By Ethan R Thies
We are starting to see signs of warmer weather, which means that planting is around the corner, and cover crops are starting to green up and grow. Overwintering cover crops, such as cereal rye, will require termination, and now is the time to make those plans. For beginning cover croppers, it is recommended to terminate cover crops 10 to 14 days before planting. This is especially important before planting corn, while beans will be more forgiving if planted into green cover crops. When planting soybeans into green cover crops, termination is recommended at or immediately following planting.
Herbicide is the most effective method of terminating all cover crop species. Tillage and roller crimping are options for termination, but are most effective at specific growth stages and often require herbicide follow-up for complete termination. When selecting herbicides for termination, be sure to choose one that matches the cover crop species, growth stage, and environmental conditions at the time of termination. Glyphosate is the most effective herbicide for terminating cereal rye. Glyphosate will terminate cereal rye quicker if the plant is actively growing, with daytime temperatures above 55°F, and night time lows above 40°F.
Create time and space between cover crops and corn:
Cereal rye and many other common cover crops are grass species, and can host pests and diseases that can affect corn plants. Cover crops can create a “green bridge” for pests and disease to carry over from harvest to planting. Terminating 10-14 days before planting reduces this risk, as does creating physical space between corn seedlings and cover crops. Strip till can create space between cover crops and corn rows, and allow for warmer soils and precision nutrient placement. Another option is precision cover crop planting, where gaps are left when cover crops are planted with a drill or planter, which can be planted into in the spring. Seed disks to plant small grains using row crop planters with vacuum or brush meters are available, which allow for planting cover crops in 30" rows, and corn to be planted in between them in the spring.
Source : iastate.edu