Organic Broadcaster

Researcher explains factors to consider when rolling-crimping rye
By Tony Ends

University of Wisconsin Organic Cropping Systems Specialist Erin Silva has a long list of important factors to consider when rolling-crimping rye, derived from more than 10 years of research. Timing is key, particularly with the wide swings in weather we’ve experienced this year.

Silva will share tips for rolling and crimping rye as a mulch for drilling cash grains at the university’s Arlington Research Station organic field day, Thursday, Aug. 31. She’ll also talk about the method at Mark Doudlah’s farm field day Aug. 3 near Evansville in Rock County, Wis. Here are some of the tips she’ll be sharing.

Organic Cropping Systems Specialist Erin Silva shows off the carpet of rolled-and-crimped rye flanking virtually weed-free rows of Honey Bear squash at the University of Wisconsin West Madison Research Station plots.

In addition to an earlier planting date, a heavier seeding rate of rye (3 bushels per acre) also helps achieve adequate biomass to suppress weeds. The dry biomass of the cover crop should be in the range of 8,000 to 10,000 pounds per acre, providing a physical barrier during early crop growth to prevent sunlight from reaching the soil surface and weed seeds from germinating. To achieve this, cereal grain cover crop planting should occur by Sept. 15, but at least by Sept. 30.

The cover crop must be terminated at a very specific stage of cereal grain growth – at anthesis (flowering). The growth stage of anthesis is easily observed in the field when pollen is visible on the cereal grain heads. Crimping before or after this growth stage risks cover crop re-growth after termination.

Terminate the cover crop (either by rolling-crimping or sickle-bar mowing) perpendicular to the direction of cover crop seeding. This helps achieve the best ground cover by the mulch, preventing sunlight from reaching the soil surface.

It pays to take the time to adjust and/or modify your equipment. No-till drills and conservation planters can both work in this system. The no-till drill set on 7.5 inch rows allows for quicker canopy cover. The wider 30-inch row spacing allows for a mid-season cultivation if weeds break through the mulch and become an issue. There also is some evidence that using a conservation planter may allow for more precise seed placement, creating a better stand of soybean.

Seeding rates of soybean should be higher than in the typical organic system (approximately 225,000 seeds per acre or higher). Recent recommendations from Cornell University state 300,000 seeds per acre.

To achieve an earlier planting date for soybeans, planting soybean into the standing rye cover crop prior to termination is also an option. This earlier soybean planting date can be particularly advantageous in regions with shorter growing seasons. Soybeans can be planted or drilled into the standing rye in mid-May, approximately 3 weeks prior to rye anthesis. After the soybean reaches the V1-V2 stage, and the rye reaches anthesis, the rye can be terminated either by rolling-crimping or mowing, crimping over the emerged soybeans.

A word of caution: there is less replicated research on this technique in Wisconsin, although 2 years of data at the Arlington test plots, as well as farmer experience, demonstrates this option has potential advantages.

Timing of rye termination depends on both soybean stage, which at V1/V2 allows for resilience against tractor and roller-crimper traffic, and rye stage, which must still be at anthesis to ensure effective termination. Terminating cereal rye may be less uniform using this technique. Use caution if this is integrated into a rotation using cereal grains to be sold off-farm, where contamination with rye seed may be of greater concern.

Strategic tillage and diversified rotations, particularly by including an alfalfa phase, can help reduce risk of building up perennial weed populations.

Summary of No-till Organic Tips

  1. Start small. Organic no-till is a significant change for many organic farmers and non-organic no-tillers alike. Try it out on a small scale to minimize risk.

  2. Choose wisely. Choose fields where you can get in early to plant a cover crop in the fall and with appropriate weed pressure – avoid perennial weeds.

  3. Don’t skimp. Get cover crops in the ground on time (cereal rye: mid-September to early October) and at recommended seeding rates (3 bushels per acre for cereal grains). Successful weed suppression requires a dense mat of cover crop residues.

  4. Alter planting strategies for cash crop. Bump up the seeding rate of soybeans (225,000 seeds per acre). Be sure to spend time setting an appropriate depth on the planter. Add extra weight to equipment if needed.
    Silva is willing to answer farmers’ questions. Email emsilva@wisc.edu, or call 608-890-1503.

Tony Ends is a certified organic farmer and writer who lives near Madison, Wis.

From the July | August 2017 Issue

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