Supplementary material to "Global and regional phosphorus budgets in agricultural systems and their implications for phosphorus-use efficiency"

Supporting Information Global P budgets in agricultural systems and their implications for phosphorususe efficiencyOur study concentrated on global and regional P budgets in agriculture and their phosphorus-use efficiency (PUE) in four main agricultural subsystems: cropland, managed grassland (hereafter, pasture), livestock, and humans.The specific P pools in this study were phosphate rock, phosphates produced from that rock, the atmosphere, pasture, livestock, cropland, harvested crops, humans, and the environment.The inputs and outputs for each P pool are described below. Phosphate RockAs a non-renewable resource, phosphate rock is the main source for most of the P that humans use (Liu et al., 2008).Mined phosphate rock is processed into phosphates (section 1.2) for subsequent use.Data for the annual quantities of mined phosphates were obtained from the International Fertilizer Industry Association (IFA; http://www.fertilizer.org/Statistics),which provided the data for global and regional levels (expressed as the P2O5 equivalent).The annual amount of P that is mined can be calculated from the proportion of the P in the P2O5 equivalent. PhosphatesThe P in phosphates is used in phosphate fertilizer, feed additives, detergents, and other uses.The Food and Agriculture Organization (FAO; http://www.fao.org/faostat/en/#home)provides the annual consumption of phosphate fertilizer for each country.Some of the phosphate fertilizer is applied to pasture in some