Simulation Study on Management of Paddy Field in Consideration of Farming in order to Promote the Surface Drainage

Abstract

Farmers must manage paddy fields for maximum reduction in the water volume that remains after surface drainage. Using computer simulation, we compared two methods for accomplishing this purpose: moving the soil to reduce the altitude on the outlet side and creating an open-ditch drainage. We found that 1) lowering the outlet side reduced the remaining water volume, 2) creating an open-ditch drainage further reduced the water volume, and 3) the effects of these methods depended on the direction of surface roughness of the paddy field.