Modeling of Soil Water Erosion in Tunisia Using Geospatial Data and Integrated Approach of RUSLE and GIS

Abstract

Soil erosion is one of the most important environmental problems which can have various negative consequences, such as land degradation affecting the sustainable development and the agricultural production, especially for developing countries like Tunisia. Moreover, soil erosion is a major problem around the world because of its effects on soil fertility by nutriment loss and siltation in water bodies. Apart from this, soil erosion by water is the most serious type of land loss in several regions both locally and globally. This study evaluated regional soil erosion risk through the derivation of appropriate factors, using the Revised Universal Soil Loss Equation (RUSLE), which was applied to establish a soil erosion risk map of the whole Tunisian territory and to identify the vulnerable areas of the country. RUSLE model take into account all the factors playing a major role in erosion processes, namely the erodibility of soils, topography, land use, rainfall erosivity and anti-erosion farming practices. The equation is thus implemented under Geographic Information System (GIS) “Arc GIS Desktop”. The results indicated that Tunisia has a serious risk of soil water erosion, showing that 6.43% of the total area of the country is affected by a very high soil loss rate estimated at more than 30 t/ha/year and 4.20% are affected by high mean annual soil loss ranging from 20 to 30 t/ha/year. The most eroded areas were identified in west southern, central and western parts of the country. The spatial erosion map can be used as a decision support document to guide decision-makers towards better land management and provide the opportunity to develop management strategies for soil erosion prevention and control in the global scale of Tunisia.

Influence of the near roadsoil contamination on the germination and biochemical factors of two species in the region of Sfax (Tunisia)

“…However, other research results showed that the distribution profiles of heavy metals in roadside soils were not always significantly correlated with road distance (Zhang et al, 2012). Referring to the standards reported by Serbaji (2000) Pb (18 mg/kg), Zn (39 mg/kg), Cr (41 mg/kg), Cu (13 mg/kg), we noted that the Zn contents exceeding the threshold have reached a distance of 50m near Gremda road, 10m near Tunis and Manzel Chaker roads. For Pb, the contamination has reached the same distance as Zn for Gremda and Tunis roads while for Manzel Chaker road, the contamination did not exceed three meter in the vicinity of the road.…”