Browsing by Author "Burger, James A."

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    The acclimation ability of the shale barren endemic Eriogonum alleni to light and heat
    Braunschweig, Suzanne Hill (Virginia Tech, 1993-09-04)
    Shale barrens are unique habitats located throughout the southern Appalachians. They are characterized by a south or south west aspect, a steep slope, and an exposed rocky surface (Platt, 1951). They have a high total irradiance and can experience temperatures higher than the surrounding deciduous forest. A variety of plant species, several of which are rare or endangered, are endemic to the shale barren habitat. One reason proposed fc)r their endemism is that the plants are obligate heliophytes (Keener, 1983). The purpose of this dissertation is tel examine the acclimation ability of the shale barren endemic Eriogonum alIeni to shade and high temperature.
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    Acid deposition effects on soil chemistry and forest growth on the Monongahela National Forest
    Elias, Patricia Elena (Virginia Tech, 2008-07-28)
    Acid deposition (AD) results largely from the combustion of fossil fuels, and has been found to negatively impact forest ecosystems. AD may acidify soils through base cation leaching or Al mobilization, may cause accumulation of nitrates and sulfates in soils, and in some cases has been related to forest decline. The Monongahela National Forest (MNF) lies downwind from many sources of AD pollution, and average deposition pH is around 4.4. Therefore, managers are concerned about the possible deleterious effects of AD on the forest ecosystem. During the 2006 Forest Plan revision, evaluation of site sensitivity to acidification was specifically stated as a step in the Forest's adaptive management process. To meet this management objective, forest practitioners must understand the effects AD has on the forest, prescribe appropriate practices, and be able to monitor for future changes. To address the needs of MNF managers we used Forest Inventory and Analysis (FIA) sites to evaluate forest growth patterns on the Forest and determined the relationship between growth and key indicators of soil acidity. Furthermore, we used those relationships to create a map of site resistance to acidification across the MNF. To further develop a monitoring scheme we assessed two soil sampling protocols and two soil analysis methods for their suitability for monitoring AD-related changes in soil chemistry. Additionally, we evaluated the utility of dendrochronological and foliar sampling as AD-specific monitoring methods. Across all FIA sites on the MNF periodic mean annual volume increment (PMAVI) ranged from -9.5 m³ha⁻¹yr¹ to 11.8 m³ha⁻¹yr¹, suggesting lower-than-expected growth on two-thirds of the sites. Growth was compared to soil indicators of acidity on 30 FIA sites. In the surface horizon, effective base saturation (+), Ca concentration (+), base saturation (+), K concentration (+), Fe concentration (-), Ca/Al molar ratio (+), and Mg/Al molar ratio (+), were correlated with PMAVI (p ≤ 0.1). In the subsurface horizon pH(w) (+), effective base saturation (+), Al concentration (-), and K concentration (-) were correlated with PMAVI. Site resistance to acidification was mapped based on site parent material, aspect, elevation, soil depth, and soil texture. There was a significant (p ≤ 0.1) positive correlation between PMAVI and a resistance index developed using five soil and site factors. Resistance was also compared with key soil indicators of AD-induced decline on 28 sites across the forest, and pH, effective base saturation, and Al content were found to be the best indicators related to resistance index. Resistance index was used to create a map of the MNF, of which 14% was highly resistant (RI ≥ 0.7), 57% was moderately resistant (0.7 > RI > 0.45) and 29% was slightly resistant (RI ≤ 0.45). The first of our monitoring program evaluations compared soil sampling and analysis methods on 30 FIA plots. Analyses of variance showed that soil pH, effective base saturation, Ca/Al molar ratio, and sum of bases varied significantly with sampling protocol. We also compared lab analyses methods and found that if sampling by horizon, a linear relationship can be used to estimate Ca/AlSrCl₂ ratio using NH₄Cl extractions. The second monitoring approach evaluated the utility of a northern red oak (Quercus rubra L.) dendrochronology on two FIA plots. This analysis suggests that pollution on the MNF caused a decrease in growth rate during the 50-year period from 1940 to 1990. There were no differences among ring width increment and basal area increment between the two sites. From 1900 to 2007 the two sites showed 58.5% similarity in growth trends, but these could not be attributed to a dissimilar influence of AD. The third monitoring approach evaluated the relationship between foliar and soil chemical indicators. Across FIA plots, nutrient concentrations varied by tree species. The first year results from a potted-seedling study suggest that soil acidity influences growth, and foliar concentrations are related to growth rates. This evaluation of the effects of AD on the MNF can be used to develop adaptive management plans and a monitoring program that will meet the AD-related objectives of the 2006 Forest Management plan.
