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Journal articleIFPRI3; CRP2; CRP7; A Ensuring Sustainable food production; DCA; ISIEPTD; PIMPRCGIAR Research Program on Policies, Institutions, and Markets (PIM); CGIAR Research Program on Climate Change, Agriculture and Food Security (CCAFS

Phosphorus (P) is a finite and dwindling resource. Debate focuses on current production and use of phosphate rock rather than on the amounts of P required in the future to feed the world. We applied a two-pool soil P model to reproduce historical continental crop P uptake as a function of P inputs from fertilizer and manure and to estimate P requirements for crop production in 2050. The key feature is the consideration of the role of residual soil P in crop production. Model simulations closely fit historical P uptake for all continents. Cumulative inputs of P fertilizer and manure for the period 1965-2007 in Europe (1,115 kg·ha −1 of cropland) grossly exceeded the cumulative P uptake by crops (360 kg·ha −1 ). Since the 1980s in much of Europe, P application rates have been reduced, and uptake continues to increase due to the supply of plant-available P from residual soil P pool. We estimate that between 2008 and 2050 a global cumulative P application of 700-790 kg·ha −1 of cropland (in total 1,070-1,200 teragrams P) is required to achieve crop production according to the various Millennium Ecosystem Assessment scenarios [Alcamo J, Van Vuuren D, Cramer W (2006) Ecosystems and Human Well-Being: Scenarios, Vol 2, pp 279-354]. We estimate that average global P fertilizer use must change from the current 17.8 to 16.8-20.8 teragrams per year in 2050, which is up to 50% less than other estimates in the literature that ignore the role of residual soil P.food security | global crop production | phosphorus depletion | hysteresis S ignificant improvements in agricultural productivity and efficiency of resource use are required to secure food production for the projected world population in 2050 (1). Food production needs to grow faster than the global population due to changing human diets (i.e., increasing per-capita consumption of meat) and production of biofuels. This challenge can be managed through significant improvements in agricultural productivity and phosphorus (P) fertilizer use efficiency.P is essential for plant growth and often a major limiting nutrient in agriculture (1-3). Many studies have raised concern about rapid depletion of the world's P reserves (4, 5). Recently, it was suggested that global P production will peak by 2033 (5). In contrast, other studies conclude that almost half of the currently available P resources will be depleted by 2100 (6), or that P rock reserves will be available for the next 300-400 y (7).Resource use efficiency, including strategies such as recycling of human P sewage sludge and other waste materials containing P, and reducing runoff and erosion, will be important to improve the sustainability of human P cycle (6).Readily available P in the soil solution provides most of the plantavailable P. The two main factors that control the availability of P to plant roots are the concentration of phosphate ions in the soil solution and the P-buffer capacity, i.e., the ability of the soil to replenish these ions when plant roots remove them (3). Soils differ in their buffering capaci...

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