bluuebunny/crossref_metadata_2025_split huggingface dataset:
Iron Redistribution in Three Boralfs (Gray Luvisols) of Saskatchewan
Authors: Santos M. C. D. , St. Arnaud R. J. , Anderson D. W. 
Published: July 2010

AbstractThe transformation and translocation of Fe in three Boralfs (Gray Luvisols)3 were studied in relation to the Fe contained within silicate minerals and that existing in oxide forms. Quantitative evaluations of the Fe redistribution using a quartz index technique provided conclusive evidence that losses of Fe from E horizons and gains in Bt horizons are largely accounted for by the translocation of silicate‐Fe as a component of fine clays. The weathering of coarse clay to fine clay was documented; the fine clay fraction remained relatively unaffected. Some dissolution and movement of Fe in solution was also evident, particularly in the two profiles showing evidence of restricted drainage and periodic reduction. Detailed analyses of one of the soils studied indicated an 11% loss of total clay from the solum, involving a 16% loss of total Fe and a 19% loss of silicate‐Fe from the clay fractions. Most of the Fe lost from the clay was recovered in glaebules of sand and silt size, both as reprecipitated oxides and as occluded clay particles. The actual loss of clay from the solum was only about one‐half of the 11% loss indicated from particle size distribution values alone.
Effect of Sodium Polymetaphosphate on Soil Crust Formation and Runoff/Rain Relations
Authors: Ben‐Hur M. , Shainberg I. , Keren R. 
Published: July 2010

AbstractThe effect of sodium polymetaphosphate (NaPMP) on crust formation and on the amount of runoff was studied with two soils, Typic Rhodoxeralfs (sandy loam) and Xeric Torripsamments (loamy sand), using a rainfall simulator. Increasing the rate of NaPMP application in the range ≤ 100 kg ha−1, increased the rate of crust formation and decreased the final infiltration rate (IR). The increased rate of crust formation increased the fraction of runoff of the total rainfall and decreased the threshold rain needed to form runoff. The dispersant, NaPMP, weakened the stability of the aggregates and increased the amount of clay that migrated with the infiltrating water and accumulated in the “washed in” layer. Hence, the effect of NaPMP was more pronounced in a loamy sand, where the low amount of clay limits the formation of a crust, compared with the sandy loam, which contains enough clay to form a crust. In consecutive short storms of 18 mm each with complete drying between storms, the rate of crust formation was slow and the amount of runoff was low in the control treatment, compared with the high efficiency of NaPMP for increasing runoff. The low amounts of NaPMP required to significantly increase runoff gives the potential for commercial use in runoff farming.
Laboratory Modeling of Northern Great Plains Salt Efflorescence Mineralogy
Authors: Keller L. P. , McCarthy G. J. , Richardson J. L. 
Published: July 2010

AbstractRecent studies of salt efflorescences in North Dakota and from several additional sites in the surrounding region indicated that the mineralogy of the efflorescences is predominantly sulfate salts of Na and Mg: mirabilite, thenardite, epsomite, hexahydrite, konyaite, and bloedite. Experiments consisting of isothermal evaporation of solutions with fixed Na2SO4/MgSO4 ratios were used to construct crystallization isotherms for the Na2SO4‐MgSO4‐H2O system at 28 and 40°C in order to model the salt efflorescence mineralogy. The first precipitates at 28°C were mirabilite, konyaite, and epsomite. At 40°C, thenardite replaced mirabilite as a first precipitate. The results indicated that the mineralogy is best described as a metastable system in which konyaite plays a dominant role. Konyaite is metastable when in contact with its saturated solution, but persists for long periods of time in dry efflorescence. The presence of konyaite in the system also allows mirabilite, thenardite, and epsomite to form supersaturated solutions with respect to the equilibrium phase assemblages. Reference to the liquidus‐solidus‐subsolidus portions of the experimental isotherms enables one to predict >90% of the observed natural assemblages that precipitate from sulfatic saline waters in North Dakota. This information allows us to determine which solid phases are controlling the shallow saline groundwater chemistry.
Water and Chloride Movement Through a Layered Field Soil
Authors: Starr J. L. , Parlange J. ‐Y. , Frink C. R. 
Published: July 2010

