Planting into cover crops, feedback needed


The photos above show the cover crop that was seeded at a rate of 60 lbs/ac PLS on October 11, 2016. The cover crop was chemically terminated May 4 and the corn was planted May 6. The photo (top) of the growing corn was taken June 3. Submitted photos.

Submitted by Sara Berges, Allamakee Soil and Water Conservation District

Jacob Groth, the NRCS sub-area Resource Conservationist out of New Hampton has been trying cover crops for several years on his family’s Winneshiek County Farm. This past year, he set up an experiment to see how much of an impact rye cover crop seeding date and seeding rate had on spring growth.  He seeded some strips on October 11 at a rate of either 30 lbs/acre pure live seed (PLS) or 60 lbs/acre PLS. He seeded other strips on October 31 at the same rates. The earlier seeded cover crop naturally outperformed the later seeded cover crop. The seeding rate on October 11 had a much lower impact on biomass production than the later seeded cover crop. Keep in mind, however, that many cost-share sources have an October 21 seeding date for winter-hardy cover crops and also have a 55 lb/ac PLS seeding rate for cereal rye. If you aren’t receiving cost-share and have the opportunity to get the cover crop seeded early, you may be able to save some money by reducing the seeding rate, assuming we have adequate fall moisture and temperatures and you get good seed to soil contact.

This spring, the cover crop was chemically terminated on May 4 when it was at least 2 feet tall. Corn was planted on May 6. They spot sprayed around terraces and field edges the weekend of June 3. They did crop scouting to determine weed pressure and don’t plan to do a second pass of herbicide on approximately 75% of their corn acres due to the cover crop reducing weed pressure.  When asked about planting into a 2 foot cover crop, Jake said that the ground was “…moist but firm. The soil was loaded with worms and the seed slots closed really well.”  The only issues he noted were that it was difficult to see the planter markers in the residue and there were a few (uncommon) spots where the corn row goes right down the rye row and the stand isn’t 100%.

The Groths first started doing no-till row crops in 2010 and all fields have been no-till since 2014. They started planting cover crops in 2012 by aerial seeding but have switched to using their Kinze planter with 15” interplants.  They applied 50 pounds pre-plant urea for corn into beans and 70 pounds pre-plant urea for corn on corn. They will side-dress 80 pounds nitrogen for corn on beans and 110 pounds N for corn on corn with urea and plan to seed cover crops on some acres with their urea at V5-V6 corn stage. This is the third year they have interseeded some cover crop and this year’s mix will include a mix of annual ryegrass, radishes, and turnips.  In the past they have also tried mixes with crimson clover, red clover, and hairy vetch, but none of the legumes have done well when interseeded.  They plan to plant cereal rye on their soybean acres after harvest.  They also plan to plant some hairy vetch with their cereal rye, let it grow longer in the spring, and plant shorter day corn in hopes that the vetch will provide more of the nitrogen for the corn. If there are other producers in the area who are trying cover crops in innovative ways (seeding method, mix, seeding timing, etc.), let the Waukon NRCS/SWCD office know so that we can talk to you and help other producers find out what works or doesn’t work for cover crops in our area.

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