Tests were harvested with specialized plot combines equipped with automatic weighing and sampling devices. Severely lodged stalks or dropped ears that could not be picked up by normal harvest procedures were not included in yield. Because harvest often is delayed until latest maturing entries are ripe, early and mid- season hybrids could lose ears simply because they must wait well past their optimum harvest date. In most years at most locations, dropped ears constitute a very small portion of lodging and do not significantly affect yields. Entries are listed in order of increasing maturity based on days to silking and harvest moisture in the current year to facilitate comparison of hybrids of like maturity.
Maturity can be critical when considering a corn hybrid for a specific cropping system.
The formula used to generate the monthly totals in individual test discussions follows. Take the maximum temperature plus the minimum temperature for each day, divide by 2, and then subtract a base temperature of 50 each day. Any temperature below 50 F was considered to be 50, and any temperature over 86 F was called 86. Growth unit accumulations for the current year are compared with the long-term average or 'normal' for each test. S mall differences in yield or other characteristics should not be overemphasized.