Provincial-level Phosphorus Flow Analysis In Food Consumption System Of China

Since China’s reform and opening up,the Chinese food consumption level has improved a lot.The residents are chasing for higher-quality nutrient and more varied diets to satiesfy their gustatory and nutritional requirements.Therefore,large quantities of phosphorus rocks are mined to produce phosphate products like phosphorus fertilizer,which exacerbates phosphorus depletionand serious resource-related crisis.Meanwhile,the part of phosphorus which cannot be absorbed by human body will be discharged into the environment,which will definitely cause environmental degradation,especially eutrophication.These food consumption-oriented activities will interfere phosphorus cycle to a great extent.As a result,it is necessary to quantify China’s phosphorus flows from a food consumption perspective between 1980 and 2013.Moreover,China has a vast territory with regional disparities,so it is essential to quantify and analyze the phosphorus patterns at a provincial level.Hence,this study uses substance flowanalysis(SFA)to quantitatively analyze the provincial-level phosphorus flows of China’s food consumption system from 1980 to 2013.Based on the residents’food consumption phosphorus flow accounting model,we calculate the phosphorus input and output of 31 Chinese provincial administrative regions(PARs)from 1 980 to 2013 and analyze the spatial and temporal distribution characteristics.The results are shown as follows:(1)The total phophorus input exhibits a rising then a down trend and the regional disparities in animal food consumption enlarge over time.The total phosphorus input increases slowly from 1.1067 milliontons in 1980 to 1.2998 milliontons(peak value)in 1991 and then decreases rapidly to 0.8427 million tons in 2013,but the phosphorus input per-capitais dereasing all the time.As to the constitution of input,plant food is the main components all the time but similar to the total input,the amount comes to the peak value in 1991 and then declines steadily while the phophorus input of animal and condiment are increasing all through these 34 years.Spatially,phosphorus inputs of all kinds offoodexhibit a progressive decrease from south-easternregionto north-westem region and the disparities haven’t been narrowed as time passes by.Phosphorus input of animal food exhibits an upward trend in these 34 years,especially in the 1980s.The growth of north-western areas lags behind that of south-eastern areas.(2)The total phophorus output exhibits a rising then a down trend and the gap between urban and rural areas has been narrowed gradually.Phosphorus output in urban areas increases guadually while the output in rural areas shows a constant state before 2000 but a rapid decrease after 2000.In 1980,the total output in rural areas is 5 times more than that in urban areas,but in 2013,the total phosphorus outputs of these two areas are almost the same.As to the constitution of output,the phosphorus outputs in excrement and food processing loss have similar tendancy with the total phosphorus output.As to the kitchen garbage,the output in urban areas is increasing wile the output in rural areas shows an opposite situation.In the aspect of kitchen waste water,the output of urban areas is rising then dropping while in the rural areas,the output maintains steady before 2000 and increases rapidly soon after.(3)The main pathways of phosphorus emissions change from farm systems to sewage treatment plants and direct discharging.From a timescale perspective,the phopsphorus emissions to surface water body reaches the peak value in the late 1990s and drops gradually soon after.The phophorus emissions to farmland decrease as time goes by and this is basically due to the significant decreasing in the re-utilization rate ofhuman excrement.The emissions to livestock&poultry raising system is steady with a slight drop after 2000.The emissions to sewage treatment plants are rising with a rapid speed.The amount of phosphorus emissions to the other two pathways(waste treatment plant and stockpiling)are very limited with an increase in waste treatment plant and a drop in stockpiling.In terms of spatial distribution,as time goes by,the regional disparities of phosphorus emission to sewage treatment plants are becoming larger and larger,especially in the gap between south-eastern and north-western areas.The spatial distributionof phosphorus emissions to livestock&poultry raising system doesn’t change much.In the 1990s,there exhibits a downward trend in eastern&northern areas and an upward trend in western and southern areas.In 2000s,all PARs show a downw\wd trend except Tibet.As to the direct emissions to surface water,all PARs increase with a growth rate of less than 5%in 1990s but decrease with a drop rate of 5%in 2000s except Tibet and Xinjiang.In order to optimize phosphorus flow process and reduce phosphorus emissions,we put forward some policy implications.1)Develop organic agriculture and further enhance cyclic utilization rate of organic fertilizers as well as strengthen the farmers’consciousness of environmental protection;2)Enhance the resourceful treatment of kitchen garbage;3)Speed up infrastructure construction of economic less-developed areas.