bluuebunny/crossref_metadata_2025_split huggingface dataset:
Plant Phenolic Acids in Soils: A Comparison of Extraction Procedures
Authors: Dalton Barry R. , Weed Sterling B. , Blum Udo 
Published: July 2010

AbstractPlant phenolic acids have been found in plants and soils and some evidence suggests their involvement in biochemical interactions between plants (allelopathy) and organisms living in the soil. This study was conducted to compare the more common extraction procedures used in the recovery of water‐soluble phenolic acids from soil. Various extraction procedures were employed in the recovery of ferulic acid (4‐hydroxy‐3‐methoxycinnamic acid) from steam sterilized soil materials sampled from the A1 and B1 horizons of a Cecil soil (Typic Hapludults, clayey, kaolinitic, thermic) and a Portsmouth soil (Typic Umbraquualts, fine loamy, mixed, thermic). Ferulic acid was added (1000 mg/kg) to soil materials, allowed to equilibrate for 90 d, extracted and quantified by high‐performance liquid chromatography. Eight extracting solutions [H2O, methyl alcohol (CH3OH), 0.5 M sodium acetate (CH3CHOONa), 0.05 and 0.5 M diethylenetriaminepentaacetic acid (DTPA), 0.05 and 0.5 M ethylenediaminetetraacetic acid (EDTA), and 2 M NaOH] and various extraction times were used to recover ferulic acid from soil materials. Amounts of ferulic acid recovered from the A1 horizons were significantly lower than the amounts recovered from the B1 horizons for both Cecil and Portsmouth soil materials. Water and CH3OH recovered the least amounts of ferulic acid, whereas NaOH and 0.5 M DTPA recovered the most. In the B1 horizon materials, a major portion of the ferulic acid anions appeared to be absorbed by polyvalent cations (either exchangeable or nonexchangeable). This paper emphasizes the necessity of choosing the appropriate phenolic acid extractant for the soil phenolic acid fraction of interest.
Macroporous Infiltration and Redistribution as Affected by Earthworms, Tillage, and Residue
Authors: Zachmann J. E. , Linden D. R. , Clapp C. E. 
Published: July 2010

AbstractThe objectives of this study were to determine if burrows produced by two species of earthworms (Aporrectodea tuberculata and Lumbricus rubellus) found in continuous corn (Zea mays L.) in Minnesota altered the infiltration rate and depth distribution of surface applied water. Each species was introduced (212 m−2) to in situ cylinders in plots initially void of worms that had been subjected to tillage with and without residue or no‐till with and without residue for 5 yr. Burrows produced by both species of worms during a 46‐d period increased average infiltration rates of 30 mm of water relative to controls after 46 d. Surface residues more than doubled the number of burrows open to the surface relative to incorporated residues (48 vs. 15 for L. rubellus, 37 vs. 15 for A. tuberculata). Cocoon production, an indicator of potential survivability, was present for both species in the no‐till‐surface residue treatment and for A. tuberculata also in the till‐incorporated residue treatment. Bromide (Br‐) tracer and mass balance for Br‐ in all treatments showed infiltration and Br‐ movement in the upper 5 cm of the profile was fastest in tillage treatments with worms and residues and that Br‐ movement beyond 19 cm was greatest for the no‐till treatments with worms and residues. Pore continuity and survival potential for worms in the no‐till‐residue treatment suggest that this treatment might increase populations of worms in cropland while altering the hydraulic status and erosion susceptibility of soils in the north central USA.
Intermittent Evaporation from Soil Columns as Affected by a Gel‐forming Conditioner
Authors: Al‐Omran A. M. , Mustafa M. A. , Shalaby A. A. 
Published: July 2010

