Certified organic crop production is the fastest growing segment of agriculture in the United States today, increasing at a rate of about 20 percent annually.  The transition from conventional farming practices to organic is complicated, yet, growers interested in organic farming have extremely limited resources in the scientific literature to turn to for guidance in making the transition.  This study focuses on the agronomic (weed management, yield, soil fertility, quality and sustainability) dynamics during the critical three-year transition phase from conventional farming to certified organic.  The research will result in the development of best management practices for growers to follow in transitioning to a certified organic system in corn, soybean, wheat and alfalfa.  Two different organic cropping systems are compared here:  A four-year organic rotation of corn, soybean, wheat and alfalfa which incorporates dairy manure and cover crops vs. one year of conventional corn followed by three years of continuous organic alfalfa without manure or cover crops.  Preliminary results indicate yields exceeding local and regional averages with no significant difference in yield between the two treatments during the initial (corn) year.  Economic analyses will determine the most cost effective method of transitional management.