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    The Appalachian Regional Reforestation Initiative
    Angel, Patrick N.; Davis, Vic; Burger, James A.; Graves, Don; Zipper, Carl E. (Appalachian Regional Reforestation Initiative, 2007-07-18)
    The Appalachian Regional Reforestation Initiative (ARRI) is a cooperative effort by the States of the Appalachian Region with the Office of Surface Mining to encourage restoration of high quality forests on reclaimed coal mines in the eastern USA. ARRI's goals are to communicate and encourage mine reforestation practices that 1) plant more high-value hardwood trees on reclaimed coal mined lands in Appalachia; 2) increase the survival rates and growth rates of planted trees; and 3) expedite the establishment of forest habitat through natural succession. These goals can be achieved when mines are reclaimed using the Forestry Reclamation Approach (FRA).
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    Appalachian Surface Mine Reforestation Techniques: Effects of Grading, Cultural Treatments and Species Selection
    Fields-Johnson, Christopher Warren (Virginia Tech, 2011-01-21)
    Surface mining for coal in the Appalachian region has removed over 0.6 million Ha of mixed mesophytic forest. Successful reforestation would be beneficial, but questions remain concerning application of reclamation and reforestation methods on operational scales. Four experiments were performed testing these methods on newly reclaimed and previously reclaimed, but unused, former mines. On newly reclaimed sites, loose grading during reclamation reduced erosion and increased plant community diversity compared to smooth grading. Seeding only annual ryegrass (Lolium multiflorum) for erosion control, along with tree planting, increased plant community diversity and improved survival and growth of hybrid American chestnut (Castanea dentata x Castanea mollissima), compared to conventional seeding. Surface water infiltration was positively correlated with herbaceous ground cover. On older mines, subsoil ripping to alleviate compaction improved tree survival and growth, in some cases, after five growing seasons. Of the three species groups planted, including Eastern white pine (Pinus strobus), mixed native hardwoods had the best survival and hybrid poplar (Populus deltoides x Populus trichocarpa) produced the most biomass. Hybrid American chestnuts survived and grew better when planted as bare-root seedlings than when planted as ungerminated nuts in tree tubes, demonstrating the potential for planting bare-root chestnut seedlings along with other species when reforesting reclaimed surface mines. This can aid in restoring American chestnut, functionally extinct since the blight (Cryphonectria parasitica), to its former range. These cultural practices can be employed to accelerate reforestation of mined lands, but many questions remain about their capability to fully restore ecosystem structure and processes.
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    Applying the diagnosis and recommendation integrated system(DRIS) to Fraser fir Christmas trees
    Kopp, Virginia Ann (Virginia Tech, 1988-05-15)
    The process of diagnosing the foliar nutrient status of Fraser fir [Abies fraseri (Pursh)Poir.] Christmas trees and prescribing fertilizers is not well understood. Agricultural researchers have established critical yield levels for agronomic crops that are objective measures of crop quality and have associated these yields with nutrient status; however, Christmas tree quality is subjective and not well associated with nutrient status. A nutrient-sensitive tree response factor that reflects tree quality is needed for a proper diagnosis. The purpose of this study was to determine the relationship between nutrient balance and indices of tree quality and to evaluate how nutrient balance and tree quality can be manipulated by fertilizer inputs based on the Diagnosis and Recommendation Integrated System. In 1984 a factorial N, P, pH, fertilizer source, and fertilizer frequency trial was installed in northwestern North Carolina. A randomized complete block design with factorial combinations of all five factors was used. After three years, the fertilizer trial was analyzed to study the effects of fertilizer additions on foliar nutrient balance and tree quality. Several tree response factors were measured in the fall after dormancy. Statistical methods such as correlations and multivariate discriminant analysis were used to determine which response factors were correlated with foliar nutrients and which factor most governed tree quality. DRIS indices were calculated for six independent plots of different fertility treatments. Basal diameter (BD) was the strongest discriminator of tree quality and was used as a substitute for yield in the DRIS analyses. The importance of nutrient intensity was demonstrated since significant nutrient / dry matter ratios were calculated for N, P, K, and Mg. Balance was shown to be important since the indices for N, K, and Mg were a function of the four other nutrient ratios other than dry matter, and the P and Ca indices were a function of three nutrient ratios other than dry matter. Nutrient balance was also shown to be important by the significant relationship of BD as a function of the nutrient balance index (NBI). When NBI had a relatively small value, large BD trees were produced; as NBI values increased, BD decreased. Fertilizer additions that created nutrient imbalances also decreased BD, in spite of the high nutrient intensities found in the foliage. These results show that nutrient balance in Fraser fir foliage, as well as nutrient intensity, is important for producing optimal Christmas tree quality.
