area of polygonal bog formation. The limited decomposition of the soil organic matter is related to the harsh climate. Subdued pedogenic development of soils in the coalescing fan area is evident by their youthful profile differentiation. Water chemistry demonstrated the functional and integrated effect between dissolved load in the water and the landform through which the stream has flown.
Nonerodible Aggregates and Concentration of Fats, Waxes, and Oils in Soils as Related to Wheat Straw Mulch
Authors: Smika D. E. , Greb B. W. 
Published: July 2010

AbstractNonerodible (>0.84 mm) soil aggregates and concentration of fats, waxes and oils in the surface 5‐cm depth were determined as related to (i) rates of initial straw mulch, (ii) date of initial fallow tillage, (iii) removal of straw, and (iv) nitrogen fertilization. Nonerodible soil aggregates were also determined as affected by tillage implements commonly used in fallow with residue removed by burning and with residue present.Increasing the amount of wheat (Triticum aestivum L.) straw mulch from 1,680 to 3,360 kg/ha on the soil surface at the start of fallow increased nonerodible aggregation by 5% and fats, waxes, and oils in the soil by 0.019 mg/g of soil. Delaying initial fallow tillage after harvest until spring increased nonerodible aggregates by 3% and fats, waxes, and oils in the soil by 0.052 mg/g of soil. Without N, mulched soil contained 7% more nonerodible aggregates and 0.010 mg more fats, waxes, and oils/g of soil than did bare soil.All implements tested, except the oneway disk, increased initial nonerodible aggregation by 2 to 7% when wheat stubble had been removed prior to the tillage operation. The oneway disk decreased nonerodible aggregation 4%. During subsequent tillage, all implements decreased nonerodible aggregation except the chisel. Successive operation with the oneway disk decreased aggregation the most at 9%/operation.Nonerodible soil aggregates at time of winter wheat seeding (Sept.) and the following spring were highest with a fallow tillage sequence of tandem disk, blade twice, and rodweed with flat chisel points twice. This sequence destroyed 67% of the initial residue. Nonerodible aggregation was lowest when the tandem disk was used three times, followed by rodweeder with flat chisel points twice. These operations destroyed 90% of the original residue. Overwinter decrease in nonerodible aggregation was smallest when only the blade and rodweeder with flat chisel points were used.
Minimal Leaching with Varying Root Depths of Alfalfa
Authors: Bernstein Leon , Francois L. E. , Clark R. A. 
Published: July 2010

AbstractAlfalfa (Medicago sativa L. cv. ‘Sonora’) was grown in greenhouse lysimeters with soil depths of 60, 120, and 180 cm to determine whether rooting depth affected tolerance to the low leaching percentage of 6.25. Salinities of the drainage waters averaged about 6 mmho/cm for the controls irrigated with 0.4 mmho/cm water, and 26 mmho/cm for lysimeters irrigated with 2.0 mmho/cm water. Steady‐state salinity profiles were maintained for 3 years. Yields with the more saline water averaged 23% less than those of the controls, in good agreement with previous findings, but were not significantly affected by lysimeter depth. Water requirements and uptake of chloride and sodium were only slightly affected by lysimeter depth. Salinity profiles with maximum salinities of 26 mmho/cm in the soil water can, therefore, be compressed into as little as a 60‐cm depth with no greater effects on yield or salt uptake by the crop than those obtained with salinity profiles extended over 120 or 180 cm.
A New Ceramic Cup Soil‐Water Sampler
Authors: Harris Alfred Ray , Hansen Edward A. 
Published: July 2010

AbstractA newly designed soil‐water sampler utilizing a miniature porous ceramic cup is suitable for either collecting large samples or for microtechniques. It eliminates sample transfer in the field and contamination from water channeling along sampler, and can be enclosed to discourage vandalism. It also permits immediate preservation of the collected sample.
Two‐Dimensional Similarity Solution: Theory and Application to the Determination of Soil‐Water Diffusivity
Authors: Turner Neil C. , Parlange Jean‐Yves 
Published: July 2010

AbstractThe Bruce and Klute methods (1956) to measure the soil‐water diffusivity (D) relies on the existence of a similarity solution for the one‐dimensional movement of water when the soil‐water potential is maintained constant at one end of a horizontal column of soil. If the flux is kept constant along a line‐source, a similarity solution exists also in two‐dimensions and an exact equation for this case is derived:
urn:x-wiley:03615995:saj2sssaj197503615995003900030013x:equation:saj2sssaj197503615995003900030013x-math-0001 where θo is the initial moisture content, θ is the moisture content after time, t, and ψ is the similarity variable.The application of this equation in measuring the soil‐water diffusivity of a sandy soil is shown.
Specific Adsorption of Trace Amounts of Calcium and Strontium by Hydrous Oxides of Iron and Aluminum
Authors: Kinniburgh D. G. , Syers J. K. , Jackson M. L. 
Published: July 2010

