GHG emissions of straw treatments in rural China and scenario simulation based on life cycle perspective

Abstract

The comprehensive utilization of straw plays an important role in GHG emissions reduction. The main breakthrough point of promoting straw resource utilization in China is on staple crops. In this study, the current straw utilization and treatment status of staple crops in rural China were studied based on data from the 2019 China Rural Development Survey, which included five provinces, 100 villages, and 1015 households. A life cycle assessment was conducted to identify the GHG emissions of the various crop straw utilization and treatment methods. The GHG emissions per unit area from the crop and household perspectives were also observed. Furthermore, the trend in GHG emissions from crop straw utilization and treatment was predicted through scenario simulation. The results showed that the comprehensive utilization rates of rice straw and wheat straw in rural China were 85.30% and 98.41%, respectively, in 2018, whereas the comprehensive utilization rate of maize straw was only 40.25%. Rice straw has the highest GHG emission level of 11771.90 kgCO2-eq/ha from a long-term perspective. On a national scale, the average GHG emissions per unit area of household is 1229.56 kgCO2-eq/ha, with significant differences between provinces, from a maximum of 12033.77 kgCO2-eq/ha in Jiangsu to a minimum of −3599.77 kgCO2-eq/ha in Jilin. According to the results of the scenario simulation, if the ambitious measures in reducing the straw incorporated into paddy soil are not taken, future GHG emissions of staple crop straw may persist and even rise rapidly in rural China.