Incentives for the adoption of maize–soybean rotation in Northeast China: Modelling the impact of future subsidy policies

Preserving soil health is a global priority for achieving sustainable food systems. Although crop rotation is widely recognised as an effective soil-conserving practice, adoption remains limited in many countries due to persistent profitability gaps relative to monoculture. Using an agent-based model and Northeast China as a case, we estimate the subsidy levels and policy portfolios required to scale up maize–soybean rotation. The simulations show that an annual rotation consistently outperforms a biennial system, and adoption increases with subsidy intensity but exhibits diminishing marginal returns. On average, each additional 1000 Chinese Yuan (CNY) is associated with a 7% increase in the adoption rate. Importantly, farmers’ awareness of rotation benefits and their willingness to adopt substantially promote diffusion, demonstrating that non-monetary measures—such as education, demonstrations, and extension services—greatly enhance the effectiveness of financial incentives. At a subsidy level of 9000 CNY/ha, the adoption rate of the combined non-monetary measures is 23.0% higher than that of monetary subsidies alone. Our analysis indicates that subsidy programs become effective only when monetary incentives are integrated with these non-monetary measures. Without such complementary support, financial incentives not only have limited influence on adoption but also risk imposing a substantial fiscal burden.