Can Rural Characteristic Industry Development Increase Farmers’ Income? Evidence from the Superposition of “One Village, One Product” and Leisure Agriculture and Rural Tourism Demonstration County Policies

Amid China’s rural revitalization and common prosperity agendas, breaking from traditional agricultural path dependence to achieve sustained income growth for farmers remains imperative. As underscored in the No. 1 Central Document, developing agricultural multifunctionality and deepening the integration of primary, secondary, and tertiary industries are strategic priorities. The One Village One Product (OVOP) and Leisure Agriculture and Rural Tourism Demonstration County (LARTDC) policies represent two key initiatives for implementing this orientation. Using county-level panel data from China for 2010–2023, this paper integrates the OVOP policy and the LARTDC policy into a unified analytical framework. It employs overlapping difference-in-differences (DID), difference-in-differences machine learning, causal mediation analysis, and quantile regression to examine the impact, mechanisms, heterogeneity, and sharing effects of policy superposition (the simultaneous implementation of the two policies) on famers’ disposable income. The results show that policy superposition can raise rural residents’ disposable income. When the two policies are disentangled, the estimated net effect of their superposition is the largest. Further analysis indicates that policy superposition significantly strengthens the income-increasing effect of the OVOP policy. Mechanism analysis reveals that improved entrepreneurship is the core transmission channel; family farms, the entry of agricultural and tourism enterprises, and organic product certification also serve as significant pathways, whereas the contributions of survival entrepreneurship and agricultural operational service organizations are limited. Heterogeneity teset demonstrates that the policy superposition effect is more pronounced in districts and counties with favorable locational endowments, a strong agricultural foundation, and convenient transportation; it also diminishes as income quantiles rise, indicating a clear pro-poor pattern. By rural industry type, the LARTDC policy exerts a subsidy effect on low-value-added industries such as food crops and fisheries. Additional analysis shows that policy superposition significantly reduces spatial inequality, improves rural income sharing, reduces the deprivation effect among low-income farmers, and narrows the urban–rural income gap, thereby exhibiting inclusive growth and common prosperity effects. This paper offers a new theoretical perspective for understanding the sharing effects of collaborative policy mixes across industrial chains.