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Browsing by Author "Bosch, Darrell J."

Now showing 1 - 20 of 95
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    Advances in Applied Econometrics: Binary Discrete Choice Models, Artificial Neural Networks, and Asymmetries in the FAST Multistage Demand System
    Bergtold, Jason Scott (Virginia Tech, 2004-04-14)
    The dissertation examines advancements in the methods and techniques used in the field of econometrics. These advancements include: (i) a re-examination of the underlying statistical foundations of statistical models with binary dependent variables. (ii) using feed-forward backpropagation artificial neural networks for modeling dichotomous choice processes, and (iii) the estimation of unconditional demand elasticities using the flexible multistage demand system with asymmetric partitions and fixed effects across time. The first paper re-examines the underlying statistical foundations of statistical models with binary dependent variables using the probabilistic reduction approach. This re-examination leads to the development of the Bernoulli Regression Model, a family of statistical models arising from conditional Bernoulli distributions. The paper provides guidelines for specifying and estimating a Bernoulli Regression Model, as well as, methods for generating and simulating conditional binary choice processes. Finally, the Multinomial Regression Model is presented as a direct extension. The second paper empirically compares the out-of-sample predictive capabilities of artificial neural networks to binary logit and probit models. To facilitate this comparison, the statistical foundations of dichotomous choice models and feed-forward backpropagation artificial neural networks (FFBANNs) are re-evaluated. Using contingent valuation survey data, the paper shows that FFBANNs provide an alternative to the binary logit and probit models with linear index functions. Direct comparisons between the models showed that the FFBANNs performed marginally better than the logit and probit models for a number of within-sample and out-of-sample performance measures, but in the majority of cases these differences were not statistically significant. In addition, guidelines for modeling contingent valuation survey data and techniques for estimating median WTP measures using FFBANNs are examined. The third paper estimates a set of unconditional price and expenditure elasticities for 49 different processed food categories using scanner data and the flexible and symmetric translog (FAST) multistage demand system. Due to the use of panel data and the presence of heterogeneity across time, temporal fixed effects were incorporated into the model. Overall, estimated price elasticities are larger, in absolute terms, than previous estimates. The use of disaggregated product groupings, scanner data, and the estimation of unconditional elasticities likely accounts for these differences.
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    Agricultural BMP Placement for Cost-effective Pollution Control at the Watershed Level
    Veith, Tamie L. (Virginia Tech, 2002-02-11)
    The overall goal of this research was to increase, relative to targeting recommendations, the cost-effectiveness of pollution reduction measures within a watershed. The goal was met through development of an optimization procedure for best management practice (BMP) placement at the watershed level. The procedure combines an optimization component, written in the C++ language, with spatially variable nonpoint source (NPS) prediction and economic analysis components, written in the ArcView geographic information system scripting language. The procedure is modular in design, allowing modifications or enhancements to the components while maintaining the overall theory. The optimization component uses a genetic algorithm to optimize a lexicographic multi-objective function of pollution reduction and cost increase. The procedure first maximizes pollution reduction to meet a specified goal, or maximum allowable load, and then minimizes cost increase. For the NPS component, a sediment delivery technique was developed and combined with the Universal Soil Loss Equation to predict average annual sediment yield at the watershed outlet. Although this evaluation considered only erosion, the NPS pollutant fitness score allows for evaluation of multiple pollutants, based on prioritization of each pollutant. The economic component considers farm-level public and private costs, accounting for crop productivity levels by soil and for enterprise budgets by field. The economic fitness score assigns higher fitness scores to scenarios in which costs decrease or are distributed more evenly across farms. Additionally, the economic score considers the amounts of cropland, hay, and pasture needed to meet feed and manure/poultry litter spreading requirements. Application to two watersheds demonstrated that the procedure optimized BMP placement, locating scenarios more cost-effective than a targeting strategy solution. The optimization procedure identified solutions with lower costs than the targeting strategy solution for the same level of pollution reduction. The benefit to cost ratio, including use of the procedure and implementation of resulting solutions, was demonstrated to be greater for the optimization procedure than for the targeting strategy. The optimization procedure identifies multiple near optimal solutions. Additionally, the procedure creates and evaluates scenarios in a repeated fashion without requiring human interaction. Thus, more scenarios can be evaluated than are feasible to evaluate manually.