AbstractFreshly prepared Fe and Al hydrous oxide gels and the amorphous product of heating gibbsite selectively adsorbed traces of Ca and Sr from solutions containing a large excess (∼1M) of NaNO3. The fraction of the added Ca (Sr) adsorbed depended principally on the suspension pH, the amount of solid present, and to a lesser extent on the NaNO3 concentration. Significant Ca and Sr adsorption occurred on the Fe and Al gels, and heated gibbsite, at pH values below the points of zero charge (8.1, 9.4, and 8.3±0.1, respectively), indicating specific adsorption. The pH (± 0.10) at which 50% of the Ca was adsorbed (pH50) occurred at pH 7.15 for the Fe gel (0.093M Fe), 8.35 for the Al gel (0.093M Al), and 6.70 for the heated gibbsite (0.181M Al); for Sr, the pH50 values were 7.10, 9.00, and 6.45, respectively. For the Fe gel and heated gibbsite, an empirical model based on the law of mass action described the pH dependence of adsorption reasonably well and suggested that for each Ca or Sr fraction adsorbed, approximately one proton was released. Failure of the Al gel to fit this model may have resulted from its rapid aging.
Infrared Study of the Sorption of Phenol and p‐Nitrophenol by Montmorillonite
Authors: Saltzman S. , Yariv S. 
Published: July 2010

AbstractThe sorption of phenol and p‐nitrophenol by montmorillonite saturated with different cations was studied by IR and X‐ray spectroscopy. Various associations between interlayer cations, water, and phenols were proven. Depending on the nature of the cation, phenol can act either as a proton donor or acceptor. The electrophylic NO2 substituent of the ring increases the acidic strength of the phenol group: therefore, p‐nitrophenol tends to behave mainly as a proton donor. The nitro‐group acts as an electron donor and, depending on the hydration status of the clay, either accepts protons from water coordinated to cations, or directly coordinates to the metallic cations.
Sulfuric Acid for the Treatment of Ammoniated Irrigation Water: I. Reducing Ammonia Volatilization
Authors: Miyamoto S. , Ryan J. , Stroehlein J. L. 
Published: July 2010

AbstractEffects of sulfuric acid applied to ammoniated irrigation waters on ammonia volatile losses are analyzed theoretically and evaluated by laboratory and field experiments. Volatile loss of ammonia from irrigation waters is directly related to the concentration of NH4OH. Sulfuric acid application reduces the concentration of NH4OH relative to the total N applied as anhydrous or aqua ammonia, principally by lowering pH. This consequently reduces ammonia volatile loss, e.g., by as much as 50% when acid is applied at rates equivalent to ammonia. The reduction of ammonia loss by sulfuric acid application through forming NH4SO4‐ is nil. Simultaneous application of acid and ammonia may serve as a practical means of controlling ammonia loss as well as disposing of large quantities of projected surplus acid without reducing pH of irrigation water.
Potassium‐Calcium Equilibria in Sandy Soils Containing Interstratified Micaceous Clay
Authors: Murthy A. S. P. , Dixon J. B. , Kunze G. W. 
Published: July 2010

AbstractNeutral to alkaline soils from several climatic and physiographic locations were studied. The clay mineralogy of these soils was characterized by interstratified mixtures of mica, montmorillonite and little vermiculite. X‐ray diffraction patterns for the most abundant clay fraction, < 0.2 µm, were composed of weak diffuse reflections for mica‐expansible components when they were Mg‐saturated and glycolated. Sand and silt fractions contained K‐feldspar and mica as possible sources of K+.The two most micaceous soils produced Q/I curves with a horizontal range indicating further K+ sorption ceased in spite of the increased K+/Ca2+ ratio. The amount of K+ in the labile pool determined by the Q/I method was correlated best with the amounts of mica in the whole soil (r2 = 0.89) suggesting that mica in coarse and fine fractions acted as a potential source of labile K+ in these soils. A multiple regression equation was developed that predicted the amount of K+ in the labile pool from the amounts of mica and feldspar in the soil (R2 = 0.96). The results of this study suggest that mica in these soils will contribute K+ to the labile pool. The multiple regression coefficient indicated that feldspar content was negatively related to labile K+.