Increasing Farm Size and Optimized Agronomic Practices to Improve Agricultural Sustainability: A Multi-Indicator Assessment in the North China Plain

CONTEXT : Farm size plays a critical role in agricultural sustainability, which has far-reaching consequences for the economic and environmental performances of food production. However, the effect of farm size on the magnitude of such impacts and their main causes are not well understood, while being essential for effective policy development, especially for countries like China where the agricultural sector is still largely dominated by small farms.OBJECTIVE : We aim to evaluate agricultural sustainability for large and small farms based on GHGs, reactive N losses, energy use efficiency, and net economic benefits. Further investigate potential ways to reduce the environmental burden for the farms in the North China Plain.METHODS : Using farm survey data from 2015-2017 in the North China Plain, the sustainability index of wheat-maize cropping systems was assessed by quantifying the greenhouse gas emissions (GHGs), reactive nitrogen (N) losses, energy use efficiency, and net profit in large and small farms (LF vs. SF).RESULTS AND CONCLUSIONS : Our results showed the sustainability index of LF (0.45-0.65) was higher than that of SF (-0.04-0.27), mainly due to the 1.4-2.1 times higher net profit in LF than SF. This was further supported by the linear relationship between sustainability index and farm size for both wheat and maize production. The LF and SF with low GHGs had a higher sustainability index relative to the high emission ones. Especially, both wheat and maize for the low GHG emission LF had the highest sustainability index (0.62 and 0.86), followed by low GHG emission SF (0.19 and 0.55). This was mainly due to the lower GHGs and reactive N losses, since low GHG emission farms had more efficient managements, i.e. optimized N fertilization and scientific irrigation schedule. The literature review further supported that increasing farm size improves agricultural sustainability in China.SIGNIFICANCE : Increasing farm size and the use of profitable low emission agronomic practices could improve agricultural sustainability by reducing the environmental consequences and enhancing economic benefits.