Submitted to: Sustainable potato production: global case studies
Publication Type: Book / Chapter
Publication Acceptance Date: November 30, 2011
Publication Date: May 31, 2012
Citation: Larkin, R.P., Honeycutt, C.W., Olanya, O.M., Halloran, J.M., He, Z. 2012. Impacts of crop rotation and irrigation on soilborne diseases and soil microbial communities. In: He, Z., Larkin, R.P., Honeycutt, C.W., editors. Sustainable potato production: global case studies. Amsterdam, The Netherlands: Springer. p. 23-41. Technical Abstract: Crop rotation provides numerous benefits to crop production, and is essential to reduce the build-up of soilborne plant pathogens and diseases that can devastate potato crops grown in multiple consecutive years. Crop rotations can reduce soilborne diseases through a variety of mechanisms, including changes in soil microbial communities, but different types of rotation crops can have very different effects. In recent research in Maine, full-season rotation crops, such as barley, ryegrass, canola, and rapeseed, substantially reduced (15-50% reduction) Rhizoctonia and other soilborne potato diseases. Addition of a fall cover crop of winter rye to existing rotations further reduced Rhizoctonia and common scab diseases by another 5-20%. Use of specific disease-suppressive rotation crops as green manures can provide even greater reductions in soilborne diseases. In an ongoing large-scale study examining the effects of several different cropping system strategies both with and without irrigation, a disease-suppressive approach (utilizing Brassica and sudangrass green manures, fall cover crops, and high crop diversity) reduced soilborne diseases better than any other cropping system (25 to 58% reduction), and both the disease-suppressive and a soil improving (with compost amendments) system substantially increased tuber yield (19 to 42%). Irrigation also increased yield (~28%) in most systems. Combining the disease-suppressive rotation with irrigation increased yield by 53% relative to non-irrigated continuous potato. Combining effective crop rotations with other compatible components of integrated pest management can provide more effective and sustainable disease management and crop productivity.