Production of Bioenergy Crops On Swine Effluent Spray Fields.

North Carolina has a prominent swine industry, which produces significant quantities of iquid waste effluent from storage lagoons in a regionally-concentrated area of the state.  By law, effluent application rate is based on manure N content and crop N removal. As such, swine waste is typically applied on fields of coastal bermudagrass hay, which when harvested removes substantial nutrients, but produces little economic value to the swine industry. If high-yield bioenergy crops can be substituted for the coastal bermudagrass, a mutually beneficial relationship could be formed between the biofuel and swine industries. The objectives of our experiment are to: i) determine biomass yield and nutrient removal of potential biofuel crops, ii) determine harvest timing impact on yield and nutrient removal, iii) establish harvest management schemes associated with the bioenergy production within spray fields, including model development to determine costs, efficiencies, and economics associated with spray field-generated biomass. This project includes establishment of 5 crop treatments (giant miscanthus, switchgrass, sweet sorghum, forage sorghum, and coastal bermudagrass (current practice)) replicated 3 times each on 3 spray field production sites. Each block of perennial crops will be split into 5 harvest times to measure yield and nutrient removal. The information will help to quantify development and establish conversion potential of perennial grasses and sorghums grown in spray fields. Ultimately, the potential commercial biofuel refining capacity from North Carolina spray field produced biomass will be estimated.