Study on Irrigation Water Requirements for the Control of Ralstonia solanacearum via Soil Solarization in Managing Tomato Cultivation

Abstract

The amount of irrigation water, soil temperature and population density of a pathogenic bacterium Ralstonia solanacearum before and after soil solarization were investigated in 6 greenhouses (located at Kaizu city, Gifu, Japan) in order to obtain the basic information of water requirement for the control of R. solanacearum via soil solarization in managing tomato cultivation. Our results showed that the soil temperature was influenced by airtight state of a glasshouse, temperature differences between inside and outside of a greenhouse, and duration and climatic conditions of the solarization period. The density of R. solanacearum decreased markedly after soil solarization with daily average soil temperature greater than 40°C for consecutive 10 days or 3 days under anaerobic condition, which was consistent with previous studies. The amount of irrigation water ranged from 155.6 to 495.2 mm (average: 291.3 mm) for 2 greenhouses where soil solarization was effective, which corresponded to 104 - 346% (average: 218%) of the amount of water requirement from some state to become saturation state.