The Impact of China's Grain for Green Program on Farmer's Income : A Systematic Review and Meta-Analysis

The Grain for Green Program (GFGP) in China, one of the largest Payment for Ecosystem Service (PES) schemes, has been regarded as an effective approach to achieving sustainable development. However, the conclusion of the impact of GFGP on farmers’ income reported in the existing literature is still controversial. It is crucial to find the combined effect of the impact of the GFGP on farmers’ income and the causes of the heterogeneous effects. In this paper, the impact of the GFGP on farmers’ income with different income sources was analyzed by using the Meta-analysis method with 66 domestic and international studies from 1999 to 2022. The farmers’ income was further divided into four different income groups, total income (including subsidies), total income (excluding subsidies), farm income, and off-farm income. It is noteworthy that the differences in methodology, such as measurement of independent variables, data acquisition methods, sample regions, and the choice of estimation model could affect the results of the impact of the GFGP on farmers’ income. Thus, the heterogeneous effect of methodology had been conducted further. The results demonstrated: (1) The GFGP had a significant positive impact on total income (including subsidies) and off-farm income. However, the GFGP on total income (including subsidies) is not significant, and it may harm the farm income. (2) Using continuous variables (area of participation and years of participation) had higher estimated coefficients as opposed to using binary variables (whether to participate). (3) The effect of using primary data on total income (excluding subsidies) and off-farm income was higher than using secondary data. (4) The impact of the GFGP on farmers’ off-farm income was strongest in the central region, followed by the western region, and weakest in the nationwide region. The sample regions had no significant difference in other income groups. (5) The GFGP also had smaller effects on total income (including subsidies), total income (excluding subsidies), and off-farm income using the endogenous model compared to not using the model