Sustainability evaluation for a circular maize-pig system driven by indigenous microbes: a case study in Northeast China.

Sustainable agricultural development is a topic of global concern aiming at satisfying food demand of the growing population while reducing impact on environment. Circular agriculture has become a promising development pattern with the advantages of complementing environmental resources, replacing feedback from outside system, and processing waste of bottom of system, etc. This study combined economic analysis, life cycle assessment and emergy accounting to evaluate sustainability of an integrated maize-pig system (IS) driven by indigenous microbes in Northeast China, compared with separated maize and pig system (SS). IS reduced input of concentrate feed, coal, vaccines, disinfectants, fertilizer and labor by 14.35%, 100%, 46.11%, 100%, 60.1% and 60.8% driven by indigenous microbes. Economic analysis results showed that IS has 82.88% higher profit than that of SS. The sum of potential environmental impacts of IS was lower than SS for 80.65% according to lifecycle assessment. The emergy results revealed that IS performed better sustainability. Internal feedback emergy for fertilizer and local resources for maize straw increasing of IS significantly improved emergy efficiency. The reduction resulted in nonrenewable resources decreased 33.01% than that of SS, and increased renewable resources by 67.81%, which reduced environmental load ratio of IS by 60.08% of IS. Meanwhile, these factors were the primary factors generating higher sustainability of IS. Overall, the integrated maize-pig system driven by indigenous microbes in this study can effectively alleviate the problems caused by agricultural waste and promote sustainable agricultural development. [ABSTRACT FROM AUTHOR]