Soil amendments for bacterial wilt management in solanaceous vegetables

摘要

Soil amendment with broccoli, radish and wild sunflower (Tithonia diversifolia) were evaluated for bacterial wilt (Ralstonia solanacearum) suppression in potato. Plant biomass was incorporated into the soil at 5 kg/m~2 during soil cultivation and allowed to decompose. Wild sunflower soil amendments reduced R. solanacearum populations in two cropping seasons of potato; thus the incidence of bacterial wilt was less compared with broccoli and radish amendment. The high amount of organic matter from wild sunflower decomposition promoted microbial growth acting as an antagonist to soil pathogens such as R. solanacearum. Wild sunflower also contains a phytotherapeutic agent, sesquiterpene lactone 1, that has antimicrobial activity. Yield consequently increased due to the lower bacterial wilt incidence in wild-sunflower-amended plots both at the research station and in farmer field trials. The higher number of tubers per plant and weight of marketable tubers harvested from plants with wild sunflower amendments could be attributed to the higher soil pH and increased organic matter and nutrient elements phosphorus and potassium added to the soil upon decomposition of wild sunflower biomass.