Role of Biochar Technology in Carbon Sequestration and Agro-Environmental Sustainability

Globally, soil-based emissions such as forest fires (as occurred in Australia and Brazil in the recent past) and biomass burning adversely affect the environment’s biodiversity and cause warming effects. In coalition, anthropogenic emissions also simultaneously augment global temperature. The Paris Climate Change Convention (Nov 2016) held a consensus to limit the rise in global temperature by below 2 °C until this century’s end. Against this backdrop, sequestering more carbon in soil has become an urgent priority. Agroecosystem soil, being both a source and sink of carbon, is therefore intervened with greater effort by the national and global agencies. Sustainable agricultural practices have shown promise in the direction of increasing organic carbon stock and restoring degraded/contaminated soils. Yet, advanced technology such as biochar use and application, progress in the method of preparation (pyrolysis), and cost-effectiveness need attention. Pyrolysis tends to convert biomass rapidly into a recalcitrant form known as biochar. This needs further developments, and newer agro-residue-based substrates need to be exploited for large-scale effective biochar preparation and their recycling in agriculture. Biochar addition in agricultural soil sequesters carbon (mainly as Soil Organic Carbon (SOC)) and, in the long run, manages various soil quality indicators, viz. C:N ratio, microbial load, ion conductivity. These harmonize the soil-water-pant-nutrient nexus and sustain crop yield. The soil’s physical property is improved (such as reduced bulk density), thereby increasing aeration, rhizospheric expansion, dense root system, and limiting soil erosion. The liming action of biochar in acidic soil maintains soil pH, which is one major driver for plant nutrition. Overall, biochar technology needs to be exploited to mitigate GHG emissions, reclaim soil health fertility, and enhance plant growth/yield. Therefore, the present chapter highlights strategies to advance the biochar technological and application-based interventions for enhancing carbon capture and managing the soil ecosystem, thereby meeting some of the important UN-SDGs (12-responsible consumption and production and 13-climate action) by the year 2030.