Comparing N Management and Productivity of Conventional and Alternative Cropping Systems in Central Iowa.

A field experiment was initiated near Boone, IA to study the effect of cropping system on N management and crop productivity. We are studying the regionally conventional soybean [Glycine max (L.) Merr.]/corn (Zea mays L.) system, as well as two ‘alternative’ systems: a wheat (Triticum aestivium L.) + red clover (Trifolium pratense L.)/corn rotation, and a canola (Brassica napus) + red clover/corn rotation. At-planting and 30-d post-emergence soil NO₃-N levels did not differ among the systems. End-of-season corn stalk NO₃-N concentrations and grain yields will be determined to further evaluate the systems. The results may show the potential value of alternative cropping systems in properly managing N while maintaining overall productivity.