L. W. Zelazny's research while affiliated with Virginia Tech (Virginia Polytechnic Institute and State University) and other places
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Publications (130)
Turbidity is an effective tool for estimating and monitoring suspended sediments in aquatic systems. Turbidity can be measured in situ remotely and at fine temporal scales as a surrogate for suspended sediment concentration (SSC), providing opportunity for a more complete record of SSC than is possible with physical sampling approaches. However, th...
The lack of a reliable method for measuring phytase activity (PA) in soil impedes efforts to elucidate the influence of these phosphomonoesterases on phytate degradation and subsequently the P cycling process in soils and sediments. The objective of our research is to develop a convenient method for measuring PA in soil using the novel chromophoric...
Adsorption experiments in which μM F solutions were equilibrated with K-, Ca-, and Al-saturated cation-exchange resins demonstrated substantial F removal to the Al-saturated resin, with the adsorbed F quantitatively recovered with a single wash with 1.0 M NHâCl, whereas no F removal was observed when either K or Ca occupied the exchange sites. Rem...
Agroecology is the attempt to apply ecological principles to agricultural systems, with the objective of sustaining those systems in an environmentally sound manner (Thomas and Kevan, 1993). Cross‐referencesEcology
Continuous N-based application of biosolids contributes to a gradual increase of trace elements and P in soils. The objectives of this study were to assess the accumulation and vertical transport of Cu, Zn, C, N, and P within the profile of two coastal plain soils. Liquid (6-8% total solids) biosolids were applied to an Acredale silt loam (fine sil...
Mineral sands mining for ilmenite, rutile, and zircon will disturb over 2,500 ha of prime agricultural farmland in Virginia and North Caro-lina (USA) over the next 20 years. Mining of the Virginia deposit was initiated in 1997 and approximately 750 ha have been disturbed to date with approximately 150 ha reclaimed to support a mix of agricultural p...
The artificial chromophoric substrate analog of phytic acid, 5-O-[6-(benzoylamino)hexyl]-d-myo-inositol-1,2,3,4,6-pentakisphosphate (T-IP5), may prove useful in measuring soil phytase activity. This chemical probe allows for direct measurement of phytase-catalyzed dephosphorylation (i.e., hydrolysis of the phosphoester bond) using high-performance...
The purpose of this 4-yr study was to evaluate tall fescue (Festuca arundinacea L.) production and changes in soil P fractions resulting from alum-treated poultry litter (ATPL) applications. Plots were es- tablished in the spring of 2000 at Orange, VA, on a Davidson loam (fine, kaolinitic, thermic Rhodic Kandiudult). Treatments included the applica...
The relationship between STP (soil test P) and DRP (dissolved reactive P) in runoff has been shown to vary with soil type due to differences in soil properties. The purpose of this study was to determine if soil tests could indirectly take into account differences in soil properties and thus provide one relationship with STP and runoff DRP among a...
A single biosolids application was made to 1.5×2.3 m confined plots of a Davidson clay loam (Rhodic Kandiudult) in 1984 at 0, 42, 84, 126, 168, and 210 Mg ha. The highest biosolids application supplied 750 and 600 kg ha of Cu and Zn, respectively. Corn (Zea mays L.), from 1984 to 2000, and radish (Raphanus sativus L.) and romaine lettuce (Lactuca s...
Concerns over the possible increase in phytoavailability of biosolids-applied trace metals to plants have been raised based on the assumption that decomposition of applied organic matter would increase phytoavailability. The objectives of this study were to assess the effect of time on chemical extractability and concentration of Cd, Cu, Ni, and Zn...
The relationship between soil test P (STP) and dissolved reactive P (DRP) in runoff has been shown to vary with soil type due to differences in soil properties. This study was conducted to determine the effect of mineralogy on P sorption behavior and DRP losses in runoff using simulated rainfall. Nine different soil types were sampled from four dif...
