Two studies were initiated in the Virginia southern Piedmont to assess characterization, classification, and productivity of soils mapped as Cecil-Pacolet (clayey, kaolinitic, thermic Typic Hapludults). Effects of erosion on Ap and Bt soil properties and soybean grain yields were studied in Pittsylvania and Lunenburg counties. Relationships between soil properties, soybean yields, and erosion classes were not observed until the soils became severely eroded. Water contents at -10kPa and -1500kPa increased as clay content increased but plant available water remained at 0.09 m³ m⁻³ across erosion classes. Available phosphorus (P) decreased with severity of erosion and was significantly correlated with soybean yield. The highest grain yields were on slightly and moderately eroded soils and were attributed to available P levels above 18 mg P kg⁻¹ critical level for optimum crop production. Low yields on the severely eroded sites corresponded to available P below 18 mg kg⁻¹. A second study on composition and variability of the Cecil-Pacolet map unit in Appomattox County showed large variation in soil properties and taxonomic classes. Variability is attributed to intrusions of mafic materials in the map unit. Variability was extreme within delineated soil bodies and was reflected in taxonomic classification in which up to six taxa can occur within the same delineation. Cecil and Pacolet soils comprise 62 percent of the map unit. Similar soils comprise 70 percent of the map unit and dissimilar soils make up the remaining 30 percent. The map unit is named Pacolet-Cecil and dissimilar soils are included in the mapping unit description. / Master of Science

Three profiles of the Beltsville soil from Fairfax County, Virginia were studied in relation to the mechanical composition, the mineralogical composition, and some of the chemical and physical properties. Soil samples were selected to represent a profile developed over Coastal Plain deposits, schist, and granite, respectively. A high kaolinite content, a low quartz and illite content, and the presence of gibbsite in the horizons below the fragipan indicate that this material has undergone more intensive or a different type of weathering than the material in the solum. Two horizons high in clay were found in each of the profiles studied: one above the fragipan, which is the present illuvial horizon, and the other below the fragipan, which may be a buried illuvial horizon. In two of the profiles the heavy textured horizon below the fragipan had a higher clay content than the present illuvial horizon. Fragipan formation possibly resulted from the deposition of material eluviated from a fine textured mantle above. The heavy texture of the material below the fragipan was probably effective in initiating the development of the fragipan. / Master of Science

The fact that when lime is added to clayey soils same very beneficial results are produced dates back into the remote past. It is not a new development, In the United States lime has been in use since l923. The objective of this study was to determine the effect of increasing soaking time of soil-lime mixtures on the strength, swell potential, and degree of saturation. In order to ascertain the exact composition of clay minerals, X-ray diffraction analysis was run on the soil sample. The analysis showed that the clayey soil contained a large amount of water with a greater percentage of halloysite minerals. The soil, it was concluded, was poorly crystalline and was found to be midway between montmorillonite and kaolinite group. / Master of Science

Because the Coastal Plain of southeastern Virginia has not been extensively studied, thirty random samples associated with Blackwater and Nottoway rivers were collected in the spring of 1987 from Surry, Sussex, and Southampton counties. Soil classification as well as mineralogical, chemical, and physical analysis were conducted for all samples. The purposes of this investigation were to: (1)classify the soils in this area, (2) determine the distribution of sand and clay minerals, (3) examine the weathering effect on clay minerals on different position of the landscape for different parent material sources. The soils examined classified as follow: Aquic Hapludults 43% > Typic Hapludults 26.6% > Ultic Hapludalfs 10% > Humic Hapludults 3% = Typic Rhodudlts 3% = Aquic Hapludalfs 3% = Typic Udipsamment 3% = Typic Quartzpsamment 3% = Psammentic Hapludalfs. Qualitative analysis of clay minerals revealed that kaolinite and hydroxy interlayer vermiculite were the dominant clay minerals; that montmorillonite, mica, gibbsite quartz, and vermiculite were of lesser quantities; that chlorite, feldspar and interstratified minerals were of trace amounts. Kaolinite represents about 21-70%, HlV 11-60%, montmorillonite 0-20%, mica 0-16%, gibbsite 0-13%, quartz 1-12%, and vermiculite 0-10%. The presence of these minerals were mainly related to the acid reaction of the soil media, which was essentially attributed to Al and H ions in soil solution. From the past history and geological composition of the Piedmont it is assumed that kaolinitic minerals were transported and sedimented in the Coastal Plain. Hydroxy-interlayer vermiculite minerals was weathering from vermiculite because most of the Al was adsorbed by vermiculite to form HIV. Therfore, gibbsite was not precipitated. Montmorillonite was assumed to have formed from mica minerals. That was substantiated by statistical analysis which showed a high negative correlation between gibbsite and vermiculite (r=0.46, n=30) and between montmorillonite and mica (r=-0.6, n=10). / Master of Science

