Indicators in the study sites

Table of Contents

1. Compilers and contributors
2. Introduction
3. Climate indicators
   1. Air temperature
   2. Annual rainfall
   3. Aridity index
   4. Annual potential evapotranspiration
   5. Rainfall seasonality
   6. Rainfall erosivity
4. Water indicators
5. Soil indicators
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

Rainfall erosivity

Rainfall erosivity is a climatic factor which can be determined from local rainfall data. Rainfall erosivity is highly related to soil loss. Increased rain erosivity indicates greater erosive capacity of the overland water flow. Soil erosion by running water occurs where the intensity and duration of rainstorms exceeds the capacity of the soil to infiltrate the rain. Where rainfalls are intense, it is particularly urgent to adopt conservation and management techniques to protect the soil during the rainy season. Rainfall erosivity depends primarily on rainfall intensity and amount. For calculating erosivity the modified version of the Fournier index (FI) has been used as follows:

Where Pi is the precipitation total in month i, and p is the mean annual precipitation total. The Fournier index has been classified as in the following Table:

Data on rain erosivity have been collected in 948 study field sites, corresponding to 12 study sites. The dominant classes of the rain erosivity indicator were two, with values from very low to low, covering 47.0%, and 28.3%, respectively, of the study field sites (Fig. 9). Such rain erosivity classes have been described in field sites of the following study sites: Boteti Area-Botswana, Novij Saratov-Russia, Djanybek-Russia, Secano Interior-Chile, Rendina Basin Basilicata-Italy, Santiago Island-Cape Verde, Guadalentin Basin Murcia-Spain, Zeuss Koutine-Tunisia, Konya Karapinar plain-Turkey, Mamora Sehoul-Morocco, and Crete-Greece. High or very high rainfall erosivity values have been estimated in 8.5%, and 15.3% of the study field sites, corresponding to the study sites of Secano Interior-Chile, Santiago Island-Cape Verde, Crete-Greece, Cointzio catchment-Mexico, and Djanybek-Russia. However, in the study site of Santiago Island-Cape Verde have been identified in a few cases very high rain erosivity values.

Fig. 9. Distribution of rain erosivity classes prevailing in the study field sites