抄録
Rot symptoms are serious yield loss factors in the production of lotus in Tokushima Prefecture, Japan. The objective of this study was to evaluate the effects of solarization on soil temperature, the density of F. oxysporum, one of the causal agents of rot symptoms, and lotus yields in different fields in Tokushima Prefecture. A survey demonstrated a significant relationship between the densities of F. oxysporum and occurrences of lotus rhizome rot. Average soil temperatures at a depth of 15 cm were 25.5°C and 29.3°C in control and solarized fields, respectively. The maximum soil temperature was 34.3°C in control and 41.4°C in solarized fields. Cumulative times above 30°C were 28–70 h in control and 81–1079 h in solarized fields. Significant reductions in the densities of F. oxysporum were observed in solarized fields but not in non-solarized fields. Solarization improved yields of lotus: the average yield was increased by 79% as compared to that of the previous cropping season. The present study revealed that solarization reduced the density of F. oxysporum in soil and, thereby, increased lotus yield.