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    Analyzing Cost Implications of Water Quality Trading Provisions: Lessons from the Virginia Nutrient Credit Exchange Act
    Aultman, Stephen (Virginia Tech, 2007-07-26)
    The purpose of this study was to analyze the cost implications of various provisions of the Virginia Nutrient Credit Exchange Act. The first objective was to estimate the cost implications of point source trading provisions of the Act. An integer programming cost minimization model was constructed to estimate the cost of achieving four point source trading policy scenarios. The model estimated the annual cost of meeting two different nutrient cap levels, each with and without a limits-of-technology concentration standard requirement for new and expanding point sources. The limits-of-technology concentration standard requirement was found to significantly affect cost while providing little apparent benefit to water quality. The second objective was to develop a screening procedure for municipalities to estimate the cost of generating waste load allocation from nonpoint source offsets under their jurisdictional control. A spreadsheet based cost screening procedure was developed for municipalities to estimate the cost of implementing of nitrogen offsets from stormwater practices, septic retirement, and land conversion. One of the important findings from developing the screening procedure is that the cost of generating WLA from non-point sources under the control of local governments was much higher than the cost of removing nitrogen at wastewater treatment plants.
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    Assessing Farm-Level and Aggregate Economic Impacts of Olive Integrated Pest Management Programs in Albania: an Ex-Ante Analysis
    Daku, Lefter S. (Virginia Tech, 2002-04-11)
    Concerns about the harmful effects of pesticides on the environment, human health, and wildlife have led to research and promotion of integrated pest management (IPM) strategies. Recently, an IPM program was introduced in the Albanian olive sector through the USAID-funded global IPM-CRSP project to develop improved olive IPM technologies. This study develops and applies a protocol for integrated economic impact assessment of olive pest management strategies designed by the IPM-CRSP project in Albania. The main components of the integrated approach for economic impact assessment of olive IPM include (i) net return analysis for measuring farm level impacts; (ii) economic surplus modeling for measuring market-level impacts; and (iii) modeling of IPM adoption under output uncertainty. The economic surplus equilibrium displacement model developed for the Albanian olive market with no international trade accounts for IPM research-induced supply shifts, increased demand due to quality improvement, and research-induced spillovers to non-target zones. The main sources of data for performing partial budgeting and economic surplus analysis were: (i) an expert survey; (ii) partial budgets compiled based on a farmer survey and expenditure records from field-level experiments; and (iii) data collected at the market level. The data used to estimate the dichotomous logit model came from a 1999 survey of 200 growers and a survey of 120 growers carried out in 2000 in the Vlora district of Albania. The net return analysis indicates that compared to conventional practices, the proposed olive IPM packages generally promise higher yields, improved quality of olive products, lower pesticide use, and higher net returns to producers. However, adoption of some of the IPM practices implied higher production costs. Based on the simulation results, the Albanian olive industry has the potential to derive a net IPM research benefit between $39 million (assuming that farmers move directly from minimum spraying to IPM) and $52 million (assuming that farmers move from full pesticide program to IPM) over the next 30 years. Farmers' reliance on pesticide use on olives and other crops does not seem to hinder IPM adoption. Grower perceptions and the process of expectation formation significantly influence adoption decisions. Addressing the process of expectation formation and changing these perceptions by educational programs and better access to information will encourage IPM adoption.
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    Assessing Landowner Level Costs for Riparian Forest Buffer System Adoption on Farms in Virginia's Chesapeake Bay Watershed
    Smith, Clifton Lee Jr. (Virginia Tech, 1998-07-22)
    Riparian Forest Buffer Systems contribute to non-point source pollution control and improve the physical and trophic qualities of streams. There is a limited understanding of the full range of costs incurred when implementing a RFBS. Establishment costs will vary with the site characteristics. The amount of forgone income will vary with the current land-use. RFBS enterprises may yield returns that partially or fully offset forgone income. Section A discusses the physical characteristics and functions of RFBS in the Chesapeake Bay Watershed. Section A argues that RFBS design and site characteristics alter the physical ability of RFBS to produce environmental services. Altering design specifications may come at little environmental loss but might greatly reduce landowner costs. Section B describes a decision support system that can provide landowners and policy makers with financial information on the site specific changes in costs that occur as RFBS designs are altered. Section C utilizes the decision support system software to simulate the common design and site characteristics found within the Chesapeake Bay Watershed of Virginia. Generalizations are drawn concerning reduction efficiencies of a RFBS based on the physical characteristics of the regions. Section D discusses government policies and incentive programs, as well as additional private income opportunities, that may influence the cost and adoption of RFBS. Findings revealed a range of annual per acre cost of adoption between $140.09 rising to a positive return of $124.79, depending on assumptions of site characteristics, land-use, and supplemental financial incentives.
