Economies of Scale and Heterogeneous Benefits of Improved Rice Varieties: Evidence from Smallholder Farmers in Cambodia – The Case Study in Bati District, Takeo Province, Cambodia

Adoption of improved rice varieties is widely promoted to enhance productivity and income, yet the magnitude of benefits may vary across farm structures and resource endowments. This study examines the heterogeneous impacts of adoption on rice yield and profit among smallholder farmers in Cambodia, focusing on economies of scale and complementary factors such as market access and asset ownership. Using the inverse probability weighted regression adjustment (IPWRA) method combined with individual interaction models, the analysis reveals that adopters experience significant gains—25.3% higher yield and 86.2% higher profit compared to non–adopters. Interaction results show that larger rice plots, better road conditions, and car ownership amplify adoption benefits, while remote locations and disease pressure also positively influence outcomes, suggesting adaptive management strategies. These findings underscore the importance of infrastructure, mobility, and technical support in maximizing the returns to improved rice technologies. Policy implications include targeted extension services, investment in rural roads, and promotion of collective farming models to leverage economies of scale.