Satisfying meat demand while avoiding excess manure: Studying the trade-off in eastern regions of China with a nitrogen approach.

Due to the rising incomes and rapid urbanization, China is facing a challenge in producing more meat while avoiding excess manure. These objectives might be in contrast: if excess manure is avoided, meat self-sufficiency might not be met; in contrast, meeting meat self-sufficiency might cause severe excess manure. Our study (1) characterizes the eastern regions of China according to the deficiency/excess of manure nitrogen and meat production, and investigates their relationships with natural resources and social economic indicators; (2) analyzes how the trade-off changes with increasing proportion of chemical nitrogen substituted with manure nitrogen (PCSM). Elaborating on data, we divided eastern regions of China into types according to satisfaction/unsatisfaction of meat demand and deficiency/excess of manure. We then re-calculated the number of regions in each type simulating the effect of increasing values of PCSM. In ~15% of the regions, meat self-sufficiency was met without manure excess, but in ~76% of the regions, manure excess occurred where meat self-sufficiency was met. In ~2% of the regions, meat self-sufficiency was not met and manure excess was absent; in ~7% of the regions, meat self-sufficiency was not met and excess manure was observed. The higher the regions' GDP (gross domestic product) per capita, the lower their ability to satisfy meat demand; the more arable land per capita in the regions, the higher their ability to satisfy meat demand and avoid excess manure. For the scenarios of increasing PCSM, our results show that some regions still cannot avoid excess manure with unchanged livestock quantity, although manure fertilizer completely replaced chemical fertilizer. Our study suggests that the regions of eastern China need to advocate a healthy diet and strengthen the management of food waste and livestock manures. The study is significant for policymakers to achieve sustainable agricultural production.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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