Tuesday, 8 November 2005
3

Relay-Cropping to Improve N Management.

James Schepers, Dennis Francis, John Shanahan, and Scott Tubbs. USDA-ARS, Lincoln NE, 113 Keim Hall, Univ. of Nebraska, Lincoln, NE 68583-0915

Winter wheat was seeded as a cover crop shortly after seed corn harvest in an attempt to remove residual N from soil so that nitrate would be unavailable for leaching. Because the growing season in the Corn Belt is not long enough to accommodate harvesting full crops of wheat and soybean in the same year using double-crop techniques, soybean was inter-seeding into wheat at heading time. The combination of two scavenger crops (wheat followed by soybean) removed nearly all of the residual N from soil and even required additional N because of the high yields of wheat (>5 Mg/ha) and variable levels of residual N remaining after seed corn. Profitability of the seed corn – wheat – soybean relay cropping system depends on the length of the growing season, ability to obtain timely seeding of the soybean crop into standing wheat, and prices for inputs and grain. Experience over the past three years indicates that producers should be able to obtain at least $100/ha extra profit by using the cover crop to harvest unused solar energy.

Handout (.pdf format, 943.0 kb)

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