The application of biochar alleviated the adverse effects of drought on the growth, physiology, yield and quality of rapeseed through regulation of soil status and nutrients availability

The depletion of soil fertility and freshwater reservoirs in dry and arid conditions of the world are alarming for food and crop productivity. Although many research studies have explored the effect of biochar on plant growth and soil fertility, however, information on the role of biochar on rapeseed under drought stress is limited. The current study was conducted to investigate the effect of biochar on photosynthesis, antioxidants activities, osmolytes contents, growth and yield of rapeseed under drought stress. Rapeseed plants at the flowering stage were subjected to two moisture conditions, no stress (NS) and drought stress (DS) along with four biochar treatments (B0:0, B15:15, B30:30 and B60:60 t ha−1). Drought stress negatively affected rapeseed growth due to the over-production of hydrogen peroxide (H2O2) by increasing 45 %, malondialdehyde (MDA) 21 % and electrolyte leakage (EL%) 40 % in (BO + DS) treatment as compared to control (BO + NS). However, the addition of biochar at 30 t ha−1 alleviated the hostile effects of drought stress in rapeseed to reduce the contents of MDA, H2O2, EL by increasing the activities of superoxide dismutase (SOD) by 63 %, peroxidase (POD) 48 %, and catalase (CAT) 62 % compared to stress-controlled treatment (BO + DS). The results revealed that biochar could alleviate the harmful effects of drought stress by enhancing the activities of antioxidants, osmoprotectants, soil fertility, and the physiological processes of rapeseed which indicate that the biochar application might be a sustainable strategy to enhance rapeseed growth under drought stress.