Abstract:
In order to effectively mitigate the phytotoxicity to tobacco caused by residues of herbicide quinclorac, detoxifying agents and formulations with better mitigating effect on the quinclorac phytotoxicity were screened through pot and field experiments. The results of the pot experiments showed that gibberellin (GA) + indoleacetic acid +urea + potassium dihydrogen phosphate (mass ratio 1 ∶ 1 ∶ 64 ∶ 32), Tianda 2116, Gefu microbial agent, GA, indoleacetic acid and urea + potassium dihydrogen phosphate (mass ratio 2 ∶ 1) all had certain restorative effects on leaf width, plant height and number of leaves of herbicide-damaged tobacco plants. Among them, the GA + indoleacetic acid + urea + potassium dihydrogen phosphate treatment (mass ratio 1 ∶ 1 ∶ 64 ∶ 32) had the best recovery effect on the herbicide-damaged tobacco plants, and there was no significant difference between the agronomic traits of the herbicide-damaged tobacco plants and the normal tobacco plants after 30 d treatment. In the field experiments, the antidote formula of 30 000 g/ha Gefu microbial agent for root irrigation combined with 1 470 g/ha GA + indoleacetic acid + urea + potassium dihydrogen phosphate (mass ratio of 1 ∶ 1 ∶ 64 ∶ 32) for foliar spraying was the best treatment for plant growth, and the plants did not show any deformity symptom. Leaf length, leaf width, plant height, stem circumference, and number of leaves of the restored tobacco plants increased by 46.51%, 162.28%, 79.70%, 79.24%, and 44.72%, respectively, and the differences reached significant levels compared with the herbicide-damaged tobacco plants. Compared to normal tobacco plants, tobacco yield, average price, production value, and proportion of high-grade tobacco leaves of restored tobacco plants increased by 12.25%, 4.48%, 17.37%, and 14.05%, respectively. In addition, the nicotine content of herbicide-damaged tobacco was significantly reduced, and quinclorac was undetectable in soil and tobacco at harvest.