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    Biogeochemistry of Carbon on Disturbed Forest Landscapes
    Amichev, Beyhan Y. (Virginia Tech, 2007-04-11)
    Carbon accreditation of forest development projects is essential for sequestering atmospheric CO2 under the provisions of the Kyoto Protocol. The carbon sequestration potential of surface coal-mined lands is not well known. The purpose of this work was to determine how to measure carbon sequestration and estimate the additional amount that could be sequestered using different reforestation methods compared to the common practice of establishing grasslands. I developed a thermal oxidation technique for differentiating sequestered soil carbon from inorganic and fossilized carbon found at high levels in mine soils along with a geospatial and statistical protocol for carbon monitoring and accounting. I used existing tree, litter, and soil carbon data for 14 mined and 8 adjacent, non-mined forests in the Midwestern and Eastern coal regions to determine, and model sequestered carbon across the spectrum of site index and stand age in pine, mixed, and hardwood forest stands. Finally, I developed the framework of a decision support system consisting of the first iteration of a dynamic model to predict carbon sequestration for a 60-year period for three forest types (white pine, hybrid poplar, and native hardwoods) at three levels of management intensity: low (weed control), medium (weed control and tillage) and high (weed control, tillage, and fertilization). On average, the highest amount of ecosystem carbon on mined land was sequestered by pine stands (148 Mg ha-1), followed by hardwood (130 Mg ha-1) and mixed stands (118 Mg ha-1). Non-mined hardwood stands contained 210 Mg C ha-1, which was about 62% higher than the average of all mined stands. After 60 years, the net carbon in ecosystem components, wood products, and landfills ranged from 20 to 235 Mg ha-1 among all scenarios. The highest net amount of carbon was estimated under mixed hardwood vegetation established by the highest intensity treatment. Under this scenario, a surface-mined land of average site quality would sequester net carbon stock at 235 Mg C ha-1, at a rate of 3.9 Mg C ha-1 yr-1, which was 100% greater than a grassland scenario. Reforestation is a logical choice for mined land reclamation if carbon sequestration is a management objective.
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    Carbon and nitrogen cycling in watersheds of contrasting vegetation types in the Fernow Experimental Forest, West Virginia
    Kelly, Charlene Nicole (Virginia Tech, 2010-04-01)
    Increased anthropogenic deposition of nitrogen (N) and land-use changes associated with planted forests have important implications for sustainable forest management and associated water quality. The purpose of the research for this dissertation was to explore how N deposition will affect the long-term health, productivity, and carbon (C) and N sequestration of conifer and hardwood forest types by examining the mechanisms controlling N cycling and NO3-N production in two watersheds with contrasting vegetation at the Fernow Experimental Forest (FEF), West Virginia. I utilized watershed C and N budgets to account for differences in stream export of NO3-N from streams draining adjacent watersheds containing (i) planted Norway spruce (Picea abies) and (ii) native Appalachian hardwoods. I also investigated spatial and temporal patterns of dissolved C and N across both watersheds and identified key soil properties associated with NO3-N in soil solution and streamwater. In a third study, I performed a soil inoculation and incubation experiment, which utilized soil from both watersheds, mixed in ratios in order to create a gradient of soil chemical and biotic characteristics. Important differences in biogeochemical cycling of C and N were documented in the watersheds after nearly 40 years of influence by contrasting vegetation. Total C and N pools were 28% and 35% lower in the spruce watershed than the hardwood watershed, respectively. Results also identify vegetation-mediated differences in soil characteristics, with lower soil pH and base cations, and higher extractable aluminum and C:N ratios measured in the spruce soil as compared to the native hardwood soil. Establishment of a spruce monoculture at the FEF significantly altered N cycling, depleted N stores, increased soil acidity, and altered organic matter dynamics, thus leading to low net nitrification rates. Carbon and N properties and processes in the soil profile should be taken into consideration in forests managed for ecosystem services including C sequestration and improvement or maintenance of water quality through alleviation of N inputs into aquatic ecosystems.
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    Carbon and nitrogen dynamics on a forest site receiving continual papermill sludge applications: a soil column study
    Duncan, Carla S. (Virginia Tech, 1992-12-15)
    Successful renovation of wastewater and sludge via land application depends upon sludge-induced soil changes associated with carbon (C) and nitrogen (N) cycles within the soil/plant system. The C, N, and hydrologic cycles within a soil/sludge system receiving a year-round, daily application of paper mill sludge were studied. Soil samples were collected from three locations on a land application site in the Piedmont of Virginia that had received papermill sludge applications for six, two, and no prior years. The average application rate was 4.4 cm/wk, each week of the year, with a N loading of 700 kg N ha⁻¹yr-⁻¹. The column study showed that C and N were still accumulating on the land application site after 6 years, but at a decreasing rate. Based on this study, C accumulation will level out after 13 years of application, but N will continue to accumulate for almost 30 years. As application period increased, soil bulk density increased in the O, A, and B horizons, the percentage of non-capillary porosity fell below 10% in the A horizon and approached zero in the B horizon, and there was a dramatic decrease in the soil's hydraulic conductivity in both the A and B horizons. Nitrogen leaching is expected to increase with time due to high amounts of N in the papermill sludge, a continued narrowing of the C:N ratio, a high percentage of nitrification, and low denitrification rates. Experimental timing and rates of sludge additions were imposed to alter the aerobic/anaerobic properties of the soil system to determine the conditions under which optimum C and N mineralization, nitrification, and denitrification would occur. Application rates were factorially arranged for single or multiple doses on a daily or alternating schedule. The C decomposition and N mineralization processes were both optimized with an increase in the length of cycle; they were maximized with an alternating 9 days on/9 off application schedule. The nitrification potential also increased with the length of cycling, with an average nitrification rate of 96%. Denitrification was minimal in all treatments, with an average denitrification rate of 16%. This was primarily attributed to movement of nitrate-N below the most biologically active zone in the soil column. Sludge renovation will ultimately depend upon the excess N being sequestered in plant biomass or denitrified. Proper management of these processes will ensure that wastes decompose, and that N is stored or evolved as a benign gas rather than leached at unacceptable levels.