AbstractThe effect of an organic super gel commercially called Jalma (containing 24% humic acids, and 3.8% polysaccharides) at rates of 0.0, 0.4, 0.8, and 1.6% on aggregation index (AI) and relative swelling index (RSI) of loamy sand, sandy loam, and clay loam soils was studied. Furthermore, the influence of these rates and two irrigation intervals, 7 and 14 d, on intermittent evaporation from surface‐treated soil columns were also investigated. Twenty‐two or 44‐mm of water were applied every 7 or 14 d, respectively. The soil columns were placed in a walk‐in controlled growth chamber with potential evaporation of 8.2 mm/d. Addition of 0.4% Jalma significantly increased AI of the three soils by 33 to 38%. Increase of the Jalma rate to 0.8% significantly improved the AI of the fine‐textured sample but not the coarse‐textured samples. Further increase to 1.6% had no significant effect on the AI of the three samples. The lowest rate of Jalma significantly increased RSI of the three samples. The results also indicated a sharp, significant increase in RSI with increase in Jalma rate to 1.6%. In general, Jalma treatment significantly reduced cumulative evaporation and hence increased the amount of water conserved (AWC) after the first wetting/drying cycle. After four evaporation cycles, on 0.4% treated loamy sand, sandy loam, and clay loam soils, the AWC values were, respectively, 4.3, 3.2, and 1.5 times that of the untreated soils. The AWC values for untreated loamy sand, sandy loam, and clay loam soils irrigated every 14 d were, respectively, 2.6, 1.7, and 1.6 times those irrigated weekly.
Effectiveness of Calcium Cyanamide as a Nitrogen Source and Nitrification Inhibitor in a Tropical Soil
Authors: Arora Y. , Nnadi L. A. 
Published: July 2010

AbstractField experiments were conducted to test the efficiency of calcium cyanamide (CaCN2) as an N source for wheat (Triticum aestivum L.) and maize (Zea mays L.) over four cropping seasons at the Irrigation Research Station at Kadawa (10°39′N, 08°02′E) Nigeria. Calcium cyanamide applied at recommended N rates, was compared with urea (120 kg N ha−1) and a mixture of urea and CaCN2 [urea (110 kg N) plus CaCN2 (10 kg N ha−1)]. Highest maize grain yields and N uptake were obtained with the mixture of urea and CaCN2 in both years of the study. Wheat yields were unaffected by form of N. Recovery of inorganic N (NO‐3 + NH+4) in the surface soil, 8 weeks after planting wheat in 1984 to 1985, was greatest for the CaCN2 treatment followed by the urea‐CaCN2 mixture, and urea in tha torder. Nitrogen recovery in the 0.6‐m depth was approximately the same for all treatments. A laboratory incubation study using the same soil gave about 80% recovery of inorganic N from added CaCN2 within 8 weeks with most of the N remaining as NH+4 throughout the 8‐week study. Addition of 10 mg kg−1 of N as CaCN2 to the soil inhibited the nitrification of added urea.
Laboratory Permeability Errors from Annular Wall Flow
Authors: Tokunaga Tetsu K. 
Published: July 2010

AbstractLaboratory saturated hydraulic conductivity measurement errors introduced by permeameter fluid flow within gaps between sample cores and permeameter walls are estimated through a simple model that idealizes gap flow as occurring within a smooth annulus. The inner annulus boundary fluid velocity is matched to the Darcy velocity within the sample core. The ratio of flow within the annulus to that within the core, QRap/Qcore, is shown to have both cubic and linear dependence on the gap width. QRap/Qcore is also shown to be inversely dependent on both the core permeability and the permeameter radius. Although the model is very idealized, the strong possibility of overestimating permeabilities in laboratory cores is demonstrated. Related concerns include flow in fractured porous media, and potential errors in interpreting solute travel times in laboratory columns and field lysimeters.
Sorption and Sorptive Interaction of Cadmium and Zinc on Hydrous Manganese Oxide
Authors: Zasoski R. J. , Burau R. G. 
Published: July 2010

AbstractAdsorption of Zn, Cd, and Ca by δ‐MnO2 was measured at pH 4, 6, and 8 by a batch technique at steady‐state conditions. Fitting the data to Langmuir and Freundlich expressions suggested that there were two or more mechanisms or sites of sorption for both Zn and Ca. The “higher energy” site(s) (first to fill) showed preference for Cd over Zn, whereas the reverse was true for the lower energy site(s). Simultaneous addition of both Cd and Zn reduced adsorption of both ions. Cadmium and Zn adsorption diminished somewhat when Ca was present at higher Zn and Cd loadings but competition from Ca was minimal at low metal loadings. It is proposed that the high energy binding is an exchange sorption on the negatively charged oxide sites by displacement of surface and diffuse layer cations and protons, which binds Cd more strongly than Zn. On a relative basis at pH 6 and 8, Zn is more strongly bound than Cd. The higher surface charge density and greater proportion of Zn hydroxy solution phase species at higher pH may favor Zn sorption. Competition between Cd, Zn, and Ca was observed at pH 4, 6, and 8, suggesting that solution bulk precipitation was not controlling solution metal concentrations.
Differences in Humic Acid Characteristics as Determined by Carbon‐13 Nuclear Magnetic Resonance, Scanning Electron Microscopy, and Infrared Analysis
Authors: Lobartini J. C. , Tan K. H. 
Published: July 2010

