Effect of Concentrations of Nutrient Solutions in Aeroponic and Drip Irrigation Systems on the Growth of Touki, Angelica acutiloba Kitagawa

Abstract

'Touki' plants, Angelica acutiloba Kitagawa, are usually cultivated in soil, under which its yield and root quality are unstable. Although fertilizer application exerts a substantial impact on yield, the optimal level has not been known for the cultivation in soil. Therefore, the present study was undertaken to examine the growth of Touki plants with different concentrations of nutrient solution in aeroponic and drip irrigation systems. Four nutrient concentrations, i.e., 100%, 200%, 50%, and 25% of the standard nutrient solution ('Enshi' formula) were tested. In the aeroponic system, where a mist of nutrient solution was sprayed around suspended roots of the plants, the plants were grown from March 15 to June 6, 2005. In the drip irrigation system the plants were grown from May 2 to July 25, 2006. In the aeroponic system, the values of the growth parameters of the Touki plants at 12 weeks after transplanting were higher in the order of 100% 50% 200% 25% of the standard solution. In the drip irrigation system the growth parameters were higher in the order of 100% 200% 50% 25% of the standard solution. The 'Enshi' nutrient solution of 100% was optimal for the growth of the Touki plants in both systems. The plant growth, especially root growth, was more vigorous in the aeroponic system than in the drip irrigation system. In the drip irrigation system, however, the root/shoot ratio and root C/N ratio were higher, and the development of secondary roots was stimulated. As the secondary roots of Touki plants are mainly used as raw materials for medicine in Viet Nam, the drip irrigation system is recommendable as an advanced culture system.