bluuebunny/crossref_metadata_2025_split huggingface dataset:
Soluble Cations Beneath a Feedlot and an Adjacent Cropped Field
Authors: Elliott L. F. , Travis T. A. , McCalla T. M. 
Published: July 2010

AbstractConcentrations of Na, K, Ca, Mg, Zn, Cu, Fe, and Mn in the soil solution were measured beneath a feedlot and an adjacent cropped field for a 12‐month period. Only Ca, Mg, and Mn were higher in the feedlot soil solution than in the cropped field at the lower depths tested. At the lower depths, Ca and Mg appeared to be two to four times higher in soil solution from the feedlot than from the cropped field. Manganese was consistently higher beneath the feedlot than the field; however, Mn levels were low, and, with the limited water movement through feedlot soil, it is unlikely feedlots contribute significant Mn to groundwater.
Field Mapping Soil Conductivity to Delineate Dryland Saline Seeps with Four‐electrode Technique
Authors: Halvorson A. D. , Rhoades J. D. 
Published: July 2010

AbstractContinuing incidence of saline‐seep areas in the northern Great Plains dryland soils has created a need for detecting and delineating encroaching saline seeps before plant growth is affected. We evaluated the four‐electrode conductivity technique for field mapping surface and subsurface soil salinity under dryland conditions.Results indicated that the four‐electrode conductivity technique can be used successfully to quickly field map surface and subsurface soil salinity boundaries of existing and potential saline‐seep areas. This technique also depicted underground flow patterns of a shallow, saline ground water table.Maps of apparent bulk soil conductivity values (ECa) were used to locate the position of the recharge area in relation to the discharge (seep) area. While maps of discrete depth interval conductivity values (ECx) provided more precise information, the time required may not warrant the additional required calculations unless a portable programable calculator is available. Mapping soil salinity with the four‐electrode conductivity technique is easy, rapid, and relatively inexpensive. This technique provides information useful in making management decisions to prevent or alleviate a saline seep or other soil salinity problems.
Chemical Distribution and Gaseous Evolution of Arsenic‐74 Added to Soils as DSMA‐74As
Authors: Akins Michael B. , Lewis Russell J. 
Published: July 2010

AbstractGaseous evolution of 74 As from a soil treated with arsenic‐74 labeled disodium methanearsonate (DSMA‐74 As) at 100 µg/g was a function of organic matter addition and moisture conditions. Loss of 74As was greatest from soils that received an exogenous carbon source and were maintained under wet conditions.Arsenic‐74 sorbed by soils of pH 4, 6, and 8 was fractionated by a differential dissolution procedure commonly used for phosphorus. Iron arsenate (soluble in 0.1N NaOH) was the most abundant form followed by aluminum arsenate (soluble in 0.5N NH4F). The soils generally contained more aluminum arsenate at pH 4 than at pH 6 or 8. Calcium arsenate fractions (soluble in 0.5N H2SO4) were usually higher at pH 6 and 8 than at pH 4. Water‐soluble forms and nonextractable forms were inversely proportional to each other.
Microbial Formation of Volatile Selenium Compounds in Soil
Authors: Doran J. W. , Alexander M. 
Published: July 2010

AbstractSelenium was volatilized from soils amended with elemental Se, selenite, selenate, trimethylselenonium chloride, selenomethionine, and selenocystine and incubated in air or anaerobically. The processes were wholly or largely the result of microbial action. The conversion of selenite and selenate to volatile products was enhanced if soil was amended with organic materials. Indigenous soil Se was also volatilized in the presence of supplemental organic matter. The products were identified by combined gas chromatography‐mass spectrometry. Dimethyl selenide was generated from all Se compounds tested when amended soils were incubated in the presence of air. Under anaerobic conditions, dimethyl selenide was produced from the three organic Se compounds and selenate, and a product tentatively identified as hydrogen selenide (H2Se) was evolved from soil receiving elemental Se, selenite, selenate, or selenocystine. Dimethyl diselenide was also formed from selenomethionine in soil incubated in air or anaerobically.
Effects of Boron and Nitrogen on Grain Yield and Boron and Nitrogen Concentrations of Barley and Wheat
Authors: Gupta Umesh C. , MacLeod J. A. , Sterling J. D. E. 
Published: July 2010

