bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of the Mass Spectral Analysis of Soil Inositol, Inositol Phosphates, and Related Compounds
Authors: L'Annunziata Michael F. , Fuller Wallace H. 
Published: July 2010

AbstractThe potential of mass spectrometry in the structure analysis of soil inositol, inositol phosphate carbon, and soil microbial metabolites was evaluated. Mass spectra of myo‐inositol (I) isolated from the organic phosphate fraction of a forest soil, quebrachitol (II), myo‐Inositol hexaacetate (III), d,l‐epi‐inosose (IV), and of compounds I and II labeled with deuterium in the hydroxyl groups were determined. Intense fragment ion spectral peaks at mass/charge (m/e) 60, 73, and 102 were common to each of the natural occurring cyclitol structures studied. Structural variations of inositol were found to be identifiable by peak shifts from m/e 60, 73, and 102 to other m/e values as due to attached groups or to other carbon oxidation states. An exchange of the hydroxyl protons with deuterium permitted the determination of the number of hydroxyl groups on a given mass spectral ion fragment and supplied evidence for the presence of attached groups. Studies dealing with phosphated compounds in soils required a hydrolysis of the phosphate esters prior to the mass spectral analysis. The mass spectral analysis was found most useful for the identification of cyclitol structures in soil, microbial, and plant metabolism studies when the sample size is limited to microgram quantities.
Fate of Fertilizer Nitrogen in a Flooded Rice Soil
Authors: Patrick W. H. , Reddy K. R. 
Published: July 2010

AbstractIn order to improve the efficiency of fertilizer N utilization by rice (Oryza sativa L.), it is important to know what happens to N applied to the soil. Field experiments utilizing 15N‐enriched ammonium sulfate were carried out to determine the fate of fertilizer N (100 kg N/ha) applied to Crowley silt loam soil. The distribution of fertilizer N in the plant‐soil system at harvest time was determined using 2.32 m2 plots. The distribution of fertilizer N in the plant‐soil‐floodwater system at six times during the growing season was measured in smaller plots (0.28 m2).The results from the larger plots showed that fertilizer N recovered in the grain ranged from 30.9 to 37.3 kg N/ha depending on the method of application. Recovery of fertilizer N in the straw ranged from 18.2 to 24.2 kg N/ha. A considerable portion of fertilizer N (24.2 to 27.1 kg N/ha) remained in the soil (including roots) after cropping. Total recovery of the 100 kg/ha addition of labelled fertilizer N in the soil‐plant system was 75.0 to 85.6 kg N/ha for the different methods of N application examined. Experiments using the smaller 0.28 m2 plots showed rapid uptake of fertilizer N immediately after application, with no apparent further uptake after about 3 weeks. Soil N was the major and perhaps sole source of N for the plant during the last part of the growing season.
Analytical Properties of the Soluble, Metal‐complexing Fractions in Sludge‐soil Mixtures: II. Comparative Structural Chemistry of Fulvic Acid
Authors: Sposito Garrison , Holtzclaw Kenneth M. , Baham John 
Published: July 2010

AbstractThe fulvic acid fractions of three representative sludge‐soil mixtures were extracted, purified, and then studied for their analytical properties. The fulvic acids extracted from sewage sludge (SS fulvic acids) were found to contain from 20 to 40 times as much S as a typical fulvic acid extracted from natural soil organic matter (SOM fulvic acid). Two of the SS fulvic acids also had somewhat less O than a typical SOM fulvic acid. Ultraviolet and visible spectra of the SS fulvic acids suggested that they may be highly aromatic materials and that they may have condensed structures, comparable even with those in SOM humic acids, in those cases where the O content is relatively low. The aromatic nature of the SS fulvic acids could be inferred indirectly from their X‐ray diffraction patterns, which yielded a γ‐band centered more nearly at 4Å than 5Å, thus implying a relatively small content of aliphatic components.The infrared spectra of the SS fulvic acids were generally similar to the Type III spectrum of SOM fulvic acid: The absorption due to C = O in carboxyl groups is not pronounced and the presence of polysaccharides and protein decomposition products is indicated. The spectra differed importantly from the Type III spectrum in showing bands due to the sulfone group and to functional groups substituted on aromatic rings.Metal‐SS fulvic acid solutions were extracted directly from the three sludge‐soil mixtures and were fractionated on Sephadex G‐10 gel. It was found that Cu, Fe, and Zn were complexed by SS fulvic acid, but that Cd and Ni were not. The relative order of complex stability for Ni and Zn implied by these results is different from what has been reported for SOM sulvic acids.
Cadmium Availability to Rice in Sludge‐amended Soil under “Flood” and “Nonflood” Culture
Authors: Bingham F. T. , Page A. L. , Mahler R. J. , Ganje T. J. 
Published: July 2010

