bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Impact of Harvesting and Site Preparation on the Physical Properties of Lower Coastal Plain Forest Soils
Authors: Gent J. A. , Ballard R. , Hassan A. E. 
Published: July 2010

AbstractThe impact of intensive forest management practices on soil physical properties was examined by collecting intact, 7.6‐cm diameter soil core samples to a depth of 30 cm before harvest, after harvest, and after site preparation in plots established in primary skid trails and areas receiving whole‐tree and conventional tree‐length harvesting treatments. Site preparation for all plots was shear, burn, chop, and bed. Harvesting increased bulk density and decreased aeration porosity in all sampled areas. Significant changes in these properties were detected to the 30‐cm depth in the skid trail plots. However, significant changes in the whole‐tree and tree‐length plots were limited to the upper 15 cm of soil. Harvesting also significantly decreased saturated hydraulic conductivity to a depth of 8 cm in the skid trail plots and 15 cm in the tree‐length plots but had no significant effect in the whole‐tree plots. Bedding proved to be effective in offsetting soil compaction in the whole‐tree and tree‐length plots by forming a new soil surface, 19 cm in height, over the surface which was trafficked during harvest. Bedding may not be as effective in the skid trail plots because the soil found at the original surface under the bed was compacted to the extent that root growth may be inhibited.
A Technique for Parallel Placement of Access Tubes
Authors: Römkens M. J. M. , Whisler F. D. 
Published: July 2010

AbstractA technique has been developed for parallel insertion of access tubes into a soil. The technique requires hydraulic equipment of the Giddings type supplemented with machined attachments. The results show a minimum of nonparallelism in both the parallel and perpendicular directions to the plant row.
A Pressure Transducer for Field Tensiometers
Authors: Marthaler H. P. , Vogelsanger W. , Richard F. , Wierenga P. J. 
Published: July 2010

AbstractField‐installed tensiometers are generally equipped with pressure gauges or mercury manometers. These read‐out devices require much maintenance, while the cost of gauges is high when used in large quantities. This paper describes a pressure transducer system for field‐installed tensiometers. The system consists of a pressure transducer with attached syringe needle and digital read‐out. The needle is inserted through the septum stopper which closes the upper end of the tensiometer. The pressure in the air below the septum stopper, in equilibrium with the water pressure, is read on the digital read‐out, which is calibrated in millibars. Upon withdrawal of the needle from the tensiometer, the septum stopper seals the tensiometer. The pressure transducer system is easy to use and requires little maintenance. Possible errors with the measurement system are discussed.
Calculation of Sorptivity from Constant‐Rate Rainfall Infiltration Measurement
Authors: Chong S.‐K. 
Published: July 2010

AbstractThe incipient ponding time equation developed by Kutilek and Parlange and Smith were rearranged and used for calculating sorptivity under constant‐rate rainfall conditions. The equations were tested using the field‐measured data obtained in Hawaii by Dangler et al. In the calculation, the incipient ponding time is assumed equal to the time of first appearance of runoff from the experimental plot. Additionally, the A value in the Philip two‐term infiltration equation is assumed to the Ksat/3. The results showed that the sorptivity values calculated from both equations have only a 1.22% difference. The accuracy of the calculated sorptivity was assessed by its use for predicting infiltration. In the comparison of cumulative infiltration, the correlation coefficient between measured and estimated values is > 0.9 with a mean error percentage of 20.09 and a median of 10.57%.
Use of Kinetics for the Study of Exchange Reactions in Soils
Authors: Harter Robert D. , Lehmann Robert G. 
Published: July 2010

AbstractSince exchange reactions are exceedingly rapid and soil phases must be separated for analysis, kinetic methods are difficult to use for their characterization. However, these methods can be used to identify the extent and contribution of exchange reactions to the retention of adsorbate ions. The difference between theoretical start concentration and the intercept of a log‐normal plot of a kinetic reaction indicates the magnitude of the initial reaction(s), and a charge balance between ions lost from solution and exchange ions gained by solution will confirm whether the reaction is partly or entirely exchange. Using different initial concentrations, it is possible to construct isotherms for the exchange reaction.
Soil Acidity and Liming: I. Effect of the Extracting Solution Cation and pH on the Removal of Aluminum from Acid Soils
Authors: Oates Kenneth M. , Kamprath E. J. 
Published: July 2010

