UAS-B présente aux agriculteurs une technologie à faible coût pour produire du biochar, les forme à l'amélioration de la santé du sol

Researchers at the University of Agricultural Sciences - Bangalore (UAS-B) have begun training 10 farmers in each of 10 districts across Karnataka to produce biochar using locally available crop residues. This initiative aims to enhance soil health and reduce the need for chemical fertilizers. The project is part of the Rashtriya Krishi Vikas Yojana (RKVY), a national program launched in 2007 to promote sustainable agricultural practices. The training involves the use of a simple and affordable portable drum system developed by Krishna Murthy and his team from the Department of Science and Agriculture Chemistry at UAS-B. The drum, which holds 200 liters, features small holes and a chimney-like pipe that allows controlled airflow during the pyrolysis process. Farmers are taught to fill the drum with crop residue such as coconut shells, sunflower heads, and mulberry prunings before lighting a fire and sealing the lid. With minimal oxygen entering through the holes, the material undergoes pyrolysis, transforming into biochar in approximately two to three hours. Biochar is a porous, charcoal-like substance created through the thermal decomposition of organic biomass in a low-oxygen environment. Unlike regular charcoal, biochar retains a high level of organic carbon, which helps rebuild soil organic carbon (SOC) levels. This process significantly reduces greenhouse gas emissions compared to open burning, which releases nearly all of a residue's carbon as CO₂. According to Dr. Murthy, pyrolysis locks 50% to 80% of the carbon into a stable form that persists in the soil for years, improving its fertility and water-holding capacity. Field trials conducted by the research team suggest that biochar application can increase crop productivity by 10% to 30% and enhance water retention by 10% to 25%. These benefits are particularly pronounced in low-SOC soils, which are prevalent in Karnataka. A 2009 state government initiative known as Bhoochetana revealed that 52% of sampled fields were deficient in SOC. More recent data from the State Agriculture Department, spanning 2017 to 2024, indicates that over half of the state’s farmland now has SOC levels below the critical 0.5% threshold. Kolar district stands out as the most severely impacted area, with over 94% of its farmland classified as low-SOC. Similarly, the black soil regions of North Karnataka, Belagavi, Vijayapura, Kalaburagi, Bidar, Yadgir, and Bagalkot, are experiencing similar depletion due to prolonged cotton and oilseed cultivation. Coastal districts, however, maintain relatively healthier SOC levels, attributed to alluvial deposits and traditional mulching techniques. Dr. Murthy emphasized that the decline in SOC is primarily linked to unsustainable farming practices, including excessive tillage and the removal of crop residues for fuel or other purposes. By encouraging the production and use of biochar, the initiative seeks to restore soil fertility while reducing reliance on synthetic fertilizers. The project provides farmers with free access to the pyrolysis drums and offers hands-on training to ensure they can replicate the process independently. As the program expands, it is anticipated that the adoption of biochar will contribute to improved agricultural sustainability and resilience against climate change impacts. The success of this model could serve as a replicable solution for other regions facing similar challenges in soil degradation.