Indicators in the study sites

Table of Contents

1. Compilers and contributors
2. Introduction
3. Climate indicators
4. Water indicators
5. Soil indicators
   1. Soil drainage
   2. Parent material
   3. Rock fragments
   4. Slope aspect
   5. Slope gradient
   6. Soil depth
   7. Soil texture
   8. Water storage capacity
   9. Exposure of rock outcrops
   10. Organic matter in surface horizons
   11. Degree of soil erosion
   12. Electrical conductivity
6. Vegetation indicators
7. Water runoff indicators
8. Forest fires indicators
9. Agriculture indicators
10. Cultivation indicators
11. Animal husbandry indicators
12. Land management indicators
13. Land use indicators
14. Water use indicators
15. Tourism indicators
16. Human characteristics indicators
17. Institutional indicators
18. Conclusions
19. References

Soil indicators

Soil is a dominant factor of the terrestrial ecosystems in the semi-arid and dry sub-humid zones, particularly through its effect on plant growth. Vegetation degradation will proceed, in a certain landscape, when the soil is not able to provide the plants with adequate rooting space for water and nutrients adsorption. One of the most important processes of desertification is soil erosion, particularly affecting hilly areas. Desertification due to soil erosion is a serious threat to the soil quality and land productivity. The effects of soil erosion on land productivity depend largely on the thickness and quality of the topsoil and on the nature of the subsoil. Any loss of soil volume from marginal lands greatly reduces the potential for biomass production, ultimately leading to desertification. In the semi-arid and the sub-humid zones, the land becomes irreversibly desertified when the rootable soil depth is not capable of sustaining a certain minimum vegetation cover. There are cases where desertification proceeds even on deep soils, when their water balance is not capable of meeting the needs of plants.

Soil quality indicators used for the purposes of the DESIRE project to define desertification risk are related to water availability, and erosion characteristics. Selection of soil quality indicators considering the multiple functions of soil in maintaining productivity and environmental well-being is a complicated issue and it requires integrating physical, chemical and biological soil attributes that define those functions. The indicators selected for this study are simple soil properties or characteristics given in regular soil survey reports, such as: drainage, soil depth, soil texture, parent material, slope gradient, slope aspect, stoniness, water storage capacity, degree of erosion, rock outcrops exposure, organic matter content in the surface horizon, and soil electrical conductivity.

Table 3. Number of field sites in which the indicators related to soils was recorded in the filled questionnaires