AbstractRice plants (Oryza sativa var. ‘Colusa’) were grown to maturity in pots containing a soil (Domino silt loam, pH 7.5, Xerollic calciorthid) amended with 1% sewage sludge enriched with variable amounts of CdSO4 ranging up to 640 µg Cd/g. Two sets of soil cultures were used, one for rice under continuous flood and the other under nonflood conditions. Grain production for rice under flood management was relatively unaffected by the Cd treatment; 25% yield decrement was associated with a treatment of 320 µg Cd/g. Under nonflood management, however, a comparable decrement in grain production was observed with a treatment of only 17 µg Cd/g. The Cd content of mature leaves at early flowering varied from approximately 0.3 µg Cd/g for the controls to 2.8 µg Cd/g for plants receiving the highest Cd treatments. Leaf Cd values were slightly higher under the nonflood culture. The Cd content of the grain under nonflood management was approximately 55% greater than that of grain under flood management. The Cd content of mature leaves correlated with grain production (r = 0.872***) for rice produced under either flood or nonflood culture. Chemical analysis of saturation extracts revealed greatly reduced Cd concentrations in soil solutions under flood management which may account for the greater tolerance of the cultivar to soil Cd under flood culture. This reduced availability of Cd in flooded soils is attributed to precipitation of CdS.
Genesis of Argillic Horizons in Soils Derived from Coarse‐textured Calcareous Gravels
Authors: Rostad H. P. W. , Smeck N. E. , Wilding L. P. 
Published: July 2010

AbstractSoils with fine‐textured argillic horizons overlying calcareous gravel are of widespread occurrence on terraces, kames, and eskers in Ohio. The objective of this study was to determine if the argillic horizon in these soils, generally containing 25–50% clay, could develop from a calcareous gravelly deposit containing < 10% clay. Two pairs of sites were chosen, one pair developed on gravel material containing 60% carbonates, the other pair on gravel containing 40% carbonates. One member of each pair occurred on a terrace whereas the other occurred on a kame.A reconstruction technique utilizing Ti and Zr contents of the soil fraction >2 µm was used to calculate the gains and losses of various constituents in the solum relative to the parent material. The residue remaining after acid dissolution of carbonates was determined for gravel, sand, and silt fractions. The carbonate content of the C horizons ranged from as high as 90% in the 16–32 mm fraction to < 5% in the clay fraction. Dissolution of carbonates and addition of clay residue from the carbonate rocks decreased the gravel content from 75 to 52% and increased the clay content from 1.4 to 10.3%. A calculation of gains and losses for weathered solum shows substantial gains of clay, silt, and sand which is balanced by a loss of gravel. It has been proposed that the gain in sand, silt, and clay is a result of disintegration of shale, siltstone, sandstone, and crystalline lithics in the sand and gravel fractions. It is therefore concluded that fine‐textured B horizons could develop from coarse‐textured calcareous gravelly outwash.
Loess Identification in Soils of Southeastern Pennsylvania
Authors: Carey J. B. , Cunningham R. L. , Williams E. G. 
Published: July 2010

AbstractA silty mantle generally 1 m thick in southeastern Pennsylvania was thought to be loess. Sorting coefficients determined from particle size analysis of horizons from 20 profiles indicate the silty materials are well sorted. Bartlett's (X2) test for homogeneity of variances of the percent clay‐free silt among 21 profiles of Duncannon soils shows a homogeneous population having a mean variance of 3.9. A mean variance of 2.3 was determined for Fayette, a known Midwest loess soil. Transects through the area of thickest loess show percent very fine sand decreasing from south to north. The mean percent very fine sand of the profiles in each transect shows a decrease from east to west. The physical properties, sorting coefficients, and homogeneity indicate the silty mantle is loess. The mantle's geographic location, gradation in thickness, and very fine sand content indicate that the Coastal Plain and the adjacent rivers are probable source areas for the loess.
Erosion of Selected Hawaii Soils By Simulated Rainfall
Authors: Dangler E. W. , El‐Swaify S. A. 
Published: July 2010

