Abstract:

In recent years, the carbon footprint of agricultural production has been a hot issue in the research on greenhouse gas (GHG) emissions reduction in China. Based on the statistical data of yield, sown area and agricultural production inputs in 14 wheat-growing provinces from 2015 to 2020, authors calculated the carbon footprint of inputs for wheat life cycle, studied the dynamic changes of carbon footprint of wheat life cycle and analyzed the proportion of carbon footprint for different agricultural inputs, and revealed the change rule of carbon footprint for wheat life cycle and the composition of emission sources. These results can provide a theoretical basis for realizing energy conservation and emission reduction in agricultural production and green low-carbon development. The results showed that the average carbon footprint per unit area and the average carbon footprint per unit yield of wheat life cycle in 14 provinces from 2015 to 2020 were 4315.4 kgCO₂eq×ha⁻¹ and 999.4 kgCO₂eq×t⁻¹, respectively, which showed a downward trend. The average carbon footprint per unit area and the average carbon footprint per unit yield of wheat life cycle in Shanxi province and Shaanxi province in northern winter (autumn sowing) wheat production region, the Inner Mongolia autonomous region and the Ningxia Hui autonomous region in spring wheat production region, and winter-spring wheat production area (Xinjiang) were higher than the average annual level of the total study regions in this paper. While the average carbon footprint per unit area and the average carbon footprint per unit yield of wheat life cycle in southern winter (autumn sowing) wheat production region (Sichuan, Jiangsu, Anhui and Hubei), Heilongjiang province and Gansu province in spring wheat production region and Shandong province and Henan province in northern winter (autumn sowing) wheat production region were lower than the average annual level of the total study regions of this paper. In the carbon footprint structure of wheat life cycle, the average carbon footprint of irrigation electricity, chemical fertilizer, diesel fuel, wheat seed and pesticides accounted for 34.2%, 51.6%, 7.3%, 3.7% and 3.2%, indicating that chemical fertilizer and irrigation electricity were the main sources of agricultural carbon footprint. Chemical fertilizer was the main source of agricultural carbon footprint in Southern winter (autumn sowing) wheat production region (Jiangsu, Anhui, Hubei and Sichuan), with an average proportion of 76.6%, 71.3%, 69.6% and 70.0%, respectively. Therefore, reducing chemical fertilizer input and increasing utilization efficiency were important emission reduction measures in these regions. Meanwhile, irrigation electricity was the main source of agricultural carbon footprint in Hebei province and Shanxi province in northern winter (autumn sowing) wheat production region and winter- spring wheat production region (Xinjiang), with an average proportion of 45.6%, 54.8% and 65.2%. Therefore, promoting the application of water-saving irrigation and developing low-energy-consuming machinery and equipment were important emission reduction measures in these regions. In short, reducing chemical fertilizer input and promoting water-saving irrigation technology to reduce the carbon footprint of wheat life cycle in study regions were effective management measures, and considering regional socio-economic and agricultural conditions of each province, formulating targeted measures to reduce agricultural greenhouse gas emissions is the key to promote the green and low-carbon development of agriculture. 

Key words:

Wheat production, Carbon footprint, Agriculture production input, Life cycle assessment, Green low-carbon