Does more work mean more gain? The inverted U-shaped effect of agricultural labor time on income among the rural elderly

Appropriate agricultural labor time and stable agricultural income are essential foundations for ensuring the well-being of the rural elderly. Based on data from the 2018 China Health and Retirement Longitudinal Study (CHARLS), this study examines the impact of agricultural labor time on agricultural operating income and its underlying mechanisms. The results reveal a robust inverted U-shaped relationship between agricultural labor time and agricultural income, with most rural elderly individuals still within the positive gain phase, having not yet exceeded the curve’s turning point. Mechanism analysis shows that agricultural labor time influences agricultural income through a nonlinear mediating effect of agricultural production input. In addition, the ownership of agricultural fixed assets significantly moderates this relationship; higher fixed asset ownership flattens the inverted U-shaped curve and shifts the turning point to the right. Heterogeneity analysis further indicates that this nonlinear relationship is only significant among rural elderly individuals with higher agricultural income, while those with lower income experience only a significantly negative linear effect. The turning point for younger elderly individuals is located further to the right than that of older elderly individuals, indicating longer effective labor time. Regionally, the labor time required to attain the maximum agricultural income is longest in western China, followed by the central region, and shortest in the eastern region. Based on these findings, it is recommended to guide rural elderly individuals to optimize their labor time based on regional and demographic characteristics, explore the establishment of labor exit compensation mechanisms, and enhance policy and service support for both agricultural operators and rural elderly participants in agricultural production.