Biochar derived from hazelnut shells mitigates the impact of drought stress on soybean seedlings

This study investigated the interactive effects of drought stress with biochar on plant growth, the physiological and biochemical attributes of soybean seedlings. A pot trial tested the effect of amending a loamy sandy soil with biochar at three doses: 0%, 3% and 6% in the alleviation of drought stress, imposed by adjusting soil moisture content at three levels (in terms of soil field capacity, FC): 100% FC, 75% FC and 50% FC. Water deficit negatively influenced the growth of soybean seedlings and chlorophyll content of leaves, particularly in non-amended plants whereas biochar amendment boosted the growth and chlorophyll content, particularly under drought stress. Drought stress elevated malondialdehyde (MDA), hydrogen peroxide (H2O2), proline, sucrose and abscisic acid (ABA) contents as well as the antioxidant enzyme activity [peroxidase (POD), catalase (CAT) and superoxide dismutase (SOD)] of soybean leaves but reduced the contents of indole acetic acid (IAA) and gibberellic acid (GA); biochar amendment counteracted the impact of drought. The findings of the study indicate that biochar amendment can enhance soybean growth by modulating the plant physiology and biochemistry under drought stress.