AbstractTwenty porous ceramic samplers at each of four soil depths were arranged in a three‐dimensional pattern to study the movement of water and Cl‐ through a layered sandy loam (sandy, mesic typic Dystrochrepts) over a gravely coarse sand with a perched water table at ∼180 cm. All samplers were used as tensiometers during the initial phase of the experiment in which salt‐free water was ponded at the soil surface. After constant flow conditions were achieved, a pulse of 0.015 M CaCl2 solution was added to the infiltrating water and all samplers were then used to obtain soil water samples for Cl‐ analysis. Variations in soil water pressure were observed to be much smaller than the variations in Cl‐ concentration. Both water and Cl‐ data moved downward in a general one‐dimensional pattern in the finer textured surface layer and in the zone directly above the water table, whereas, the movement between these two depths was three‐dimensional, i.e., by fingering.
Effect of Terrazole on Nitrogen Transformations and Movement in Irrigated Corn
Authors: Mikkelsen R. L. , Jarrell W. M. , Letey J. , Whaley S. 
Published: July 2010

AbstractA field study was conducted on two sandy loam soils to determine the effect of Terrazole nitrification inhibitor (5‐ethoxy‐3‐[trichloromethyl]‐1,2,4‐thiadiazole) on N movement and transformations. Sweet corn (Zea mays L.) was fertilized with (NH4)2SO4 twice during the growing season for a total application of 250 kg N ha−1. The N applied to one‐half of the fertilized treatments was coated with Terrazole. Three levels of irrigation were established for each field. The treatments on Arlington (Typic Durixeralfs) sandy loam received 55.9, 69.0, and 78.1 cm infiltrated water. The Hanford (Typic Xerorthents) sandy loam treatments received 62.0, 76.7, and 88.2 cm infiltrated water. Soil samples were taken at 20, 40, 60, 80 and 90 d after planting and analyzed for NO‐3 and NH+4. Movement of N was correlated with both the presence of Terrazole and the quantity of water applied. Soil NH+4 was consistently higher in Terrazole treatments, suggesting that nitrification was reduced by the Terrazole. However, there was no significant increase in tissue N concentrations or yield due to Terrazole additions. Denitrification losses in the field were found to be 64% lower due to the presence of Terrazole.
Characterization and Stratigraphy of Soil Parent Materials of West‐central Minnesota
Authors: Crum J. R. , Rust R. H. 
Published: July 2010

AbstractWithin the Alexandria Moraine Complex in west‐central Minnesota there are “islands” of fine textured soils and parent materials embedded within a matrix of coarser textured soils. To study the soils and the stratigraphic relationships of the parent materials, deep borings were made along two transects perpendicular to the Alexandria Moraine. A total of 27 sites were investigated. Particlesize distribution, CaCO3 equivalent, clay‐sized carbonate, and the dominant mineralogy of the >2 mm, 1 to 2 mm very coarse sand (vcos), and <2‐µm fractions were determined. Four glacial materials were identified in this study: New Ulm till, Kandiyohi till, Granite Falls till, and a “mixed” drift of mainly New Ulm and Granite Falls materials. The average clay content of the glacial materials ranges from about 370 g kg−1 in the Kandiyohi to about 130 g kg−1 in the Granite Falls and mixed drifts. The average shale content in the vcos fraction ranges from about 620 g kg−1 in the Kandiyohi till to about 60 g kg−1 in the Granite Falls till. The average CaCO3 equivalent ranges from about 220 g kg−1 in Granite Falls till to about 170 g kg−1 in the mixed drift. Statistically significant differences occur among the glacial materials in the concentration of sand, silt, clay, concentration of shale, carbonate, and crystalline pebbles in the vcos fraction, and the concentration of coarse fragments. A stepwise discriminant analysis was made and the four glacial materials were numerically defined by the first two canonical variables. The stratigraphic relationships of the two areas of Kandiyohi till outcrop studied seem to be quite different. The data from the western part of the county indicate much mixing of New Ulm and Granite Falls tills. Data from the eastern transect indicate the Kandiyohi till is an older till that has been thrust to the surface. It is suggested that the Kandiyohi till is a distinctly different glacial till in that: (i) the soils developed on this till are taxonomically distinct from soils on adjacent tills; (ii) the shale concentrations within the four defined glacial materials in the study region are statistically different; (iii) no other areas of this glacial till have been observed except in the Alexandria Moraine; and (iv) the glacial till outcrops are characteristically narrow linear features.
Parameters for Characterizing Tillage‐induced Soil Surface Roughness
Authors: Linden D. R. , Van Doren D. M. 
Published: July 2010