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    Assessing the Economic Impacts of Tomato Integrated Pest Management in Mali and Senegal
    Nouhoheflin, Theodore (Virginia Tech, 2010-07-07)
    This study assesses the research benefits of IPM technologies and management practices aimed at reducing the virus problem in tomatoes in West Africa. Surveys are conducted with producers, extension agents, scientists, and other experts to obtain information and economic surplus analysis is used to project benefits over time. The determinants of adoption are assessed using a probit model. Results show that adoption of the host-free period reduced the amount of insecticide sprays by 71% and the production cost by $200/ha in Mali. The cost-benefit analysis indicated that the use of virus-tolerant seeds generated profits ranging from $1,188 to $2,116/ha in Mali and from $1,789 to $4,806/ha in Senegal. The likely factors influencing adoption of the technologies in both countries are the frequency of extension visits, farmer's field school training, gender, education, seed cost, tomato area, and experience in tomato losses. The benefits in the closed economy market vary from $3.4 million to $14.8 million for the host-free period, $0.5 million to $3 million for the virus-tolerant seeds, and $4.8 million to $21.6 million for the overall IPM program. In the same order, the benefits under the open economy market range from $3.5 million to $15.4 million, $0.5 million to $3million, and $5 million to $24 million. The distribution pattern indicates that producers gain one-third and consumers two-thirds of the benefits. Our results support policies aiming to increase the adoption rate or the expected change in yield.
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    Assessing the effects of cattle exclusion practices on water quality in headwater streams in the Shenandoah Valley, Virginia
    Maschke, Nancy Jane (Virginia Tech, 2012-01-27)
    Livestock best management practices (BMPs) such as streamside exclusion fencing are installed to reduce cattle impacts on stream water quality such as increases in bacteria through direct deposition and sediment through trampling. The main objective of this study is to assess the effects of different cattle management strategies on water quality. The project site was located near Keezletown, VA encompassing Cub Run and Mountain Valley Road Tributary streams. During two, one-week studies, eight automatic water samplers took two-hour composites for three periods: baseline, cattle access, and recovery. During the cattle access period, livestock were able to enter the riparian zone normally fenced off. Water samples were analyzed for E.coli, sediment, and nutrients to understand the short-term, high-density, or flash grazing, impact on water quality. Additional weekly grab and storm samples were collected. Results show that cattle do not have significant influence on pollutant concentrations except in stream locations where cattle gathered for an extensive period of time. Approximately three cattle in the stream created an increase in turbidity above baseline concentrations. E.coli and TSS concentrations of the impacted sites returned to baseline within approximately 6 to 20 hours of peak concentrations. Weekly samples show that flash grazing does not have a significant influence on pollutant concentrations over a two-year time frame. Sediment loads from storms and a flash grazing event showed similar patterns. Pollutant concentrations through the permanent exclusion fencing reach tended to decrease for weekly and flash grazing samples.
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    An Assessment and Modeling of Copper Plumbing pipe Failures due to Pinhole Leaks
    Farooqi, Owais Ehtisham (Virginia Tech, 2006-05-19)
    Pinhole leaks in copper plumbing pipes are a big concern for the homeowners. The problem is spread across the nation and remains a threat to plumbing systems of all ages. Due to the absence of a single acceptable mechanistic theory no preventive measure is available to date. Most of the present mechanistic theories are based on analysis of failed pipe samples however an objective comparison with other pipes that did not fail is seldom made. The variability in hydraulic and water quality parameters has made the problem complex and unquantifiable in terms of plumbing susceptibility to pinhole leaks. The present work determines the spatial and temporal spread of pinhole leaks across United States. The hotspot communities are identified based on repair histories and surveys. An assessment of variability in water quality is presented based on nationwide water quality data. A synthesis of causal factors is presented and a scoring system for copper pitting is developed using goal programming. A probabilistic model is presented to evaluate optimal replacement time for plumbing systems. Methodologies for mechanistic modeling based on corrosion thermodynamics and kinetics are presented.