The long-term mobility of trace metals has been cited as a potential hazard by critics of EPA 503 rule governing the land application of biosolids. The objectives of this study were to assess the accumulation of Cu, Ni, Cd, and Zn within the soil profile; the distribution of exchangeable, specifically adsorbed, organic, and oxide fractions of each...
Methods for environmental risk assessment of P loss potential from soils lack uniformity and see generally difficult for routine analysis. Mehlich-1 extractable P (M1-P), an approach that is widely used to assess soil P status for plant growth, was used as a soil test P (STP) estimator of the degree of P saturation (DPS) of a soil. The concept of D...
Many states have passed legislation that regulates agricultural P applications based on soil P levels and crop P uptake in an attempt to protect surface waters from nonpoint P inputs. Phytase enzyme and high available phosphorus (HAP) corn supplements to poultry feed are considered potential remedies to this problem because they can reduce total P...
The Old Hickory mineral sands orebody in Virginia is >2,000 ha (>5,000 acres) in size and currently supports a productive row-crop agriculture. Reclamation experiments were implemented on pilot-scale mining pits from 1995 to 1998. Half of each mining pit was, topsoiled with 25 cm (10 in.) of soil. The remaining half was left as either mixed tails/s...
The long term availability of trace metals to plants and their possible leaching below the root zone have been cited as potential hazard by critics of EPA 503 rule governing the land application of biosolids. The objectives of this current research are to assess the availability of
Cd, Cu, Ni, and Zn to plants and their distribution within the soil...
The Virginia Phosphorus Index (P-Index) is a management tool for assessing risk of P
delivery to surface waters. The P-Index considers the interaction of source and transport factors to
estimate the average annual risk of P delivery to water bodies. Source factors include residual P in
the soil and P applied via fertilization. Transport factors inc...
There is great interest in returning coal combustion products to mining sites for beneficial reuse as liming agents. A column study examined the effects of blending two coal fly ashes with an acid-forming coal refuse (4% pyritic S). Both fly ashes were net alkaline, but had relatively low neutralizing capacities. One ash with moderate alkalinity (C...
The eastern hardwood forests of the US may be threatened by the changing atmospheric chemistry and by changes in harvesting levels. Many studies have documented accelerated base cation losses with intensive forest harvesting. Acidic deposition can also alter nutrient cycling in these forests. The combination of increased harvesting, shorter rotatio...
defined as follows: low (LEP ,3%, COLE ,0.03); mod- erate (LEP 3-6%, COLE 0.03-0.06); high (6-9%, Soil properties indicative of shrink-swell potential were studied COLE 0.06-0.09); and very high (LEP .9%, COLE for 12 soils encompassing several parent materials in Virginia. Soils are rated from moderate to very high shrink-swell potential. The .0.09...
A study was conducted in the Culpeper Basin in northern Virginia to quantify soil shrink-swell indicators, to relate the indicators to soil properties, and to partition variability into map unit components. Five delineations in each of five map units were selected for study. Three profiles were sampled within each delineation to complete a nested s...
The widespread occurrence of reworked sediments on 'stable' landforms throughout much of the Appalachians strongly suggests that climatic or tectonic fluctuations have resulted in major changes in the erosional stability of the region throughout the Quaternary. However, the causes and timing of erosional and depositional events are complex and poor...
It is known that PO4 is retained by soils through ligand exchange, i.e., inner sphere complexation, but the mechanism for SO4 adsorption at the mineral-water interface has been in debate. By studying the effects of ionic strength on ion adsorption, it is possible to distinguish between inner and outer sphere ion surface complexes. This study was co...
There is a release of OH- from soil colloids with the addition of SO2-4. The ratio of moles of OH- released per mole of SO2-4 adsorbed is referred to as the OH/SO4 exchange stoichiometry. The OH/SO4 stoichiometry not only provides an important constraint on surface complexation models but also is a critical area of research to explain the effects o...
