Comparative analysis of phosphorus use within national and local economies in China

Material/substance flow analysis (MFA/SFA) approaches have been broadly applied to bridge the knowledge gaps in material metabolism within modern economies¿and the environmental consequences it cause. While the structural feature of material use can vary along a physical dimension, there is a need to analytically normalize the implications derived from various material flow models to facilitate policy making, with respect to the associated socio-economic profiles. This is particularly important in accounting for material throughput, given various data uncertainties. This study attempts to develop an illustrative framework combining the mass balance approach [Adriaanse A, Bringezu S, Hammond A, et al. Resource flows: the material basis of industrial economies. Washington, DC: World Resources Institute; 1997] and proposed material use indictors at a substance level. The methodology is then applied for the case of the phosphorus cycle in China, the largest developing country currently in transition. Our discussion is conducted on the basis of two updated static SFA models which have been developed recently [Liu Y, Mol APJ, Chen JN. Material flow and ecological restructuring in China: the case of phosphorus. J Ind Ecol 2004;8(3):103¿20; Liu Y, Chen JN, Mol APJ. Evaluation of phosphorus flows in the Dianchi Watershed, southwest of China. Popul Environ 2004;25(6):637¿56]. Taking mineral reserve, commodities trading and environmental accumulation into account, the aggregated physical features of phosphorus flows are identified at both the national and local levels, respectively, by treating the overall lifespan of substance use within these economies as a whole. Material use efficiencies of six subsystems ¿ involving the phosphate industry, crop farming, intensive livestock husbandry, family-based animal rearing and urban and rural households ¿ are analyzed. The results highlight that both the aggregate and sectoral features of phosphorus use varies significantly with the shift in geographic boundary from national to local economies. With respect to the substantial differentiations, the discussion on desired structural adjustment strategies and efficiency-enhancement options towards a systematical improvement of phosphorus use could facilitate future rational policy-making.