Abstract
To elucidate the effects of irrigation management on the lodging tolerance of directly seeded rice, pushing resistance, lodging degree and yield were compared among rice plants grown under several irrigation management conditions differing in the frequency and length of drainage treatment. A higher value of pushing resistance was found in the field plot drained more frequently and for a longer duration. This tendency was approximately similar among rice plants seeded at different seeding depths including rice plants seeded in shallow layers less than 1 mm depth from the soil surface. The field lodging degree of broadcasted rice to the soil surface was significantly improved by drainage. Although serious lodging occurred in the field plot submerged continuously, less lodging was found in the field plot with more frequent and longer drainage treatment without a significant decrease in grain yield and quality.
