Effects of Different Irrigation and Drainage Practices on Drainage Process in Paddy Fields

Field experiments were conducted to study the effects of different irrigation and drainage practices on drainage process in paddy fields and analyze the drainage process ofpaddy-ditchsystem after rainfall and irrigation.Results showed that drainage water from ditch was 8 041m3/hm2 under controlled irrigation and drainage practices,which decreased by 50.6%compared to conventional irrigation and drainage practices(16 373m3/hm2).After rainfall and irrigation,the controlled irrigation and drainage practices reduced the peak flow from paddy-ditchduring drainage processes and changed the drainage characteristic in paddy fields,which could be helpful in reducing non-point source pollutions in runoff form paddy fields caused by rainfall and irrigation.