Effects of Forest Communities and Various Depths on Soil Enzyme Activities in the Hyrcanian Forest

Detailed information on soil quality can be ascertained by measuring soil enzymatic activities, which are often affected by soil biological chemical processes and depth. This study investigates the activity of four enzymes, acid phosphatase, alkaline phosphatase, urease and dehydrogenase in three various tree communities; Parrotio-Fagetum, Parrotio-Carpinetum, and Parrotietum at 0-20 cm depth with and without rhizosphere and 20-40 cm depth in the Kheyrud forest, Northern Iran. We found the higher enzyme activities in rhizosphere than without rhizosphere in all the communities. Soil enzyme activities decreased with increasing soil depths. There was a significant difference in acid phosphatase between 0-20 cm without rhizosphere and 20-40 cm. These findings were attributed to the observation that ischolar_main propagation was reduced across the depths. Alkaline phosphatase and dehydrogenase, both showed a significant difference in activity among the communities, but acid phosphatase and urease did not. Microorganisms producing alkaline phosphatase and dehydrogenase were found to be significantly affected by the vegetation. Alkaline phosphatase activity in both depths and dehydrogenase at 0-20 cm with and without rhizosphere were greater in Parrotietum than those of Parrotio-Fagetum and Parrotio-Carpinetum. It appeared that the microbial community in Parrotietum was much greater than the other two types.