The Potato Systems Planner: Cropping System Impacts on Soilborne Diseases and Soil Microorganisms.
Robert Larkin, C. Wayne Honeycutt, John Halloran, and Tim Griffin. USDA-ARS, New England Plant, Soil, & Water Laboratory, Orono, ME 04469-5753
Different 2-yr and 3-yr crop rotations, consisting of barley/clover, canola, green bean, millet, soybean, and sweet corn in various combinations followed by potato, were evaluated for their effects on the development of soilborne potato diseases and soil microbial communities over several cropping seasons in Maine. All rotations significantly affected soil microorganism populations and activity, resulting in unique microbial profiles. Rotations with canola preceding potato were most effective at reducing the soilborne diseases stem canker and black scurf, caused by Rhizoctonia solani, and common scab, caused by Streptomyces scabies (25-75% reduction relative to continuous potato). Barley, millet, and sweet corn rotations were somewhat effective in reducing disease (15-40% reduction). However, potato following soybean, green bean, or red clover, resulted in high disease levels of stem canker and black scurf. These results, along with data on yield, nitrogen recycling, and economic viability, were used to develop The Potato Systems Planner, an interactive CD-Rom decision-support tool to aid in establishing improved cropping and disease management systems for potato production. Also included in the Planner CD is a Potato Disease Database, containing descriptions, symptoms, and management information for most potato diseases.