AbstractIn field experiments, 4.48 kg B/ha added to the soil decreased the grain yield of barley (Hordeum distichon L.) and wheat (Triticum aestivum L.). Under greenhouse conditions, 0.5 ppm, added B reduced wheat yields while 1.0 ppm added B reduced barley yields. The B toxicity in wheat in 1974 and barley and wheat in 1975 at 2.24 kg B/ha as associated with reduced yield was alleviated somewhat by the additions of N to the soil in field experiments, but the effect was not significant. Under greenhouse conditions, addition of 50 ppm N or more reduced B uptake and alleviated B toxicity. In general, the B toxicity symptoms on the foliage under field conditions were associated with >11 ppm B in wheat boot stage tissue (BST) and >14 ppm B in BST of barley. Added B increased the N concentration of grain where yields were decreased due to B toxicity. Wheat yields increased with increased rates of N application in all field experiments, while barley yields increased with increased rates of N in 2 of the 3 years. In field experiments the highest B value was 34 ppm. Concentrations as high as 312 ppm B were found in greenhouse experiments. In the presence of added B under greenhouse conditions, the barley tissue B concentration was much lower when the moisture level near the fertilizer band was low than when it was high.
Arsenic Stability in Contaminated Soils
Authors: Hess R. E. , Blanchar R. W. 
Published: July 2010

AbstractVarious Al, Ca, Fe, Mn, and Pb arsenate compounds were formed and their solubility products determined. The amount of arsenate in solution for each of the compounds could be predicted as follows: AlAsO4 · 2H2O(pAsO4 = 24.51‐3pH), FeAsO4 · 2H2O or Fe(OH)3 · FeAsO4(pAsO4 = 26.07‐3pH), Ca3(AsO4)2 · 14H2O(pAsO4 = 9.29‐1.5pCa), Pb3(AsO4)2 · 4H2O(pAsO4 = 19.75‐1.5pPb), and Mn3(AsO4)2 (pAsO4 = 35.6‐12.8Eh‐2.3pH), or (pAsO4 = 47.3‐25.3Eh‐3pH), with either Mn2O3 or MnO2.Samples from Sharpsburg and Menfro soils were equilibrated for 7 days at 25°C with dilute HCl and NaOH. Aluminum, Fe, Ca, Mn, Pb, and As contents and pH and E (platinum) were determined on the solution portions. The values of pAl + 3pOH, pAl + pAsO4, pFe + 3pOH, pFe + pAsO4, 3pCa + 2pAsO4, 3pMn + 2pAsO4, and 3pPb + 2pAsO4 were computed for each soil. The values of the ion products indicated that equilibrium solutions from both soils were undersaturated with respect to Al, Fe, and Ca and that Pb and Mn arsenate were stable in the Menfro and Sharpsburg soils.
Correction of “Tube Contribution” Interference in the Determination of Heavy Metals by X‐ray Spectroscopy using the “Additions Technique”
Authors: Keramidas V. Z. , Fanning D. S. 
Published: July 2010

AbstractCr and W X‐ray tubes emitted not only the target characteristic lines but the lines of Fe, Zn, Cu, and Ni as well. Such extraneous radiation, which probably originates primarily from contamination of the tube target by the metals and is referred to as “tube contribution,” may lead to erroneous qualitative interpretation of X‐ray spectra because peaks of the elements may appear in the spectra when the element is not present in the sample. The additions (or spiking) technique allows matrix problems to be overcome in the quantitative measurement of Zn, Cu, and Ni in soils and other materials, but an accurate estimation of the background under the peak is essential. Because of the “tube contribution” to the line of the element concerned, the background under the peak is increased and results in a positive error with the additions technique if no correction is made. The ratio of the peak to background beside the peak for the “tube contribution,” for each element, was found to be nearly constant in different materials free of Zn, Cu, and Ni. Thus, a background that includes the “tube contribution” may be calculated, for unknown samples containing the element concerned, by multiplying the background beside the peak by the ratio factor. Using the additions technique including measurement of the background as described, accurate measurements were made of Zn, Cu, and Ni in soils, sewage sludges, and plant and animal tissues.
Microbial Inorganic Polyphosphates: Factors Influencing Their Accumulation in Soil
Authors: Pepper I. L. , Miller R. H. , Ghonsikar C. P. 
Published: July 2010

