News & Information, AgBio Communications Unit, Cooperative Extension Service, South Dakota State University
For Release: July 29, 2002

Take Special Care in Handling
Drought-Stressed Corn After Rain

BROOKINGS, S.D. -- Producers ideally should wait four to five days before harvesting drought-stressed corn in fields that have just received rain, a South Dakota State University specialist said.

SDSU Extension Dairy Specialist Alvaro Garcia explained that drought-stressed corn is busy taking up nitrogen immediately after a rain so nitrate levels will be high for several days.

"You need to give the plant time to metabolize the uptake of nitrogen," Garcia said.

Ideally, Garcia said, producers whose corn was damaged by hail or wind during recent thunderstorms should wait four or five days, then harvest the corn for silage. Properly ensiling corn is the safest method of dealing with corn because the fermentation process usually reduces the nitrate concentration. The silage should not be fed until the fermentation process is complete, which takes between three to four weeks.

Garcia cautioned that when moisture content of the ensiled material is higher than normal, fermentation might be inadequate. This might result in nitrate levels similar to those of the fresh-cut forage.

"Testing for nitrates is highly recommended before attempting to feed the silage," Garcia said. "Diluting the silage with low-nitrate forages and/or feeding grain may also help to reduce the risk of nitrate toxicity."

More on the topic can be found in SDSU Extension Extra 4017, "Harvesting and Feeding Drought-Stressed Corn." The publication is available through county Extension offices, or find it online at the SDSU drought Web site, http://sdces.sdstate.edu/drought/.

SDSU Extension Economist Matt Diersen added it's crucial that producers consult their crop insurance agents before making any change in management plans for the crop.

"They will need to communicate with the crop insurance agent and let the agent know they're interested in cutting that corn for silage. They don't want to put their indemnity payment at risk," Diersen said.

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Contact: Alvaro Garcia, (605) 688-5488
Editor: Lance Nixon, (605) 688-4653