Agronomic phosphorus imbalances across the world's croplands

Graham K. MacDonald, Elena M. Bennett, Philip A. Potter, Navin Ramankutty

Research output: Contribution to journalArticlepeer-review

493 Scopus citations


Increased phosphorus (P) fertilizer use and livestock production has fundamentally altered the global P cycle. We calculated spatially explicit P balances for cropland soils at 0.5° resolution based on the principal agronomic P inputs and outputs associated with production of 123 crops globally for the year 2000. Although agronomic inputs of P fertilizer (14.2 Tg of P·y-1) and manure (9.6 Tg of P·y-1) collectively exceeded P removal by harvested crops (12.3 Tg of P·y -1) at the global scale, P deficits covered almost 30% of the global cropland area. There was massive variation in the magnitudes of these P imbalances across most regions, particularly Europe and South America. High P fertilizer application relative to crop P use resulted in a greater proportion of the intense P surpluses (>13 kg of P·ha-1·y -1) globally than manure P application. High P fertilizer application was also typically associated with areas of relatively low P-use efficiency. Although manure was an important driver of P surpluses in some locations with high livestock densities, P deficits were common in areas producing forage crops used as livestock feed. Resolving agronomic P imbalances may be possible with more efficient use of P fertilizers and more effective recycling of manure P. Such reforms are needed to increase global agricultural productivity while maintaining or improving freshwater quality.

Original languageEnglish (US)
Pages (from-to)3086-3091
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number7
StatePublished - Feb 15 2011
Externally publishedYes


  • Agriculture
  • Eutrophication
  • Nutrient balances
  • Phosphorus depletion


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