Significant deposits of mineral sands were discovered in Virginia (USA) in 1989. The Old Hickory Deposit is the largest ore body in the state (>2000 hal and supports a productive rowcrop agriculture based on tobacco, peanuts, corn, wheat, soybeans and cotton. In 1990 we generated simulated mine tailings and slimes from deep driliing bulk samples an...
Highly acidic and metal-rich runoff from coal storage facilities can have a dramatic impact on local surface water and groundwater quality. In order to identify important reactions governing metal transport within subsurface environments subject to infiltration of coal pile runoff (CPR), samples of uncontaminated subsoil adjacent to a coal stockpil...
A total of 35 pedons at elevations >450 m were characterized on the high mountain peaks of eastern Tennessee, western North Carolina, and southwestern Virginia. Soil chemical and mineralogical properties inherited from different parent materials were sufficiently different between study areas to result in the clear separation of soils into distinct...
Four pedons representing a development weathering sequence ranging from soils having distinct spodic field morphology (E plus Bhs horizons) to those having either minimal (weak E horizons) or no spodic character were selected for further study. Surface-horizon clay fractions were dominated by regularly interstratified mica/vermiculite and high-char...
Concerns over the effects of acid rain have stimulated numerous hydrometric and geochemical studies on forested watersheds with an emphasis on stream water chemistry. However, integrated studies are seriously lacking, and inferences of soil hydrogeochemical processes from periodic stream water chemistry may be grossly misleading. A small forested s...
Geochemical studies of transport from watersheds to date have focused on stream chemistry and/or soil lysimeter data to interpret soil processes. Direct measurements of subsurface transport of solutes from hillslopes during storm events and integration with hydrometric analyses is seriously lacking. This study presents subsurface transport of solut...
This study was conducted to determine the effects of Ca on the mobilization of Al and organic matter in a Cecil soil (clayey, kaolinitic, thermic Typic Kanhapludult). Acidic solutions (pH 4.2) containing ambient or near-ambient precipitation concentrations of Ca, K, and SO4 were used to infiltrate columns containing Oa, EB, or Oa/EB bihorizon soil...
The subsurface transport of dissolved organic carbon (DOC) through a proposed waste burial site during rain events was investigated in order to assess the role of colloid-mediated contaminant mobility. A sub-watershed (0.45 ha) located on a forested hillslope in eastern Tennessee, U.S.A., was instrumented with an isolated soil pedon for one-dimensi...
A batch equilibration study evaluated the influence of naturally occurring low-molecular-weight mono- and diprotic aliphatic acids on the rate of Al and SOâ²⻠release in a Cecil soil (Typic Hapludult). The authors adjusted the pH of the organic acids (OAs) and of the soil suspension (3.8% w/w) to pH 4.0 and allowed them to equilibrate thermally...
Investigations of the physical and chemical characteristics of macropores and mesopores at two forested sites established for subsurface transport research are summarized. The hydrologically active macroporosity (pores larger than 1 mm diameter) is a very small fraction of the total soil porosity but is sufficient to conduct a large proportion of p...
Acidic deposition is capable of altering the geochemistry of several elements important to forest productivity (Reuss and Johnson 1986). Long-term effects of acidic deposition may include accelerated depletion of base cations and increased concentrations of aluminum in soil solutions. Forest soils, which generally do not receive fertilizers and lim...
A procedure is presented for estimating cation exchange capacity (CEC) and exchange selectivity coefficients from miscible displacement experiments on undisturbed soil columns. The procedure provides an alternative to batch experiments and is applicable to scenarios involving either binary homovalent exchange or binary monodivalent exchange. Gapon'...
In a previous study we demonstrated the phytotoxicity of polynuclear hydroxy‐Al, a finding that disagrees with a number of existing reports. The objectives of this study were to examine how toxicity of polynuclear Al might vary with experimental conditions or with choice of test plants, and to identify and characterize the toxic polynuclear species...
