Submitted to: Northeast Potato Technology Forum Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 3/1/2003
Publication Date: 3/15/2003
Citation: Larkin, R.P. 2003. Cropping system effects on soil microbial communities and soilborne diseases. Northeast Potato Technology Forum Abstracts. cd-rom DISK 3/15/2003 Interpretive Summary:
Technical Abstract: Cropping systems, consisting of barley, canola, clover, green bean, soybean, and sweet corn in various combinations in 2- and 3-yr rotations with potato, were established in replicated field plots in Newport and Presque Isle, ME, and effects on soil microbial communities and soilborne diseases evaluated. Soil bacterial populations and microbial activity were highest following barley, canola, and sweet corn crops, and lowest with consecutive potato plantings. Substrate utilization data (from Biolog GN2 plates) also indicated greater substrate richness and substrate diversity associated with barley and canola crops. Soil fatty acid methyl ester (FAME) profiles provided clear distinctions among different cropping systems, representing numerous changes in soil microbial communities related to cropping system. Incidence and severity of stem and stolon canker and black scurf of potato, caused by Rhizoctonia solani, were reduced for most rotations relative to the continuous potato control, with lowest disease observed following barley and canola. Soybean and clover preceding potato, however, resulted in high levels of disease in some years. When present, common scab, caused by Streptomyces scabies, was also reduced following barley, canola, and soybean rotations. Overall, potato crops following canola, barley, or sweet corn provided the lowest disease levels, highest yields, and best tuber quality. Several characteristics of microbial communities were negatively correlated with disease parameters and positively correlated with yield, indicating microbial factors that may be associated with aspects of crop health and productivity.