[Spatial and Temporal Variation Characteristics and Driving Factors of Carbon and Nitrogen Footprint in Wheat and Maize Production Systems in Henan Province].

As the main producing area of wheat and maize in China, Henan Province produces considerable greenhouse gases during the production and planting processes. Determining the characteristics of carbon and nitrogen footprint changes during the growth process and analyzing the key driving factors will provide a basis for the green production of wheat and maize. Based on the life cycle assessment and LMDI model, the spatio-temporal characteristics, composition change trends, and driving factors of the carbon and nitrogen footprint during wheat and maize production in Henan Province from 2011 to 2020 were systematically evaluated. The results showed that： ① The production cost of wheat was higher than that of maize. ② The carbon footprint per unit area （ CO₂-eq ） of wheat and maize in Henan Province was 1.98 t·hm^-2 and 1.76 t·hm^-2, and the nitrogen footprint per unit area （N-eq ） was 48.28 kg·hm^-2 and 28.37 kg·hm^-2, respectively. The carbon footprint of wheat and maize in Henan Province showed a fluctuating upward trend, and the nitrogen footprint showed a decreasing trend year by year. ③ Irrigation emissions and NH₃ volatilization were the main components of the carbon and nitrogen footprint of wheat and maize, accounting for 28.64 % and 81.27 % of the carbon and nitrogen footprint of wheat and 35.28 % and 82.21 % of the carbon and nitrogen footprint of maize, respectively. ④ The carbon and nitrogen footprints of different cities in Henan Province were different, showing a higher trend in the southeast and a lower trend in the northwest. ⑤ The results of the LMDI model analysis showed that economic factors increased carbon and nitrogen emissions during wheat and maize production, whereas labor and production factors reduced carbon and nitrogen emissions. In summary, to reduce the carbon and nitrogen emissions of agricultural production in Henan Province, we should reduce labor and production costs, develop fertilizer-saving and water-saving technologies, strengthen agricultural science and technology innovation capabilities, and combine policies and economic incentives to promote the development of green and low-carbon agriculture and finally achieve carbon neutrality.