To be honest I really haven't figured it out with all the variables we are faced with from year to year. Just the difference in getting planted a few days earlier, irrigation or rainfall timing, how hot the summer is and not getting dicamba drifted on your crop. Any more I don't seem to have the same variety or technology two years in a row. Also pretty much been going back on the same row year after year. I actually planted notill directly into the old row last year on most of our crop but had a variety and technology that I had never had before. Yield was off some. It also had dicamba drift. Last fall I did run a paratill across everything and plan on having about half of the farm in corn.