AbstractInfrared spectra of microbially synthesized, acid labile, inorganic P compounds extracted from soils provided additional evidence that they are inorganic polyphosphates (poly P). Incubation studies with glucose amended soils demonstrated the transient nature of naturally occurring poly P. Experiments are reported on the conditions which optimize poly P synthesis in soil. A 2‐week incubation period (preincubation) with a source of carbon (2% glucose or 4% straw) and a further 2‐day incubation period (postincubation) after adding a source of ortho P resulted in the maximum accumulation of poly P. The quantity of poly P also increased with increasing rates of orthophosphate from none to 1,000 µg soil/g. Longer periods of postincubation reduced poly P accumulation. Poly P synthesis was greater when relatively insoluble sources of P were added to soils and accumulation followed the order; FePO4 · 2H2O > rock phosphate > Ca(H2PO4)2 · H2O > KH2PO4. These results suggest that poly P synthesis may accompany P solubilization in soils and be an integral part of the soil P cycle.
The Red Latosols of Sri Lanka: II. Mineralogy and Weathering
Authors: de Alwis K. A. , Pluth D. J. 
Published: July 2010

AbstractSoil samples from the principal soil series of the Red Latosols of Sri Lanka were subjected to (i) mineralogical analysis of the fine sand fractions by density, magnetic and optical methods, and (ii) mineralogical analysis of the clay and silt fractions by X‐ray diffraction, DTA, chemical, and electron optical methods in order to characterize these soils and elucidate their genesis.Mineralogical analysis of the fine sand fractions confirmed that the parent materials were uniform with depth and within series, but differed among series. The near‐complete absence of easily weatherable minerals indicates intense weathering either before deposition or during soil formation.The fine (< 0.2 µm) clays of all three Red Latosol soil series consist almost exclusively of well‐crystallized kaolinite. The remainder is made up of free iron oxides and a small amount of amorphous components. Similarly the coarse (2–0.2 µm) clays are dominated by kaolinite, but they also contain minor amounts of other minerals, chiefly mica and mixed layer minerals with anatase and possibly some interstratified materials being present as traces. Coarse clays from the Wilpattu series contain, in addition, a clay mineral that is probably a vermiculite‐smectite intergrade. The mica in the surface horizons appears to be stabilized against weathering, possibly by phytocyling of K. Free iron oxides are present mainly as discrete particles of hematite. Small amounts of amorphous materials also occur.
Sand and Coarse Silt Mineralogy of Selected Soils on the Lower Coastal Plain of North Carolina
Authors: Smith B. R. , Granger M. A. , Buol S. W. 
Published: July 2010

AbstractMineralogical characterization studies were made of sandy, loamy, and silty soils on the Pamlico, Talbot, and Wicomico terraces of the Lower Coastal Plain of North Carolina. Soils on the Pamlico terrace contain substantial amounts of weatherable minerals (as much as 35%), primarily feldspars. Soils on the higher Talbot and Wicomico terraces contain a stable mineral assemblage (mostly quartz) and only very minor amounts of weatherable minerals (<5%). Drainage class did not influence the sand mineralogy. The relationship between mineralogical composition of these soils and their occurrence on particular terraces is useful from the standpoint of soil classification because it affords a means of delimiting soils which belong to mixed or siliceous mineralogy families on the Lower Coastal Plain.
Persistence of Subsoil Compaction in a Mollisol
Authors: Blake G. R. , Nelson W. W. , Allmaras R. R. 
Published: July 2010

AbstractPersistence of subsoil compaction was tested in Nicollet clay loam (a Mollisol) in southwestern Minnesota. Plots were either not packed or packed in 1960 in the bottom of each plow furrow using about 7.5 bars pressure, and were cropped to corn (Zea mays L.) and alfalfa (Medicago sativa L.) 9 years. Halves of plots were irrigated each year just prior to soil freezing. All plots were tilled with normal farm equipment after initial packing.Soil bulk density below the plow layer did not change over the 9‐year period, but there were small trends for increased bulk density on the not‐packed treatment. Neither crop nor overwinter soil water content affected the packed subsoil. The packed layer was easily identified by penetrometer measurements.Alfalfa root samples taken at the close of the experiment showed that packing reduced mean root weights by as much as 36% in the 40‐ to 90‐cm layer compared to 11% or less in the surface 40 cm. Packing affected the distribution of taproots and fibrous roots in the profile.Soil hydraulic conductivity (K), either saturated or unsaturated, was reduced by packing. Decreases in saturated K averaged 65% in 10‐cm soil depths between 21 and 48 cm and 56% between 61 and 88 cm. Unsaturated K measured in situ also showed persistence of the packing treatment in the 18 to 55‐cm soil layer.
Soil Compaction After Tree‐Length Skidding in Northern Mississippi
Authors: Dickerson B. P. 
Published: July 2010

