Graduate Thesis Or Dissertation

 

Implementing best management practices in small commercial and non-commercial animal enterprises Öffentlichkeit Deposited

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https://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/hd76s318x

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  • Small commercial and non-commercial animal enterprises (SCAEs) raise a few beef cows, horses, pigs, sheep, poultry, and other animals on a few acres. These enterprises are often located in suburban areas of watersheds and show potential for degrading water quality through to increased bacterial, nitrogen, and phosphorus concentrations. SCAEs implement Best Management Practices (BNIPs) on a voluntary basis to control their water quality impacts. Off-stream watering areas, with animal access to streams, and covered manure storages are two BMPs which were analyzed in this thesis for effectiveness in reducing bacteria, nitrogen, and phosphorus from entering surface and groundwater in four SCAEs. The four cooperating SCAEs were located in the Tualatin River Basin, and the potential water quality improvements from implementing these two practices in all SCAEs in the basin were discussed. The BMP analyses use results from several studies. Two of these studies analyzed off-stream watering areas for reducing time animals spend watering at the stream. This time was measured and used to estimate the manure defecated in the stream. Reducing time animals spend at the stream decreases direct defecations in the stream and reduces water quality impacts of SCAEs. A third study analyzed a pasture pump as a possible off-stream watering device. It was analyzed for its ability to provide water to 27 Holstein dairy heifers without limiting water consumption. Daily water consumption from the pasture pump was not significantly different than daily consumption from an open water trough. A fourth study predicted the rainfall required to produce runoff from pastured areas in the Dairy-McKay Hydrological Unit Area within the Tualatin River Basin. These required rainfall amounts and runoff frequency were predicted for summer and winter soil conditions. The BMPs were analyzed for a variety of wet and dry conditions during the summer and winter. Off-stream watering areas were most effective in reducing water quality impacts of SCAEs for dry conditions during the summer and winter, while the covered manure storages were most effective during winter days of continuous rain. Off-stream watering areas reduced the time animals spent at the stream by 75%. Consequently, defecations at the stream were assumed to be reduced 75% and the SCAEs'water quality impacts decreased. Covered manure storages protect manure piles from rain and surface water runoff and prevent bacteria and nutrients from entering the stream or leaching to groundwater regardless of the weather. However, the amount prevented varies with weather conditions. An uncovered manure pile was estimated to cause no water quality impacts during dry weather. During wet weather, the bacteria and nutrients reaching the stream from an uncovered manure pile was estimated to be 60% of the quantity released. The maximum amount of nitrogen leaching to groundwater was estimated to be 10% of the amount applied to the pile since the previous rain. In addition to implementation costs of BMPs, there are changes in annual revenue and costs associated with the management changes. Partial budget analyses were conducted for the four SCAEs to determine their changes in annual monetary returns to management. Both BMPs resulted in negative changes in annual returns to management for all four enterprises.
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