AbstractExtractable Al is one criterion used for predicting the lime requirement of acid soils; therefore, a reliable measurement of extractable Al across a broad range of soil properties is desirable. The amount of Al removed from exchange sites may be affected by the exchanging cation and the extracting solution pH. This study was conducted to determine (i) the efficiency of Cu, La, and K, and (ii) the effect of solution pH in removing Al from soils with different organic matter content. Nine soils with an organic matter range of 0 to 58% were successively extracted seven times with Cu2+, La3+, and K+ nonbuffered chloride salt solutions and buffered acetate solutions at three pH values. With the buffered acetate solutions there was no cation effect in the removal of Al from mineral soils, but for organic soils (> 30% organic matter) there was an efficiency order with Cu > La > K. The nonbuffered chloride salts of La and K removed similar amounts of Al from mineral soils, but La removed more Al than did K from organic soils. The Al removed was linearly related to extractant solution pH for organic soils, but did not change appreciably for mineral soils when the solution pH was below pH 4.2.
Application of Phosphorus, Potassium, and Zinc to Corn Grown for Grain or Silage: Nutrient Concentration and Uptake
Authors: Rehm G. W. , Sorensen R. C. , Wiese R. A. 
Published: July 2010

AbstractAlthough the nutrient composition of the ear leaf of corn (Zea mays L.) at tasseling or silking has been used widely in estimating the nutrient status of this crop, addition of a fertilizer to correct a discovered nutrient deficiency is very difficult, if not impossible, at this late stage of growth. Development of “critical” levels of plant nutrients in corn tissue at earlier stages of plant development should he more practical and useful. Twenty‐three treatment combinations of rates of P, K, and Zn from a 53 factorial arrangement were selected and applied annually to a sandy soil for irrigated corn that was grown for either silage or grain production from 1974 through 1978. Whole plant samples were collected when the corn was 40 to 60 cm tall. Ear leaf samples at silking and grain and whole plant samples at physiological maturity were collected. All samples were analyzed for P, K, and Zn.The P concentration in whole plants at the early growth stage increased linearly as the rates of applied P and K were increased. In general, the P concentration of the ear leaf at silking increased linearly as the rate of applied P was increased for both systems of harvest. For the whole plant samples at the early growth stage, the critical P level was 0.220% P in the silage harvest system and 0.256% P in the grain harvest system. The critical levels for the ear leaf at silking were 0.220 and 0.225% P for the respective harvest systems. Phosphorus uptake by young plants, compared to the P concentration, was more closely associated with relative yield. When corn was harvested for silage, P uptake by young plants, rather than the P concentration of the ear leaf, was more closely associated with relative yield in 3 of the 5 years. Under the grain harvest system, P uptake by young plants was more closely associated with relative yield compared to the P concentration of the ear leaf tissue in all years.
Formation of Calcic and Argillic Horizons in Selected Soils of the Texas Coast Prairie
Authors: Sobecki T. M. , Wilding L. P. 
Published: July 2010

AbstractIn a previous paper the soil‐geomorphic relationship and microtopographic expression were described for Mollisols with calcic horizons and associated noncalcareous Alfisols of the Texas Coast Prairie. This paper describes the development of calcic and argillic horizons in the above soils. Microfabric of soil carbonates, carbonate clay depth functions, and acid residues from carbonate nodules confirm the pedogenic nature of carbonates in the Mollisols. Carbonate contents in the calcic horizons range up to 40%, with up to 50% of the total carbonates in the clay‐size fraction. Clay‐size carbonates have impregnated the soil matrix in the upper part of the main zone of carbonate accumulation, forming a dense K‐fabric. Such abundance and expression decrease with depth. Complex pedological features—fine‐grained calcans, crystallaria, and coarse‐grained carbonate glaebules—in lower horizons of the Mollisols suggest a fluctuating water table within 1 m. Carbonate‐free clay distribution data supported the microfabric analyses, which indicate the lack of argillic horizons in the Mollisols. Associated leached Alfisols have well‐expressed argillic horizons. Lateral redistribution of allogenic and authigenic carbonates from microdepressions to adjacent micro‐highs via saturated and unsaturated moisture flow is proposed to explain carbonate distribution in some landscapes of the Texas Coast Prairie. A weathering origin for the carbonates was discounted because weatherable minerals in parent sediments were insufficient to account for the 550 to 750 kg/m2 of carbonate in the calcic horizons. Carbonates inherited with fluviatile‐deltaic sediments are considered the single most plausible carbonate source for these soils.
Bromide and Phosphate in Runoff Water from Shaped and Cloddy Soil Surfaces
Authors: Ahuja L. R. , Lehman O. R. , Sharpley A. N. 
Published: July 2010

