Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: June 1, 2009
Publication Date: July 20, 2009
Citation: Larkin, R.P., Honeycutt, C.W., Griffin, T.S., Halloran, J.M., Olanya, O.M., He, Z. 2009. Cropping system effects on soilborne potato diseases and soil microbial communities. Phytopathology. 99:S69. 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 (SQ) standard rotation control, were evaluated for their effects on soilborne diseases of potato and 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-potato), SI added yearly compost amendments to the SC system, 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. All rotations reduced black scurf (28-58%) 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 overall. Each rotation resulted in distinctive changes in SMCC as represented by microbial populations, substrate utilization, and FAME profiles. Overall, soil water, soil quality, and soilborne diseases were the primary factors constraining productivity, and systems addressing these constraints enhanced productivity and sustainability.