A column study was conducted using selected horizons from three soils that were leached with pH 4.8 solutions containing either SO 42- or NO 3- at various ionic strengths. The quantity of dissolved organic C (DOC) release into the soil solution decreased with increasing ionic strength. The addition of SO 42- to the leaching solution resulted in ele...
The root system of alfalfa (Medicago sativa L.), known for extreme sensitivity to Al toxicity, has been observed to penetrate acid subsoil horizons high in exchangeable Al. In our previous studies we noted that root penetration into acid subsurface horizons occurred where lime had been surface applied under both no‐till and conventional tillage man...
Crystal growth theory was applied to describe edge sites of phyllosilicates. Three face config- urations were found to exist. One face has one tetrahedral site per tetrahedral sheet and two octahedral one-coordinated sites per crystallographic area ac sin/3, where a and c are layer dimensions and/3 is the angle between them. The other two faces are...
Although it has long been recognized that toxicity of Al to plants is a major growth-limiting factor in acid soils, relationships between the aqueous chemistry of Al and phytotoxicity are still not fully understood. The effect of added hydroxyl ions remains particularly problematic in that although raising solution pH generally relieves Al toxicity...
Laboratory and greenhouse research was conducted to study effects of soil properties on the availability of native and applied
B in 14 Virginia soils. Boron absorption could be described by the Langmuir equation in 12 of the 14 soils, and maximum B
adsorption (Vmax) in these 12 soils ranged from 3.3 to 26.5 mg kg−1. A multiple regression equation,...
Saprolite 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...
Increasing interest in the relationships between aluminum (Al) speciation and biological toxicity has created a need for accurate methods for speciating aqueous Al. Polynuclear hydroxy-Al complexes are generally viewed as metastable species, and are thus more amenable to empirical than to computational approaches to speciation. The objectives of th...
The fractionation of soil B and the plant availability of each fraction have not been examined extensively. This laboratory and greenhouse research was conducted to study the distribution and plant availability of B in different soil fractions. Total B in the 14 soils under study ranged from 21. 5 to 96. 3 mg kg** minus **1. A trace to 0. 34% of th...
The kinetic reactions of ferron (8-hydroxy-7-iodo-5-quinoline-sulfonic acid) with unneutralized and partially neutralized Al solutions in the presence of various inorganic anions were investigated for the purpose of differentiating mononuclear and polynuclear Al. Development of a general order reaction function indicated that ferron interactions wi...
The kinetic reactions of ferron (8‐hydroxy‐7‐iodo‐5‐quinoline‐sulfonic acid) with unneutralized and partially neutralized Al solutions in the presence of various organic anions were investigated with the intent of distinguishing mononuclear and polynuclear Al. Mononuclear Al solutions containing malate, glutarate, succinate, salicylate, formate, ma...
We conducted a column experiment, using individual and combined soil horizons from a Cecil series soil, to study the influence of ambient and near-ambient levels of SO42- in acid precipitation on exchangeable Al. The columns were leached with two pore volumes of solution containing either 0, 5, 10, or 20 mg L-1 SO42+. We analyzed the leachates for...
Little is known about the characteristics of undisturbed soils in the eastern USA, since few exist. Eight sites with virgin forest soils formed under southern Appalachian hardwood vegetation were stud-ied in the Joyce Kilmer Memorial Forest, an unlogged watershed in western North Carolina. Sites ranged in elevation from 720 to 1200 m with only two...
Eights undisturbed soils derived from feldspathic meta‐sediments in the Joyce Kilmer Memoiral Forest were studied. Gibbsite was common throughout all soils, and inceased in aboundance in the clay fraction with depth. The clay content in most soils decreased with depth, with intergrade 2:1 type minerals occurring as the dominant phyllosilicates in s...
Copper was added to three soils in the laboratory at a rate of 48 mg Cu kg⁻¹ in the form of either CuSO4 or a swine (Sus scrofa domesticus) manure obtained from swine fed a high-Cu ration (equivalent to 100 Mg manure ha⁻¹ containing 1060 mg Cu kg⁻¹). In order to assess the potential transformations of the added Cu among various chemical forms in th...