AbstractEffects of soil surface shaping and clods on the release of applied bromide and phosphate to runoff were investigated experimentally with small pervious boxes and simulated rainfall. The soil material used for the surface shaping experiment was a sample of Ruston loam subsoil, < 4 mm in size. Phosphate as Ca (H2PO4)2 · H2O was mixed with the dry soil (0.008% P by weight) before packing in boxes. Triangular ridges, 3.5 cm in width and 1.7 cm in height, were made either along the slope or across the slope of the soil surfaces. Both types of ridges exposed about 12% more surface area than the control soil boxes without ridges. The soil boxes were wetted with a KBr solution (4000 ppm Br) before application of rainfall. Average Br concentration of runoff from a 1‐h, 6.8 cm/h, rainfall in both lengthwise‐ and cross‐ridged boxes was nearly four times that of the control boxes. The ridging also increased dissolved and reactive P concentration of runoff, but only by about 15%. When the upper 2.5 cm of the packed soil consisted of 4‐ to 20‐mm clods, the average Br concentration of runoff was nearly 48 times that of the control, even though the infiltration was 2.5 times more. Increasing the thickness of the surface cloddy layer to 5.0 cm delayed the start of runoff considerably, and yet the Br concentrations of runoff were higher then those with a 2.5‐cm layer of clods. In another soil (Parsons clay subsoil material), having more stable clods than Ruston loam, the Br concentrations of runoff were two orders of magnitude greater than control.
Field‐Measured Limits of Soil Water Availability as Related to Laboratory‐Measured Properties
Authors: Ratliff L. F. , Ritchie J. T. , Cassel D. K. 
Published: July 2010

AbstractAccurate evaluation of the soil water reserves available for plant use is vital in developing optimum water management for crop production in marginally dry regions. Laboratory estimates of the upper and lower limits of soil water availability used to calculate the soil water reservoir often deviate significantly from the limits measured in the field. To make a unified and broad assessment of the accuracy of laboratory measurements for estimating field soil water, we obtained and evaluated a comprehensive data base of field‐measured upper and lower limits of the soil water reservoir. The field‐measured upper limit was taken as the water content at which drainage from a prewetted soil had practically ceased. The lower limit was taken as the water content of the soil at which plants were practically dead or dormant as a result of the soil water deficit. These field‐measured limits were compared to laboratory measurements at −0.33 and −15 bar made on samples removed from each field site. A total of 401 observations were available for the comparisons of −15 bar measurements to the field‐measured lower limits and 282 observations of −0.33 bar measurements were available for comparison with the field‐measured upper limit. Variation often existed within a soil series at a particular site for the field‐measured upper and lower limits. However, the differences between the field‐measured limits, the total available water reservoir, were relatively constant. Crop species caused only minor differences in the lower limit water content for the upper part of the soil profile where root length density was apparently above some critical limit. However, some annuals extracted water to greater depths than others. The laboratory estimates of the upper limit obtained by −0.33 bar water contents were significantly less than the field‐measured drained upper limit for sands, sandy loams, and sandy clay loams and were significantly more than field measurements for silt loams, silty clay loams, and silty clays. The laboratory estimates of the lower limit obtained by −15 bar water content measurements were significantly less than field lower limit measurements for sands, silt loams, and sandy clay loams and significantly more than field observations for loams, silty clays, and clays. Because our study included relatively few measurements of loamy sands, silts, sandy clays, and clays, it was difficult to generalize about differences in field‐measured and laboratory‐estimated water limits for those textures. The results suggest that if absolute accuracy is necessary in water balance calculations, laboratory‐estimated soil water limits should be used with caution and field‐measured limits, if available, would be preferred.
Relationships Among Iron, Aluminum, Carbon, and Sulfate in a Variety of Forest Soils
Authors: Johnson Dale W. , Todd D. E. 
Published: July 2010