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    Assessment of SWAT to Enable Development of Watershed Management Plans for Agricultural Dominated Systems under Data-Poor Conditions
    Osorio Leyton, Javier Mauricio (Virginia Tech, 2012-05-02)
    Modeling is an important tool in watershed management. In much of the world, data needed for modeling, both for model inputs and for model evaluation, are very limited or non-existent. The overall objective of this research was to enable development of watershed management plans for agricultural dominated systems under situations where data are scarce. First, uncertainty of the SWAT model's outputs due to input parameters, specifically soils and high resolution digital elevation models, which are likely to be lacking in data-poor environments, was quantified using Monte Carlo simulation. Two sources of soil parameter values (SSURGO and STATSGO) were investigated, as well as three levels of DEM resolution (10, 30, and 90 m). Uncertainty increased as the input data became coarser for individual soil parameters. The combination of SSURGO and the 30 m DEM proved to adequately balance the level of uncertainty and the quality of input datasets. Second, methods were developed to generate appropriate soils information and DEM resolution for data-poor environments. The soils map was generated based on lithology and slope class, while the soil attributes were generated by linking surface soil texture to soils characterized in the SWAT soils database. A 30 m resolution DEM was generated by resampling a 90 m DEM, the resolution that is readily available around the world, by direct projection using a cubic convolution method. The effect of the generated DEM and soils data on model predictions was evaluated in a data-rich environment. When all soil parameters were varied at the same time, predictions based on the derived soil map were comparable to the predictions based on the SSURGO map. Finally, the methodology was tested in a data-poor watershed in Bolivia. The proposed methodologies for generating input data showed how available knowledge can be employed to generate data for modeling purposes and give the opportunity to incorporate uncertainty in the decision making process in data-poor environments.
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    BMP Cost and Nutrient Management Effectiveness on Typical Beef and Beef-Poultry Farms in Shenandoah County, Virginia
    Dickhans, Megan F. (Virginia Tech, 2010-05-04)
    This study analyzes the change in whole-farm net revenues and nutrient reduction from the implementation of five best management practices (BMPs) on a typical beef and beef-poultry farm in Shenandoah County. Whole-farm net revenues, resource allocation, nutrient loss reductions, and the cost efficiency of reducing nutrient losses were analyzed to assess which BMPs are the most cost efficient to implement, assuming the baseline scenarios have no voluntarily applied BMPs. The effects of stacking additional BMPs, in combinations of two or more, were also assessed. No-till cropping, winter wheat cover crop, herbaceous riparian buffer, fencing, and P-based NMP were the BMPs that were analyzed. Incentive payments from state and federal governments were incorporated into the cost of BMP adoption. A brief analysis of a farmer's time value of money, with respect to incentive payments, was also conducted. Results indicated that no-till crop management was the most cost efficient BMP, and was the only BMP to increase net revenues for both farm models. Fencing and P-based NMP were the least cost efficient for the beef farm. For the beef-poultry farm, fencing was the least cost efficient. The implications of this study are that farmers that choose to adopt BMP should evaluate both their interests in maintaining (or increasing) farm net revenues along with their interest in improving water quality through the reduction of nutrient losses. There is potential for implementing multiple BMPs, while increasing net revenues from a farm's baseline scenario. For farmers and policy makers, no-till cropping can be a profitable and therefore cost efficient BMP to implement. Incentive payments are intended to encourage the adoption of BMPs by subsidizing a portion of the start-up costs. Policy makers should attempt to make cost-share payments reflect nutrient reduction goals. This can be done by analyzing both the compliance cost to farmers and the nutrient reduction effectiveness of BMPs.
