Alteration of dehydrogenase and urease enzymes activity and some chemical properties of soil in different development stages of beech stand (Case study: Rezvanshahr forest)

Occurrence of development stages in the virgin forests including initial, optimal and decay are determined by species composition, which is independent from human activity. In all development stages, some differences such as the amount of light reaching to the forest floor influences soil chemical properties and activity of the soil microorganisms. Soil is a living system in which many biological and biochemical processes occur. In all these processes, enzymes play main roles. This study was carried out to investigate the alteration in activity of dehydrogenase and urease enzymes and some chemical properties of soil in different development stages of Fagus orientalis Lipsky forests in Rezvanshahr area. Soil samples were randomly taken from 0-10 and 10-20 cm depths. Activity of dehydrogenase and urease enzymes, using the substrate and the reaction was measured by spectrophotometer. Chemical properties of soil pH, N, P, K and organic matter were also measured. The results indicated that pH and activities of dehydrogenase and urease have significant differences in different development stages and activity of these enzymes in decay stage is higher than the other stages. This study indicated that decay stage could be a better condition for activity of soil microorganisms. Our findings showed that soil enzymes are suitable indices for presenting differences in developmental stages, and soil chemical characteristics can be effective in the interpretation of results.