Cooperation between specialized cropping and livestock farms at local level reduces carbon footprint of agricultural system: A case study of recoupling maize-cow system in South China

Decoupling of crop and livestock production has become increasingly common in the world during to past decades. The cooperation between specialized crop and livestock farms have been paid more attention for the development of sustainable agriculture. This study assumed that rebuilding the linkage between specialized crop and livestock farms through cooperation at the local level would decrease agricultural GHG emissions. Therefore, we designed a cooperative crop-livestock farming model (CCLS) in South China by recoupling the cow farm with the sweet maize cultivation farms around it to demonstrate the hypothesis based on carbon footprint (CF) method. The CFs under two cooperative scenarios (CCLS20 and CCLS50) were compared with the corresponding decoupling models (DCLS20 and DCLS50). Results showed that CCLS significantly reduced GHG emissions from cropping systems in comparison to DCLS primarily by increasing the soil organic carbon storage while decreasing accumulative N2O emissions. In specific, the CFs of CCLS20 and CCLS50 were 48.78% and 623.34% lower than DCLS20 and DCLS50, respectively. The yield-based CFs of CCLS20 and CCLS50 were 66.30% and 165.99% lower than DCLS20 and DCLS50, respectively. Meanwhile, the CF of the cow farm in CCLS20 and CCLS50 were 8.80% and 8.22% lower than that in DCLS20/50 by lowering relative GHG emissions of straw supply in roughage forage and shortening manure storage time in the manure management process. Finally, the yield-based CF in CCLS20 and CCLS50 were 67.68% and 168.51% lower than the DCLS20 and DCLS50, respectively, demonstrating that the cooperation between specialized planting and livestock farms at local level reduced the CF of the agricultural production chain by the synergistic reduction effects of GHG emissions in cropland, livestock rearing and transportation processes. The results would provide a quantitative understanding of the net GHG emission of cooperative crop-livestock system at the local level in China and valuable information for the development of sustainable farming system in the world.