AbstractAmong several soil properties tested, percent Fec (i.e., Fe by citrate‐dithionite minus oxalate extraction) was the single parameter most closely related to SO2‐4 adsorption properties in a variety of forest soils. There were exceptions to this general relationship, however, and a combination of percent C, citrate‐dithionite, and oxalate extractions for both Fe and Al appear most promising in predicting sulfate adsorption. Percent clay, pH, and pyrophosphate‐extractable Fe + Al were either insignificantly or inconsistently related to SO2‐4 adsorption. Because organic matter had a decidedly negative influence upon SO2‐4 adsorption, surface soils and B horizons of Spodosols (and highly podzolized soils) had relatively poor SO2‐4 adsorption properties, even when their dithionite‐extractable Fe values were high. Organic matter also reduced Fe crystallinity (i.e., increased Feo/Fed, or the ratio of oxalate to dithionite Fe), and the results of this study suggest that crystalline rather than amorphous, inorganic Fe (i.e., oxalate minus pyrophosphate Fe) is most highly correlated with adsorbed, water‐insoluble SO2‐4.
Direct Colorimetric Measurement of Ammonium in Potassium Chloride Extracts of Soils
Authors: Dorich R. A. , Nelson D. W. 
Published: July 2010

AbstractAlthough 2M KCL is widely used as an extractant for inorganic N in soils, there is no manual colorimetric methods for direct measurement of ammonium‐N (NH+4‐N) in KCl extracts. The indophenol blue method previously used for measurement of NH+4‐N in aqueous solutions has been modified to permit estimation of NH+4‐N in extracts of soils. The method entails the addition of 1 mL of 6% (wt/v) disodium ethylene‐diamine‐tetraacetic acid (EDTA) solution to an aliquot of a 2M KCl extract of soil followed by addition of phenol‐nitroprusside and buffered hypochlorite reagents. Maxiumum color development occurs in 60 min at room temperature (23°C), but color development time is reduced to 30 min and molar absorptivity of the chromophore is enhanced (60%) by incubation of the sample at 40°C. Although previous studies have shown that precipitates form when indophenol blue color developing reagents were added to KCl extracts of soils, the addition of EDTA eliminated precipitate formation in samples containing as much as 6 mg of Ca2+ or 4 mg of Mg2+ per 25 mL of final analytical volume. The proposed procedure quantitatively measures the NH+4‐N present in KCl extracts of soils and is sensitive to concentrations of NH+4‐N as low as 0.2 µg per 25 mL of final analytical volume. The proposed procedure was the most precise of the three NH+4‐N methods (steam distillation and acidimetric titration, steam distillation into phenol‐nitroprusside and NH+4‐N determination by the indophenol blue colorimetric method, and the proposed procedure) studied. The proposed method provides a sensitive, precise, and accurate colorimetric method for direct measurement of NH+4‐N in KCl extracts of soils.
Kinetics of Nonexchangeable Potassium Release from Two Coastal Plain Soils
Authors: Martin H. W. , Sparks D. L. 
Published: July 2010

AbstractThe kinetics of nonexchangeable‐K release using H‐saturated resin were investigated on Kalmia (fine‐loamy, siliceous, thermic Typic Hapludults) and Kennansville (loamy, siliceous, thermic Arenic Hapludults) soil profiles from the Coastal Plain of Delaware. Calciumsaturated soil samples were equilibrated with H‐saturated resin from 0.5 to 960 h. Equilibrium in K release in both soil profiles was attained in about 960 h. The kinetics of K release were evaluated using the Elovich, parabolic diffusion law, first‐order diffusion, and zero‐order equations. The first‐order diffusion equation described the K‐release kinetics best as evidenced by the highest correlation coefficient (r) and the lowest value of the standard error of the estimate (SE). The parabolic diffusion law also described the data satisfactorily indicating diffusion‐controlled exchange. The zero‐order and Elovich equations did not describe the data well as shown by higher SE values than those found with the first‐order diffusion and parabolic diffusion law equations. Nonexchangeable‐K release rate coefficients (k2) ranged from 1.20 to 2.2 × 10−3 h−1 in the Kalmia soil and from 1.5 to 2.9 × 10−3 h−1 in the Kennansville soil. The magnitude of the k2 values suggested low rates of nonexchangeable‐K release from the two soils.
Effect of Precipitation of Alkaline Earth Carbonates and Magnesium Hydroxide on Na‐Ca‐Mg Exchange in Wyoming Bentonite
Authors: Levy Rachel , Tanji K. K. , Whittig L. D. 
Published: July 2010

