Submitted to: Potato Association of America Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 5/1/2008
Publication Date: 7/10/2008
Citation: Larkin, R.P., Olanya, O.M., Griffin, T.S., Honeycutt, C.W., He, Z., Halloran, J.M. 2008. Identifying Constraints to Potato System Sustainability: Diseases. Potato Association of America Proceedings. CD-ROM.
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 and foliar diseases of potato, as well as on soil microbial community characteristics (SMCC). 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), SI added yearly compost amendments, and DS featured diverse crops with known disease-suppressive capability (3-yr, mustard/ rapeseed-sudangrass/rye). Each system was also compared to a continuous potato control (PP) and was conducted under both irrigated and rainfed management. In both the 2006 and 2007 potato years, the DS, SI, and SC rotations all reduced stem canker (by 20-50%) relative to PP, and DS and SC reduced black scurf and common scab. Overall, the DS system, utilizing Brassica and other disease-suppressive rotation and cover crops, resulted in the lowest disease levels for all three soilborne diseases observed (canker, black scurf, and common scab). The SI system, characterized by yearly compost amendments, resulted in the greatest effects on soil microbial parameters, including greater microbial populations and activity, as well as higher yields, but also resulted in greater levels of common scab. Irrigation also resulted in increased yield, but also higher levels of common scab. All cropping systems had distinct and consistent effects on SMCC. All rotations reduced early blight relative to PP, but cropping system had little effect on microclimate conditions or potential for late blight based on model simulations.