Closed Soilless Cultivation System of Roses Planted in Rice Hull Substrate with TiO2 Photocatalytic Treatment of Waste Nutrient solution

Abstract

From the viewpoint of conservation-oriented agriculture, this study investigated a closed cultivation system using a combination of rice hull substrate and TiO 2 photocatalytic treatment of the waste nutrient solution. First, an extract of rice hulls in distilled water was treated with a TiO 2-coated porous alumina filter under ultraviolet light irradiation. Then, rose (Rosa hybrida) rooted cuttings were soaked in the treated extract, untreated extract, or pure nutrient solution. The total weight of the shoot and leaves soaked in the photocatalytically treated extract was heavier than that in the untreated extract, and was similar to that in the pure nutrient solution. Next, rose growth was compared in three practical cultivation systems two closed systems using rice hull substrate with photocatalytically treated or untreated waste nutrient solution (photocatalytically treated and untreated systems), and an open system using rockwool substrate (current system). The growth and yield in the photocatalytically treated system were significantly greater than those in the untreated system and were comparable to those in the current system. These results show that the TiO 2 photocatalytic treatment of the waste nutrient solution is effective in closed soilless cultivation using rice hull substrate.

Inactivation of Bacterial Wilt in Closed Soilless Cultivation by Photocatalytic Treatment and Silver

“…Numerous researchers have attempted to exploit this photocatalytic reaction to decompose environmental pollutants in air and water (Ollis et al, 1991;Noguchi et al, 2003;Pichat et al, 2005). In our previous study, we have confirmed that phytotoxic compounds from rice hulls substrate in waste nutrient solution are decomposed and detoxified through the treatment system with TiO2 under solar light irradiation (Sunada et al, 2008;Miyama et al, 2009;2012). Furthermore, the growth and yield of tomatoes in a closed cultivation with the treatment system were significantly higher than those with untreated system.…”