Submitted to: Phytopathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/3/2010
Publication Date: 12/7/2010
Citation: Larkin, R.P., Honeycutt, C.W., Griffin, T.S., Olanya, O.M., Halloran, J.M., He, Z. 2010. Effects of different potato cropping system approaches and water management on soilborne diseases and soil microbial communities. Phytopathology. 101:58-67. Interpretive Summary: Current potato production based on short (2-yr) rotations faces numerous constraints to productivity, including high potential for soilborne diseases, high pesticide and fertilizer requirements, soil erosion, and degrading soil quality. We evaluated the importance of these factors using cropping systems designed to reduce these constraints. The systems included a soil conserving (SC), soil improving (SI), disease suppressive (DS), and status quo (SQ) standard rotation, compared with a nonrotation control (PP) under both irrigated and non-irrigated conditions. Each cropping system resulted in distinctive changes in soil microbial communities. Overall, soil water, soil quality, and soilborne diseases were all important factors affecting productivity, and cropping systems addressing these constraints improved production. Cropping system approaches need to balance these factors to achieve sustainable production and disease management. This research is useful for scientists, extension personnel, and growers, providing information on the factors constraining potato production and the development of cropping systems that address these constraints.
Technical Abstract: Four different potato cropping systems, designed to address specific management goals of soil conservation (SC), soil improvement (SI), disease suppression (DS), and a status quo standard rotation control (SQ), were evaluated for their effects on soilborne diseases of potato and soil microbial community characteristics. SQ consisted of barley underseeded with red clover followed by potato (2-yr). SC featured an additional year of forage grass and reduced tillage (3-yr, barley/timothy-timothy-potato), SI added yearly compost amendments to the SC rotation, and DS featured diverse crops with known disease-suppressive capability (3-yr, mustard/rapeseed-sudangrass/rye-potato). Each system was also compared to a continuous potato control (PP) and evaluated under irrigated and non-irrigated conditions. Data averaged over three potato seasons demonstrated that all rotations reduced stem canker (10-50%) relative to PP. SQ, SC, and DS systems reduced black scurf (18-58%) relative to PP, and scurf was lower in DS than all other systems. The SQ, SC, and DS systems also reduced common scab (15-35%), and scab was lower in DS than all other systems. Irrigation increased black scurf and common scab, but also resulted in higher yields for most rotations. SI produced the highest yields under rainfed conditions, and DS produced high yields and low disease under both irrigation regimes. Each cropping system resulted in distinctive changes in soil microbial community characteristics as represented by microbial populations, substrate utilization, and FAME profiles. Overall, soil water, soil quality, and soilborne diseases were the primary factors responsible for constraining productivity, and systems addressing these constraints enhanced productivity and sustainability.