Severe storms in some areas of the state have resulted in crop damage that will markedly restrict potential yield of corn and soybeans. Questions have been raised about the potential for nitrogen carryover from fields that have reduced corn yield. The rough guideline for calculating this carryover is to subtract the yield of corn from the current year's nitrogen application, and divide the answer by 2, as in the following equation.
(N applied for 2003 crop year - corn yield in bushels per acre)/2
If yield loss was from hail damage, this will likely provide a good estimate of carryover, particularly if you will be growing wheat next year. If corn will be grown in the field, the carryover will be realistic, assuming that excessive rain is not received next spring. If excessive rain is received, then denitrification or leaching will reduce this carryover figure.--Robert G. Hoeft