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    Changes in loblolly pine seedling root growth potential over time, during cold storage, and among half-sib families
    DeWald, Laura E. (Virginia Polytechnic Institute and State University, 1986)
    Root growth potential (RGP), the ability of a transplanted seedling to rapidly elongate existing roots and initiate new roots, is used as an indicator of seedling physiological quality. Three separate experiments were conducted on loblolly pine RGP during 1983-84 and 1984-85 using 1-0 nursery-grown seedlings. In the first study, seedlings were hand-lifted from September to April at 17-day intervals in 1983-84 and 7-day intervals in 1984-85. The RGP variation over time was related to environmental and seedling phenological changes. In addition, the new root systems were morphologically described. In the second study, changes in loblolly pine seedlings following different lift-date X cold storage duration treatments were described. These changes were compared to the RGP, shoot activity, and new root system morphology of fresh-lifted seedlings. Genetic variation in RGP on different lift-dates was quantified in the third study. Variation patterns over time among 14 half-sib loblolly pine families hand-lifted at one-month intervals were examined. Root growth potential was low in the autumn until the cessation of shoot activity. Seedlings stored poorly if put in cold storage during this time, or prior to the accumulation of at least 400 chilling hours. Seedling RGP increased in the early-winter to a late-February peak, and then decreased when spring shoot elongation occurred during the RGP tests. Similar trends over time were noted with seedlings removed from cold storage during these times. The RGP pattern over time was consistent among years and among the half-sib families, although there were some minor differences among half-sib families in the rate of increase to, and decrease from, the late-winter peak. Most new roots resulted from elongation of existing roots rather than initiation of new roots regardless of lift-date; however, when seedling metabolism was high (early autumn and late-winter) both root initiation and elongation of existing roots contributed to the new root system. In addition, the morphology of root systems of cold-stored seedlings was similar to fresh-lifted seedlings. Differences in numbers and lengths of new roots among half-sib families were due to the differential ability to produce new roots through both root initiation and elongation.
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    Changes in Soil Nitrogen Following Biosolids Application to Loblolly Pine (Pinus Taeda L.) Forest in the Virginia Piedmont
    Arellano Ogaz, Eduardo (Virginia Tech, 2009-01-12)
    Application of biosolids as an alternative source of Nitrogen (N) is becoming a common silviculture practices on loblolly pine forest. However, little is known about how biosolids type, application rate, and timing affect forest floor and soil N availability in pine plantations. The objectives of this study were to determine the effect of different types, rates, and season of application of biosolids on forest floor and soil N. The study was established in a 17-year-old loblolly pine plantation in Amelia County, VA. Anaerobically digested (AD225), lime stabilized (LS225), and pelletized (Pellet225) biosolids and a conventional inorganic urea plus diammonium phosphate fertilizer (U+DAP225) were surface applied at a rate of 225 kg ha-1 based on Plant Available Nitrogen (PAN) between March 5th and 10th, 2006. Anaerobically digested biosolids were also surface applied at the rates of 900 kg PAN ha-1 and 1800 kg PAN ha-
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    Characterizing the Respiration of Stems and Roots of Three Hardwood Tree Species in the Great Smoky Mountains
    Rakonczay, Zoltán (Virginia Tech, 1997-06-16)
    Carbon dioxide efflux rates (CER) of stems and roots of overstory and understory black cherry (Prunus serotina Ehrh., BC), red maple (Acer rubrum L., RM) and northern red oak (Quercus rubra L., RO) trees were monitored over two growing seasons at two contrasting sites in the Great Smoky Mountains to investigate diurnal and seasonal patterns in respiration and to develop prediction models based on environmental and plant parameters. CER of small roots (d<0-8 mm) was measured with a newly developed system which allows periodic in situ measurements by using permanently installed flexible cuvettes. Temperature-adjusted CER of roots showed no diel variation. The moderate long-term changes occurred simultaneously in all species and size classes, suggesting that they were driven mostly by environmental factors. Mean root CER ranged from 0.5 to 4.0 nmol g⁻¹ d.w. s⁻¹. Rates were up to six times higher for fine roots (d<2.0 mm) than for coarse roots. CER (per unit length) of boles (d>10 cm) and twigs (d<2 cm) was related to diameter by the function lnCER = a+D·lnd, with D between 1.2 and 1.8. A new, scale-invariant measure of CER, based on D, facilitated comparisons across diameters. Q₁₀ varied with the method of determination, and it was higher in spring (1.8-2.5) than in autumn (1.4-1.5) for all species. Daytime bole CER often fell below temperature-based predictions, likely due to transpiration. The reduction (usually <10%) was less pronounced at the drier site. Twig CER showed more substantial (often >±50%) deviations from the predictions. Deviations were higher in the canopy than in the understory. Mean bole maintenance respiration (at 20°C and d=20 cm) was 0.66, 0.43 and 0.50 μMol m⁻¹, while the volume-based growth coefficient was around 5, 6 and 8 mol cm⁻³ for BC, RM and RO, respectively. In a controlled study, BC and RM seedlings were fumigated in open-top chambers with sub-ambient, ambient and twice-ambient levels of ozone. The twice-ambient treatment reduced stem CER in BC by 50% (p=0.05) in July, but there was no treatment effect in September or in RM. Ozone reduced root/shoot ratio and diameter growth in BC, and Pmax in both species.
