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Long-term effects of potato cropping system strategies on soilborne diseases and soil microbial communities

Robert Larkin: USDA-ARS, New England Plant, Soil, & Water Lab

<div>Cropping systems incorporating soil health management practices, such as longer rotations, disease-suppressive crops, reduced tillage, and/or organic amendments can substantially affect soil microbial communities, and potentially reduce soilborne potato diseases and increase productivity, but long-term research trials are needed. In field trials originally established in 2004, different 3-yr potato cropping systems focused on specific management goals of soil conservation (SC), soil improvement (SI), and disease-suppression (DS) were evaluated and compared to a 2-yr standard rotation (SQ) and a non-rotation control (PP) for their effects on soilborne diseases and soil microbial communities over time. After 12-14 years, SI system produced higher potato yield and microbial activity than all other systems. DS maintained significantly lower disease (black scurf and common scab) severity than all other systems, and increased yield and microbial activity relative to SQ and PP. Soil microbial community characteristics and composition, as determined by fatty acid methyl ester (FAME) profiles and genus-level IDs from 16s rDNA (bacterial) and ITS2 (fungal) amplicon sequencing, were distinctly different among the systems, and may be responsible for disease suppression. These results indicate that soil health management practices incorporated into potato cropping systems can alter soil microbial communities and sustainably reduce soilborne diseases and enhance productivity.</div>