Chemical contamination in plants, soil, and ground water has become serious by overuse of pesticides and nitrogen fertilizers in agriculture. We propose the use of ozone generated by atmospheric pressure plasma for soil disinfection as one of the plasma applications into agriculture. Because ozone has strong oxidation potential to decompose organic substances in soil, it is considered to be one of the candidates as potential alternative to both pesticide and nitrogen fertilizer. In this paper, fundamental studies on changes in acidity and amounts of nitrogen nutrients, bacteria, mold, and soil DNA remained in soil after ozone treatment were carried out with a system using a quartz chamber. Surface barrier discharge that operates in atmospheric oxygen was used in the system as the ozone generator. In addition, growth of radishes that seeded on soils in pots that were treated by ozone diffusion method was also evaluated.

Recently, application of plasma technologies to the agricultural field has attracted much interest because residual pesticides and excessive nitrogen oxides contained in plants, soil, and groundwater have become a serious issue worldwide. Since almost all of the atmospheric discharge plasma generates ozone, the effects of ozone are among the key factors for their agricultural applications. We have proposed the use of ozone generated using surface barrier discharge plasma for soil disinfection or sterilization. In this work, the ozone consumption coefficient and diffusion coefficient in soil were measured by the ultraviolet absorption method. The pH(H2O) and amount of nitrogen nutrient in soil after ozone diffusion treatment were studied and plant growth was observed simultaneously. The effect of ozone treatment on the amount of DNA in soil was also investigated and compared with that determined from the obtained ozone consumption coefficient.

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In this study, the influence of ozone treatment on physical properties of soil with low ozone dose rate was investigated. Ozone was generated by oxygen plasma using a dielectric surface barrier discharge and injected into soil in a quartz container which is rotated by a motor. The amount of soil used for the treatment was 100 g. Treating time was 1 min. The ozone dose rate, which is defined as ozone dose weight per unit weight of soil, was 0.1 %. Flow rate of ozone gas was 1.5