ABSTRACT Rodney Eugene Wright ECONOMIC AND ENVIRONMENTAL MODELING OF AN AGRICULTURAL WATERSHED IN THE MISSISSIPPI DELTA: CROP SELECTION USING AN LP MODEL AND WATER QUALITY IMPACTS OF BIOENERGY CROPS USING THE ANNAGNPS MODEL The conventional ethanol mandates set forth by the renewable fuel standards in the Energy Independence and Security Act (EISA) of 2007 have resulted in an increased demand for corn. The requirement has translated into a 20% increase in corn hectares in the U.S, based on the three-year period prior to 2005 to the most recent three-year period, 2012-2014. This economic study optimized crop selection on a case study farm in the Arkansas Delta with the Purdue Crop/Linear Programming model. The cropping optimization was performed at six corn price levels consisting of near the loan rate, pre-EISA, post-EISA low, post-EISA average, and post-EISA high. These values were $57 m-3, $85 m-3, $114 m-3, $142 m-3, and $170 m-3, respectively. A sixth level ($133 m-3) was an average of the 10-year forecast price by FAPRI and USDA. The investigation indicated conventional Arkansas Delta crops compete favorably with corn. An agricultural watershed in the Arkansas Delta was modeled to analyze best management practices (BMPs) and cropping scenarios with the Annualized Agriculture Non-point Source (AnnAGNPS) watershed model. The objective of this research was to determine if water quality was degraded or improved by planting bioenergy crops and utilizing BMPs versus conventional crops. Conventional crops tested included 100% plantings of corn (Zea mays L.), cotton (Gossypium hirsutum L.), rice (Oryza sativa L.), sorghum (Sorghum bicolor L.), and soybeans (Glycine max L.). Advanced biofuel crops switchgrass (Panicum virgatum L.) and alfalfa (Medicago sativa L.) were tested. BMPs included no-tillage, nutrient management, cover crops, and conservation reserve program (CRP) areas. Advanced biofuel crops reduced sediment and P losses by 90% or more and N losses to less than 2 kg ha-1. No-tillage and cover crops were the most effective BMPs at reducing nutrient runoff. CRP levels were tested and placing just 5% of the most erosive area in CRP resulted in a 25% reduction in nutrient loading. The AnnAGNPS model indicates that advanced biofuel crops, BMPs, and CRP land allocations are important ways to reduce the sediment and nutrient losses from agriculture watersheds.
|Advisor:||Bouldin, Jennifer L.|
|Commitee:||Bingner, Ronald L., Green, Steven, Griffin, Terry, Guha, Gauri-Shankar|
|School:||Arkansas State University|
|School Location:||United States -- Arkansas|
|Source:||DAI-B 76/12(E), Dissertation Abstracts International|
|Subjects:||Agriculture, Agricultural economics, Environmental science|
|Keywords:||Agricultural watershed, Agriculture economics, Annagnps model, Bioenergy crops, Lp model, Water quality|
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