AbstractTillage‐induced soil roughness is an important consequence of tillage because water and air transport phenomena are affected. Characterizations of roughness have been statistical in nature and have lacked a physical connection to the configuration features affected by roughness. A new method of analyzing microrelief data is presented that improves the description of the soil surface and should lead to better information about the physical processes affected by tillage. The new procedure results in two surface configuration parameters, limiting slope (LS) and limiting elevation difference (LD), that are based on the slope or inclination of the surface of soil clods and to the average relief (elevation difference), respectively. These two indexes are directly related to the configuration of the surface and also sensitive to differences in roughness. They should help allow roughness to be used simultaneously with other soil properties to predict transport phenomenon.
Effect of Gypsum and Deep‐rooting Perennials on Subsoil Mechanical Impedance
Authors: Radcliffe D. E. , Clark R. L. , Sumner M. E. 
Published: July 2010

AbstractSubsoil root growth in highly weathered southeastern soils is limited because of poor chemical conditions and high soil strength. Surface‐applied gypsum can leach into the subsoil and amend the chemical properties of these soils. The objective of this study was to determine if gypsum also had a physical effect. Mechanical impedance was measured using a tractor‐mounted penetrometer that gave values of cone index (CI) in gypsum‐treated and nontreated plots of several ongoing experiments. Cone index was lower in the gypsum‐treated plots where alfalfa (Medicago sativa L.) or peach trees [Prunus persica (L.) Batsch] had grown for several years, but there was no reduction in CI in fallow plots treated with gypsum. Samples from the alfalfa plots treated with gypsum had larger stable soil aggregates than samples taken from nontreated plots. We conclude that gypsum amendment increases subsoil root activity, which in turn reduces subsoil mechanical impedance.
Sources of Acidity in Some Forested Udults
Authors: Richter D. D. 
Published: July 2010

AbstractThree sources of soil acidity (bicarbonate leaching; base‐cation accumulation in aboveground wood, roots, and forest floor; and acid atmospheric deposition) were evaluated in relation to exchangeable acidity of three forested Udults in Tennessee. The Udults have low effective CEC (CECe), from 2.4 to 3.7 cmolc kg−1. In the three soils, H+ from bicarbonate leaching averaged 0.60 kmolc ha−1yr−1 over 2 yr. In five forest stands, 30 to 80 yr in age, H+ from accumulation of excess base (EB) cations [EB = (Ca + Mg + K) − (P + S)] in aboveground wood, roots, and forest floor averaged 1.11 kmolc ha−1yr−1. Atmospheric H+ inputs, estimated from bulk precipitation, averaged 0.67 kmolc ha−1yr−1. Total deposition of atmospheric acidity to these eastern Tennessee forests is on the order of 1 kmolc ha−1yr−1. Variations in H+ inputs were caused by annual differences in the hydrologic cycle and by stand differences due to nutrientcycling and soil‐chemistry effects. In these forest ecosystems, sources of soil acidity from annual bicarbonate leaching and cation accumulation appeared to exceed atmospheric inputs. Exchangeable acidity in the forested Udults was large compared with annual fluxes of acidity. In the upper 60 cm of the three soils, KCl‐exchangeable acidity ranged from 100 to 274 kmolc ha−1, and BaCl2‐TEA (trieth‐anolamine) acidity ranged from 505 to 820 kmolc ha−1. Despite low precipitation pH and low soil CECe, the additional H+ from acid deposition has not caused significant alteration of soil acidity or base solution of these Udults.
Changes in Nitrogen, Carbon, and other Surface Soil Properties During Secondary Succession
Authors: Bush J. K. , Van Auken O. W. 
Published: July 2010

