Impact-oriented assessment of carbon, water and energy footprints for maize production: a case study in Shandong, China

The continuously increasing demands of food, feed and various corn-derived products accelerate the concern about the corn production on environment. Nevertheless, few researches simultaneously address the issue from different perspectives of carbon, water and energy as well as their temporal variations. Herein, a systematic cradle-to-gate life cycle assessment of maize production was conducted with a case study in Shandong, China. Different midpoint and endpoint indices including 10-year average data from 2011 to 2020 and their temporal variations were investigated. The contribution analysis of different processes to these indices revealed that irrigation dominated the midpoint of water scarcity, whereas the sum of direct consumption, fertilizer and diesel production contributed more than 80% to all the other indices. The sensitivity analysis also illustrated that these environmental indices can be reduced by as high as 4% when the aforementioned inputs were individually decreased by 5%. The temporal variation of the global warming potential, aquatic eutrophication and fossil depletion demonstrated that all the three indices were decreased by about 25.0%-31.7% over the last decade. Further persistent efforts to enhance mechanized operation efficiency and explore green and efficient methods for fertilizer and diesel production were highlighted. Moreover, implementations of rational agricultural management such as scientific fertilization and water-efficient irrigation were suggested, in order to have an eco-friendly maize production system.