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    Consequences of nitrogen fertilization and soil acidification from acid rain on dissolved carbon and nitrogen stability in the unglaciated Appalachian Mountains
    Taylor, Philip Graham (Virginia Tech, 2008-02-04)
    The expansion and proliferation of reactive nitrogen (N) sources, predominantly fertilizer application and fossil fuel combustion, has enriched the earth with N and acidified ecosystems. Acid rain is a primary vector of both N fertilization and acidification, initiating a cascade of consequences that alter biogeochemical cycling and global biological structure and function. Studies on N and acid influences are however rarely linked despite their common source. We used a wide, chronic gradient of N deposition (5.5 – 31 kg N ha⁻¹ yr-1) to explore patterns in carbon (C) and N cycling in light of recognized biogeochemical responses to acidic deposition. Specifically, we examined the response of key controls on dissolved C and N stability because soluble pools are involved in decomposition and nutrient recycling, the formation of soil organic matter (SOM), and the translation of elements through the biogeochemical continuum from atmospheric to soil to water. Results suggest that N deposition led to reduced organic matter C/N, enhanced net nitrification, and greater DON generation; and, these patterns were associated with changes in C composition. Conversely, physiochemical processes in the mineral soil seemed to control organic matter dynamics, with effects on N processing. Moreover, pH dependent controls on DOC stability were evidenced by changes in DOC concentration, chemical complexity and recalcitrance. These horizon-specific, differential responses to acid rain indicate that changes in the forest floor N economy were responsible for increased surface water NO3-N concentrations, whereas enhanced organomineral stability of DOC caused a significant increase in DOM concentrations in export.
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    Costs of Reclamation on Southern Appalachian Coal Mines: A cost-effectiveness analysis for reforestation versus hayland/pasture reclamation
    Baker, Katherine (Virginia Tech, 2008-04-24)
    The two most common options for post-mining land uses in the southern Appalachians are forestry or hayland/pasture. Hayland/pasture has become the predominant reclamation type due to ease of establishment and strict regulation standards requiring quick and dense erosion control by herbaceous cover. Recently, more landowners have become interested in returning mined land to an economically valuable post-mining land use, such as forestry. Landowners are becoming more aware of the possible future profits from timber stand harvests, as well as other benefits (monetary and aesthetic) derived from a forestry post-mining land use. Although hayland/pasture lands can provide economic returns through forage and grazing rents, many post-mining pasture lands are left fallow, with no economic returns being gained. Current research has provided the biological and technical information needed to reclaim mine lands to productive forest stands and achieve bond release. Cost information though has been lacking, or variable at best. The purpose of this study is to understand the processes of reclamation for both forestry and hayland/pasture, and calculate detailed cost estimates for both reclamation types. Total costs of reclamation are determined using a cost engineering method, in conjunction with Office of Surface Mining Regulation and Enforcement bond calculation worksheets. In Kentucky, Maryland, Pennsylvania, Tennessee, Virginia, and West Virginia, hayland/pasture reclamation is more costly on a per acre basis. The cost of hayland/pasture reclamation is greater than the cost of forestry reclamation by $140 per acre to $350 per acre. In Ohio, forestry reclamation is more expensive by nearly $60 per acre. Grading costs are four times as costly for hayland/pasture reclamation, as compared to forestry reclamation. Pasture reclamation requires more grading passes to prepare the seedbed, requiring four passes. Forestry reclamation typically involves only grading the site with one dozer pass to prevent compaction of minesoils which inhibits tree growth. Hyrdoseeding costs are also higher for hayland/pasture reclamation due to higher application rates of fertilizer and herbaceous seed. The hydroseeding costs make up the largest percentage of the total per acre cost for both forestry and hayland/pasture reclamation. Lime and mulch costs are equal for both reclamation types and are included in the hydroseeding equation. Due to the increased grading costs and higher hydroseeding costs, hayland/pasture reclamation is more expensive for all states analyzed in the Appalachians, other than Ohio. These cost estimates can provide useful tools for mine operators and landowners to determine the most economical and suitable post-mining land use for their individual property.
