MANHATTAN, Kan. -- Producers should consider double-cropping with wheat this fall in areas where moisture conditions are good, said Kansas State University agronomist Jim Shroyer.

Three common questions that producers have about double-cropping wheat are: "How much nitrogen should be applied," "What seeding rate should be used," and "What is the best variety of wheat to use?" said Shroyer, who is the agronomy state leader with K-State Research and

"There is only limited time to take a soil profile nitrogen test between the time of sorghum, soybean, or sunflower harvest and wheat planting," said Dale Leikam, K-State nutrient management specialist. "So the amount of nitrogen that should be applied when double-
cropping wheat following harvest is usually based on a producer's yield goals alone."

Nitrogen from soybean residue won't be available in fields until the next spring, so producers should use the normal rate of nitrogen that they would use for full-season wheat when following soybeans with wheat, he said.

An extra 30 pounds of nitrogen per acre should be added to the normal nitrogen rate applied for wheat following grain sorghum or sunflowers, but producers should have enough time to take a soil profile nitrogen test following corn.

Soil profile nitrogen tests provide an accurate fertilizer nitrogen recommendation and can be important when following drought-affected crops where there is a potential for nitrogen carryover, Leikam said.

"In a no-till situation, an additional 20 pounds of nitrogen above the normal rate is recommended," Shroyer said. "In any cropping system, it's a good idea to use some starter fertilizer (such as 18-46-0, 11-52-0, or 10-34-0) if equipment is available. The remainder of the nitrogen needed can be applied in late fall or winter."

When doublecropping wheat after soybeans, corn, or sunflowers, producers should plant seed at a rate of 90 pounds per acre, and 120 pounds per acre after grain sorghum, he said.

"Producers should make sure the sorghum crop has died before planting wheat, since living sorghum will continue to take up water and nutrients and produce allelopathic toxins," Shroyer added. "If a freeze hasn't killed the sorghum, it may need to be sprayed with glyphosate prior to planting wheat."

No research has been done to show what variety of wheat is best for double-cropping, Shroyer said. However, producers should not double-crop varieties such as Overley or 2137 after corn since both are highly susceptible to head scab. The fungus Fusarium, which causes stalk rot in corn, also causes head scab in wheat. The problem occurs when it rains for an extended period of time when wheat is heading or flowering.

SOURCE: K-State Research and Extension news release.