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    A case study of investment in agricultural sustainability: adoption and policy issues for nitrogen pollution control in the Chesapeake Bay drainage
    Norris, Patricia E. (Virginia Polytechnic Institute and State University, 1988)
    Nutrient loadings to the Chesapeake Bay are a source of concern for water quality agencies. In particular, excess nitrogen loadings from agricultural production activities threaten water quality in the Bay. Questions have been raised about how effectively traditional BMPs can control nitrogen loss from crop production. This study examines agricultural nitrogen pollution control from an input management perspective. Using an economic and physical model, seven production systems and nitrogen management strategies are compared in terms of input use, profitability, and nitrogen loss potential. Results suggest that several of the production systems will reduce residual nitrogen without reducing profits. However, it is recognized that factors in addition to profitability will influence producers' nitrogen management decisions. Therefore, using the results of a farmer survey, adoption models are estimated to examine the impact of production system characteristics and producer characteristics on the decision to use an alternative production system and nitrogen management strategy. Finally, a sensitivity analysis is conducted to examine the impact of alternative policy tools on adoption incentives. Both financial incentives and education and information programs are found to be important tools for influencing producers' decisions. Producers' interest in the alternative systems and desire for information on the systems suggest that agricultural research will contribute by assuring that producers have access to adequate information on the alternative systems.
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    Comparing Relative Convenience of Non-Commute Trips in Battery Electric Vehicles Versus Internal Combustion Engine Vehicles in the Contiguous United States
    Starner, Joshua D. (Virginia Tech, 2021-05-26)
    Technological advancements in battery electric vehicles (BEVs) have developed alongside increases in vehicle size and the introduction of vehicle styling more similar to internal combustion engine vehicles (ICEVs). Increases in the distance a BEV can travel on a single charge have been accompanied by the ability to recharge the vehicle much faster than the BEV models available just 10 years ago. The Environmental Protection Agency (EPA) reports for model year 2021 include 40 BEV models and many manufacturers have signaled plans to increase the number of battery electric vehicle models offered. As more consumers consider purchasing a battery electric vehicle the question of how well that vehicle can meet all their needs is asked more frequently. This research examines the current DC-Fast charging infrastructure to evaluate how the current distribution of chargers impacts consumer convenience for non-commute routes. No study has evaluated the impact that the current DC-Fast charging infrastructure has on the consumer driving experience and we fill this research need because it will allow consumers to understand more accurately how a (BEV) may meet their needs while also allowing BEV manufacturers to better understand the impacts of potential investments in charging infrastructure. The authors examine over 30,000 pairs of simulated BEV and ICEV routes and compare the distance and duration variations for each pair. Due to our effort to consider the suitability for long distance trips, we have ensured that more than 50% of the simulated routes have a minimum travel distance of 500 miles and over 15% of the routes exceed 1000 miles. Working from this data, 99.7% of the locations in a sample of 360 places in the contiguous U.S. can be reached without relying on the ability to charge a BEV overnight. We further identify a median increase in BEV trip duration of 13.1% and a median increase in distance of 0.06%. The differences in median travel time, particularly when trips exceed 400 miles suggests that long trips made with a BEV may result in longer total travel time, however, differences in route length between BEVs and ICEVs were minimal. These findings serve as the foundation to discuss challenges and solutions related to widespread non-commuter adoption of BEVs in a variety of geographic locations, including how and where the consumer experience may vary. The results from this work will support consumer awareness about the ability of a BEV to meet their needs as well to aid in the evaluation of infrastructure investment as it relates to improving the consumer experience. The methods employed serve as a foundation for future work to investigate the relationship between vehicle type and consumer experience as well as to advance algorithms capable of evaluating routes that require a selection to be made from a set of optional stops.
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    Competitiveness of Virginia dairy producers in a national setting given changing marketing and policy conditions
    Nubern, Chris (Virginia Tech, 1996)
    The objective of this study is to determine Virginia dairy producers’ competitiveness in an industry that is experiencing changing policy and marketing conditions. The competitiveness of Virginia dairy producers is examined in a National Dairy Model that compares both producers’ cost of production across market areas and spatial relationships among producers and consumers. The National Dairy Model (NDM) is a mathematical programming model that minimizes the total costs of producing milk and the assembly costs of shipping dairy products to the final consumer. A state's cost of production in the NDM is determined with a translog cost function. The cost functions are estimated with data collected in the 1989 and 1993 dairy versions of the Farm Costs and Returns Survey (FCRS). The supply and demand information in the NDM is annual data for 1994. Transportation costs are determined with current hauling rates and actual mileage between supply and demand points. Once the costs of production and spatial components of the NDM are formulated, the NDM is solved using the General Algebraic Modeling System (GAMS). The NDM is evaluated under the guidelines of several different scenarios. For example, some alternative marketing scenarios that provide important information about the future of the dairy industry are (1) simulations where the hauling rates are varied, (2) scenarios in which the U.S. becomes a major participant in the export market, and (3) situations where the marketing environment leads to increasing costs of production. Another alternative scenario involves only the spatial dimension of the NDM. Given the current marketing conditions in the dairy industry, the results of the NDM indicate that Virginia dairy producers are competitive in a marketing environment where the location of milk production is determined by a producer's costs of production and location advantages. Using Virginia's translog cost function, the cost per cwt. at the mean of the FCRS production data is $10.60. The cost estimate applies to Virginia's representative dairy farm where the average herd size is 91 cows and annual production per cow is 14,160 pounds. With these estimates and the fact that Virginia producers are near large population centers, the results of the NDM show that Virginia dairy farms are competitive in a deregulated market.
