Jake, as I understand it, the maximum ear size is determined at about 30 days after emergence. This is why good, quick, uniform early growth is very important. Even though delayed plants may appear to catch up later visually from the road, the max ear size, and max yield, has been determined. Good uniform seed depth and uniform seed to soil contact along with good P availability early will usually pay off in yield providing no later factors limit that potential ear's development. Yield can go down from that 30 day point but it can not go up, as I understand several expert opinions.

Jim at Dawn