AbstractAn investigation was conducted on the usefulness of 13C nuclear magnetic resonance (NMR) spectroscopy in the characterization of humic acids (HA) isolated from selected soils. Soil samples for extraction of HA were collected from Indonesia, USA, and Argentina. The analyses were conducted by liquid 13C NMR, scanning electron microscopy (SEM), infrared (IR), and chemical analysis. The NMR spectra indicated that all HA samples had in common aliphatic, polysaccharide, aromatic, and carboxyl groups. However, the NMR signals for the chemical groups were different in intensities, producing a distinctive spectrum for each HA studied. The NMR analysis demonstrated that HA from the tropical region soils were highly aliphatic in nature, with a combined carbohydrate and polysaccharide C content of 59.5 to 67.6%. On the other hand, HA from the seven temperate region soils contained more COOH and aromatic C. The highest aromatic C concentration together with the strongest NMR signals for aromaticity were exhibited by HAs of the Mascotte (Ultic Haplaquod) and the Argentina (suborder unknown) soil. The differences in NMR spectra were accompanied by differences in SEM micrographs and IR spectra. A significant correlation was noted between NMR and especially IR spectra. Humic acid samples with strong NMR signals for aromatic C exhibited IR spectra with strong bands at 1240 cm−1, whereas HA with weak NMR signals for aliphatic C had IR spectra with weak bands at 2980 to 2900 cm−1. Therefore, IR spectroscopy can also be an important tool in the characterization of humic matter when used in conjunction with 13C NMR.
Effects of Parent Material Weathering on Chemical and Mineralogical Properties of Selected Hapludults in the Virginia Piedmont
Authors: Wysocki Douglas A. , Lietzke D.A. , Zelazny L.W. 
Published: July 2010

AbstractSaprolite is a parent material prevalent in the Piedmont of the USA. Chemical weathering during saprolite development, but prior to soil formation, may obliterate chemical and mineralogical influences due to parent rock differences. The Cullen series and associated red Hapludults mapped in the Piedmont are an example. Cullen soils are derived from saprolites weathered from rocks of varying mafic and felsic composition. The mafic influence (Fe content) is manifested in the Cullen series as a dark red (1OR or 2.5 YR 3/6) B subhorizon. Soils that lack this feature are presumed to be less productive. Family control section chemical and physical properties were consistent among pedons studied, and did not relate to parent rock type or B horizon color. Lesser amounts of extractable Al in the lower part of the series control section provide a clue as to why Cullen soils are preferred for agricultural use over other Hapludults. Fourteen of the pedons studied were in the mixed mineralogy class, two were oxidic, and none were kaolinitic. In the northern Piedmont kaolinitic soils do not appear to exist, except on mafic parent materials. Soils studied had a high iron oxide content (2.0–15%), which did not correlate with dark red colors or parent material. Conversely, they contain small amounts of gibbsite. This data and discrepancies in the oxidic definition question the validity of the present osidic family requirements as a means for identifying soils dominated by weathered minerals. Soils derived from saprolites weathered from a variety of parent rocks have reached a similar mineralogical and chemical state in the family control section.
Cationic Polymer Effects on Infiltration Rates with a Rainfall Simulator
Authors: Helalia Awad M. , Letey J. 
Published: July 2010

