Spraying paraquat in a few days before harvest had little impact on yield, and it could fulfil the requirement of harvesting and threshing at the same time.

• 百草枯抑制油菜生长、促使油菜落黄和脱水的效果最好，喷药后第2天植株即全部变黄，在收获前几天喷施对产量影响小，能达到一次收获脱粒的要求。