A meta-analysis of economic and environmental benefits of conservation agriculture in South Asia

Agriculture plays a key role in ensuring food and livelihood security in South Asia. However, this region is vulnerable to climate change which is likely to impact the livelihoods of millions of marginal and small holders. Agriculture is not only impacted by climate change but also one of the major contributor to global warming in South Asia. As compared to the traditional practices, Conservation Agriculture (CA) practices help mitigate the impact of climate change through a reduction in carbon emission and conservation of natural resources. In this article, a meta-analysis of the important studies was done for the impact of CA on carbon sequestration, water use, greenhouse gas emissions and cost and net returns. Carbon sequestration potential was found significantly higher in the CA practices (+16.30%) as compared to the conventional tillage. Inclusion of legumes, clay-rich soils, irrigation and presence of soil cover are the major drivers for higher carbon sequestration potential in the region. Additionally, a significant amount of water was also saved as CA practices led to relatively less consumption of water over the conventional tillage. Further, the adoption of CA based management practices resulted in a substantial reduction of CO₂ (−4.28%) and CH₄ (−25.67%) emissions both in aerobic and anaerobic soil conditions. However, the emission of NO2 and N2O–N gases were higher under the CA, +14.45 and + 5.20% respectively. Nevertheless, the emission of N₂O–N was lesser in CA (−1.78%) under aerobic conditions whereas it is increased under anaerobic soil conditions (+12.15%). The adoption of CA practices resulted in higher returns and lower costs as compared to the conventional system. Although CA has significant environmental benefits, the study suggests judicious use of inorganic inputs under CA for managing the impact of climate change in South Asia. Therefore, CA is a sustainable agricultural practice that deserves outscaling in South Asia for mitigation and adaptation of climate change.