Sustainability evaluation of protected vegetables production in China based on emergy analysis

Protected vegetables have undergone rapid development in recent decades in China, accompanied by high resource consumption and environmental load. This study adopts emergy synthesis to evaluate the sustainability of protected vegetable production system (PVPS) in China. The emergy input structure and emergy flow of the PVPS were first determined to reveal its unique artificial environment from the perspective of facility structure and internal environment. Then, a new emergy indicator of artificial environment sustainability (EIAS) and conventional emergy-based indicators were proposed to evaluate the regional heterogeneity of PVPS in China's four major producing regions. Finally, six hypothetical scenarios were designed to explore the future development direction and sustainability of the PVPS. The results showed that the total emergy input for PVPS was 3.79E+22 sej in 2018, which mainly depended on non-renewable purchase emergy, such as labor and services (41.67%), artificial environment construction (23.35%), and land cost (10.83%). The provinces with the highest emergy inputs were concentrated in the Huang-Huai-Hai temperate region, followed by the subtropical region of the Yangtze River Basin. The proportion of artificial environment construction input in the northeast temperate region was the largest, while that in the subtropical region of the Yangze River Basin was the smallest. Compared with the baseline scenario, emergy input can be reduced by 1.79%, and sustainability can be improved by 1.96%, by reducing artificial environment construction input by 2030, with a limited optimization effect. Integrated technological improvements, such as advanced farmland management, water-saving irrigation technology, and energy-efficient utilization, can improve the sustainability of PVPS by 5.99% without sacrificing vegetable yield. This study provides a better understanding of the sustainable management of PVPS.

Automated summary

This study evaluates the sustainability of protected vegetable production system in China using emergy synthesis and proposes new indicators for artificial environment sustainability. The study reveals the total emergy input and regional heterogeneity of the system, and explores future development directions and sustainability through hypothetical scenarios. The results show that reduction in artificial environment construction input and integrated technological improvements can improve the sustainability of the system without sacrificing vegetable yield.