AbstractErodibilities, or K values of the universal soil loss equation, were determined for ten soils representing five soil orders on the islands of Oahu and Hawaii. Two successive simulated rainstorms were used, each with an approximate intensity of 6.35 cm/hour and duration of 2 hours. Values obtained covered the wide range from 0 to 0.60 metric tons/ha per metric erosion index × 0.00774 (tons acre‐1 erosion index‐2)3 and, in most cases, were higher for the second (wet) than for the first (dry) storm. Erodibility values for cropped Oahu soils, belonging to four soil orders, ranged from 0 to 0.26 for dry storms and from 0.001 to 0.41 for wet storms. Values for volcanic ash soils on Hawaii, belonging to only two orders, had the considerably wider range of 0.08 to 0.60 for dry storms and 0.07 to 0.51 for wet storms. Three of these soils exhibited essentially the same erodibility for dry and wet conditions.Dry and wet values were combined to calculate a weighted mean erodibility for each soil based on the distributions of natural rainfall throughout the year at the test sites. The weighted erodibility of a soil at a given location was in general, inversely related to the amount of natural precipitation at that location.
Predicting Runoff Initiation Times Under Field Conditions in Tropical (Hawaii) Soils
Authors: Ahuja L. R. , Dangler E. W. , El‐Swaify S. A. 
Published: July 2010

AbstractRunoff initiation times measured during field rain‐simulation studies on 10 important Hawaii soils are examined in relation to antecedent soil‐water status. The experimental data show considerable scatter due mainly to natural soil variability within a soil series. However, the data exhibited a fairly proportional relationship between runoff initiation time and antecedent soil saturation deficit (final minus initial soil‐water content), in accordance with a simple Green‐Ampt type equation. The results indicate a potential method for estimating erosive portions of rainstorms and subsequent soil loss hazards in relation to varying antecedent soil‐water contents during different seasons of the year.
The Transfer of Heat and Hydrophobic Substances During Burning
Authors: Debano L. F. , Savage S. M. , Hamilton D. A. 
Published: July 2010

AbstractWet and dry sand was tested for water repellency, after burning pine litter (Pinus coulteri D. Don). Four conditions were studied: a burn of 25 min over dry or wet sand and a burn at 5 min over dry or wet sand. The thickest and most intense water‐repellent layer was produced by a 5‐min burn over dry sand. Although organic materials were translocated deeper in the dry sand during the 25‐min burn (down to 4 cm), some of the water repellency was destroyed in the upper 1‐cm layer. In wet sand, water repellency was concentrated in the upper 0‐ to 1.5‐cm layer. The translocation of hydrophobic substances and resulting water repellency depends on changes in their polarity and oxidation state. Relationships developed for fire over a dry soil may not adequately account for movement of organic substances in a moist soil. These results suggest prescribed burning should be done when the soil is moist on areas where water repellency is a problem.
The Necessity of Independent Testing of Soil‐Site Equations
Authors: McQuilkin Robert A. 
Published: July 2010

AbstractA black oak (Quercus velutina) soil‐site study in Missouri has shown that the standard regression statistics (R2, standard error, etc.) of soil‐site equations are not reliable indicators of the accuracy of these equations. Data from 54 plots were used to derive a soil‐site equation that had an R2 of 0.66 and a standard error of 1.00 m. These statistics plus a graphed comparison of observed vs. predicted site indexes indicated that the equation satisfactorily predicted site index. When the equation was tested with data from 27 additional plots, however, the correlation between the observed and predicted site indexes had an R2 of only 0.01 and a standard error of 1.81 m. These statistics plus a graphed comparison of observed vs. predicted site indexes showed that the equation was completely unreliable as a site index predictor.Inadequate sampling, incomplete data analysis, or chance correlations may have caused the errors in the equation, but the errors were undetectable until the equation was tested with the independent data.
Large‐scale Zonal Rotors in Soil Science
Authors: Francis C. W. , Brinkley F. S. , Bondietti E. A. 
Published: July 2010