AbstractThe cationic polymer “CP‐14” was applied to three soils at concentrations of 0, 5, 10, 20, and 50 mg L−1 in synthesized canal water (CW) (0.05 dS m−1) and well water (WW) (0.7 dS m−1) through a rainfall simulator. This first cycle was followed after drying by two cycles with untreated water. In some cases, a fourth cycle was conducted with the same polymer concentration as the first cycle. The infiltration rate (IR) was measured in each case. With one exception, the IR increased as the polymer concentration increased for all soils and both waters. The IR was higher with WW than with CW in all cases. The IR decreased successively from the first through the third cycle due to dispersion at the soil surface caused by drop impact and chemical effects of the applied water. Although the IR increased during the first cycle with increasing polymer concentration, the highest effects were obtained at 5 and 10 mg L−1 concentrations with diminishing effects at higher concentrations. In most cases, benefits of the higher concentrations were observed during the two cycles when polymers were not added to the water. The IR during the fourth cycle with polymer addition was higher than for the second and third cycle but lower than for the first cycle. The clay concentration in the effluent from CW did not change with polymer addition but the IR changed significantly. In addition, the clay concentration in the effluent from WW was very much lower than for CW. The IR values in the present study were correlated with the results of a flocculation test at 5% significance. Therefore, the flocculation test appears to be a useful, quick technique for determining the relative effectiveness of water quality and polymer addition on IR.
Urea and Biuret Stimulate Growth of Douglas‐fir and Western Hemlock Seedlings
Authors: Miller Richard E. , Anderson Harry W. , Young Donald C. 
Published: July 2010

AbstractTwo experiments were conducted in a greenhouse to test a theory that biuret in urea fertilizer reduces growth of Douglas‐fir [Pseudotsuga menziesii (Mirb.) Franco] or western hemlock [Tsuga heterophylla (Raf.) Sarg.]. Newly germinated seedlings in 2.5‐L pots were treated with 0, 0.224, 2.24, or 22.4 kg biuret ha−1 (40% N) in factorial combinations with 0, 84, or 168 kg N ha−1 as reagent‐grade urea (46% N). The biuret was applied as a solution to either the sandy loam soil or the foliage. Four of the eight replicates were harvested 203 d after treatment. For Exp. 2, the remaining seedlings were retreated as they were initially and harvested 305 d later. In both experiments, the two species responded strongly to urea; moreover, seedling dry weight increased with increasing biuret (P = 0.003). Averaged over all other factors, weight of seedlings treated with the highest biuret dosage was 14% more than the weight of seedlings with no biuret. Unfertilized hemlock responded as much to 0.2 kg biuret ha−1 (0.08 kg N ha−1) as to 84 kg N ha−1 as urea; this suggests that biuret functions as a hormone. The results indicated that biuret is unlikely to reduce growth of seedlings of either species even when urea heavily contaminated with biuret is applied at high dosage.
Effect of Nitrogen Source and Dicyandiamide on Growth and Water Relations of Cotton
Authors: Reeves D. W. , Touchton J.T. , Rickerl D. H. 
Published: July 2010

AbstractNitrification inhibitors such as dicyandiamide (DCD) may improve N efficiency for cotton (Gossypium hirsutum L.) grown on sandy Coastal Plain soils. Research has demonstrated that cotton is sensitive to DCD, and field experiments suggest a possible link between cotton response to DCD and rainfall distribution. A green‐house experiment was conducted to investigate the effect of DCD and N source on growth and water relations of cotton on a typical Coastal Plain soil. Cotton (Deltapine 90) was grown in pots containing a Norfolk sandy loam (fine‐loamy, siliceous, thermic, Typic Paleudults). Nitrogen (50 mg kg−1) as NaNO3 or urea, and DCD (0, 2.5, 5, 10, 15, and 20 mg DCD‐N kg−1) were applied to the soil at first true leaf. Soil water content, leaf xylem water potential (ψ1), and stomatal conductance were monitored during a 3‐d drying period, commencing at first bloom, following which plants were harvested. Both N source and DCD affected plant growth and water relations, but there were no significant interaction effects. Fertilization with NaNO3 increased leaf dry weight 9.1% compared with fertilization with urea. Plants fertilized with NaNO3 depleted soil moisture faster than plants fertilized with urea, resulting in lowered stomatal conductances and more negative ψ1 throughout the drying period. Dicyandiamide lineraly reduced leaf area and dry weight, and stem dry weight. Dicyandiamide did not affect soil‐water depletion, ψ1, or stomatal conductance in the morning. Under more stressful afternoon conditions, DCD, especially at rates ≥10 mg DCD‐N kg−1, increased stomatal conductance over the range of available soil water. Dicyandiamide‐induced increases in stomatal conductance under conditions of nonlimiting soil water could increase photosynthesis and possibly lint yield. In years when soil water is limiting, however, additional stress from DCD phytotoxicity could result in yield reductions.
Column‐Profile Measurements Using Fiber‐Optic Spectroscopy
Authors: Kulp Thomas J. , Bishop Dorothy , Angel Stanley M. 
Published: July 2010

