Biogeochemical Flows: Phosphorus

Planetary Boundary

  • Global P Boundary: 11 Tg P/year*
  • Regional (watershed) P Boundary: 6.2 Tg P/year*
  • Current global rate of P fertilizer to croplands* (primary source of P to regional watersheds): 14.2 Tg P/year*
    • Total P flow through international agricultural trade increased from 0.4Tg to 3.0 Tg between 1961-2011**
    • The fraction of P taken up by crops that is subsequently exported increased from 9% to 20% between 1961 and 2011**
    • Global P flows through international trade of agricultural products have become an important feature of the global P cycle, accounting for 20% of the P in global crop production, 17% of the P globally used as mineral fertilizer, and 27% of the P that was traded as mineral fertilizers in 2011.**
  • (Sources: *Steffen, W., K. Richardson, J. Rockström, S.E. Cornell, 2015. Planetary boundaries: Guiding human development on a changing planet. Science 347: 736, 1259855, **Nesme, T.,  G.S. Metson, and E.M. Bennett. 2018. Global phosphorus flows through agricultural trade. Global Environ. 50:133–141.Change 50:133–141. doi:10.1016/j.gloenvcha.2018.04.004

*Phosphorus and Agricultural Trade

Global phosphorus fertilizer application to cropland


  • Critical element for all living organisms
  • Availability drives the productivity of many aquatic and terrestrial ecosystems worldwide
  • In agricultural systems, additional P can be supplied to soils as mineral fertilizer or manure to support crop growth and sustain high yields
  • Mineral P fertilizer production is dependent on the physical and economic availability of mined rock phosphate resources (non-renewable, diminishing, geopolitically concentrated)
    • The P cycle has been greatly transformed since the pre-Industrial era through increased agricultural mineral P fertilizer use
  • P losses to water bodies through runoff and erosion from fertilized agricultural soils and from the inadequate management of animal manure or human excreta has led to aquatic eutrophication
  • International trade of agricultural products (food, feed, fiber and fuel) are a key component of the global phosphorus cycle; agricultural flows of P are driven by trade of cereals, soybeans, and feed cakes
  • 28% of global P traded in human food, 44% in animal feed and 28% in crops for other uses in 2011

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