AbstractA large‐scale zonal rotor was developed to band isopycnically soils and sediments in nonaqueous density gradients. The major advantage of such a rotor over conventional swinging bucket rotors is that relatively large quantities may be segregated; 15 g in large‐scale zonal rotors vs. 0.25 g per centrifugal tube with swinging bucket rotors. The rotor was used to isolate and identify soil‐sediment reaction sites of 137Cs, 60Co, and 106Ru. The 137Cs was found to be associated with micaceous minerals, the 60Co with Fe‐sesquioxides, and the 106Ru with organic rich soil components. An edge‐unloading rotor containing sucrose gradients (max. density 1.3 g/cm3) was used in a rate‐zonal mode to isolate Cd and Ni enriched fractions of sediment taken near the wastewater discharge of a Cd‐Ni battery plant. In sediments enriched in carbonates, Cd was found to be largely associated with the carbonates while Ni was concentrated in the organic rich soil components. Biological availability of Cd was evaluated by growing bush bean seedlings (Phaseolus vulgaris L.) in nutrient solutions containing density fractions of a soil clay. Density gradient separations using large‐scale rotors were shown to be a valuable adjunct to chemical extraction techniques for characterizing trace element interactions with soils and sediments.
Adsorption of Alkaline Earth, Transition, and Heavy Metal Cations by Hydrous Oxide Gels of Iron and Aluminum
Authors: Kinniburgh D. G. , Jackson M. L. , Syers J. K. 
Published: July 2010

AbstractFreshly precipitated Fe and Al gels (points of zero change at pH 8.1 and 9.4, respectively) strongly specifically adsorb divalent cations from 1M NaNO3 solution. Adsorption from a mixed solution of eight divalent cations (each 0.125 × 10‐3M) in suspensions of freshly precipitated Fe and Al gels (0.093M with respect to Fe or Al) was measured as a function of pH in 1M NaNO3. The selectivity sequence (lower pH = greater selectivity) for the retention of the alkaline earth cations by Fe gel was Ba > Ca > Sr > Mg, but for the Al gel was Mg > Ca > Sr > Ba. The selectivity sequence (Figures in parentheses indicate pH ± 0.2 for 50% retention) for the Fe gel was: Pb (3.1) > Cu(4.4) > Zn(5.4) > Ni(5.6) > Cd(5.8) > Co(6.0) > Sr(7.4) > Mg(7.8), whereas the sequence for the Al gel was: Cu(4.8) > Pb(5.2) > Zn(5.6) > Ni(6.3) > Co(6.5) > Cd(6.6) > Mg(8.1) > Sr(9.2). Significant adsorption occurred even when the extent of cation hydrolysis was much < 1%, and invariably occurred at a pH lower than that for hydroxide precipitation. Although the adsorption‐pH sequences are related to cation hydrolysis and hydroxide precipitation pH values, the relationship is far from perfect, as is evidenced by the different sequences for the two gels. On aging of the Al gel in the presence of alkaline earth cations, the retention of Mg increased, while that of Ca, Sr, and Ba decreased. This result was thought to result from the structural incorporation of some Mg and the exclusion of the other cations.
Experimental Study of Wetting Front Instability Induced by Sudden Change of Pressure Gradient
Authors: White I. , Colombera P. M. , Philip J. R. 
Published: July 2010

AbstractTwenty‐two experiments were performed on stability of infiltration flows in Hele‐Shaw cells. Flows were perturbed by suddenly changing G, the pressure gradient behind the wetting front, from a definite negative to a definite positive value. Three methods were used: (i) increasing air‐pressure ahead of the front, (ii) employing a nonwetting stratum, and, (iii) suddenly stopping liquid supply and preventing air‐entry. Glycerol and silicone, with contrasting properties, were used as the infiltrating liquids. The experiments confirmed the theory of Philip (1975a): immediately G was made positive, all flows became unstable, and the observed wavelengths of fingering agreed closely with those predicted by the theory.A modification of the theory to take account of the geometry of the microscopic air‐liquid interface predicts wavelengths in soil about twice as large as does the original theory. A preliminary experiment on infiltration of water in a coarse sand confirmed the theory qualitatively, but the observed wavelength was twice that predicted theoretically. In a preliminary experiment on infiltration in a fine sand, perturbation failed to produce instability. This divergence from theory is attributed to deviations from the delta‐function model on which the theory is based. Further experimental and theoretical work is needed.
Error Propagation in Determining Hydraulic Conductivities from Successive Water Content and Pressure Head Profiles
Authors: Flühler H. , Ardakani M. S. , Stolzy L. H. 
Published: July 2010

