The critical role of phosphorus in world production of cereal grains and legume seeds

The production of food for the nearly 7 billion people on the earth today requires a large input of phosphorus (P), a non-renewable resource. Over the 14 year period 1995–2008, the global production of dry cereal grains plus legume seeds has not increased per capita and the area farmed to obtain these yields has declined steadily. There is great concern about the availability of food, the rising cost of food and the availability of P to maintain crop yields of key food staples. Known P reserves are finite. We report the rates of change in the area of agricultural land, the production of food staples, the use of fertilizer P and the export of elemental P in the major cereal and legume crops on a per capita basis. We seek to draw attention to the urgent need to utilize world P reserves more wisely so as to delay the impact of dwindling amounts of P and increasing costs of P on world food security. We strongly urge agriculturalists to pursue more P-efficient crop genotypes and land management which reduces losses of P from agricultural ecosystems and we support the engineering of P-recycling schemes which convert the current P-loss system nearer to a closed P-cycle system. Unless these avenues are developed in the immediate future there are likely to be severe consequences for food security in the longer term.