What is the herbicide used before onion seedling raising?

Acetochlor, metolachlor, pendimethalin and oxyfluorfen are generally used as herbicides for onion plugging, and it is best to use 50% metolachlor, pendimethalin and oxyfluorfen. The advantage of this formula is that it does not contain acetochlor, and garlic grows vigorously, which can not only block common small seed weeds, but also block malignant weeds such as Stellaria, shepherd's purse and so on. If there are other weeds that are difficult to control, it is suggested to mix oxadiazon to increase the sealing effect.