2018 Volume 60 Pages 71-76
Conditions for effective anaerobic soil disinfection (ASD) using sugar-containing diatomite and dried molasses were investigated. In the laboratory, ASD using diatomite and dried molasses (1% [w/w]) were more effective for disinfection of Ralstonia solanacearum compared with use of the control molasses. At 20–50°C, oxidation-reduction potential of soil after ASD decreased with increasing temperature. In addition, R. solanacearum population in soil decreased to a level below the detection limit at 30°C when sugar-containing diatomite was used and no R. solanacearum were detected from untreated soil after 14 days incubation at 40 and 50°C. During soil disinfection in the summer greenhouse in Wakayama prefecture, soil temperature at 30 cm depths was maintained above 40°C for 12 days. Soil temperature at 40 cm depth was maintained above 40°C or did not reach 40°C depending on the field. From the above, in the shallower layer than 30 cm underground, R. solanacearum population is assumed to decrease due to the high soil temperature. On the other hand, in the deep layer than about 30–40 cm underground, it is expected that R. solanacearum population decrease due to ASD caused by eluted component of sugar-containing diatomite and dried molasses.
