Don’t overlook cover crops as an option to help with nitrogen management. Many cover crops are excellent nitrogen scavengers. These cover crops growing through winter can take up and hold on to leftover nitrogen or nitrogen produced from soybeans.
These cover crops can work the same as late-season applications of nitrogen. As the cover crops begin to break down in mid- to late summer, nitrogen scavenged earlier becomes available to the corn.
The trick is to make sure you allot for nitrogen that will be tied up early in the season until the cover crop residue breaks down and releases it. Presenting to the Top Farmer Workshop at Purdue University, Shalamar Armstrong, Purdue Extension agronomist, reported a yield advantage for applying nitrogen as starter following cover crops, especially cereal rye.
Cover crops can also be beneficial when using manure for nitrogen and other nutrients. Manure application timing is generally less forgiving than commercial fertilizer. You may have to apply manure in fall or early spring to relieve storage facilities.
If you apply manure into a green living cover crop, nutrients can be better held in place. Cover crops prevent nutrients from running off, leaching through the soil or volatilizing into the atmosphere. Those cover crops provide a bank to hold on to those nutrients until they begin to break down in the early summer, providing nutrients to crops.
As profit margins tighten, becoming more efficient in the use of nitrogen is crucial. Explore ways to make your cropping system better. Consider spoon-feeding with multiple applications, making late applications right before tassel, using cover crops and conducting on-farm research trials to determine what works best on your farm.
Harrison is a district soil conservationist with the Natural Resources Conservation Service. Tom J. Bechman contributed to this story.