The kinetic reactions of ferron with unneutralized and partially neutralized Al solutions in the presence of various inorganic and organic anions were investigated with the intent of distinguishing mononuclear and polynuclear Al. Mononuclear Al solutions containing ClO/sub 4//sup -/, Cl/sup -/, NO/sub 3//sup -/, SO/sub 4//sup 2 -/, H/sub 2/PO/sub 4...
The computer programme GEOCHEM is widely used by soil scientists for the equilibrium chemical speciation of aqueous solutions. Two shortcomings have been observed and are described. The first is that the programme interprets pH as a concentration term, rather than as the negative logarithm of the proton activity. This can result in significant spec...
Commercially available filter papers and membranes of varying composition were examined for their effect on solution Al. This investigation was conducted in order to assess the impact of filter materials on environmental water samples and solubility studies. Many of the filter materials in equilibrium with unneutralized and partially neutralized Al...
The kinetic reaction of ferron (8‐hydroxy‐7‐iodo‐5‐quinoline‐sulfonic acid) with partially neutralized Al solutions of varying basicity and age were investigated with the intent of separating mononuclear and polynuclear Al. Ferron solutions buffered with varying quantities of NaOAc, NH 2 OH·HCl, and acetic acid suggested that reduction of ferron by...
While many workers have utilized various reagents for sequential extraction of soil trace metals, few studies have examined the order of extraction for key steps in the sequential procedure. In this study, several sequences involving both adsorbed and structural (occluded) metal extractants were evaluated to determine the most appropriate sequentia...
Thirteen organic acids and fulvic acid were used in dissolution experiments with laboratory-synthesized noncrystalline Fe oxide, hematite and goethite to determine the effect of the organic acid properties on the kinetics and pH-dependence of oxide dissolution. After 100 h of reaction the noncrystalline oxide had completely dissolved at pH 3.5 in t...
Seasonal variations in Al and Fe content of pasture forage samples have been generally attributed to soil contamination although mechanisms for plant Al uptake have been suggested. Aluminum and Fe concentrations in annual ryegrass (Lolium multiflorum Lam.) grown at two soil moisture levels, flooded and 80% field capacity (FC), with Al added as chel...
Manure from swine fed high levels of copper (Cu) was extracted sequentially and non sequentially with reagents designed to selectively solubilize specific Cu forms from the manure. Fresh (slurry), freeze-dried, and oven-dried samples were used. Water-soluble Cu increased from 2% to 30% with increasing severity of drying. Salt solutions (calcium (Ca...
Biotite kaolinization was examined for acidic, well-drained Virginia Piedmont soils with respect to extent, profile trends, and grain morphological effects. All profiles contained kaolinized biotite sand grains and had kaolinite-dominated clay fractions. Vermiculite was a minor component of most samples. Kaolinization increased with decreasing part...
Kaolinized zones in soil biotite grains were investigated by x‐ray diffraction (XRD), microprobe, and optical methods. These zones displayed microcrenulations and thus a dulled luster on (001) cleavage surfaces. Compared to unaltered biotite, kaolinized zones were lighter in reflected light but darker in transmitted light, probably because the cren...
Kinetics of Al adsorption on Ca-kaolinite at selected concentrations, pH, and column lengths were studied using a miscible displacement technique. Observed breakthrough curves (BTC) for continuous injection of pH 4. 3, 0. 75 to 7. 75 mu g mL** minus **14 Al solution were well-described by a two-site nonequilibrium transport model which assumes that...
Mechanisms of Al adsorption on Ca-saturated kaolinite, montmorillonite, and peat were studied by miscible displacement methods. Partially neutralized 1.0 x 10 U M AlCl3 solutions with basicities of 1.0 were leached through monomineralic columns and effluent analyzed for monomeric and polymeric Al, titratable acidity, and desorbed Ca as functions of...