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    Diagnosis of Loblolly Pine (Pinus taeda L.) Nutrient Deficiencies by Foliar Methods
    Sypert, Robert Hall (Virginia Tech, 2006-08-18)
    Quick identification of loblolly pine nutrient deficiencies has troubled foresters who wish to increase productivity through fertilization. In the past, extensive field trials were established that did not allow for quick identification of a large number of possibly limiting nutrients in individual stands. This study used single-tree fertilization with macro-nutrients (N, P, K, Ca, Mg, S) and micro-nutrients (Mn, Zn, B, Cu, Fe, Mo) to identify deficiencies using foliar techniques in one growing season. Four study sites in TX, AL, GA, and SC were established in loblolly pine plantations at or near canopy closure. Nutrient concentrations relative to the critical level, optimal nutrient ratios, DRIS methodology, vector analysis, and changes in individual fascicle and total current year foliage weight/area were used to identify deficiencies. Phosphorus was repeatedly indicated as most limiting growth at TX while K was implicated at SC. The GA site revealed multiple deficiencies including N, K, and S. The AL site revealed only a very suspect B deficiency. Critical level methodology was effective in identifying deficiencies of N, P, and K, while B, S, and Cu appeared to be available at sufficient quantities when concentrations were below the published critical levels. Concentrations of S were especially below the critical levels and not increased by fertilization indicating that the critical levels were too high. Nutrient ratio interpretability was reduced by luxury uptake of N in comparison to other deficient nutrients. DRIS methodology was hampered by the inability to create effective comparative norms. Deficiency detection with vector analysis created problems when B and Mn displayed greater uptake relative to controls than the macro-nutrients that provided relative foliage mass increases. Resulting diagnosis indicated deficiencies when B and Mn were really taken up as luxury consumption. Vector analysis may not be as effective as its individual parts. Foliage weight/area responses detected fewer deficiencies than the other techniques. No significant foliar responses were seen at the TX or AL sites. However, K at the SC site was identified as deficient by all foliage mass variables, and multiple deficiencies were detectable at the GA site.
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    Dynamics and Characterization of Soil Organic Matter on Mine Soils 16 Years after Amendment with Topsoil, Sawdust, and Sewage Sludge
    Bendfeldt, Eric S. (Virginia Tech, 1999-07-14)
    The present state and future prospect of the world's soil resources has prompted scientists and researchers to address the issue of soil quality and sustainable land management. Soil quality research has focused on intensively-managed agricultural and forest soils, but the concept and importance of soil quality is also pertinent to disturbed systems such as reclaimed mine soils. The restoration of soil function and mine soil quality is essential to long-term ecosystem stability. The objectives of this study were (i) to determine the comparative ability of topsoil, sawdust, and sewage sludge amendments, after 16 years, to positively affect mine soil quality using the following key soil quality variables: organic matter content, aggregate stability, and mineralizable nitrogen, (ii) to determine the effects of these key soil quality variables on plant productivity, and (iii) to determine the comparative ability of trees and herbaceous plants to persist and to conserve or maintain mine soil quality. In 1982, a mined site was amended with seven different surface treatments: a fertilized control (2:1 sandstone:siltstone), 30 cm of native soil + 7.8 Mg ha-1 lime, 112 Mg ha-1 sawdust, and municipal sewage sludge (SS) at rates of 22, 56, 112, and 224 Mg ha-1. Four replicates of each treatment were installed as a randomized complete block design. Whole plots were split according to vegetation type: pitch x loblolly pine hybrid (Pinus rigida x taeda) trees and Kentucky-31 tall fescue (Festuca arundinacea Schreb.). Soil analyses of composite samples for 1982, 1987, and 1998 were evaluated for changing levels of mine soil quality. The positive effect of these organic amendments on organic matter content, total nitrogen, and other soil parameters was most apparent and pronounced after 5 growing seasons. However, after 16 years, soil organic matter content and total nitrogen appear to be equilibrating at about 4.3 and 1.5%. There was a significant difference in organic matter content and nitrogen mineralization potential between vegetation types. Organic matter inputs by vegetation alone over the 16-yr period in the control plots resulted in organic matter and nitrogen mineralization potential values comparable to levels in the organically amended plots. The results suggest that about 15 years is needed for climate, moisture availability, and other edaphic features to have the same influence on overall organic matter decomposition, N accretion, organic nitrogen mineralization levels, system equilibrium, and overall mine soil quality as a one-time 100-Mg ha-1 application of organic amendment. Tree volume and biomass were measured as indices of the effects of organic matter content 16 years after initial amendment. Individual tree volumes of the sawdust, 22, 56, and 112 Mg ha -1 SS treatments retained 18 to 26% more volume than the control, respectively. Overall, fescue production was the same among treatments. Organic amendments improved initial soil fertility for fescue establishment, but it appears that they will have little or no long-lasting effect on plant productivity.
