Will the substitution of capital for labor increase the use of chemical fertilizer in agriculture? Analysis based on provincial panel data in China.

Abstract

Major changes have taken place in the agricultural factor input structure in China, which will inevitably affect fertilizer input in agriculture. However, there is no consistent conclusion about the impact of capital and labor input on chemical fertilizer input. This paper employed directed acyclic graphs (DAGs) to clarify the influence of capital-labor input structure on the use of chemical fertilizer. Using inter-provincial panel data, the dynamic panel system GMM method was adopted to examine the mechanism of factor substitution elasticity in determining the impact of agricultural capital-labor input on chemical fertilizer input. The results showed that agricultural labor and capital input are positively correlated with chemical fertilizer input. In the process of capital and labor input affecting fertilizer input, the elasticity of factor substitution plays a negative moderating role. From 1996 to 2018, the trend of capital replacing labor was evident, and the increase ratio of capital input was greater than the decrease ratio of labor input. Therefore, an increase in capital input and its substitution for labor is the main driver of the increase in fertilizer input. At the same time, the elasticity of fertilizer-capital substitution declined during the period 1996-2018, thereby reinforcing the increase in fertilizer input caused by the increase in capital input. In order to reduce agricultural pollution caused by the increase in chemical fertilizer input, it is crucial to reverse the declining trend in the elasticity of fertilizer capital substitution.