Soil Degradation and Decline in Productivity

Over the past decades, the cumulative loss of productivity of cropland has been estimated at about 13%. However, aggregate global food security does not appear to be under a significant threat.12,51 There is no conclusive evidence that soil degradation has in the past affected global food security. We cannot conclude to such relationship because 1) the database on the extent and magnitude of various types of soil degradation is inadequate and 2) the impact of soil degradation on land productivity is very site-specific, often anecdotal and difficult to quantify at regional and global levels. In fact, globally, per-capita food production has increased by about 25% since 1961 when the first production surveys were conducted by Food and Agriculture Organization of the United Nations (FAO)J121 The yields per unit area of the major cereals (i.e., wheat, rice, maize) have steadily increased and are still rising.11,121 This, however, does not imply that sufficient food is—and will be—available in all countries and regions. Food is not necessarily produced where it is most needed. A top priority should therefore be to improve inventories of land degradation at regional, national, and subnational levels.

However, the evidence is conclusive that soil degradation affects food security at the subnational and national levels in the developing countries by the gradual decline of the land’s productive capacity and that this trend will continue in the future. We therefore have to assume that, eventually, land degradation will constitute a serious threat to global food security by its particular impact on the developing countries. According to most scenarios, these countries are most vulnerable to degradation induced by increasing pressure on their land resources, the effects of climate change and their inability to finance programs to rehabilitate affected areas and prevent further degradation and decline of productivity.

References

  • 1. FAO. The State of Food Insecurity in the World; Food and Agriculture Organization of the United Nations (FAO): Rome, Italy, 1999.
  • 2. Engelman, R.; LeRoy, R Conserving Land: Population and Sustainable Food Production; Population and Environment Program; Population Action International: Washington, DC, U.S.A., 1995.
  • 3. Saad, M.B. Food Security for the Food-Insecure: New Challenges and Renewed Commitments; Position Paper: Sustainable Agriculture; Centre for Development Studies, University College Dublin: Dublin, Ireland, 1999.
  • 4. Kindall, H.W.; Pimentel, D. Constraints on the expansion of the global food supply. Ambio 1994, 23 (3), 198-205.
  • 5. Scherr, S. J. Soil Degradation—A Threat to Developing-Country Food Security by 20201 Discussion Paper 27; International Food Policy Research Institute: Washington, DC, 1999.
  • 6. vanLynden, G.W.J.;01deman,L.R. The Assessment of the Status of Human-Induced Soil Degradation in South and Southeast Asia; International Soil Reference and Information Centre: Wageningen, the Netherlands, 1997.
  • 7. Greenland, D.; Bowen, G.; Eswaran, H.; Rhoades, R.; Valentin, C. Soil, Water, and Nutrient Management Research—A New Agenda; IBSRAM Position Paper; International Board for Soil Research and Management: Bangkok, Thailand, 1994.
  • 8. Lai, R. Soil management in the developing countries. Soil Science 2000,165 (1), 57-72.
  • 9. Stocking, M.; Murnaghan, N. Land Degradation—Guidelines for Field Assessment; UNU/UNEP/ PLEC Working Paper; Overseas Development Group, University of East Anglia: Norwich, UK, 2000.
  • 10. Lai, R.; Singh, B.R. Effects of soil degradation on crop productivity in East Africa. J. Sustain. Agricul. 1998,13 (1), 15-36.
  • 11. Stocking, M.; Benites, J. Erosion-Induced Loss in Soil Productivity: Preparatory Papers and Country Report Analyses; Food and Agriculture Organization of the United Nations: Rome, Italy, 1996.
  • 12. FAO. FAOSTAT. Statistical Database of the Food and Agriculture Organization of the United Nations. Internet Web-Source http://www.fao.org (accessed January 2001), Rome, Italy, 2000.
  • 13. Oldeman, L.R. Soil Degradation: A Threat to Food Security? Report 98-01; International Soil Reference and Information Centre (ISRIC): Wageningen, the Netherlands, 1998.

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