The role of soil science in estimating global food security in 2040

Food demand for the year 2040 is estimated for 15 major regions of the world. It is compared with potential food production in these regions, which is computed from the area with soils suitable for cropping and grazing, the amount of irrigation water available, and the farming system used. Application of the best known techniques for sustainable farming is assumed, but two alternatives are explored: integrated agriculture, with intensive use of chemical inputs and energy to produce maximum yields for minimum prices, and ecological agriculture, in which legumes provide all N, intensity is lower, agriculture is more diverse, but hectare yields are lower. Comparing future scenarios of demand and supply of food shows that most regions can avoid serious food security problems but that in Asia, situations may arise where a moderate or affluent diet is out of reach of its population, even when maximum use is made of all natural resources. Implications for soil science are (i) more accurate global soil data bases are required, containing more characteristics (e.g., soil depth); (ii) more knowledge is required as to how to scale up field data bases and models to national or regional levels; and (iii) more knowledge is needed at field and regional scale about leaching of nutrients, particularly from organic manure. Future challenges are to (i) increase P availability, (ii) reduce loss of nutrients under high and low input systems, and (iii) increase water-use efficiency in irrigation systems.