Abstract:

To determine the optimal sowing time for winter rapeseed and evaluate the regulatory effects of wood vinegar on alleviating salt stress in saline-alkali soils of the Yellow River Delta, a field plot experiment was conducted using two winter rapeseed cultivars, ‘Hengyou 8’ and ‘Ganyou 202’. Three sowing dates (September 20, September 30, and October 10) and two wood vinegar application methods(foliar spraying and root irrigation during the budding and early flowering stages) were set to systematically assess their effects on plant development and yield components. The results showed that sowing date significantly influenced emergence rate, overwintering survival, and yield traits. The seedling emergence rate and overwintering rate on September 20 were 24.4% - 24.9% and 19.9% -25.0% higher than those on October 10, respectively. The number of effective siliques per plant was significantly increased, and the yield per plant was increased by 34.15%-48.01%. Under saline conditions, wood vinegar treatment significantly enhanced plant height, stem diameter, and yield performance. Foliar application notably increased the thousand-seed weight (6.15%), single-plant yield (13.77%), and field yield (16.75%) of ‘Hengyou 8’, while ‘Ganyou 202’ exhibited increases in silique number (9.15%), single-plant yield (15.69%), and field yield (8.62%). Root irrigation showed a more pronounced effect on increasing main stem silique number and yield for both cultivars, with field yields rising by 21.63% and 10.06%, respectively. Overall, early sowing combined with wood vinegar treatment effectively alleviated salt stress, optimized agronomic traits, and significantly enhanced yield. In the future, the concentration and period of wood vinegar application can be optimized, combined with physiological mechanism research, to provide more accurate technical support for green and efficient production of rape in saline-alkali land.

Key words: wood vinegar, sowing date, rapeseed, agronomic traits, yield, saline-alkali soils