Drought–salinity stress poses a significant threat to agriculture, negatively impacting the growth and productivity of vital crops like chickpea (Cicer arietinum L.). This study investigated the efficacy of biochar as a soil amendment to alleviate these concurrent stresses. In a controlled pot experiment, chickpea plants were subjected to two main conditions: a control (75% field capacity), and combined salinity–drought stress (150 mM NaCl at 35% field capacity). Each condition was tested with and without biochar soil amendment. Key morphological traits, photosynthetic activity, and biochemical stress indicators were assessed in chickpea plants.

Combined drought–salinity stress severely impaired plant growth. However, the application of biochar significantly mitigated these adverse effects, leading to a substantial recovery in key morphological traits, including a 56% increase in shoot biomass and an 87% improvement in root development compared to untreated stressed plants. Under drought–salinity stress, photosynthetic parameters and the integrity of chloroplast structure were compromised. The application of biochar significantly mitigated these damages by restoring photosynthetic efficiency. Moreover, biochar amendment effectively reduced oxidative stress markers, decreasing malondialdehyde and hydrogen peroxide levels by 37% and 45%, respectively, compared to the control. Correspondingly, the activities of crucial antioxidant enzymes, namely superoxide dismutase, catalase, and ascorbate peroxidase, which were suppressed by stress, were significantly enhanced following biochar treatment.

This study highlights the beneficial effects of biochar under drought–salinity stresses, which could be used in the management of chickpea cultivation in drought- and salinity-prone regions.