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    The Effect of Management on Erosion of Civil War Battlefield Earthworks
    Azola, Anthony (Virginia Tech, 2001-02-01)
    Since 1936 National Park Service has been charged with preserving Civil War Earthworks while allowing public access. Soil erosion, both natural and human-induced, is a major concern facing the preservation of the earthworks. Currently, the National Park Service is committed to preserving these earthworks for future generations by determining which maintenance activities cause the least soil erosion. This study was undertaken to determine which management practice; burned, mowed, park-forest, forested, or trimmed, best minimized soil erosion. A secondary objective was to determine how several empirical formulas (e.g. Universal Soil Loss Equation) and one field estimate (e.g. erosion pins) compared soil erosion trends for the 5 treatments. A third objective of this study was to gather information regarding the soil development which has occurred during the 135 + years since the earthworks were constructed. Earthworks managed by prescribed burning suffered the greatest erosion rates while the forested earthworks eroded the least. The trimmed and mowed management regimes were not significantly different and would provide adequate erosion protection while the forested treatment had significantly less erosion. Based on the empirical models, erosion was primarily a function of ground cover; on the other hand, rain intensity was highly influential for erosion as measured by the erosion pins. All of the erosion estimation methods concurred that the burned treatment should be avoided due to the high erosion rates while the erosion pins indicated that the park-forest treatment could potentially have erosion problems as well. Soil profile descriptions from the earthworks revealed that A horizon depths on the earthworks were not significantly different then the A horizons found on the relatively undisturbed adjacent forest floor and that subsurface soil structure has begun to develop on earthwork soils.
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    Effects of a Control Release Nitrogen Fertilizer and Thinning on the Nitrogen Dynamics of a Mid-Rotation Loblolly Pine Stand in the Piedmont of Virginia
    Elliot, James Robertson (Virginia Tech, 2006-12-15)
    Nitrogen deficiency is characteristic of many mid-rotation loblolly pine (Pinus taeda L.) plantations in the Piedmont region of the southeastern USA. Fertilization with urea is the most common method used to correct this deficiency. Previous studies show that urea fertilization produces a rapid pulse of available nitrogen (N) with only a portion being utilized by plantation trees. Controlled release fertilizers release available N more slowly over a longer period of time and therefore may result in greater uptake efficiency. The objective of this study was to compare Nitroform®, a urea-formaldehyde controlled release N fertilizer versus urea and a control by measuring the effects of the two fertilizer treatments on N availability and loss as: total KCl extractable-N, total ion exchange membrane-N (IEM-N), N mineralization, and N volatilization, in a mid-rotation loblolly pine plantation in the Piedmont of Virginia. In addition, mid-summer and mid-winter fertilizations were compared to assess fertilizer uptake as a function of season. After the summer fertilization, Nitroform® significantly increased total KCl-extractable N, IEM-N, and N mineralization for two to three months over urea and the control. Three hundred times more N volatilized from urea than from controlled release Nitroform®. Interestingly, seven months after the summer application, the controlled release Nitroform® showed marked immobilization for three months while urea demonstrated greater N mineralization. After the winter application, fertilization with urea demonstrated greater soil inorganic N concentrations for two to three months over Nitroform®, very little N was immobilized, and volatilization was only 10 times that of Nitroform®. After summer and winter fertilizations, both fertilizer treatments significantly increased soil inorganic N concentrations and N volatilization over controls, however did not significantly increase N mineralization over controls when average response was tested over the entire sampling period. In addition to the fertilizer effects measured, a thinning only treatment was also incorporated into this study with soil N-availability indices compared to a control with no thinning or fertilization. The results from the thinning only treatment demonstrated no significant increases over the control in total KCl extractable-N, IEM-N, N-mineralization, or N volatilization when average responses were tested over the entire sampling period.