A 1954 soil survey of Bland County, Virginia, was evaluated to determine if remapping was required to meet current soil survey standards. Considerable savings of time and money may be realized if a complete remap was not required. Ten random transects were chosen to study soil landscape units which formed the basis for the evaluation of soil boundary placement. The soil landscape units were determined by evaluating slope, parent material, and landscape position for each traversed delineation. Based on a binomial distribution, a numerical rating was used to evaluate each delineation. Out of 89 total delineations, there were 70, 71, and 81 successful observations with respect to slope, parent material, and landscape position, respectively. Out of 10 random observations of slope, parent material, and landscape position, the probability of observing 7 or more correct observations was approximately 85, 88, and 99%, respectively. Five mapping units occurring on sideslope and/or colluvial positions were sampled according to a random effects, two-level nested analysis of variance (ANOVA) design. Physical and chemical analyses of the control section for 104 profiles were determined. All soils were described in the field and classified according to Soil Taxonomy of 1975. Variability in all mapping units with respect to cation exchange capacity (CEC), base saturation, total sand, and clay content was primarily among sites within delineations. All mapping units were composed of more than one soil. Similar soils comprised major percentages of each mapping unit. The methodology proposed by this study suggested that the Bland County soil survey could not be significantly improved upon by remapping. However, a redefinition of mapping units and redrafting onto an aerial photobase would increase its usefulness to the comparable state of many current soil surveys. / Master of Science

The genetic and morphological characteristics of Hagerstown silt loam, Pisgah silt loam and Clarksville cherty silt loam, three southwest Virginia soils which were formed from material weathered from limestone, were studied by means of mechanical and chemical analyses, and field studies or the soil profiles. The soils used in this investigation are all related in a general way, that is, they all occur within the Gray-Brown Podzolic region and are all derivatives of relatively highly carbonated rocks. Samples of all three soils were taken in Russell County, Virginia within the same vicinity. Therefore, the variation in the physical and chemical composition are due to variation in parent rock and relief and not to variations in climate. Chemical analyses of the parent rock showed that the Hagerstown silt loam and Clarksville cherty silt loan were formed from material weathered from a dolomitic limestone, and that the Pisgah silt loan was formed from material weathered from a high grade limestone. Total chemical analyses of the various horizons of the soil profiles showed that the soil forming processes of the three soils studied were podzolic is nature. The parent materials or C horizons of all the soil profiles studied were clays. Hagerstown, which contained approximately 38 percent clay in the A₁ horizon and 75 percent clay in the C horizon, was the heaviest of the three soils studied. Laboratory and field classifications of soil class conflicted in the case of the Hagerstown profile. The ratios of silica to alumina, and silica to iron showed clearly the accumulation of alumina or iron in the lower horizons. The base to alumina ratio showed the thoroughness of the weathering of the three soil profiles. Calculations of the percentages of bases lost during the soil forming processes showed that calcium was lost from the soil to a greater extent than the magnesium. / Master of Science