AbstractFiber‐optic spectroscopy was used to measure the flow of a fluorescent dye in a column packed with glass beads. Optical fibers inserted between the packed beads served as light pipes to transmit excitation light to the measurement zone at their distal end and to return fluorescent emission to a spectrometer. In this way, the dye concentration at the point of measurement was monitored. Data are presented demonstrating that flow can be monitored at several points in the column by multiplexing more than one fiber into a single spectrometer. This technique provides a tool to make fundamental flow measurements that have to date been experimentally impossible.
Phosphate Adsorption by Aluminous Hematites of Different Shapes
Authors: Barron V. , Herruzo M. , Torrent J. 
Published: July 2010

AbstractThe phosphate adsorption capacity of 43 synthetic hematites having widely different shapes, specific surface areas and Al2O3 mole fractions ranged between 0.19 and 3.33 µmol P m−2, with a mean value of 0.97 µmol P m−2. There was a significant decrease in the adsorption capacity when the diameter/thickness ratio of the particles increased; this agrees with the hypothesis that, because of the distribution and type of surface hydroxyls, the basal faces of hematites are not able to adsorb phosphate, in contrast with some of the nonbasal faces. The low adsorption capacity of the hematites studied here, as compared to many natural and synthetic goethites, gives a reason why, as reported in the literature, red (hematitic) soils adsorb less phosphate than similar yellow (goethitic) soils.
Effects of Field Methods and Soil Cover on Estimating Ammonia Loss from Nitrogen‐15‐Urea
Authors: Reynolds C. M. , Wolf D. C. 
Published: July 2010

AbstractAmmonia loss from urea fertilizers is difficult to measure accurately in the field. In a field study we compared two methods for measuring NH3 loss from 15N‐urea surface applied to bare and bermudagrass (Cynodon dactylon L.) covered Captina silt loam (fine‐silty, mixed, mesic, Typic Fragiudult). The two methods were semiopen chambers and open microplots using 15N recovery. Labeled urea was applied at 100 kg N ha−1, and chambers and microplots were shaded and protected from rainfall. Estimates of NH3 losses from the bare soil after 357 h were 24.6 and 48.0% of the applied N from the semi‐open chambers and open microplots, respectively. Estimates of NH3 losses from the bermudagrass after 357 h were 34.5 and 42.7% of the applied N for the semi‐open chambers and open microplots, respectively. In the bermudagrass microplots, 78.6% of the applied 15N either remained in the plant‐thatch layer above the soil or was volatilized 18 h after urea application. Transport and transformations in the soil had little influence on NH3 loss from bermudagrass plots. These data indicated that measured NH3 loss from bare soil in semi‐open chambers was significantly less than NH3 loss in open microplots using 15N recovery techniques. Cumulative NH3 losses from urea retained on bermudagrass and thatch above the soil were similar in the semi‐open chambers and open microplots.
Basal Mixing Zones in Loesses of Louisiana and Idaho: II. Formation, Spatial Distribution, and Stratigraphic Implications
Authors: Miller B. J. , Schumacher B. A. , Lewis G. C. , Rehage J. A. , Spicer B. E. 
Published: July 2010

AbstractBasal mixing zones of loess with different underlying materials in Louisiana and Idaho have been identified. Formation of basal mixed zones occurs when loess is deposited on a pedogenically active surface and becomes incorporated into the underlying stratigraphic unit through bioturbation and pedoturbation processes. Factors influencing basal mixed zone formation include climate, nature of stratigraphic materials underlying the loess deposits, and rate of loess deposition. The warm, humid climate in Louisiana is more conducive to the formation of thicker basal mixed zones than the cool, semiarid climate of Idaho. In Louisiana, thicker basal mixing zones were found where loess was underlain by coarse textured, unconsolidated materials than where underlain by unconsolidated materials with similar or finer textures. Amount and distribution of precipitation in Idaho appears to override the influence of underlying materials on basal mixed zone formation. A progressive thickening of basal mixing zones and thinning of the unmixed loess mantle was found as distance from the loess source increased until a point was reached where all loess was incorported or lost through erosion and the basal mixed zone occurred at the soil surface. Implications of the existence of basal mixed zones with respect to loess stratigraphy are discussed.