Beyond the land quantity: Rethinking the role of land quality in agriculture from the efficiency perspective

With the development of production frontier theory, the technical efficiency analysis framework integrating quantitative and quality indicators has become a new trend. Few studies have tried to embed land quality as an input into the technical efficiency analysis, but the discussion on the scientificity and necessity of the selected indicators is still insufficient. This study selected soil organic carbon (SOC) as the characteristic index of land quality and embedded it into the parametric directional distance function to discuss the difference between the unconstraint model and constraint model. The results show that regarding the econometric test, the model with SOC has better realistic interpretation ability. Regarding technical efficiency, the model without SOC cannot reflect the actual characteristics of agricultural production. Regarding shadow price, the ideal market value of SOC is much higher than that for land quantity. Regarding substitution elasticity, the SOC cannot be substituted by land quantity in arable land use. We propose to select key indicators from the soil that participate in the crop growth process, serve as components of crop nutrients, and have a positive correlation with crop yield as representative indicators of land quality to be incorporated into the production function after the necessary and scientific systematic evaluation of the indicators to promote the sustainable use of land resources.