Dynamic Substance Flow Analysis Of Phosphorus Resource Metabolism In China And Its System Dynamic Model Research

Phosphorus (P) ore belongs to one of the nonrenewable resources with strategicimportance. Against the backdrop of economic development, population growth andaccelerating urbanization process, the tension between the supply and the demand of Pore, the decline in its ore grade, the rise in its price and related environmental problemshave imposed a great threat on China’s resource security, ecological security and evenfood security. Therefore, the formulation and implementation of active and effectivepolicy measures as soon as possible, with the goal of easing the supply-demand tensionand meanwhile gaining environmental benefits to the largest extent, means a lot for theconstruction of a recource-conserving and environment-friendly society within China.This research employed quantitative analysis and model research methods toinvestigate what policy measures could be carried out to realize scientific managementof anthropogenic P flows and sustainable utilization of P resource in China. In thisdissertation research framework of the dynamic substance flow analysis approach usedfor the national P resource metabolism in China, was firstly proposed. Dynamic changecharacteristics of P ore mining, P chemical product manufacturing, P-contaning productconsumption, plus the recycling and the emissions of P wastes, were then quantitativelyanalysed during1980to2010, and at the same time critical factors which affected thesupply and the demand of P resource were identified respectively. After that, a systemdynamic model for China’s national P resource metabolism was developed based onresearch framework. Consequently this model was utilized to explore the future changetrend of China’s P resource metabolism during2011to2050under social-economicdevelopment baseline scenarios. Beisdes, policy simulation was conducted with the aidof the model, towards a series of supply-side and demand-side policy options whichwere designed according to critical supply-side and demand-side factors. Their medium-and long-term effects on China’s P resource metabolism were elaborated and compared,from which the best policy measures could be recommeded, for the sake of the betterrealization of the scientific management of anthropogenic P flows within China.P inputs into P-containing product consumption system rose from3.1million ton Pin1980to10.1million ton P in2010, whereas its recycling rate of P wastes decreased from70.6%in1980to43.9%in2010, inevitably leading to the outcome that the overalltrait of nutrient loss and environmental pollution was intensified, which was embeddedin China’s national P resource metabolism. It was identified in quantitative analysis thatsupply-side critical factors included recycling ratios of living wastes from city life andanimal manure from intensive breeding, and that demand-side critical factors includedthe percentages of livestock products in the daily diet of urban and rural residents, theconversion rate of animal fodder P and the apparent application efficiency of fertilizers.Under baseline scenarios, P resource consumption in China will grow rapidly, resultingin the consequence that the present ensured reserves of P ore in China will be used up in2029. Supply-side policy options cannot effectively extend the service life of present Preserves, because their threshold was rather low and a period for gradual developmentand accumulation is a necessity for them to achieve a rather high level. In contrast, all ofdemand-side policy options can prolong the service life to different degrees. However,they do not take the recycling of P wastes into account and will undoubtedly bring aboutnutrient loss and environmental risks. Under the best integrated scenario of supply-sideand demand-side measures, the recycling ratios of city life’s living wastes and intensivebreeding’s anminal manure, the conversion rate of animal fodder P and the apparentapplication efficiency of fertilizers are respectively raised to61.1%,65.2%,29.3%and0.94kilogram per ton in2050, and meanwhile the percentages of livestock products inthe daily diet of urban and rural residents are adjusted reasonably. As a result,34.2%ofthe present ensured reserves will remain and at the same time the average emissions ofP wastes per capita will keep falling after reaching peak values in2018, which indicatesthat both resource conservation and environmental friendliness are both realized. Thesesimulation results strongly suggest that an integrated policy framework, combining bothsupply-side and demand-side policy options, can be considered as a better tool for thetimely achievement of sciecntific management of anthropogenic P flows and sustainbaleuse of P in China.