Yao Zhi, Zhang Wushuai, Wang Xiaozhong, Lu Ming, Chadwick Dave, Zhang Zhe, Chen Xinping
Key Laboratory of Efficient Utilization of Soil and Fertilizer Resources, Chongqing, 400715, China.
Interdisciplinary Research Center for Agriculture Green Development in Yangtze River Basin, College of Resources and Environment, Southwest University, Chongqing, 400715, China.
Environ Sci Pollut Res Int. 2021 Jun;28(22):28680-28691. doi: 10.1007/s11356-021-12663-w. Epub 2021 Feb 5.
Maize production is critical in tropical/subtropical regions, especially in developing countries where maize is a staple food. However, its environmental costs remain unclear. Southwest China is a tropical/subtropical region with large-scale maize production in each of its sub-regions. In the present study, we used Southwest China as a case study to evaluate the greenhouse gas (GHG) emissions and carbon footprint (CF) of maize production during 1996-2015 using life cycle assessment to identify the driving factors behind the GHG emissions and CF and to propose potential mitigation strategies. The mean GHG emissions of maize production per year during 1996-2015 was 4132 kg CO-eq·ha, and the CF during this period was 961 kg CO-eq·Mg. The GHG emissions and CF in Southwest China were 2-4 times higher than those of other major maize-producing regions worldwide. The GHG emissions and CF were both significantly correlated with the N surplus. The N surplus was also linearly correlated with annual precipitation, annual temperature and growing degree days, but not significantly related with soil pH. Scenario testing showed that the CF of maize production in Southwest China could be reduced by 41%, i.e. to 437 kg CO-eq·Mg, by farmers adopting a comprehensive strategy including recommended fertiliser application rates, innovative fertilisers, and crop management to decrease GHG emissions and achieve the yield potential in the region. Integrated soil and crop management is essential for sustainable maize production in tropical/subtropical regions with complex and changeable ecological conditions, especially in developing countries where maize is a staple food.
玉米生产在热带/亚热带地区至关重要，特别是在玉米作为主食的发展中国家。然而，其环境成本仍不明确。中国西南地区是一个热带/亚热带地区，其各个子区域都有大规模的玉米生产。在本研究中，我们以中国西南地区为例，利用生命周期评估法评估了1996 - 2015年期间玉米生产的温室气体（GHG）排放和碳足迹（CF），以确定温室气体排放和碳足迹背后的驱动因素，并提出潜在的缓解策略。1996 - 2015年期间玉米生产的年均温室气体排放量为4132千克二氧化碳当量·公顷，这一时期的碳足迹为961千克二氧化碳当量·吨。中国西南地区的温室气体排放和碳足迹比世界其他主要玉米产区高出2 - 4倍。温室气体排放和碳足迹均与氮盈余显著相关。氮盈余也与年降水量、年平均气温和生长度日呈线性相关，但与土壤pH值无显著关系。情景测试表明，通过农民采用包括推荐施肥量、创新肥料和作物管理等综合策略来减少温室气体排放并实现该地区的产量潜力，中国西南地区玉米生产的碳足迹可降低41%，即降至437千克二氧化碳当量·吨。在生态条件复杂多变的热带/亚热带地区，特别是在玉米作为主食的发展中国家，综合土壤和作物管理对于可持续玉米生产至关重要。
