Beyond Yield Maximization: The Evolving Efficiency and Sustainability of Grain Production in Jiangsu Province, China, 1975–2024

Ensuring grain self-sufficiency through sustained yield growth is central to China’s food security policy. Yet, the long-term sustainability of this yield-centric model is in doubt. This study shifts the analytical focus from single-factor yield to a holistic measure of productive efficiency. We calculate Technical Efficiency (TE) scores for Jiangsu Province’s staple grains (rice, wheat, maize) from 1975 to 2024 using a Super-Slacks-Based Measure (Super-SBM) model, integrating physical output and output value. A Tobit regression identifies drivers of TE change. Results show that TE evolved in three phases aligned with major policy shifts: incentive restoration, market liberalization, and production support. While TE improved sequentially, the post-2004 support phase reveals a critical paradox: yields now exceed the economic efficiency frontier, yet this coincides with systematic input redundancy, particularly capital overuse, and suppressed profitability. This indicates that efficiency gains, driven mainly by pure technical efficiency, are being eroded by diminishing economic sustainability. Regression analysis shows that urbanization and cropping structure hinder TE, whereas market prices, irrigation, and mechanization enhance it. The study concludes that the prevailing yield-maximization paradigm undermines economic viability. A sustainable transition requires shifting from chasing maximum yields to optimizing productive efficiency through cost-saving technologies and market-conforming incentives.