Human activities have often led to degradation of the world' s land resources, which are the basis for sustained food security. The global assessment of human-induced soil degradation (GLASOD) has shown that damage has occurred on 15 percent of the world's total land area (13 percent light and moderate, 2 percent severe and very severe), mainly resulting from erosion, nutrient decline, salinization and physical compaction. These impacts frequently lead to reductions in yields. Land conservation and rehabilitation are essential parts of sustainable agricultural development. While severely degraded soil is found in most regions of the world, the negative economic impact of degraded soil may be most severe in the countries most dependent on agriculture for their incomes.
The information for this map ( ISRIC, UNEP, FAO, 1996) was provided by ISRIC and UNEP. It is strongly generalized from their 1990 Global Assessment of Soil Degradation, made in cooperation with the Winand Staring Centre, the International Society of Soil Science, FAO and ITC (Enschede, the Netherlands), with help and information from several hundred persons throughout the world. For documentation and downloading of the GLASOD map, go to http://www.isric.nl/GLASOD.htm.
Ref: Oldman, L.R., Hakkeling,
R.T.A. and Sombroek, W.G., 1990 (rev. ed. 1991) World Map of
the status of human-induced soil degradation. Three maps and an explanatory
note, iii + 34 pp., ISRIC, Wageningen, the Netherlands, and UNEP, Nairobi,
Kenya.