Five years ago a lot of the ground was left bare during winter without any cover crops. Recent surveys have indicated that the number of farmers using cover crops in the Corn Belt states is increasing every year.
Many benefits of cover crops have been reported but a major advantage has not been emphasized. While scouting corn fields during the last three years, I have noticed fewer disease lesions of fungal diseases like Northern Corn Leaf Blight (NCLB) and Gray Leaf Spot (GLS) in fields following cover crops than those following corn or even soybeans. The disease lesions were more prevalent even on fields where corn was grown two years ago in a corn-beans rotation.
I scouted some corn fields near Batesville, Indiana in the last three years and saw several fields with NCLB and GLS where cover crops were not used. However, less than 20 miles away where Marshall Alford has been using cover crops for many years, I had hard time finding any disease lesions on hybrids with exactly the same genetics. These fungal diseases can have viable spores on the corn crop residue for years but cover crops residue seems to cover up those spores and prevent them from splashing onto the crop plants and starting the disease cycle.
Cover crops help in increasing the organic matter content and improving the Cation Exchange Capacity of the soil. High organic matter helps in improving the water retention of the soil and increasing yields. Cover crops can also lead to healthier soils with improved tilth and fewer soil insects that can harm the following crops.
There is a lot of Northern Corn Leaf Blight and Gray Leaf Spot this year and I am sure farmers who have used cover crops will have fewer disease lesions and may not even need foliar fungicides. Now is the time to plan for the future and plant cover crops this year that fit your operations.