Submitted to: Sustainable Land Management International Workshop Proceedings
Publication Type: Proceedings
Publication Acceptance Date: January 15, 1995
Publication Date: N/A
Improved farming practices have significantly increased crop productivity, but they have also been responsible for groundwater contamination in some areas. Farming practices are therefore being evaluated in several midwestern USA states to determine their effect on groundwater quality. In one Iowa study, field experiments were conducted for a period of eight years to investigate the effect of split N applications. In a second study, field experiments were initiated to evaluate effects on five different management practices (late spring N test with differential rates, reduced application at rates of N at 112 and 135 kg/ha, use of swine manure as an N source, narrow strip cropping to increase spatial diversity, and an alfalfa crop) on shallow groundwater quality. Preliminary results indicate that split or lower N applications have the potential to reduce the leaching of nitrate N to shallow groundwater. Growing alfalfa or using strip cropping resulted in the lowest nitrate concentrations in the drainage water.