The ecological and physiological water require-ment of rice and rice yield was studied underthree irrigation patterns, which were A: moistirrigation, remains 70-90% of saturated soilwater content except 3-4 cm deep water layerin tillering stage in paddy; B.. flood irrigation,remains 4-5 cm deep water layer except 80%relative water content in the late tillering stagein paddy; and C: intermittent irrigation, re- The ecological and physiological water require-ment of rice and rice yield was studied underthree irrigation patterns, which were A: moistirrigation, remains 70-90% of saturated soilwater content except except 3-4 cm deep water layer in tillering stage in paddy; flood irrigation, remains 4-5 cm deep water layer except 80% relative water content in the late tillering stagein paddy; and C: intermittent irrigation, re-