BROOKINGS, S.D. — Winter rye is a cover crop that is consistently performing in South Dakota fields hosting corn-soybean rotations.
“Growers with strict corn-soybean rotations are limited in their options for cover crop species, since there is not enough growing degree days left for cover crops to grow after primary grain crop has been harvested,” said David Karki, SDSU Extension Agronomy Field Specialist.
Karki explained that when cover crops are integrated into small grain crop rotations there are many more options because the earlier harvest allows for an adequate seasonal window for a variety of cover crops to establish.
Benefits of winter rye
Winter rye is known for its winter hardiness, allowing late fall planting and rapid growth the following spring.
“Furthermore, adding a cool season small grain component into a corn-soybean rotation not only adds diversity to the cropping system but also helps break pest pressures in the field,” Karki said.
Winter rye is also known for its inherent ability to suppress weeds because of its allelopathic characteristics. “Basically, winter rye produces biochemical compounds that inhibits germination, growth and reproduction of other plants,” Karki explained.
Over the long term, incorporating cover crops also improves soil health and provides supplemental forage.
Fitting winter rye into the rotation
Considering growing habits of all three crops is essential when determining the order of winter rye within the cropping sequence.
“Planting rye after corn and ahead of soybeans, seems to be a better fit than to grow rye before corn,” Karki said.
He explained that by planting the cover crop before soybeans, the corn residue provides protection to rye seedlings. “In addition, soybeans can tolerate later planting in the spring better than corn which allows rye to accumulate more spring growth.”
Rye biomass in the spring can be terminated as cover or utilized as forage depending on the grower’s need.
Research conducted in various Southeast South Dakota in recent years has shown no negative impact on soybean yields when grown on rye cover crop residue.
On the other hand, Karki said corn yield tends to suffer following a rye cover crop.
“This could be due to allelopathic effects of growing rye cover crop or the micro climate created by the rye residue on the soil surface at the time of corn seeding,” he said.
It is suggested to terminate rye two to three weeks prior to corn planting to avoid any negative impact on corn plant health and grain yield.
- Seeding rate is about 40 pounds-per-acre as a cover crop, however, it can be increased to 75 pounds-per-acre if weed suppression is the primary objective.
- Aerial seeding can be done during mid to late corn seed-filling stage (early September). Research results show that aerial seeded (or broadcast method) rye produces about 80 percent of the spring biomass of drill-seeded following grain harvest.
- Producers of small grains, such as wheat, oat, barley, etc. are suggested not to use winter rye as a cover crop because it may act as significant contaminant or weed in small grain crops.
- As winter rye accumulate rapid growth in the spring, it is a good practice to look out for short or medium term spring weather so that rye can be terminated early when conditions are drier than usual.
To learn more about implementing cover crops into your rotation, contact Karki at email@example.com.
— SDSU Extension
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