PRIMGHAR, Iowa — There has been a lot of buzz about the use of cover crops in the last few years. The benefits are:
- They grow and pull nutrients out of the soil and into the growing biomass.
- They protect the soil from erosion during the season when corn or soybeans are not growing.
- They improve water quality coming out of tile lines by reducing nitrate concentration and reducing water flow.
2021 will be a good year to evaluate how they perform in a year with moderate to severe drought (D1 to D2). The dry fall made establishment a little more difficult than normal and stands were a little more spotty, but without the heavy spring rains having done their job at protecting water quality and preventing erosion.
In normal years, the tile line flows are reduced with a rye cover crop by 4 to 5 inches during the winter and spring, reducing the overall nutrient loss. This year the soils in drought without cover crops have had no tile flow as well.
It has been a while since we have started out with lower subsoil moisture and I am concerned that every inch the cover crop uses may be one less inch for the main crop. This will be a good year to see what will happen and if we should refine our recommendations in drought. If you do experience lower overall yields do not abandon cover crops, plan to learn from it and adjust your management to do better next time.
— Kris Kohl, Ag Engineering Specialist
Iowa State University Extension and Outreach
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