Paddy weeds are the most serious problems in transplanted rice production. Traditionally,the weed control strategy has three steps: a single pre-emergence herbicide application followed by a post-emergence herbicide treatment and an optional late post-emergence chemical spray,if required,to eliminate escapes. But this treatment combination has been unable to meet the requirements for weed control in mechanically transplanted fields. In this paper,combined with the district test and large area demonstration,...