Many Reasons to Desiccate Sunflower Crops

The promising potential of this year’s sunflower crop, both oil and confectionery, is providing the incentive for producers to think about getting a jump on the harvest season–especially those producers with both good crops and large sunflower acreage. Applying desiccants is one way to dry down the crop and speed up this year’s sunflower harvest, but there are many other reasons for producers to make this move, says a crop specialist with the North Dakota State University Extension Service.

"Bird pressure is always a concern for many sunflower producers," says Duane Berglund, extension agronomist at NDSU. "By applying a desiccant, you narrow the window of opportunity for those migrating birds that feed on your sunflower crop."

Another argument favoring desiccation involves head rot and seed shattering. The quicker harvest time comes, the less time large sunflower heads will spend knocking against each other during windy periods, Berglund says. Likewise, accelerating the sunflower harvest season will prevent further deterioration of crops affected by disease and head drop.

Weed interference is another reason. "Using a desiccant to control weeds–especially large weeds like kochia and marshelder–will result in less dockage, less wear and tear on combines and easier drying costs which equates to reduced drying costs," says Berglund.

In North Dakota, Gramoxone (paraquat) and Drexel Defol (sodium chlorate) are labeled as sunflower desiccants. Both herbicides have a seven-day preharvest interval.

Producers need to apply either desiccant only after the backside of the sunflower heads have turned yellow and the bracts are turning brown (R9 growth stage). Sunflower plants having reached physiological maturity need to have a seed moisture content between 33 to 35 percent.

"Some of our sunflower hybrids now have a stay-green stalk characteristic, so go by the heads or seeds," Berglund advises. "Another means of telling whether physiological maturity has occurred is to rub the chaffy material on the front of a sunflower head. If it rubs off easily, the plant is physiologically mature."

Berglund says sunflower producers planning to apply a desiccant this fall should check the herbicide label or consult the NDSU Extension Service’s "2001 North Dakota Weed Control Guide" for further details. The guide is available via the World Wide Web at http://www.ext.nodak.edu/extpubs/plantsci/weeds/w253/w253w.htm 

###