Submitted to: Meeting Abstract
Publication Type: Proceedings
Publication Acceptance Date: July 22, 1998
Publication Date: N/A
Technical Abstract: Field studies were conducted to evaluate the effects of swine manure application on N loss with subsurface drainage water. Reduced N fertilizer application rates of 112 and 135 kg/ha were used for corn-soybean and continuous corn production, respectively. Similar N application rates of 112 and 135 kg/ha from swine manure were used for both cropping systems. Experiments were conducted in north central Iowa using 0.4 ha plots. Results of this study show that yearly average nitrate-N concentrations in subsurface drainage water were significantly higher from manured plots than from the fertilized plots. However, yearly nitrate-N loading losses (kg/ha) were the same for manured and non-manured soils. The corn-soybean rotation system resulted in significantly lower nitrate-N concentrations in the subsurface drain water in comparison with the continuous corn production system. This indicates that manure application rates can be successfully managed for corn-soybean production systems with minimal impact to subsurface drainage water quality provided the correct manure rates are applied.