AbstractAfter skidding with a rubber‐tired skidder, bulk densities of wheel‐rutted soils increased an average of 20% to 1.55 g/cm3; the increase was 10% for the soils between the ruts which were compacted by the movement of logs. Macropores were reduced 68% for wheel‐rutted soils and 38% for log‐disturbed soils; micropore space of both increased about 7%. Percolation rates decreased initially but recovered gradually. Wheel‐rutted soils require about 12 years to recover and log‐disturbed soils about 8 years.
Splash Erosion of Primary Particles and Aggregates
Authors: Kinnell P. I. A. 
Published: July 2010

AbstractThe previously supposed similarity between primary particles and aggregates in resisting splash erosion was shown to be partially incorrect. Mathematical treatment of splash‐cup data on which the earlier conclusion was based showed that for surfaces containing aggregates, the quantity of material lost per unit quantity of artificial rainfall varied with rainfall intensity; a result which contrasts to observations for primary particles.
Solute Movement in a Field Soil
Authors: Van De Pol R. M. , Wierenga P. J. , Nielsen D. R. 
Published: July 2010

AbstractSolute and water movement was studied under steady‐state flow conditions in a field soil consisting of 70 cm of clay to silty clay over a medium sand. A steady‐state water flow condition was maintained by applying irrigation water at a constant flux of 2 cm per day. During the steady‐state condition some of the water leached into the plot was labelled with chloride and tritium. The positions of the chloride and tritium as functions of soil depth and time were measured by extracting samples of the soil solution with soil suction probes. Extremes in solute displacement occurred at equal and different depths within the plot. An analysis of these measurements indicated that observations of the pore‐water velocity and the apparent diffusion coefficient were log normally distributed. Twenty‐four soil suction probes, used to identify the rate at which a solute was displaced in the soil, will yield an estimate of the mean pore‐water velocity of this soil within a range of approximately ±25% of its true value providing the effects of potential solute‐soil interactions are taken into account.
Thermodynamic Stability and Solubility of Molybdenum Minerals in Soils
Authors: Vlek P. L. G. , Lindsay W. L. 
Published: July 2010

AbstractThe chemical reactions of molybdenum in soils were studied in the laboratory. Solubility diagrams were constructed from thermodynamic data obtained from the literature and from measurements made on pure minerals. Included in these diagrams were solubility relationships for MoS2 (molybdenite), Mo3O8 (ilsemannite), Fe2(MoO4)3 (ferrimolybdite), CaMoO4 (powellite), and PbMoO4 (wulfenite). From these diagrams it appears that wulfenite is one of the most stable Mo minerals likely to form in soils. Lack of thermodynamic data on other Mo minerals prevents their evaluation as possible reaction products.The solubility of Mo in selected Colorado soils in the pH range of 5.5 to 7.7 was plotted on the wulfenite solubility diagram. Of the 13 soils used in this study, only one showed equilibrium with respect to wulfenite. When wulfenite was added to several other soils, the molybdenum solubility increased 10‐ to 100‐fold, confirming that wulfenite was not initially present. These wulfenite‐amended soils showed a close correspondence between soluble Mo and the wulfenite solubility isotherm.In the absence of solid phase Mo compounds, the solubility of Mo in soils is controlled by specific adsorption.
Hydrologic Differences between Selected Forested and Agricultural Soils in Hawaii
Authors: Wood Hulton B. 
Published: July 2010

AbstractComparisons of hydrologic characteristics of soil under different land uses were made at 15 sites on the islands of Hawaii, Maui, and Kauai. A site consisted of at least two adjacent but different land uses on the same soil series. One land use at a site was always an ungrazed forest; the others were planted either to sugarcane (Saccharum officinarum) or pineapple (Ananas comosus), or used as pasture. Infiltration rates on 14 of the 15 sites were found to be higher under forest cover than agriculture uses. Mean weight diameters of the surface soil aggregates were larger for forested soils than for soils planted to sugarcane or pineapple. Aggregate size also varied with soil order and soil moisture content at time of testing. Lower bulk densities and greater porosities were found in forest‐covered soils than in the nonforested soils.
History of Chemical Fertilizer Development
Authors: Russel Darrell A. , Williams Gerald G. 
Published: July 2010