AbstractThe flux of water in unsaturated soils can be determined indirectly by using Darcy's Law. The critical part of this approach is the determination of the hydraulic conductivity at a given depth and time. In this paper we analyze the relative errors of hydraulic conductivities determined from a transient drainage field experiment. Knowing the errors of this method would be useful in planning future experiments. It allows putting limitations on the conclusions to be drawn from such experiments and it further allows re‐examination of already published field data.In the wet range of the conductivity function errors are 20–30% of the k‐value. In the range where k‐values are small, the relative errors may be > 100%. Errors stemming from tensiometer readings are significant when the hydraulic gradient is < 0.3 mbar · cm‐1. During the early stage of the transient drainage experiment these errors are always considerable and are more important than other errors. On the other hand, the errors in the measured water content changes are dominant when drainage is slowed down due to desaturation of the soil.The errors contained in the conductivity, k, are calculated by means of error propagation equations. These errors are also simulated using the Monte Carlo technique. The simulation shows that the conductivity errors predicted by explicit error propagation equations are optimistic minimum estimates.
Heterovalent Cation Exchange Equilibria in Soils with Variable and Heterogeneous Charge
Authors: Munns D. N. 
Published: July 2010

AbstractDivalent cations were incrementally displaced, from limed and unlimed samples of three soils, by suspending the soils in increasing volumes of 2mM KCl. Mass action coefficients for exchange between Ca and Mg were constant. But for the exchange of divalent cations by K, the exchange coefficients of Kerr, Vanselow, Gapon, Krishnamoorthy and Overstreet, and Gaines and Thomas increased markedly as potassium saturation or pH increased.For each cation species, separate fractions which were relatively tightly or relatively loosely adsorbed could be estimated by a simple regression analysis. The loosely adsorbed Ca, which may control Ca availability to plants, could be independently estimated by a leaching procedure. Mass action exchange coefficients for the loosely adsorbed cations were approximately constant under all conditions tested.The variable charge mobilized by liming differed from the fixed charge in having a slightly higher proportion of sites with high divalent affinity, in an Oxisol, and a much lower proportion in a Vertisol and a Mollisol.
An Improved Technique for Measuring Soil pH
Authors: Mubarak A. , Olsen R. A. 
Published: July 2010

AbstractSoil solution is obtained by immiscible displacement using centrifugation in the presence of an excess of carbon tetrachloride. A combination glass electrode is then introduced into the soil solution which is floating on top of the carbon tetrachloride. By keeping the system closed, changes in pH induced by loss or gain of carbon dioxide are avoided. No water need be added to a naturally occurring soil so changes in pH induced by the dilution effect and/or the salt effect are obviated. There is no contact between reference electrode and soil particles so there is considered to be no junction error involved in the measurement. The technique is simple and reasonably convenient; the readings are stable and apparently reliable.
The Red Latosols of Sri Lanka: I. Macromorphological, Physical and Chemical Properties, Genesis, and Classification
Authors: de Alwis K. A. , Pluth D. J. 
Published: July 2010

AbstractThe Red Latosols of Sri Lanka have developed on the Quaternary Red Earth Formation into very deep, excessively drained soils with weak horizon differentiation. The three major soil series of this subgroup, the Gambura, Mullaitivu and Wilpattu series, were studied from the point of view of their morphological properties, particle size distribution, bulk density, 1/3 and 15 bar moisture, pH, organic carbon, total nitrogen, CEC, exchangeable cations and free Fe and Al oxides by means of representative pedons for purposes of characterization and determination of the genetic processes.The Red Latosols all show some clay illuviation with the vertical distribution of the illuviated clay inversely related to the clay content. Free iron oxides are present largely as discrete particles and have themselves migrated downward, though to a lesser extent than the clay. The CEC values are low and consistent with clay fractions dominated by the kaolinite group. The CEC's also indicate a high proportion of pH‐dependent exchange sites. The exchange acidity appears to result largely from the presence of Al‐hydroxy compounds in the exchange complex. The dominant basic cation is Ca. The free iron oxides are almost entirely crystalline and seem to have moved principally by physical translocation of the particles, although another mechanism has also been postulated. Differences in the properties of the three series of the Red Latosols mainly reflect differences in clay and iron oxide contents.According to the USDA Soil Taxonomy the Gambura series is a fineclayey kaolinitic isohyperthermic Rhodic Oxic Paleustalf, whereas the other two series are fine‐loamy siliceous isohyperthermic Rhodic Oxic Paleustalfs.