Soybeans will be able to take up some of the nitrogen released by the breakdown of a cover crop, but then might fix less from the atmosphere, depending on when the nitrogen is released. Thus, there not likely to be a significant economic gain from having a cover crop tie up nitrogen and release it during soybean growth. However, it will keep some nitrogen in the field, thereby reducing the amount that reaches surface water.
"While we know there is some nitrogen left in dry soils now, the amount available to next year's crop will depend on the weather between now and next spring," Nafziger says.
Other factors associated with a drought-damaged corn crop may actually improve field conditions for the next corn crop. Corn that stops growing in mid-season does not produce much lignin, so its residue is softer, it breaks down faster, and planting into it is easier. There is also less residue to contend with.
"This is not a suggestion to plant more corn and fewer soybean acres next year following this year's corn crop," Nafziger concludes. "Corn following corn is showing more stress effects again this year, in some areas for a third year in a row. Even though a field with a short corn crop this year may be more 'corn-friendly' than normal next year, it is unlikely that corn following a corn crop - even a low-yielding one - will yield more than corn following soybean."