Agricultural carbon emission efficiency and its regional convergence in China: Role of land use modes and economic factors

China’s agricultural sector is a key contributor to global carbon emissions, making improvements in Agricultural Carbon Emission Efficiency (ACEE) crucial for achieving climate and food security goals. Departing from traditional studies that often assume a singular nationwide evolutionary path, this research investigates the divergent convergence dynamics of ACEE through the lens of land-use modes to map its long-term evolution. By applying a club convergence methodology to provincial panel data from 2004 to 2020, we reject the hypothesis of a unique steady state and identify instead five distinct convergence clubs with heterogeneous equilibrium pathways, alongside a small group of non-converging provinces. The results reveal that agricultural land-use modes act as a fundamental sorting mechanism: while diversified systems generally facilitate higher efficiency equilibria, specialized production bases often face efficiency bottlenecks despite their scale advantages. Furthermore, the economic drivers of efficiency differ markedly across clusters, showing that imbalanced fixed-asset investment constrains further gains in high-efficiency regions, whereas narrowing urban-rural income gaps consistently supports efficiency across most clubs. These findings underscore the necessity of club-specific, locally adapted strategies that align production systems, land-use modes, and factor inputs with regional realities to foster sustainable agricultural development and enhance China's contribution to global carbon reduction.