Environmental impacts of land management on the sustainability of natural resources in Oriental Erg Tunisia, North Africa

In southwestern Tunisia, the intense exploitation of the natural resources (soil, water, hydrocarbons, etc.) bears unrecoverable consequences on the local environment. In fact, the harsh climate conditions, the expansion of irrigated areas (date plantation and greenhouses) and the overexploitation of water resources in these ecologically fragile lands increase understandably desertification in the Kebili field. The field observations in the study indicate that the sustainability of natural resources is threatened, besides increasing soil salinization and water degradation. The used water quality indexes (BCWQI, OWQI and WAWQI) indicate that more than 55% of the samples are unsuitable for domestic consumption and irrigation purposes. The contamination of the CI water and the agricultural lands by crude mature organic matter is confirmed by the elevated concentrations of organic compounds that range between 1.8 and 16 mg/L in the sampled waters, while they reach the 80 mg/L in the surface horizon in the oases in Mazraa Neji and Oum El Fareth areas. The sensitivity of the study area to different processes of land degradation is evaluated by two multi-criteria models (MEDALUS and IMDPA), which indicate high to very high risks of environmental degradation in the study area with an average geometric mean of 1.67 and 2.8, respectively. Given the potential relevance of the contamination and its long-term impacts on the healthy environmental functioning, this paper outlines the main baselines aspects, the rehabilitation measures and the decontamination actions that should be taken in account in the planning of the most adopted management projects.