It is very important to develop new techniques for soil sterilization because the use of methyl bromide, which had been widely used all over the world, was banned in 2005 in Japan. Using hot water for soil sterilization has become popular in Japan as an alternative for methyl bro-mide. However, because using hot water is relatively new, few studies have been conducted. In this study, we inves-tigated solute dynamics by measuring temporal changes in the concentration of chloride, nitrate, nitrite, and ammo-nium ions in soil. Hot water with the temperature of 90 ◦C was applied to the soil surface at the rate of 204 L m−2 dur-ing the experiment. Soil samples were manually collected for analyzing solute concentration in triplicates between the soil surface and 40 cm deep with a 5 cm interval just before starting, 9 days after, and 3 months after the hot-water application. As the result of the experiment, leach-ing with high temperature was found to be more hastened than that with normal temperature. We found that solute concentrations increased between 30 cm and 40 cm deep by solute diffusion from a deeper portion in 3 months after the hot-water application. On the other hand, applying hot water suppressed the form change at first because nitrify-ing bacteria was killed by the hot water in soil. However, ammonium nitrate decreased with time in deep layers by nitrifying bacteria restored from a deeper layer.
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