2025 Volume 15 Issue 2 Pages 16-21
Application of electrokinetic treatment powered by a 6 V solar cell (ET-6V) has been found to release essential nutrients (N, P, and K) from saturated organic soil. Additionally, this treatment accelerates the growth of Japanese mustard spinach near the anode due to oxidation reactions. However, growth inhibition occurs near the cathode due to reduction reactions. These effects may vary in unsaturated soils managed with irrigation water. Therefore, the aim of this study was to determine the effects of ET-6V on plant growth in unsaturated soils through laboratory experiments. Specifically, we examined changes in electrode potential and the growth rate of Japanese mustard spinach after applying ET-6V to andosol mixed with cow manure compost. Although reduction reactions occurred at the cathode, facilitating the flow of irrigation water through the soil layer maintained a stable cathode potential exceeding 0 V. Growth rate measurements revealed a 1.2–1.8-fold increase in the wet weight of Japanese mustard spinach near both the anode and cathode. Notably, the growth rate of spinach was higher in the soil located 5–20 cm from both electrodes. Surprisingly, reduction reactions did not negatively affect growth rate but instead contributed to increased Japanese mustard spinach growth in unsaturated soil. The enhancement of soil potential through irrigation water is a key driver underlying this growth. Therefore, ET-6V should be applied to upper-land soils to boost crop productivity.
