Soil microbial biomass and activity of oak forest in three different regions in Ilam province

Climate is the most important factor that determines the plant yield and soil microbial activity. Therefore, this study aimed to investigate the soil biological properties in three different climate zones including Eyvan (humid), Ilam (semi-humid), and Syrvan (semi-arid) under seed-origin and coppice oak trees. To this purpose, three plots (100 × 100 m dimension) randomly prepared in less undisturbed forest consist of both growth types. Soil sampling took place randomly at 0-20 cm of soil depth under each seed-origin and coppice oak trees in three regions. The results showed that growth type had no significant effect on microbial biomass carbon in the Ilam and Syrvan climates. However, in Eyvan forest soils, the amount of microbial biomass carbon under seed-origin was 1.71 times higher than the coppice trees. The highest amount of microbial biomass nitrogen (5.32 mg.kg-1) was observed in the Eyvon climate, which did not have a significant difference with the Ilam climate and it was the lowest (2.90 mg.kg-1) in the Syrvan climate. The highest metabolic quotient (qCO2) was observed in coppice type in the Eyvan and Syrvan climate and the least amount was observed in the Ilam climate. Growth type had no significant effect on the metabolic quotient of the soil in the Ilam climate. The highest basal and substrate-induced respiration was obtained in the Eyvan climate, while the Syrvan soils showed the least amount of these parameters. The highest amount of organic carbon and nitrogen were observed in the Ilam forest soils and the least amount was obtained in the Syrvan forest soils.