Low-lying or poorly drained areas in many corn fields around the state have been ponded or saturated for many days, if not weeks in some cases, and the effects on the corn in those areas have become vividly noticeable. Where corn was literally submerged for three to four days, nothing but bare soil reappeared when the water finally drained away. Around the fringes of the ponded areas, or in areas ponded less than three days, surviving corn plants are stunted and discolored with conspicuous "firing" of lower leaves.
Even more depressing are those less poorly drained areas where no water actually stood, yet the soils were nonetheless saturated for days if not weeks due to frequent rainfall events with little time for soil drainage or dry out in between. Lower leaves of corn plants in these areas also began "firing" last week, often becoming bright orange or yellow. Subsequent plant growth has been noticeably less than in those areas of better drainage. Fields that were uniform early have turned "ugly" where significant drainage or compaction differences exist.
The rapid deterioration of corn plants during the past seven days suggests that loss of soil nitrogen is not the only culprit. Indeed, what has likely happened is some combination of outright nitrogen loss due to saturated soils (see accompanying article by Sylvie Brouder) and loss of root function or outright root death due to the lengthy duration of the oxygen-deficient conditions in the soil.
Consequently, as soils dry out (assuming the monsoon season is over!), some of these areas of fields may recover fairly dramatically as root growth resumes. Row cultivation can help root recovery by improving soil aeration, assuming the corn is not too tall to get over. "Knifing-in" anhydrous ammonia or UAN in a sidedress operation (see accompanying article by Sylvie Brouder) will offer the additional benefits of some soil cultivation also.
The bottom line is that while these areas of stunted corn will never recover to their full potential, they may recover more dramatically than you think as these soils continue to dry.
Don't forget, this and other timely information about corn can be viewed at the Chat 'n Chew Café on the World Wide Web at http://www.agry.purdue.edu/ext/corn/chatchew.htm. For other information about corn, take a look at the Corn Growers' Guidebook on the World Wide Web at http://www.agry.purdue.edu/ext/corn/