ISHS Acta Horticulturae 761: XXVII International Horticultural Congress - IHC2006: International Symposium on Advances in Environmental Control, Automation and Cultivation Systems for Sustainable, High-Quality Crop Production under Protected Cultivation
DISINFECTION SYSTEM WITH IODINATED ANION EXCHANGE RESIN FOR NFT SYSTEM |
| Authors: | R. Ogai, T. Maruo, Y. Amemiya, Y. Shinohara, H. Yamaguchi |
| Keywords: | hydroponics, Ralstonia solanacearum, iodine, tomato, modified NFT system |
| Abstract:
The objective of the present study was to develop a disinfection system for the circulating nutrient solution of a NFT system using iodinated anion exchange resin (I2 resin), which releases a constant concentration of molecular iodine (I2) into water over a long period of time. The first experiment was conducted to evaluate the behavior of iodine in the nutrient solution of a NFT system. It was observed that the I2 concentration decreased and the iodide (I-) concentration increased as it circulated through the channel with tomato plants. The purpose of the second experiment was to evaluate a disinfection system to control Ralstonia solanacearum (Rs) using two disinfection methods in a modified NFT system. In the 2-step type method, in which the whole NFT system is disinfected, Rs in the nutrient solution was not detected after the first disinfection. In the series type method, in which only the nutrient solution is disinfected in the disinfection system, the bacterial population of Rs decreased at the end of each disinfection treatment, and then increased at the beginning of the next treatment. In this method, the bacterial population of Rs in the daily treatment was always lower than the intervals treatment, which disinfects at 3- or 4-day intervals. Consequently, it was observed that 60% of the plants in control were diseased, while 6.7% in intervals treatment of series type and 0% in 2-step treatment and daily treatment of series type at the end of cultivation. On the other hand, it was found that the I- concentration of the nutrient solution in 2-step treatment was higher than that in both series of treatments during cultivation. However, physiological disorders were not observed in treatments. The results of these experiments suggest that a disinfection system using I2 resin is highly effective to control Rs. | |
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