Thesis (Ph. D.)--University of Pennsylvania, 1943. / Bibliography: p. 195-197.

The evaluation of production alternatives in agriculture requires a close examination of their economic and environmental impacts. This study was conducted to identify the crops with the highest profit potential given terminal market prices over the last five years, evaluate the feasibility of adopting new crop alternatives, given historical price information and limited production resources, and determine the potential environmental impacts of adopting new cropping strategies in Accomack and Northampton Counties on the Eastern Shore of Virginia. A database of daily terminal price information was created to identify the market windows for specific commodities, their respective high, median and low prices, and their price variability over the last five years. A linear programming model was used to determine optimal farming operations for those farmers that grow only wheat and soybean versus farmers who are willing and able to include vegetables in their crop mix. PLANETOR, an environmental impact computer program, was used to estimate the potential soil erosion, pesticide leaching and runoff, nitrogen leaching, and phosphorous runoff for different scenarios. The model shows that some of the new vegetable commodities could substantially increase the net returns of the farming operations in question. Romaine and Boston Lettuce were consistently selected as the most profitable alternatives while the region's traditional crops offered little competition. Wheat and soybean production showed acceptable levels of soil erosion, as defined by the T-values for the region, and low potential for nitrogen leaching. They did, however, exhibit a higher potential for water contamination, through leaching, or runoff, of high toxicity chemicals. Although lettuce production had higher than recommended soil losses, a well-diversified crop mix offsets its negative impacts at the farm level. Lettuce also uses low toxicity chemicals, decreasing potential health hazard from their leaching or runoff. The introduction of the new vegetable commodities is recommended on the basis of the high profits that they offer, as well as the more positive pesticide leaching and runoff potential. Their final adoption, however, should take place only after establishing a well defined marketing strategy and resolving potential marketing problems. No crop exists that could offer both high profits and have no impact on the environment. Kenaf was thought to be one, but it was soon eliminated on both grounds. This study showed, however, that the new vegetable crops considered may offer better net returns, while they do not necessarily translate into environmental disasters. / Master of Science

This project investigates the effect of plasticulture and copper-based crop protectants on water quality on the Eastern Shore of Virginia. Water and sediment copper concentrations in both plasticulture and non-plasticulture containing watersheds were measured to determine the scope of copper in Eastern Shore tidal creeks. Runoff from a variety of land-uses including agricultural, plasticultural, residential and natural areas were collected and measured for copper to determine where copper-containing runoff originates. Copper concentrations in plasticulture impacted tidal creeks were higher than background (0 - 3 ug/L) only in spikes, during or immediately after runoff-producing rainfall events. These spikes registered as high as 263 ug/L total copper, or 127 ug/L dissolved copper. Plasticulture and copper-based crop protectants were affirmed as the cause of these spikes because control watersheds indicated no high copper spikes. Runoff from different land-uses verify that copper is present in high concentrations only in runoff from fields engaged in plasticulture and using copper-based crop protectants. Sediment copper concentrations were found to be within the natural range, but exhibited some variability based on proximity to agricultural copper inputs. / Master of Science

This thesis develops a philosophy for management, preservation, and interpretation of Woodlands Farm and Thomas's Wharf in Northampton County on Virginia's Eastern Shore. The U. S. Department of the Interior, National Park Service methodology for historic properties, including cultural landscapes, is used to complete this study. The National Park Service method includes four interrelated steps: (1) historical research, and (2) inventory and documentation of existing conditions, (3) site analysis and evaluation of significance and integrity, and (4) recommendations for future management. Essential to the future of Woodlands Farm and Thomas's Wharf is continued use of the property while retaining character defining features that make them significant. The most suitable management philosophy for a historic property that allows for protection and maintenance of significant features, as well as future use and development, is Rehabilitation. Thomas's Wharf's significance is derived from fragments of many periods and histories can be read on the landscape; a palimpsest. The U.S. Department of the Interior, National Park Service evaluates a landscape much as one evaluates a historic building, defining it as a type or from a specific time period. The U.S. Department of the Interior's criteria for significance does not address a landscape, like Thomas's Wharf, as part of the continuum of history. Rather the study of landscapes is limited and the criteria does not acknowledge a site's broader continuum of significance. Landscapes that are records of change and evolution, palimpsests of a people, culture, and place, need to be identified and deemed significant for that quality. / Master of Landscape Architecture

