Increase herbicide effectiveness: soil treatment option is to spray the herbicide directly to the soil surface, kill the germination of weeds. Herbicides effect proportional to the level and temperature. High temperature herbicides in rice fields, absorption and transport functions weed herbicide strong herbicidal activity is high, easy to give full play to the role of herbicide site of action weeds. Herbicide Classification: According to the mode of action classification. Selective herbicides: Herbicide for different types of seedlings, different degrees of resistance, this drug can kill weeds week saliva paddy herbicide, while the seedlings harmless. Herbicide: All plants are toxic herbicide herbicides in rice fields in Zhejiang, as long as the contact with the green parts, regardless of seedlings and weeds, will suffer or be killed. Mainly before sowing, before emergence after sowing, nursery primary and secondary lane use.