World Phosphorus Use Efficiency in Cereal Crops Guilherme Torres, Natasha Macnack, Bee Chim, Jeremiah Mullock, and William Raun Oklahoma State University, Plant and Soil Science Department World demand for phosphorus Global Phosphorus Use Efficiency Cereal Production and P Consumption • Phosphorus (P) is the second most limiting nutrient in crop systems and positively correlated with world food production. • 50 years (1961 to 2011) of world fertilizer P consumption, cereal harvested area, and production were obtained from the FAOSTAT database (2011) to estimate phosphorus use efficiency (PUE). • Over the last 50 years, world fertilizer P consumption has -1 been increasing at a rate of 212,855 Mg yr (Figure 1). • Batjes (1997) estimated that P deficiency can be found in 67% of the world land designated for crop production. • Soil orders with potential P deficiency account for approximately 51% of the world soils (Brady and Weil, 2008) (Table 1). • Based on current consumption, P reserves have been estimated to last from 100 years (Heffer et al., 2006) to 343 years (Roberts and Stewart, 2002). • Crops included maize, rice, wheat, sorghum, barley, millet, oats, rye, triticale and minor cereal crops. • Cereal harvested area represents 55% of the total harvested area. Andisols (Ancepts) Andosol 0.7 Ultisols Acrisol 8.5 P, Ca, Mg N, P, Ca Ultisols/Alfisols Nitosol P Spodosols (Podsols) Podsol 2.6 N, P, K, Ca Oxisols Ferreasol 7.6 P, Ca, Mg 6.9 Al Al, Mn, Fe Mn Al Al, Mn, Fe Na Mollisols (ustolls) Mollisols (rendsols) (shallow) Vertisols Kastanozem Vertisol 2.4 N, P S Aridsols Xerosol 12.7 P, K, Mg Na Aridsols/ arid entisols Alfisols/ ultisols (Albic) (poorly drained) Alfisols/ ultisols/ molisols (Natric) (high alkali) Yernosol P, K, Mg Na, Se Most nutrients Al N, P, K Na Rendzina Planosol P, K Element Toxicity P 9.6 Solonets †Adapted from Baligar et al. (2001). ‡ Brady and Weil, 2008. Objective • Macro data was used to estimate mean and current global P use efficiency of cereal crops based on harvested area, fertilizer consumption, and production quantity. • World cereal yield increased from 1.35 to 3.57 Mg ha-1 between 1961 and 2010. • 50 year and current world PUE for cereal crops was 15.7% and 19.2% R² = 0.7779 • PUE ranged from 12.0% in 1980 to 20.2% in 2008 (Figure 2). 25 15 10 5 Phosphorus Use Efficiency (%) FAO Soil Group Potential Macronutrient Deficiency • Cereal production was 2,432,818,753 Mg in 2010 Phosphorus Use Efficiency P Fertilizer Consumption (Millions Mg) U.S. Taxonomy Soil Order Soil Order Global Distribution (%)‡ • 50-year cereal production average was 1,704,807,560 Mg. • Cereal P consumption = World P consumption x 55%. 20 Table 1. Global distribution, potential macronutrient deficiency and nutrient toxicity associated with major soil orders†. • There was a 346% increase in P fertilizer usage in 50 years. World P consumpion Cereal P consumption y=212855+7E+06 1961 1971 1981 1991 2001 Year 20 15 PUE Figure 1: Global phosphorus fertilizer consumption and fertilizer phosphorus consumption by cereal crops from1961 to 2011. 10 1961 1971 1981 1991 2001 Year Grain P uptake and P removed from the soil Figure 2: Historical estimates of world phosphorus use for cereal crops. • Cereal grain P uptake was calculated by multiplying the crop specific grain P content by the production of that given crop. Conclusion • It was assumed that 79.3% of the P found in the grain came from the soil and not the fertilizer. This value was computed from averaging data found in literature for P removal. • Global PUE is low (12-20%), indicating that P fertilization methods need to be improved in order to preserve the longevity of P reserves. • PUE was calculated as: References Baligar, V.C., N.K. Fageria, and Z.L. He. 2001. Nutrient use efficiency in plants. Commun. Soil Sci. Plant Anal. 32:921-950. PUE = Cereal Grain P uptake - P Removed P Fertilizer Consumptio from the Soil n by Cereal Crops Batjes, N.H. 1997. A world dataset of derived soil properties by FAO–UNESCO soil unit for global modelling. Soil Use Manage. 13:9-16. * 100 Brady, N.C., and R.R. Weil. 2008. The nature and properties of soils. 14th ed. Prentice Hall, Upper Saddle River, NJ. Food and Agriculture Organization. 2011. FAOSTAT: Statistics database. [Online.] Available at http://faostat.fao.org/ (verified 9 Jul. 2012). Heffer, P., M.P.R. Prud'homme, B. Muirheid, and K.F. Isherwood. 2006. Phosphorus fertilisation: issues and outlook. Proc. Int. Fert. Soc. p. 1-32. Roberts, T., and W. Stewart. 2002. Inorganic phosphorus and potassium production and reserves. Better Crops 86:6-7.