High-elevation spruce-fir forests in the southern Appalachians may potentially be in a state of decline as a result of either natural or anthropogenic causes. Soils were investigated in areas representative of 117 permanent intensive field plots established to evaluate changes in forest composition that may be influenced by the deposition of atmospheric pollutants. A total of 35 pedons were described, sampled, and characterized. Over 75% of the soils studied were classified in the field as either Typic or Pachic Haplumbrepts, but weakly developed spodic horizons were identified in 13 of the soils by chemical determinations in the laboratory. A high degree of morphological similarity exists between soils in these areas despite widespread differences in parent material and local geology. This similarity is the result of physical mixing of these soils by climatically-driven slope processes. A considerable amount of chemical variability exists in these soils which is not expressed in morphological characteristics. Multiple discriminant analysis established that physical and morphological properties used to separate and classify these soils in the field were not significantly different between study areas. Parent material differences, however, expressed in both soil chemical and mineralogical properties, were sufficiently different between study areas to result in the clear separation of soils into distinct groups. The importance of nutrient cycling in these spruce-fir forests is underscored by high levels of exchangeable bases in surface horizons relative to lower in the profile. This suggests that disturbances to the forest floor resulting from fire, overgrazing, logging, or erosion could have a major impact on ecosystem resilience during stress. / Master of Science

The Cullen soil series concept in the Virginia Piedmont has been the subject of much debate. This series was originally named Lloyd and was mapped throughout the southeastern Piedmont. In 1969 the Lloyd series was deactivated because of conflicting concepts. The Cullen series was established in 1970 to cover the Lloyd concept in Virginia. This soil is developed from a mixed felsic and mafic parent material and has been mapped over various rock types. A dark red (10R or 2.5YR 3/6) B subhorizon is the major morphologic feature of this soil series. Field and laboratory evaluations were undertaken to: (1) examine the relationship of Cullen and associated soil series and provide a method for their separation, (2) determine if geomorphic or weathering differences exist in Cullen and associated soil series, and (3) determine the classification of the Cullen series in Soil Taxonomy. The majority of Cullen pedons sampled classified as Typic Hapludults, clayey, mixed, thermic, but bordered on the kaolinitic and oxidic mineralogy classes. Chemical and physical properties were consistent in the pedons sampled and did not relate well to parent rock type or B horizon color. Weathering for an extensive time period has brought soils derived from various parent materials to a similar mineralogical state. We recommend that the Cullen series concept be broadened to include red (10R or 2.5YR) soils that have a mixed mineralogy. This concept covers a range between the Davidson and Tatum series and includes what has been mapped as Georgeville in Virginia. / Master of Science

Deficiency of available nitrogen (N) is one of the major factors limiting the establishment of a long term self-sustaining vegetative community on mine soils. This investigation was conducted to study the nature of N form and dynamics in southwest Virginia mine soils. Fresh mine spoils contained a large amount of indigenous N, ranging from 650 to 2500 mg/kg soil, which complicated N studies. Most of the indigenous N was "geologic N" which was unavailable to plants. The geologic N came from either 2:1 silicate minerals (fixed NH₄⁺) or coal fragments (nonhydrolyzable organic N). Active N, consisting of hydrolyzable organic N and exchangeable N, comprised the minor fraction of indigenous N available to plants. / Ph. D.

This paper's objective is to determine the best approaches for clean-up of an underground oil leak using cost-benefit analysis. The background aspects of the leak, including a description and history of the oil plume, aspects of the site, and applicable Federal and local regulations, are discussed. Several remediation methods are chosen for examination. The costs associated with each method are estimated. An analysis of the area's property value data using the hedonic approach to benefits estimation is also conducted. Costs of the clean-up of the oil plume are compared to the benefits. It was determined that the amount of estimated benefits from restoration programs is $7.6 million. Based on this information and the cost data, the microbial fence / hydraulic containment method and the enhanced groundwater extraction / hydraulic containment method should be considered as remediation approaches. / Master of Arts