Dr. Dan Talks Agronomy
By Dan Davidson
DTN Contributing Agronomist
Cover crops provide multiple benefits to the soil and next year’s crop. The trick is to get them seeded in a timely manner.
I have been seeding fall covers for a decade — mostly cereal rye and mostly too late. I haven’t had good experiences with aerial seeding into standing corn and soybeans in northeast Nebraska, even at the optimal window (leaf drop in beans and all leaves below the ear dead in corn). In my experience, the stands were poor and did not justify the investment.
Broadcasting seed didn’t do the trick for me either. Broadcasting rye and incorporating with vertical tillage tools at a higher seeding rate (70 to 80 pounds per acre) has worked adequately.
Drilling at 50 to 60 pounds per acre is what works best on my farm. Getting the seed in the soil gives me good stands, regardless of whether I plant in September, October, November or December. The tradeoff for planting late is I generally experience less growth the following spring and miss out on many of the benefits of cover cropping. Planting earlier also expands the number of cover crop species that can be blended together and increases the number of benefits cover crops can provide.
Over the years, I’ve come to the realization that cover crops need to be planted as early as possible in September. That’s a busy time of year, so that also puts a priority on getting them planted as fast as possible.
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Aerial seeding is fast and doesn’t extract someone from the labor force. However, moisture is often limited in the fall and that doesn’t help seed to soil contact.
A better approach starts with corn and soybean seed selection for 2016. Successful cover croppers almost always include some earlier-maturing hybrids and varieties into their cropping mix. My family works with neighbors who plant some early corn and soybeans and take them out in September to apply hog manure and plant covers. They also make sure they have a person designated to run the seeder.
I’ve never thought every acre needed a cover every year, but including covers on part of your acres every season makes sense — how many acres depend on what you can manage and get seeded early.
Over the years, I have seeded with 15-foot and 20-foot drills and our neighbor has seeded covers with his 60-foot planter. Planting in 15- and 20-foot widths seems too slow, and planting a cover crop with a high-priced drill or planter with all their mechanical complexities puts unneeded wear on an expensive machine.
I have my eye on the future. I want to plant a quarter (160 acres) with covers in four to six hours with only a single fill (need to carry about 150 bushels of seed or up to a bushel an acre). I do not want planting row units that engage the soil and place seed in a furrow.
One solution might be to adopt a rolling harrow and mount a seed box and air fan on the harrow or mount it on a separate cart ahead of the harrow. These rolling harrows come in 40-foot, 60-foot or wider widths and can cover acres fast at 8 miles per hour.
Several vertical tillage companies have seed boxes and fan options available, but they also tend to process residue and work the top 2 inches of soil. A rolling harrow would only fluff the residue and put the seed in contact with the soil without really disturbing the soil surface. This option could be especially good for no-till farmers.
I’d be interested to know if readers have developed a better system for getting cover crops in the ground. We spend a lot of time worrying about other aspects of cover cropping, but those management tactics should be secondary to establishing a good stand.
For more ideas on cover cropping, go to: http://mccc.msu.edu/…
If you have a question, e-mail Dr. Daniel Davidson at firstname.lastname@example.org
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