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    Costs of Meeting Water Quality Goals under Climate Change in Urbanizing Watersheds: The Case of Difficult Run, Virginia
    Giuffria, Jonathon Michael (Virginia Tech, 2016-06-28)
    Urban environments have been identified as a non-point source contributor of nutrient loadings into watersheds. Interannual surges of nutrient loadings into local water systems are more damaging than mean interannual nutrient loadings. Virginia has outlined the need to reduce urban nutrient loadings. Mean interannual nutrient loadings and interannual nutrient loadings variability are expected to increase under climate change (CC). However, there are few studies that provide a predictive framework for abating nutrient loadings under CC. Thus, there is a lack of information regarding how effective water quality policy will be in the future. Using the Difficult Run watershed in Fairfax County, VA, as a site of study, we used mathematical programming to compare how the costs of abating nutrient loads differed under differing climates in the Mid-Atlantic. We first compared the costs of abating mean interannual nutrient loadings in the watershed based on historical climate conditions to those predicted for CC. We then evaluated how changes in the interannual variability of nutrient loadings for CC affect the costs of meeting watershed goals. We found that abating mean interannual nutrient loadings was substantially costlier for CC relative to meeting the same goals under historical climate conditions. Further, we found that the costs of abating interannual nutrient loadings variability increased under CC relative to meeting the same goals under historical climate. One implication of this study suggests that policy makers seeking to meet water quality goals over time must front-load supplemental BMPs today in order to offset the changes predicted for CC.
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    Cotton Yield as Related to Selected Physical and Chemical Properties of Soils of the Coastal Plain of Virginia and North Carolina
    Adcock, Clyde Wesley (Virginia Tech, 1998-08-28)
    Cotton (Gossipium hiristum, L) is a warm season perennial with indeterminant growth habit. In 1995, 42,500 and 300,000 hectares were grown in Virginia and North Carolina, respectively. Soil physical and chemical properties may limit cotton yields. The objective of this study was to; 1) determine influences of soil physical and chemical properties on yield, 2) validate existing preharvest yield estimators, and 3) determine the effect of subsoiling and/or subsurface liming on cotton development and root growth. Two hundred sites were sampled across the Coastal Plain of Virginia and North Carolina to a depth of 92 cm representing 5 major soil series. Soil samples were analyzed for selected physical and chemical properties from each horizon. Boll and plant counts were obtained while harvesting a 3-meter length of row at each site to determine yield for the 1996 and 1997 growing season. Cotton was grown in the greenhouse on 30 cm diameter cores of a soil with low subsoil pH and a hard pan to determine the effects of subsoiling and/or subsurface liming. Ninety days after planting, the cotton plants were harvested and the above ground biomass and rootmass were analyzed. Physical and chemical properties explained 52% of yield variability in 1996 and 27% in 1997. Physical and chemical properties that were significant to yield were surface bulk density, available water holding capacity, depth of the water table and Bt horizon, Mg, K, Ca, and Al content. Soil analysis for nutrient status at depths up to 45 cm were better indicators of cotton yield. Subsoiling with or without subsurface liming increased rooting depth over the untreated check. The subsurface liming reached first flower 11 days prior to the other treatments. The additional period for flowering and boll set in Virginia and North Carolina could increase potential yield.
