One example of evolving cover crop management is growing corn in cereal rye that was terminated after corn planting (“planting green”). Picture taken June 17, 2020 at the Eastern Nebraska Research and Extension Center near Mead, Nebraska. Credit: Katja Koehler-Cole Winter cover crops benefit soil health and can suppress weeds in subsequent row crops but may also lead to lower yields. Some farmers and agronomists speculate that allelopathic chemicals released by cover crops may be the cause for some of the observed yield reductions, but cause-and-effect relationships are rarely established. We know that allelopathic cover crops inhibit weed seed germination and early growth, but do they also impact row crops?
In an article recently published in Agricultural & Environmental Letters , a publication of the American Society of Agronomy, Crop Science Society of America and Soil Science Society of America, researchers reviewed literature documenting effects of allelopathic winter cover crops on four row crops. Studies that used known allelochemicals in the lab or measured allelochemicals in the field were included.
Only seven studies met the criteria for inclusion and six of them were lab studies. Corn and wheat germination and root length were sometimes impacted by allelopathic chemicals from cereal rye […]
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