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For most effective cover crop seeding, use a drill or air-seeder to place the seeds directly into the soil, about 1½-2 in. deep. Both provide some soil smoothing and cut up some of the surface debris. If the drill or air-seeder is equipped to apply fertilizer, some starter fertilizer could be applied to help cover crop establishment. Another option would be to apply fertilizer for the following cash crop when seeding the cover crop. Compaction will be less than with tillage as most drills and air-seeders are pulled with smaller tractors than those needed for tillage equipment of the same width. In addition, the seed metering, seed distribution, seeding depth and seed-to-soil contact will be more uniform than broadcast seeding, providing a better cover crop stand, especially at lower seeding rates.
Broadcast seeding followed by a light tillage operation may be an option for some producers, especially if some tillage is needed to deal with erosion, scouring or sedimentation. Most producers have access to a dry fertilizer applicator that could be used to distribute the cover crop seed. Depending on fertility needs, the seed could be mixed with dry fertilizer to accomplish two things in one trip while improving seed distribution. The light tillage with a spike-tooth harrow, Aerway, coulter tillage tool or similar fluffing harrow would incorporate the fertilizer and provide some seed-to-soil contact and some smoothing of the soil surface.
If the soil is dry enough, tillage with a disk or field cultivator could be performed to level the soil surface and better incorporate larger seeded cover crops, but compaction and soil smearing is a risk if the soil is wet. Depending on the soil moisture situation and the depth of tillage, the broadcast seeding rates should be increased by 50% compared to drilling.