Herbicides prevent: those degrading long residual effect in the soil herbicide Zhejiang wheat field herbicide, planting structure adjustment in wheat field herbicide, be careful when switching to crops, the crop species to find out what, with what weeding Zhoukou wheat field herbicide agents, Vinca long, what should replant crops, after the crop safety. Try not to use long residual effect of herbicides. Herbicides conditions: additive effect. Addition effect refers to the herbicidal effect of two herbicides actual herbicidal effect equal calculated based on the relevant model and two herbicides alone. Synergies. Synergism refers to two herbicides herbicidal effect is greater than the actual calculated based on the relevant model two herbicides alone herbicidal effects combined.