Dr. Koehler-Cole was promoted to assistant research professor in the Department of Agronomy and Horticulture Dec. 1, 2018. You can find the article she wrote as a Post-Doctoral Research Associate here.
The middle to end of September is a good time to establish cover crops by broadcasting seeds into corn or soybean before harvest. Broadcast interseeding before harvest allows cover crops to capture more sunshine, growing degree days and rainfall than drilling after harvest.
Biomass production, N uptake, and C:N ratio vary widely across the United States. The N in cover crop biomass will be released within a few weeks after termination, however, decomposition varies with soil moisture, soil temperature and C:N ratios.
Growers that switched to planting green, say it was much easier to plant compared with planting into the decomposing-dying cover. In spite of these observations, planting green is not for everyone and one needs to assess the risk of doing so.
Weed control in organic soybean usually includes frequent pre-plant tillage operations but spring rains often make it difficult to get into the fields for timely tillage. As a result, weed pressure can be high. Cover crops can help suppress weeds, but after corn harvest it is often too late to establish cover crops. Spring-planting cover crops may be an alternative to fall-planting.
Red clover can be an excellent green manure that fixes nitrogen, suppresses weeds, and increases corn yields. As a slow-growing cool-season legume, it is suitable to undersowing into winter small grains in early spring.
Two new guides from the Midwest Cover Crops Council and Nebraska Extension offer key "how to" information for growers interested in integrating cover crops into their traditional corn-soybean rotation.