Economic and Soil Health Impact of Grazing Different Cover Crops Mixes...Iowa’s Driftless Area, a region known for ridges, valleys and karst geology. Glawe began using cover crops in his integrated crop and livestock operation 15 years ago. “The first reason... Can We Reduce N Rates and Improve ROI?...Northwest Iowa Plains; Southern Iowa Drift Plain). All farmers used two treatments: Typical - Their typical N fertilizer rate applied to a corn crop. Reduced - An N fertilizer...