AbstractSoils were analyzed from 10 river terrace plant communities ranging in age from 5 yr to more than 150 yr. Soil C and N concentrations increased significantly with plant community development up to 25 yr. When quadratic transformations were used, soil N accretion was correlated with huisache (Acacia smallii Isely) stem basal area. Texas sugarberry (Celtis laevigata Willd.) basal area was correlated with the soil N concentration and soil C accretion was correlated with total community basal area. Plant community development (measured as basal area) was examined using stepwise multiple linear regression analysis. Seventy‐six percent of the variance of huisache basal area could be explained by community age, soil N, K, Mg, and silt content. Seventy‐seven percent of the variance of Texas sugarberry basal area could be explained by community age, soil N, Mg, and clay content. Ninety‐one percent of the variance in total community basal area could be explained by community age, soil pH, N, and clay content. Changes in other soil chemical and physical properties occurred during succession and may be important in determining community species composition and structure.
Influence of Selected Organic Ligands on the Formation of Allophane and Imogolite
Authors: Inoue K. , Huang P. M. 
Published: July 2010

AbstractThe role of organic ligands of different ability to complex with Al3+ in affecting the formation of allophane and imogolite and the nature of the precipitation (>0.01 µm) and soluble (<0.01 µm) products was investigated at initial Si concentration of 1.6 × 10−3 mol.L−1, Si/Al molar ratios of 0.5 and 1.0, OH/Al molar ratios of 2.0, and 3.0, and organic ligand/Al molar ratios of 0 to 0.2. DL‐aspartic and p‐hydroxybenzoic acids showed a very weak impeding effect on the formation of allophane and imogolite; salicylic acid showed a weak to moderate impeding effect on the formation. Tannic, DL‐tartaric, citric, and DL‐malic acids with a strong affinity for Al greatly perturbed the interaction of hydroxy‐Al ions with orthosilicic acid at Si/Al ratio of 0.5, OH/Al ratio of 2.0, organic ligand/Al ratios of 0.03 to 0.1, and thus hindered the subsequent formation of imogolite, leading to the formation of pseudoboehmites, hydroxy‐Al‐organic complexes, and/or ill‐defined aluminosilicate complexes. These strong complexing organic ligands also hampered the formation of allophane at Si/Al ratio of 1.0, OH/Al ratio of 3.0, and organic ligand/Al ratios of 0.1 to 0.2, resulting in the formation of ill‐defined aluminosilicate complexes and/or hydroxy‐Al‐tannate complexes. Chemical composition, size, number, and nature of the functional groups, and concentration of organic ligands played a vital role in perturbing the formation of allophane and imogolite in the precipitation products. The order of effectiveness of organic ligands was: tannic >> DL‐tartaric > citric > DL‐malic >> salicylic > DL‐aspartic ≥ p‐hydroxybenzoic. Organic ligands with a strong affinity for Al significantly modified the nature of the soluble products which range from “proto‐imogolite” sol complexed with organic acids to hydroxy‐Al‐organic complexes.
Rapid and Slow Phosphate Sorption by Mediterranean Soils: Effect of Iron Oxides
Authors: Torrent J. 
Published: July 2010

AbstractThe rate of phosphate sorption (for different levels of P application) by the clay fractions of 20 soils of Mediterranean Spain ranging widely in mineralogical properties could be described by a modified Freundlich equation. The coefficient giving the P sorbed at unit concentration and unit time (taken as a measure of the rapid sorption) was significantly correlated with the amount of crystalline Fe oxides but not with other properties. The time course of the slow P sorption could not be visualized adequately by the modified Freundlich equation. For that particular purpose a simple Elovich type equation was used. This equation fitted the data well and its coefficient describing slow sorption was also correlated with the crystalline Fe oxide content. Both rapid and long‐term P sorption decreased when clays were treated with citrate‐bicarbonate‐dithionite to dissolve Fe oxides.
The Effect of Growing Plants on Denitrification at High Soil Nitrate Concentrations
Authors: Haider K. , Mosier A. , Heinemeyer O. 
Published: July 2010

