Pursuing carbon neutrality by smallholder farmers through technology and policy innovation blocs

Abstract Carbon peak and carbon neutrality are the top priorities for global sustainability1,2. However, the optimal strategy is unclear because minor attention has been given to smallholder farmers' activities. This study used farming data from 4547 smallholder farmers in 356 smallholder communities across China and life cycle assessment methods to evaluate carbon mitigation progress on three major grain crops in China between 2009 and 2019 and the carbon neutrality strategy for 2030 and 2060. The results showed that small farmers in China changed their practices of farming, i.e., from straw burning to straw retention in the soil between 2009 and 2019. These significant changes decreased the three crops' greenhouse gas (GHG) emission intensities by 56.2%. The estimated GHG mitigation at the national scale was 617 Tg CO2-eq in the ten-year period. The national actions for controlling straw burning were driven by the two-wheel innovation of technologies and policies. However, other low-carbon technologies have yet to be widely adopted due to insufficient innovations and have contributed less or even more negatively to carbon neutrality. Therefore, the current staple grain production system is still a net emitter. By transferring the successful approach from no straw burning to other farming practices, including nutrient management, tillage, irrigation, non-flooded aerobic rice and closing the yield gap, could lower the GHG intensity to -0.16, -0.16, -0.11 t CO2-eq t-1 for rice, wheat, and maize, respectively, achieving carbon neutrality in 2060. This research also implies that the involvement of multiple factors through integrated policies and technological innovation is critical to achieving carbon neutrality in grain production.