Let's begin with corn. Now, as you drive by, most fields have a level canopy, with tassels visible across the field. As I've walked through fields I've noticed the big differences in plant maturity as seen when observing corn silks. Many ears have completed pollination and kernels are large and yellow. Other plants are just beginning to pollinate.
Silks are still green and ears are small with few well developed kernels.
The only way immature plants will catch up with earlier pollinated corn will be a delayed frost this Fall. If that happens, yields could be excellent this season. Even a normal frost in early October could prevent late pollinated corn from reaching maturity. An early frost will limit yield potential and result in high moisture corn that will have to be dried if marketed as grain. Corn that did not receive a full rate of nitrogen are showing nitrogen deficiency signs.