CONSIDER AERIAL SEEDING WINTER COVER CROPS AHEAD OF MANURE APPLICATIONS Natalie Rector, July 2003

EAST LANSING, Mich.—Farmers who invest some time and thought to plant a winter cover crop now can reap the rewards well into the next growing season. Aerial seeding a cover into a standing silage, corn or soybean crop can be a good option for improving fall and winter manure management, protecting surface waters and improving overall soil tilth. A rye or wheat cover crop will provide surface residue to help absorb liquid manure applied through the fall and winter, decrease the possibility for runoff and provide a growing crop to take up nitrogen and recycle nutrients for the following season’s crop. The cover can also help decrease winter surface compaction, improving infiltration next spring. Both the roots and the top growth of cereal grain crops will benefit fields planned for manure applications. “Corn silage and soybean fields provide very little residue and should be prime targets for seeding a cover crop, especially if winter manure applications are planned on these fields,” says Natalie Rector, Michigan State University (MSU) Extension nutrient management specialist. Aerial seeding doesn’t require a significant investment in fuel, machinery or time, is simple to schedule and practical for many farmers. In addition to reducing potential erosion from fall tillage to establish a cover crop, aerial seeding does not create soil compaction. It should take place several weeks prior to silage harvest, during corn’s early dent stage or prior to soybean leaf drop. Bin-run wheat can be a good seeding choice. It is readily available and can be applied at a cost-effective, one and a half or two-bushel per acre rate. Farmers should not use treated seed, as it can show up in the fall harvested crop. Oats are another option, though they need to be planted early enough to provide sufficient top growth. Oats will winterkill yet still provide significant surface residue. Many growers have used a cereal rye cover. It grows longer in the fall and begins growing earlier in the spring than wheat, but cereal rye can be very vigorous in the spring and needs to be controlled with herbicides or tillage before it gets tall and dries out the soil. When managed well, rye is an excellent scavenger for nutrients and sponge for liquid manures. When considering strategies for winter manure applications, think about the potential for manure to reach surface waters and select fields with the lowest risk. Fields with no adjacent surface waters, minimal slopes and no erosive areas are the first choice for winter applications. “Cover crops will reduce the risk on moderately risky fields but cannot work miracles on high-risk fields,” Rector says. “High-risk fields should not receive manure when soils are frozen and or snow covered.” Cover crops offer many benefits, including capturing nutrients after harvest, decreasing soil erosion and improving soil structure, which can result in, yield increases for the following crop. MSU cover crop research has shown that soil quality improves the longer live roots are in the soil, whether you plan to spread manure or not. For more information about cover crops, contact your county MSU Extension office.

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