Wheat and barley are cool-season crops that require relatively cool temperatures to achieve their highest yield potential. Because of the wet spring, many producers will be getting into their fields later than normal, which could cause reduced yields.

“The biggest concern with late planting small-grain crops, such as wheat and barley, is that they will develop when temperatures are warmer than optimum, so yields will be reduced,” says Joel Ransom, North Dakota State University Extension Service agronomist.

The optimum planting dates range from the second week in April in southern counties to the first week May in counties bordering Canada. However, for some regions of the state, the optimum planting dates may have past. There is a three- to four-week window beyond this optimum where reasonable yields can be achieved.

“Expect a yield loss of 1.5 percent per day beyond the optimum for wheat and 1.7 percent per day for barley,” Ransom says. “However, if the weather stays cool, there may be little or no yield reduction if planting takes place as soon as fields can be planted.”

When planting is delayed beyond the optimum date, it may be beneficial to increase the seeding rate by 1 percent per day of delay up to a maximum of about 1.7 million seeds. This increase will compensate partially for the decrease in grain yields associated with the reduced tillering that occurs when plants develop in warmer rather than optimum temperatures.

“Though differences in the maturity of commonly grown small-grain varieties are not great, earlier-maturing varieties are recommended for later planting,” Ransom says. “For spring wheat, most varieties from South Dakota (Briggs, Select, Forefront and Brick), along with Glenn, Kelby and RB07, are among the earliest maturing.”

NDSU Agriculture Communication – April 25, 2013