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    Effects of Black Walnut and Honey Locust on Forage Growth, Soil Water, and Soil Quality Indicators
    DeBruyne, Scott Alexander (Virginia Tech, 2009-01-16)
    The goal of this research was to determine the interactions between forage and tree components of a silvopasture system. Two studies were performed on adjacent sites established in 1995 at Virginia Tech's Kentland Research Farm. The objectives of the studies were to: 1. Determine the influence of honey locust and black walnut silvopastures on indicators of soil quality when compared to open pasture. 2. Determine if silvopasture systems changed forage mass production and soil water compared to open pastures. The study on soil quality indicators was performed in a previously grazed silvopasture. Samples were collected from the upper 15 cm of soil at three distances from the tree rows. Total N (p= 0.0219), total C (p= 0.0216), extractable P (p= 0.063), extractable K (p= 0.0347) and microbial organic C (p= 0.0255) were greater in honey locust silvopastures. The highest concentration of soil nutrients and best soil physical and chemical properties were observed 1.5 m from the tree stem. Forage growth and soil water were measured in silvopastures in 2006 and 2007. In 2006 there was higher forage growth in the black walnut and honey locust than beneath 70% shade cloth. In 2007, with a 50% shade cloth, forage growth was similar in all treatments. Initial soil water content was highest under shade cloth in 2006. In 2007 the rate of soil drying was lowest beneath the shade cloth. The presence of trees did not negatively effect forage growth and silvopasture systems improved the soil quality indicators compared to open pasture.
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    Effects of Disturbance History on Forest Soil Characteristics in the Southern Appalachian Mountains
    Jones, Michael David (Virginia Tech, 2000-01-28)
    Minimally disturbed virgin forest soils in the Little Santeetlah Creek (LSC) watershed of western North Carolina were sampled along with soils from the adjacent disturbed Slickrock Creek (SRC) watershed. Soils with similar elevation/landform/vegetation/parent material characteristics were initially sampled at nine random locations each on north and south aspects within each watershed with a soil push probe. Some differences in parent materials were noted on south aspects (metasandstone vs. phyllite), but parent materials under north aspect soils were identical (metasandstone). Soils in LSC were significantly deeper and relatively free of solum coarse fragments while SRC soils were shallower and higher in coarse fragments. Subsequent auger observations of three typical pedons on each aspect indicated that soils in LSC were well-developed with gradual horizon boundaries and common diffuse transition horizons, while soils in SRC were more compact in horizonation and lacked diffuse transitional horizons. Vegetation communities were similar across both watersheds, except that SRC south sites were higher in Pinus spp. Litter layer morphology differed strongly between the two watersheds. Specifically, well-developed humus (H) layers were typical in LSC, but completely absent in all typical pedons described in SRC. Data obtained from these two watersheds indicate strong differences in surface soil (O + A horizon) properties between the two. These observed differences could be due to differential anthropogenic effects, particularly logging and associated erosion in the early 1920's. However, further study over multiple disturbed watersheds in the region, and of the distribution of sediments and colluvium within them would be required to test this hypothesis.
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    Effects of hydrology-altering site preparation and fertilization/release on plant diversity and productivity in pine plantations in the coastal plain of Virginia
    Hauser, James W. (Virginia Tech, 1992-08-15)
    Biological diversity, or biodiversity, is declining on a global scale at unprecedented rates. These declines are largely the result of human activities and resource use. Intensive forestry is often cited as a contributing factor in biodiversity declines. Because forestry practices are being placed under increased scrutiny with respect to biodiversity impacts, the objective of this project was to determine the effects of specific silvicultural practices on plant diversity in pine plantations on wet flats in Virginia. The study area consisted of three sites in the Coastal Plain. The sites were originally established in 1969 to study the effects of various treatments on loblolly pine growth. The three treatments applied were chop and burn, bedding, and ditching. Fertilization subplots of P, N and P, N, P, and lime, and a control were added to the treatment areas in 1978. This study was conducted in 1991 when stands were 23 years old, nearing rotation age. Bedding exerted the greatest effect on plant diversity. Diversity was lower on the bedded treatment, although total biomass was higher. Bedding appears to increase pine growth by providing seedlings with more available soil volume and by reducing the vegetative regeneration of hardwoods and shrubs, thereby decreasing site diversity. Ditching likewise increased pine growth by lowering water table levels, but ditching had little effect on plant diversity. Fertilization exhibited only minor effects on diversity, and those effects that were observed did not reveal any definitive trends. Of the treatments applied, liming appeared to increase pine growth most, possibly due to increased calcium availability. Water table level was highly correlated to mid story diversity, though it was less correlated to other canopy layers. In addition, correlation analyses indicated a significant degree of interaction between canopy layers. It appears that diversity, particularly in the lower canopy layers, is affected directly by treatments and indirectly by shifts in overstory characteristics. Intensive forest management involving hydrology-altering site preparation and fertilization impacted plant diversity within these wet flat plantations. Whether such changes affect wildlife habitat or ecosystem functioning requires further study.