Effect of Biochar and Biosulfur on grain yield and some ecophysiological traits of rapeseed (Brassica napus L.) under drought stress conditions in winter planting

Environmental stress, especially drought stress, is one of the most important factors that reduce the growth and development of oil plants such as rapeseed in arid and semi-arid regions. The purpose of this research is to investigate the effect of biochar and biosulfur on seed yield and some ecophysiological traits of rapeseed under drought stress conditions in winter cultivation.

This research was carried out in form of a factorial split-plot with randomized complete block design having three replications in 2019 in Karaj. In this experiment, irrigation treatment witnessed three levels of 30%, 60%, and 100% of crop capacity as main plots, while biochar treatment saw three levels of no application and application of three and six tons per hectare and biosulfur treatment, two levels of application and non-application as plots. Subsidiaries were considered.

It was found that drought stress had a significant effect on the seed and oil yield of rapeseed. Thus, the amount of these traits in drought stress showed a decrease of 50% and 52%, respectively, compared to the control. Also, the use of six tons per hectare of biochar had increased by 49% and 36% in terms of its number of pods per plant and the number of seeds per pod. Also, the interaction effect of biosulfur application and the use of six tons of biochar had the greatest effect on the traits of the number of pods per plant and harvest index.

The results showed that the use of biofertilizers can be used as a suitable method to increase the yield of rapeseed. Increasing oil percentage and grain yield will ultimately increase the field and economic yield (oil) of the rapeseed plant.