Delay in wheat harvest cuts time to plant double-crop soybeans

WEST LAFAYETTE, Ind. - Frequent rain is delaying some Indiana farmers who need to harvest winter wheat and then plant a crop of soybeans right after that while there is still time in the summer growing season. 

While nearly all of Indiana's soybean crop already is in the ground, some farmers who "double crop" have not yet planted their beans. They are facing crucial dates this month for planting them, generally sooner in the central parts of the state and later in the south. Double-cropping is not recommended in the north because of its shorter season.

"This year's wheat harvest is a polar opposite compared with 2012, when nearly every acre was already harvested by now," said Purdue Extension soybean specialist Shaun Casteel. "Delayed wheat harvest directly affects our double-crop soybeans."

Only 32 percent of the winter wheat acreage in Indiana had been harvested as of the week ending July 7, compared with 98 percent last year and the five-year average of 69 percent, according to the U.S. Department of Agriculture's National Agricultural Statistics Service. Still, 76 percent of the crop was rated good to excellent.

Wheat development was delayed this season when cooler temperatures extended into the spring, Casteel said. The cool and wet spring, however, benefited many wheat fields with extended period of grain fill.

"Unfortunately, the rain cycle continued for many of our areas as the wheat matured in June and now into July," he said.

Farmers who double-crop would need to plant their soybeans so the plants can reach maturity before the first freeze in autumn. Because double-crop soybeans need about 90 days to reach the first harvestable stage of development, Casteel recommended that farmers target July 15-25 as estimated planting deadlines depending on their location in the state.

Farmers in southern Indiana usually have more time because that part of the state typically does not have a first freeze until late October. But a first freeze by mid-October is possible anywhere in Indiana depending on weather conditions at the time, Casteel noted.   

In addition, the timeline of 90 days to maturity is more accurate from the time plants emerge rather than the planting date, Casteel said. Although double-crop soybeans should emerge in 5-7 days, they could take several weeks should soil be dry after planting.

He said farmers would need to assess their field conditions and adjust their planting schedule accordingly.

A detailed report that Casteel wrote on planting decisions for double-crop soybeans is available at http://www.agry.purdue.edu/ext/soybean/News/2013/DC_Soy_Plant_Decisions_20130709.pdf.

Writer: Keith Robinson, 765-494-2722, robins89@purdue.edu

Source: Shaun Casteel, 765-494-0895, scasteel@purdue.edu

Related website: 
Purdue Department of Agronomy

Ag Communications: (765) 494-2722;
Keith Robinson, robins89@purdue.edu
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