Master of Science

The freshwater-saltwater transition zone was investigated in an unconfined aquifer on Virginia’s Eastern Shore. The Steelman’s Landing study site consisted of a well transect which began in an 800 meter wide upland agricultural field, and proceeded seaward through a 300 meter wide mesic forest, 300 meter wide saltmarsh, and 550 meters offshore into Magothy Bay. Wells in the surficial, Columbia aquifer were screened over 30 centimeters at depths of 3.05, 9.14, and 15.25 meters below the surface. Most monitoring sites consisted of clusters of multiple wells which were periodically sampled for inorganic nutrients and salinity. In the saltmarsh portion of the study site, salinity of monitoring well samples indicated the presence of two horizontal flow systems. The deeper flow system contained freshwater flowing seaward from upland areas. The shallower system contained saline water recharged by the tides and concentrated by evaporation. Salinity measurements and positive vertical (0.019-0.046 meters/meter) and horizontal (0.001-0.005 m/m) hydraulic gradients of wells located across the marsh suggested movement of freshwater offshore which was confirmed by the direct measurement of submarine groundwater discharge (SGWD) using seepage meters. Upland wells contained high nitrate freshwater (>600μmol / 1 NO₃⁻, <1.0% salinity), while shallow (3.05m) wells located from the marsh-forest interface across the saltmarsh to Magothy Bay contained increasingly saline water and reduced nitrate levels (<1μmol / 1 NO₃⁻, 4-21% salinity). Deeper (9.14m) wells across the study site from the agricultural field seaward 420 meters offshore, contained fresh water (<1.0%). A deep (9.14m) well located 550 meters offshore contained water of nearly equal salinity to ambient water in Magothy Bay (30-32%). This represented a point on the saline side of the transition zone. In order to more completely identify and account for movement of nutrients in groundwater across the study site from upland agricultural fields to Magothy Bay, the second portion of the study consisted of an investigation of nutrient movement through a small tidal creek located adjacent to the Steelman’s Landing study site. Creek water had a higher velocity and shorter residence time in comparison to groundwater. Exercises describing nutrient movement were conducted in February and May, 1993 in Wall’s Landing Creek. A seasonal component of nutrient reduction was investigated as indicated by ambient creek samples, and bulk flux of nutrients across the sediment-water interface using light and dark benthic dome chambers. Nitrate flux measurements for the February and May sampling exercises were approximately 14,500 μmol/sec (17.6kg/day as N) and 5400 μmol/sec (6.5kg/day as N), respectively. The primary mechanism of nitrate reduction on reaching the creek channel was physical dilution by seawater. / Master of Science

The movement of nitrogen from the surface, where it is applied as fertilizer, to groundwater is of importance due to the health concerns associated with nitrate and potential eutrophication of groundwater impacted surface water. The computer model, PRZM (Pesticide Root Zone Model) was used to simulate the transportation of nitrogen through the soil column, past the crop root zone to groundwater. Then MOC (Method of Characterization), a groundwater model, was used to transport the nitrogen that had reached the water table offsite. Results were compared to existing field data in an attempt to verify the validity of the simulation. / Master of Science

Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1998. / "UMI Number: 9911825." Includes bibliographical references. Available also on the web.

In March 2002, The Nature Conservancy purchased a 9,000-acre tract of land on and near Warm Springs Mountain in Bath County, Virginia. The purpose of this paper is to examine community-based conservation strategies utilized by The Nature Conservancy in two well-established Virginia reserves to determine the effectiveness of those strategies in the protection of Warm Springs Mountain. The Conservancy's previous work on Virginia's Eastern Shore and in the Clinch Valley of southwest Virginia reveals the organization's transition from a strategy of mere land acquisition to the use of community-based conservation in an effort to involve local citizens and promote a proper balance between economics and the environment. The community-based conservation model developed by TNC on the Eastern Shore and utilized further in the Clinch Valley works well for ecoregions that fit a particular typology. The paper discusses the differences between that typology and the factors affecting the protection of Warm Springs Mountain. In addition, the paper outlines the lessons TNC learned from both positive and negative experiences in the two earlier preserves and proposes how these lessons can be applied to the Warm Springs Mountain Preserve. / Master of Urban and Regional Planning

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