Experimental site and season over-control the effect of Pinus halepensis in microbiological properties of soils under semiarid and dry conditions

• Season had a significant influence on microbiological soil properties.
• Experimental site had a significant influence on microbiological soil properties.
• Microbiological soil properties were not significantly affected by tree coverage.
• Climate significantly affects microbiological soil properties.

The aim of this work was to investigate the effect of experimental site, season and canopy coverage on soil microbial and biochemical properties in Aleppo pine (Pinus halepensis M.) forest stands. Two experimental sites were chosen (dry and semiarid climate). Twelve subplots were selected at each site, six under pine cover orthogonal projection and six subplots about 5 m off the orthogonal projection of pine in patches without plant material. Soil sampling was done in two different seasons: winter and summer. Physicochemical soil properties (i.e., soil texture, pH, carbonates, total organic carbon, organic matter, electrical conductivity, Total N and P), soil enzymes (urease, phosphatase, β-glucosidase and dehydrogenase activities), soil respiration and soil microbial biomass carbon were analysed in the selected forests areas and uncovered areas. In general, the results show that the effect of canopy coverage did not influence soil properties. Significant experimental site variation was generally seen on microbiological parameters and soil enzymes, as for the season. Results allowed us to conclude that Aleppo pine coverage does not influence soil properties. Climate plays an important role in soil properties, and soil properties vary in the dry climate depending on the season, which should be considered for the sampling season.