AbstractNeolithic man probably used fertilizers, but the first fertilizer produced by chemical processes was ordinary superphosphate, made early in the 19th century by treating bones with sulfuric acid. Coprolites and phosphate rock soon replaced bones as the P source. The K fertilizer industry started in Germany in 1861. In North America the K industry started during World War I and expanded with development of the New Mexico deposits in 1931 and the Saskatchewan deposits in 1958. Modern K fertilizers are more the product of physical than of chemical processes. The first synthetic N fertilizer was calcium nitrate, made in 1903 from nitric acid produced by the electric arc process. The availability of synthetic ammonia after 1913 led to many new N fertilizers, but physical quality was poor. In 1933 TVA was formed with a national responsibility to increase the efficiency of fertilizer manufacture and use. More than 75% of the fertilizer produced in the United States is made with processes developed by TVA.Major fertilizers and fertilizer intermediates introduced by TVA include ammonium nitrate, high‐analysis phosphates, diammonium phosphate, nitric phosphates, ammonium polyphosphate, urea ammonium phosphates, 11‐16‐0 and other liquid base solutions, superphosphoric acid, wet‐process superphosphoric acid, suspensions, granular urea, and S‐coated urea. These have had major impact upon the production of mixed fertilizers, bulk blending, and the fluid fertilizer industry. Future fertilizers not only must be technologically feasible, economical, and agronomically suitable—as have been past fertilizers—but also must meet various air and water pollution standards during production and have reduced total energy requirements.
Ion Activity Products of Calcium Carbonate in Waters Below the Root Zone
Authors: Suarez Donald L. 
Published: July 2010

AbstractThe pH, Ca2+, and HCO3‐ relations were investigated in 28 well waters obtained from beneath irrigated fields in Arizona. The mean [Ca] [CO3] ion activity product (IAP) was 11.3 × 10−9 (pIAP = 7.95) with a standard error of 0.7 × 10−9 based on field measurements of pH. As indicated by ionic strength the residence time of the waters in the soil vary widely. The lack of a trend in pIAP vs. ionic strength indicates the kinetics of calcite equilibration (from supersaturation) is quite slow in soil‐water systems. This conclusion was supported by an average pIAP of 7.97 calculated from 35 water analyses obtained from wells in the Grand Valley of Colorado and by a pIAP value of 7.96 obtained from a soil water sample in a lysimeter study. Since these pIAP values are quite consistent and were obtained under a wide variety of conditions, a pIAP value of 7.95 is recommended for use in predictive models when CaCO3 precipitation occurs.
Exchange Capacity of Calcium and Sodium Soils as Determined by Different Replacing Cations
Authors: Ravina Israela , Gurovich Eliezer 
Published: July 2010

AbstractExperimentally determined CEC values are dependent on the nature of the initially adsorbed cation and the replacing one. Cation exchange capacities of Na‐saturated and Ca‐saturated soils were determined using monovalent and divalent cations. In the exchange of initially adsorbed Na or Ca by monovalent cations, the magnitude of CEC increases with increasing ionic radius or polarizability of the replacing cation. The Na soil shows a greater CEC than the Ca soils.The Na soil and Ca soil behave differently with respect to the exchange by divalent cations. While the CEC of a soil initially saturated with Ca increases as the ionic radius of the replacing cation is larger, the magnitude of CEC of a Na soil decreases.
Titration Studies on the Polynuclear, Polyacidic Nature of Fulvic Acid Extracted from Sewage Sludge‐soil Mixtures
Authors: Sposito Garrison , Holtzclaw Kenneth M. 
Published: July 2010

AbstractAqueous solutions of two fulvic acids extracted from sludge‐soil mixtures were studied by potentiometric titration with either KOH or HCl in an ionic medium of 0.1 mol/kg KCl. Data were obtained for a range of concentrations of FA at 25°C and for a single concentration at 35°C that duplicated one of those employed at the lower temperature. Formation functions giving the amount of H+ neutralized as a function of the free OH‐ concentration or of the pH were computed for each set of titration data. Analysis of these functions led to the conclusions that: (i) sludge‐derived FA contains functional groups ranging in acidity from very strong (ionized at pH < 2) to very weak (ionized at pH > 10); (ii) the strongly acidic groups are probably sulfonic acid groups and are relatively numerous; (iii) the more weakly acidic groups are probably carboxyls, N‐containing groups, phenolic OH, and SH groups; (iv) the strongly acidic groups can bind H+ from solution (counter‐ion condensation) when they get close to complete neutralization; (v) the H+ binding effect is enhanced by lowering the concentration of FA or by raising the temperature; and (vi) the reversibility of the titration curves is influenced greatly by the presence of the strongly‐acidic functional groups. These conclusions support the conceptualization of sludge‐derived FA as a heterogeneous polynuclear polyacid whose intrinsic acidity will show a pronounced dependence on its concentration and on the temperature. Thus the behavior of this material in soil solutions may be expected to be quite complex.