Soils: Challenge To Be Met by 2050.

The world population of 6.5 billion in 2007 is expected to be 7.5 billion by 2020 and 9.5 billion by 2050. Almost the entire increase of 3.0 billion by 2050 will occur in developing countries where the soil and water resources are already under great stress. The average grain yield of cereals in developing countries will have to be increased by 63% from 2.64 Mg/ha in 2000 to 4.30 Mg/ha by 2050 without changes in dietary habits, and by 227% to 6.0 Mg/ha with likely changes in food habits. Total cereal production in developing countries by 2050 is expected to be 1995 and 2786 million Mg, respectively. Such drastic increase in cereal yields can only be achieved through: (i) improvement in quality of degraded soil, (ii) increase in use efficiency of essential inputs (e.g., N, water), (iii) creation of positive nutrient budget, especially in soils of sub-Saharan Africa and South and Southeastern Asia, through integrated nutrient management and judicious use of chemical fertilizers, (iv) increase in area under supplemental irrigation through expansion of micro-irrigation projects in West African Sahel and elsewhere in semi-arid regions by using sub-drip irrigation, and (v) adoption of improved cultivars and appropriate cropping systems with high water use efficiency. The bigger challenge is to enhance adoption of recommended management practices (RMPs) by resource-poor small land holders faced with numerous social, cultural, economic and policy issues. Because of numerous competing uses of crop residues and animal dung, farmers are unable to use these biosolids as soil amendment. Furthermore, essential inputs (e.g., fertilizers, irrigation, machinery) either not available or are prohibitively expensive. In addition to biophysical challenges of soil and climate, there are also numerous social and economic constraints to adoption of RMPs which must be effectively addressed.