Use of crop rotations, cover crops and green manures for disease suppression in potato cropping systems

Authors: Larkin, Robert - Bob

Submitted to: Review Article
Publication Type: Review Article
Publication Acceptance Date: 10/18/2021
Publication Date: 11/15/2021
Citation: Larkin, R.P. 2021. Use of crop rotations, cover crops and green manures for disease suppression in potato cropping systems. Review Article. https://doi.org/10.15377/2409-9813.2021.08.12.
DOI: https://doi.org/10.15377/2409-9813.2021.08.12

Interpretive Summary: Crop rotations and inclusion of cover crops and green manures are primary tools in the sustainable management of soilborne diseases in crop production systems. Certain types of rotation crops produce compounds that reduce soilborne diseases through a process called biofumigation, but also have other effects on soil microbiology that are important in disease suppression. Efficacy of rotations for reducing soilborne diseases is dependent on several factors, including crop type, rotation length, rotation sequence, and use of the crop (as full-season rotation, cover crop, or green manure). Years of field research with biofumigant and non-biofumigant rotation crops in potato cropping systems in Maine have documented the efficacy of different rotations for the reduction of multiple soilborne diseases, including Brassica and sudangrass green manures, barley, ryegrass, and buckwheat. In general, crops provided better disease control when grown as a green manure, but the addition of a fall cover crop can improve control provided by most rotation crops. In long-term cropping system trials, rotations incorporating multiple soil health management practices, such as longer rotations, disease-suppressive rotation crops, cover crops and green manures, and/or organic amendments, have resulted in greater yield and less disease problems than standard rotations. This article summarized research demonstrating the use of disease-suppressive crop rotations for the reduction of soilborne diseases. This information is useful for scientists, extension personnel, growers, and consumers, providing information on the use of soil health management practices to reduce soilborne diseases and increase productivity in potato cropping systems.

Technical Abstract: Crop rotations and inclusion of cover crops and green manures are primary tools in the sustainable management of soilborne diseases in crop production systems. Brassicas, sudangrass, and related plant types are disease-suppressive crops well-known for their biofumigation potential, but also have other effects on soil microbiology that are important in disease suppression. Efficacy of rotations for reducing soilborne diseases is dependent on several factors, including crop type, rotation length, rotation sequence, and use of the crop (as full-season rotation, cover crop, or green manure). Years of field research with Brassica and non-Brassica rotation crops in potato cropping systems in Maine have documented the efficacy of Brassica green manures for the reduction of multiple soilborne diseases, but have also indicated that these crops can provide disease control even when not incorporated as green manures, and that other non-biofumigant crops (such as barley, ryegrass, and buckwheat) can be as effective as Brassicas under the right conditions. In general, all crops provided better disease control when used as a green manure vs. as a cover crop, but the addition of a cover crop can improve control provided by most rotation crops. In long-term cropping system trials, rotations incorporating multiple soil health management practices, such as longer rotations, disease-suppressive rotation crops, cover crops and green manures, and/or organic amendments, have resulted in greater yield and microbial activity, and less disease problems than standard rotations. These results indicate that improved cropping systems may enhance productivity, sustainability, and economic viability.