Corn Grain and Nutrient Uptake Response to Different Swine Manure Application Methods.

Farmers are looking for better management practices to enhance production and reduce negative environmental impact from nitrogen (N) fertilizer application since N is one of the most important and costly nutrient inputs for crop production. In this field experiment pre-plant swine effluent application methods were evaluated for no-till corn grain production.  The treatments included a control, an inorganic fertilizer treatment receiving 179 kg N ha^-1 as urea ammonium nitrate (UAN), and three effluent application methods that received a target rate of 200 kg N ha^-1.  The effluent application methods included: surface broadcast, direct injection, and application in combination with soil aeration “Aeration”. Corn grain yield was not significantly different among the three methods of swine effluent applications. Also no significant differences occurred among the UAN application methods in 2007 and 2008. The timing of the UAN application (preplant or sidedress) also did not influence corn grain yield for both years. Swine effluent application by surface broadcast resulted in lowest grain N, P, and K uptake. Swine effluent application by injection method produced the greatest corn grain yield (11.88 Mg ha^-1) and significantly greater biomass (18,892 kg ha^-1) than other treatments in 2007 a relatively dry year. The limited response to UAN fertilizer and swine effluent application may have been affected by the high level of residual N in soil from previous years.  However, results demonstrated that the swine effluent and UAN application methods may not be very important agronomically for corn production in this region, but injecting effluent and N fertilizer may preventing nutrient losses and negative environmental impact when evaluating the impact of N fertilization and liquid manure management.