Influence of soil type and sampling depth on soil biological properties and enzymatic activities

Study of soil enzymatic activities and biological properties gives us potentials of soil in supporting biochemical processes and maintaining soil fertility. Current study was conducted to investigate the effect of soil type and depth on some of soil biological properties and on soil enzymatic activity including the Urease، Invertase، Akaline phosphatase and Aryl sulphatase enzymes in two types of Histosols. In each region، sampling was carried out from 3 soil profiles (0-120 cm، at each 20 cm interval). Results showed that the influences of soil type، depth and their interaction on the activities of the studied enzymes were statistically significant (p < 1%). The activity of these enzymes was affected strongly under environmental conditions. Soil depth had a significant effect on soil enzymatic activity. In lower horizons، enzymatic activities were truncated compare to upper horizons of the studied soils. Investigating the relation between enzyme activities with soil organic carbon and microbial biomass carbon designated the positive role of organic carbon (r = 0. 86**) and microbial biomass carbon (r = 0. 87**) in two soil types. The results of soil respiration showed that microbial respiration increased over time and it seems that soil biological activity increased during the experimental time.