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    Crop selection, tillage practices, and chemical and nutrient applications in two regions of the Chesapeake Bay Watershed
    Bosch, Darrell J.; Shanholtz, Vernon O. (Virginia Water Resources Research Center, Virginia Polytechnic Institute and State University, 1992-11)
    The objectives of this study were to obtain information on crop selection, tillage, and nutrient and chemical use on cropland having varying sediment loading and leaching potential. Additional objectives were the determination of economic, attitudinal, and demographic factors related to these agricultural practices. The study was carried out in Virginia in three counties of the Northern Neck region (Lancaster, Northumberland, and Westmoreland) and in Rockingham County. In each area, a stratified random sample of 120 sites with varying leaching and sediment loading potential was drawn from the Virginia Geographic Information System (VirGIS) database of cropland. Information on cultural practices on the sites as well as other farm and farmer characteristics was obtained through personal interviews with farm operators. Survey responses indicate that farmers are concerned about the effects of pollution on water quality-particularly drinking water. However, farmers tend not to see actions on their own farms as contributing to water quality damage. Most farmers do not agree that runoff and leaching of nutrients and chemicals from their farms contribute to water quality problems. When asked about the sampled sites on their farms, farmers generally responded that the potential for water quality damage caused by leaching and erosion was low. Their assessment of potential damage did not increase significantly on sites with high leaching or sediment loading potential. In the Northern Neck, farmers generally apply nitrogen and phosphorus at close to recommended rates. In Rockingham County, nitrogen is applied at below recommended rates, while phosphorus is overapplied due to heavy manure applications. Farmers' tillage practices, crop rotations, and nutrient and pesticide application rates generally do not vary according to site leaching and sediment loading potential. Thus, sites with higher leaching and/or sediment loading potential are likely to contribute a disproportionate share of potential loadings to groundwater and surface water. Further research is needed to determine whether targeting nonpoint pollution control to sites with higher leaching and sediment loading potential is a cost-effective way to achieve water quality protection goals.
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    Determining Costs of Conventional and Conservation Agricultural Practices
    Alwang, Jeffrey R.; Boatwright, Jessica; DuBreuil, Katherine; Gaffney, Robert; Moore, Lauren; Latané, Annah; Simmons, Trevor (Blacksburg, VA: SANREM CRSP, 2011)
    Farmers in the Chimbo watershed face problems with soil erosion as a result of the steep slopes and mountainous terrain. In order to help address these environmental concerns and increase farmer profitability and yields, an analysis was conducted to determine the costs of production under conventional and reduced tillage methods on fava beans, beans, maize, and potato. A specific questionnaire was created for both the Illangama and Alumbre watersheds and utilized in these areas. The information provided from research performed in the Chimbo watershed indicates that only conventional tillage bean and reduced tillage bean budgets experience positive net revenue. All other budgets were indicative of net losses for farmers. The data sets all contained considerable variation alluding to the fact that research yielding more accurate measurements is necessary in the future. Additionally, the variability in price at both the farm level and commercial markets make it difficult to accurately judge the cost of production at this time for the investigated crops. By identifying the actual costs of production, research agencies will be able to better understand the constraints faced by agricultural producers within the watershed. Addressing these limitations and practices will help researchers identify factors that affect crop yields, in an effort to improve farmer profits and soil health.
