Impact of human activities on soil degradation and sustainability of oasis ecosystems in the Middle Draa (Morocco)

Resumen

This study assesses the impact of anthropogenic activities on the sustainability of the oasis ecosystem in the Middle Draa Valley (Morocco), integrating the analysis of demographic evolution, soil degradation, transformations in agricultural systems, and the environmental effects of uncontrolled extraction of materials. A methodological approach combining field investigations, laboratory analyses, and demographic data processing was adopted. Soil degradation was quantified by sampling sites along an upstream-downstream gradient of the Middle Draa Valley (Tinzouline, Ternata, and Fezouata oases). Analyses focused on salinity (conductimetry), organic matter content (Walkley and Black method), and pH (pH meter). Demographic evolution was studied using census data (1994, 2004, 2014) and field interviews (douars of Amezrou and Tinfou). A spatiotemporal analysis of agricultural areas and date palm density was conducted using Google Earth Pro imagery in the Fezouata (2002-2018) and Beni Ali (2010-2019) oases, and in Tamegrout (2009-2016). The results indicate moderate population growth associated with a heterogeneous spatial distribution and the expansion of habitat at the expense of agricultural land. Significant soil degradation was evidenced, characterized by salinization (0.299-5.11 mS/cm), low organic matter content, and elevated pH, correlated with unsustainable irrigation practices. Market-driven agricultural intensification leads to overexploitation of water resources and increased vulnerability of palm groves. These results underscore the need for integrated and sustainable resource management to preserve the long-term viability of the oases in the Middle Draa Valley.