How does land renting-in affect chemical fertilizer use? The mediating role of land scale and land fragmentation

Chemical fertilizer overuse poses a significant challenge for sustainable agriculture and food safety. Against this background, land transfers that raise farmers' resource allocation efficiency and achieve scale agricultural operation are especially valuable. Based on survey data from 12 rice-producing provinces in the south of China during the period between 2018 and 2019, this paper employs the control function approach to explore the impact of land renting-in on chemical fertilizer use. The results show that land renting-in reduces the usage of chemical fertilizers by 50.34%. The fertilizer-reduction effect is weakened with farmers who have received cultivated training but enhanced with farmers who have purchased crop insurance and farmers who hold more household assets. It is interesting to note that the reduction effect of land renting-in remains stable with an increase in household head age. Furthermore, the marginal treatment effects suggest that the reduction effect of land renting-in is significant for those rice farmers with high resistance to rent in cultivated land. Finally, we find that both land scale and land fragmentation play a mediating role between land renting-in and chemical fertilizer use. Our analysis emphasizes the importance of land transfer in fertilizer reduction and the need for policies that improve the willingness to land transfer to reduce environmental pollution and ensure food safety.