Abstract
Arid zones are very harsh environments characterized by binding edaphic and climatic factors, their rainfall is low and irregular accentuated by high temperatures and their soils are fragile and vulnerable. In recent years, it has been noted that vegetation is regressing and that the majority of reforestation has been a failure. Our study aims to know the physico-chemical and microbiological characteristics of forest soils in the pinewoods of an area of the highlands of western Algeria (Naama). For this we analyzed several soil samples spread over five sampling stations in a forest of Aleppo pine. The results show that the forest soils of our study area are characterized by a generally sandy texture and an orange color for all the selected stations. They are characterized by: a very high C/N ratio that indicates a slow evolution of organic matter and a nitrogen deficiency that is necessary for carbon decomposition. The conductivity shows that the soil contains some salinity, its permeability is strong and its humidity fairly low with an alkaline pH (> 8) due to the increase in the limestone level in the area. Basal respiration is low compared to microbial biomass due to poor physico-chemical quality of soils and the effect of water stresses that slow down microbial activities. Soils in this arid forest are generally characterized by soil homogeneity sensitive to the influence of environmental factors mainly poverty into elements necessary for its proper functioning such as nitrogen and water that accentuate soil degradation of these forest formations, which results in the risk of degradation being triggered.