Influence of crop rotation and conservation tillage practices on the severity of soil-borne potato diseases in temperate humid agriculture

Abstract

A field trial was established in 1994 in Prince Edward Island, Canada, to determine the effects of 2- and 3-year crop rotations, with either conventional or minimum tillage treatments, on the severity of potato diseases caused by soil-borne pathogens. The 2-yr rotation consisted of spring barley and potato (cv. Russet Burbank) and the 3-yr rotation was barley (undersown with red clover), red clover and potato. In the potato years only, the main plots were split to examine conventional and minimum tillage (sub-plot) treatments. Potato diseases were assessed during the period 2000–2002, 6–8 yr after the initial establishment of the field trial. In each year of the study, potato plants grown in 3-yr rotations developed significantly (P = 0.05) lower levels of stem and stolon canker and black scurf (Rhizoctonia solani) compared with those from 2-yr rotations. Overall, rotation duration (not tillage type) was the main factor contributing to reduction of disease caused by R. solani. The severity of silver scurf (Helminthosporium solani) was significantly (P = 0.05) lower in tubers from plots managed in 3-yr rotations under minimum tillage practices in 2000, significantly higher in plots managed with minimum tillage in 2001, and unaffected by treatment in 2002. The severity of dry rot (Fusarium spp.) was significantly (P = 0.05) lower in tubers from plots managed with 3-yr rotations under minimum tillage practices in 2000, but was unaffected by either tillage regime in 2001 and 2002. The severity of common scab (Strep tomyces scabiei) was low and not influenced by tillage or rotation in any year of study. In summary, a 3-yr crop rotation combined with minimum tillage reduced potato diseases caused by R. solani and did not affect disease caused by other soil-borne pathogens. From a crop health perspective, there appear to be no constraints to the use of minimum tillage practices in association with 3-yr rotations in potato production in regions of temperate humid agriculture. Key words: Crop rotation, minimum tillage, potato, Solanum tuberosum, soil-borne pathogens, Rhizoctonia solani