Dynamics of chemical and microbial properties of Algerian forest soils: Influence of natural and anthropogenic factors (Northwest of Tlemcen)

Abstract

In Djebel Fellaoucene, mattorals and their regressive and progressive dynamics are affected by several factors, namely climate, geography, human activities, overgrazing and fires. This research aims to investigate whether these factors have an impact on the structural dynamics of the area’s forest soils and show a correlation between the soils’ chemical and microbial properties and these factors. In this regard, we have analysed chemical properties: organic matter, pH, conductivity, calcium carbonate (CaCO3), moisture and carbon as well as microbial properties: basal respiration, microbial biomass and metabolic quotient (qCO2), all from 80 soil samples collected from degraded mattorals on different altitudes and exposures. Principal Component Analysis (PCA) which has been made revealed that soil dynamics and correlations between chemical and microbial properties depend on the aforementioned factors; an increase in moisture, organic matter, carbon and conductivity as well as a decrease in the mass and bacterial respiration in the North-exposed sites under anthropogenic pressure and overgrazing by sheep and goats. Whereas opposite results were found in the South-exposed sites degraded by fires and undergrazing by cattle. Anthropogenic pressure and overgrazing in sites which have recently been burned lead to a decrease in microbial properties despite an increase in organic matter and moisture content. Qualifying and quantifying the impact of these degradation factors on forest soils allows us to establish effective restoration, conservation strategies and defend rangelands in arid areas.