Forage subsurface drip irrigation using treated swine wastewater.

摘要

The rapid expansion of animal production in the eastern USA in the 1990s resulted in large quantities of concentrated animal waste that must be utilized or disposed of in an efficient and environmentally friendly manner. To address these environmental concerns for waste water utilization, we installed a subsurface drip irrigation system to apply treated swine waste water effluent for bermuda grass hay production. The overall study objective was to determine the feasibility of using subsurface drip irrigation (SDI) for treated waste water effluent applications. The specific objectives for the SDI system were to compare bermuda grass hay production using: (1) commercial and waste water effluent for nutrients; (2) two SDI lateral spacings (0.6 and 1.2 m) installed at 0.3 m below the surface; and (3) two irrigation application rates based on calculated evapotranspiration (ETc) requirements (75 or 100%). The two-year study measured hay yields, hay biomass, soil nutrients, and soil water nutrients. The SDI system was successfully operated for two years applying effluent and commercial fertilizer to supply the nutrient requirements of the bermuda grass hay. Bermuda grass hay production for 2004 and 2005 ranged from 5.65 to 14 tonnes ha-1. Results from the SDI system indicated no significant differences between the SDI lateral spacings or irrigation application rates. Treatments using wastewater effluent had significantly higher hay yields and significantly higher nutrient biomass removal rates than the commercial fertilizer treatments. Nitrate-N observed in soil water lysimeters increased with depth, indicating the potential for leaching without proper management. Soil nitrogen and carbon were not significantly different for any of the treatments but did vary slightly over the life of the project.