ROLE OF MOVABLE BENCH SYSTEM FOR STRAWBERRIES IN RECONSTRUCTION PROJECT IN MIYAGI PREFECTURE

The Great East Japan Earthquake and Tsunami destroyed a strawberry-producing district in Miyagi Prefecture in 2011. Of 98.6 ha of small polytunnels located along the sea front, 94 ha were destroyed by the tsunami. A demonstration greenhouse has been built in Yamamoto, Miyagi Prefecture to show new strawberry production techniques as a part of the reconstruction project, within which the Bio-oriented Technology Research Advancement Institution (BRAIN) has installed a circulating-type movable bench system. The system is 13.5 m long and 7.7 m wide, and chiefly comprises two longitudinal conveying units, two lateral conveying units, two nutrient supply units, a chemical sprayer, 52 planting benches, and a control unit, providing high-density cultivation of 50 cm interplant space and 12.5 cm plant distance. The system has three operational modes: working, nutrient solution applying, and chemical spray modes, and enables unmanned operation. The lateral conveying can be selected from three speeds, giving cycle times of 44.5 s at low, 28.8 s at medium, and 23.8 s at high speed. The results indicate that the waiting time can be shortened. The movable bench demonstration system provides farmers affected by the tsunami disaster with information and knowledge on new cultivation techniques.