Navigating Biomass Trade-Offs: Earmarking Sustainable Food Security Through Biochar Interventions in Mung Bean Cultivars Under High Ozone Atmosphere

Abstract

The rapid increase in tropospheric ozone levels, exceeding the phytotoxic threshold (40 ppb), threatens crop yields in India's Indo-Gangetic plains, necessitating the exploration of antiozonants. Biochar application offers a promising, low-risk solution to mitigate the harmful effects of ozone and other abiotic stressors on agriculture. This study investigates the ameliorative effects of biochar amendments (2.5 and 5%) on selected mung bean cultivars (HUM-1 and HUM-6) under elevated ozone (ambient + 20 ppb). Biochar amendments improved foliar characteristics and reduced chlorotic and necrotic spots generated by elevated ozone. Reductions led by ozone in the growth and root-shoot ratio were significantly mitigated in biochar-treated plants. Despite decreased nodulation, the size and biomass of individual nodules increased under biochar treatments. Under ozone stress, the HUM-1 cultivar allocated more photosynthetic assimilates to vegetative parts of the plant, whereas, the HUM-6 cultivar directed greater photosynthates to reproductive structures. Floral and fruit characteristics improved in both cultivars after biochar supplementation, indicating enhanced carbon allocation towards reproductive parts. Biochar treatments also alleviated seed shriveling and size reduction observed under ozone stress, improving seed quality. Biochar amendment was more beneficial in yield protection of sensitive cultivar (HUM-1) than less sensitive cultivar (HUM-6). Findings of the present study suggested that biochar applications of 2.5% and 5% have significant potential to mitigate the adverse impact of ozone on mung bean plants. This study underscores the potential of biochar as a viable agronomic intervention to enhance crop resilience against tropospheric ozone, contributing to food security and sustainable agriculture in the context of climate change.