AbstractWyoming bentonite saturated with Ca and Mg at five different ratios was equilibrated with NaCl solution. It was found that the preference of the bentonite for Ca over Mg was not affected by the presence of exchangeable Na. The separation factor, αNaCa+Mg, of the bentonite equilibrated with NaCl was compared to that of bentonite in which alkaline earth carbonates and magnesium hydroxide precipitated. It was found that in the presence of alkaline earth precipitation only, αNaCa+Mg was a function of ionic strength and equivalent fraction of soluble Na. However, precipitation of the carbonates caused a different distribution of the exchangeable ions in the bentonite crystallite compared to the distribution in the absence of precipitation. Where carbonates precipitated, Na was found between the interlayers and Ca and Mg occupied the outside surfaces of the clay. As the pH of the equilibrium solution increased and additional precipitation of alkaline earth carbonates and magnesium hydroxide occurred, αNaCa+Mg increased with decrease in ionic strength. Apparently this increase in the preference for Na was due to the restriction on Na, occupying the internal surface of the bentonite, to diffuse into the equilibrium solution because of hydroxide coating of the crystallites.
Cation Selectivity in Sodium‐Calcium, Sodium‐Magnesium, and Calcium‐Magnesium Exchange on Wyoming Bentonite at 298 K
Authors: Sposito Garrison , Holtzclaw Kenneth M. , Jouany Claire , Charlet Laurent 
Published: July 2010

AbstractExchange isotherms were prepared for Na+ in Na+→Ca2+ and Na+→Mg2+ exchange reactions, and for Mg2+ in Na+→Mg2+ exchange reactions, at 298 K on Wyoming bentonite suspended in a 0.05M perchlorate background. These isotherms were essentially congruent with the appropriate thermodynamic nonpreference exchange isotherms. It was concluded from this fact that there is essentially no difference in the affinity of montmorillonite clay for Ca2+ vs. Mg2+. However, exchange isotherms prepared for Na+ in Na(I) → Ca(II) and Na(I) → Mg(II) exchange, as well as published ones for Mg(II) in Ca(II) → Mg(II) exchange on montmorillonite suspended in a 0.05M chloride background consistently indicate a slight preference on the clay for Ca(II) over Mg(II). This preference for Ca(II) is concluded to be the result of the formation of CaCl+ complexes, which are more stable thermodynamically and have a greater affinity for the clay than MgCl+ complexes.
Soil Temperature Regimes in Nevada
Authors: Schmidlin T. W. , Peterson F. F. , Gifford R. O. 
Published: July 2010

AbstractEstimates of the 12‐month mean annual soil temperature (MAST) for well‐drained soils in Nevada can be made from two—or better—three, four, or six equally spaced monthly readings. A regression of MAST (°C) against elevation (ELEV), in meters, and latitude (LAT), in decimal degrees, using 84 well‐drained sites with < 15% slope, allows estimation of MAST for similar soils in Nevada by the equation: MAST = 50.1 − 0.0064(ELEV) − 0.66(LAT). This equation was used to construct a soil temperature regime map for Nevada that shows mesic soils are by far most extensive, thermic soils next most extensive, and that inextensive hyperthermic soils occur only in southern Nevada. Frigid and cryic soils are inextensive and occur only high on major mountain ranges or isolated peaks. Comparison of minimum elevations of frigid and cryic soils suggests that the latter are much more common in the steep mountains where they both occur. These elevations were estimated from the MAST regression and a second regression for mean summer soil temperature (MSST) using the same sites: MSST = 72.4 − 0.0077(ELEV) − 0.95(LAT). Steep slope and aspect affect both MAST and MSST in the high mountains, hence affect the location of mesic/frigid/cryic boundaries. Pergelic soils probably do not occur in Nevada.