AbstractThe availability of plant rhizosphere C deposits and its influence on microbial denitrification is not clearly defined. Conflicting reports as to the influence of plants and root exudation on denitrification continue to appear in the literature. The results of our earlier phytotron study indicated that denitrification was not stimulated in soils planted with corn or wheat compared to unplanted soils. Lower nitrate concentrations in the planted soils, however, may have led to misinterpretation of this data. A second study was conducted, to evaluate the effect of actively growing plants on denitrification where the NO‐3 content of planted soils was maintained similar to unplanted soils. Simultaneously the C fixed by corn (Zea mays) and the fate of fertilizer N applied to the soil during the growing season were quantified. The corn was grown in a phytotron under a continuous supply of 14CO2 in 15N fertilized soils to which 15N‐NO‐3 was added periodically during the growing season. The results of these studies showed that denitrification was not stimulated in soils planted with corn during active plant growth phase even when soil NO‐3 was relatively high. Denitrification was, however, greater in corn planted than unplanted soil when the recoverable root biomass began to decrease. Less N was immobilized and net 15N immobilization was lower in planted soils than in unplanted soils. As denitrification was lower in planted soils during the time of active plant growth, the study suggests that root exudates did not stimulate either process.
Competition for Nitrogen‐15 Depleted Ammonium Nitrate and Nitrogen Fixation in Arrowleaf Clover‐Gulf Ryegrass Mixtures
Authors: Morris D. R. , Weaver R. W. 
Published: July 2010

Abstract‘Yuchi’ arrowleaf clover (Trifolium vesiculosum Savi) and ‘gulf’ ryegrass (Lolium multiflorum Lam) are commonly grown together but their competitive relationship for fertilizer N has not been determined. Two greenhouse experiments were conducted to examine this relationship and to determine the effects on biological N2 fixation. Seeds were sown in a Norwood soil (fine‐silty, mixed [calcareus], thermic Typic Utifluvent) that was mixed with vermiculite (Exp. I) or sand (Exp. II). Nitrogen was applied at different rates during the seedling stage to plants sown in pure and mixed stands. In Exp. I, plants were grown for 8 weeks. In Exp. II, plants were grown for 20 weeks and three clippings were taken. The N source was 99% 15N depleted NH4NO3. Ryegrass in mixed stand accumulated several times more fertilizer N than its clover component. But clover in pure stand accumulated similar quantities of fertilizer N as the ryegrass in pure stand. The percentage of total N2 fixed in the clover was usually decreased with increasing fertilizer N rates due to increased fertilizer N uptake. Total N in the clover from N2 fixation was often not significantly altered with increasing fertilizer N rates which indicates that fixed N was complimenting the N taken up from the fertilizer.
Characterization and Classification of Soils with Spodic Morphology in the Southern Appalachians
Authors: Lietzke D. A. , McGuire G. A. 
Published: July 2010

AbstractSixteen pedons with varying degrees of spodic morphology were sampled for characterization and classification on upland landforms in three areas of the southern Appalachians. Sites were located on Clingmans Dome and Unaka Mountain, both astride the Tennessee‐North Carolina border, and Poor Mountain located in southwestern Virginia. Vegetation is dominately spruce (Picea rubens)‐fir (Abies frazieri) with an ericaceous understory. Parent materials are almost exclusively feldspathic‐quartzites that were extensively frost shattered during the late Pleistocene and are now being chemically weathered. Coarse fragments that have been softened by chemical weathering cause pronounced tonguing and streaming of organic compounds from the 0 horizons through the E horizon into the Bhs/Bs horizon beneath. This results in highly variable vertical and lateral expression of spodic morphology over very short distances. Soils with few or without coarse fragments had a more typical expression of spodic morphology. High organic C contents of O and A horizons when mixed with underlying E horizons to a depth of 18 cm imparted umbric colors to all pedons. All Bhs/Bs horizons had accumulations of C, Fe, Al, and clay‐sized particles. Three of the 16 pedons met all three chemical criteria for spodic horizon determination. The pyrophosphate extractable Al and Fe to clay ratio was the most critical criterion in this study. The clay content, 14 to 35% in Bhs/Bs horizons reduced this ratio to less than the required 0.2. We propose that this Al + Fe to clay ratio be lowered to >0.1 and <0.2 to identify Entic Haplorthods, and >0.2 to recognize Typic Haplorthods in soils with loamy Bhs/Bs horizons. Two chemical field tests differed in their ability to distinguish spodic horizons from other horizons with spodic character.