Crop yield and carbon sink potential with precipitation in maize and potato cropland ecosystems over the summertime monsoon transition zone of China

Abstract China has significantly enhanced vegetation coverage and terrestrial carbon sink functions through ecological restoration. However, cropland ecosystems are sensitive to a changing climate over the summertime monsoon transition zone of China (SMTZC), which has implications for carbon cycling. For example, it is unclear how changes in precipitation will affect the cropland ecosystem carbon sinks (CS e ) and carbon sink potential (CS p ), and the mechanisms of tradeoffs that develop between plant and soil organic carbon (SOC) are unclear. Here, we integrated crop yield, total biomass (TB) and water coefficient in a combined field and modelling experimental. We explored the mechanisms of ecosystem carbon cycling and CS p in the SMTZC under different precipitation scenarios. We found that soil organic carbon sink (SOC s ) was strongly correlated with the plant organic carbon sink (POC s ) and discovered. Significant differences in CSp between ecosystems resulting from interannual precipitation. The C 4 (maize, Zea mays ) and C 3 (potato, S olanum tuberosum L ) carbon sinks (CSs) were 68.59, 190.73, 160.37 Mt and 10.21, 30.97, 14.59 Mt for the 3 years, respectively. Precipitation effectively increased TB and yield, but excessive precipitation in them, which was most obvious in C 3 ecosystem ( R 2 > 0.60) and reduced POC s , evident in C 4 ecosystem ( R 2 > 0.16). This study provides data and a scientific basis for increasing CS and achieving carbon neutrality in cropland.