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    A Discrete Choice Mean Variance (EV) Cost Model to Measure Impact of Household Risk from Drinking Water Pipe Corrosion
    Sarver, Eric Andrew (Virginia Tech, 2017-06-08)
    In traditional investment decision making, one tool commonly used is the mean variance model, also known as an expected-value variance (EV) model, which evaluates the anticipated payout of different assets with respect to uncertainty where portfolios with higher risk demand higher expected returns from an individual. This thesis adapts this framework to a cost setting where decision makers are evaluating alternative physical assets that carry lifetime cost uncertainty for maintenance. Specifically, this paper examines homeowner choices for their home plumbing systems in the event of a pinhole leak, a tiny pin-sized hole that forms in copper, drinking-water pipes. These leaks can cause substantial damage and cost homeowners thousands of dollars in repairs. Since pinhole leaks are not related to the age of pipe material, a homeowner is subject to the risk of additional costs if a pinhole leak occurs again despite their repair efforts. The EV cost model in this paper defines two discrete choices for the homeowner in the event of a leak; to apply a simple repair at lower cost and higher future cost uncertainty, or to replace their plumbing with new pipe material, usually made of plastic, at a higher upfront cost but lower likelihood of future expenses. The risk preference of homeowners are demonstrated by their repair strategy selection, as well as the level of cost they incur to reduce uncertainty. Risk neutral individuals will select the repair strategy with the lowest lifetime expected cost and high variance, while risk averse homeowners will prefer to replace their plumbing with higher cost but lower variance. Risk averse individuals are also exposed to indirect costs, which is an additional unobserved cost in the form of a risk premium the homeowner is willing to pay to remove all uncertainty of future pinhole leak expense. Expected costs and variances are also higher for regions in the U.S. that experience elevated leak incident rates, known as hotspots. Using this mean variance cost framework, indirect cost can be quantified for homeowners in hotspot regions and compared to the rest of the U.S. to evaluate the magnitude of pinhole leak risk. The EV cost model estimates risk premiums on pinhole leaks to be $442 for homeowners in hotspots and $305 for those in the rest of the U.S. Finally, this paper examines the impact of pinhole leak cost uncertainty on the U.S. economy. Of an estimated $692 million in annual pinhole leak costs to homeowners, this study estimates a lower bound cost of $54 million per year (7.8% of estimated national annual cost) in risk premium that homeowners would be willing to pay to avoid pinhole leak cost uncertainty. Information in this study on the role of risk in home plumbing decisions and indirect costs would be helpful to policymakers and water utility managers as they deal with infrastructure management decisions. Furthermore, the EV cost methodology established in this paper demonstrates an effective use of mean variance modeling under cost uncertainty.
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    An economic analysis of nitrogen fertilization regimes in Virginia
    Maiga, Alpha S. (Virginia Tech, 1992-09-15)
    The loss of nitrogen from agricultural land to ground and surface waters is currently a major concern in the Commonwealth of Virginia. Farmers use nutrients on plants to maximize profit from the selling of a crop. For them losses of nutrients through inappropriate nutrient application are undesirable. Thus more effective nutrient management is beneficial for both the farmers and the remainder of society. Achieving environmental quality goals while taking into account farmers' income risk is essential when making fertilization recommendations. This study on Richmond county, uses the EPIC model and stochastic dominance analysis to compare four different fertilization regimes at the field and farm level; and then uses a sensitivity analysis to examine how the ranking of different regimes are affected by changes in crop prices. Results suggest that regime 4 which is the EPIC automatic fertilization regime has a better performance than the other regimes. However potential costs not accounted by EPIC involved at the farm level when using regime 4 may negatively affect its adoption by farmers. Thus further studies need to be done to understand and assess the performance of regime 4. The results do not show any significant difference between farm and soil type levels of analysis. The sensitivity analysis mainly affects the less risk averse decision makers, and change only the ranking of the three fertilizer regimes specified by the researcher as opposed to the automatic fertilizer option of EPIC.
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    Economic Analysis of Recapturing and Recycling Irrigation Techniques on Horticulture Nurseries
    Ferraro, Nathaniel Klug (Virginia Tech, 2015-09-22)
    The horticulture industry is facing limited water resources and public pressure to reduce non-point source pollution. In some circumstances, recapturing and recycling of irrigation water in horticultural nurseries can generate significant savings relative to the costs of alternative water sources and potentially reduce non-point source pollution. However, obtaining these savings may also incur substantial risk and capital cost outlays. Disease risk may increase in nurseries that implement recapturing and recycling if recycled water is not properly treated. These added costs must be compared with costs of alternative sources of water, such as municipal or well water. This study employed partial budgeting to compare irrigation water being extended or supplemented through recapturing and recycling against the most feasible alternative. On-site visits were conducted to obtain information for partial budgets and to clarify the reasoning of nurseries choosing to recycle irrigation water. The partial budgets were supplemented with sensitivity analysis with regard to the extraction cost of water and opportunity cost of land used for recapture of water. Six of eight nurseries obtained water from recapturing and recycling at a lower cost compared to a feasible alternative source. The regrading of land for maximum recapture, opportunity cost of land dedicated to a recapture pond, and the cost of municipal water were parameters that were critical to the irrigation choice. Sensitivity analysis indicated that water price and land cost had little effect on the least cost option. Irrigation recycling could be incentivized to motivate further water conservation within the horticulture industry.