Effects of Different Agronomic and Forest Land Uses on Soil Enzyme Activity

In this study, the effects of agronomic, orchard and forest land uses on soil enzymes activities in West Azarbaijan were evaluated. About 75 soil surface samples were collected from studied land usees and soil enzyme activities including acid phosphatase (ACP), alkaline phosphatase (ALP), urease and dehydrogenase were assessed using substrate-reaction methods. Results showed that ALP and ACP activities in the forest land use (344.3 and 582.3 µg pNP/gr.h, respectively) were higher than orchard followed by agronomic. However,urease enzyme in agronomic land use (84.4µg NH4+N/gr.2h) showed higher activity uses which can resulted from high urea application in the agronomic farms. Dehydrosenase activity in the forest (7.2 µg TPF/gr.24h) was significantly higher than agronomic land use. Assessment of soil quality index (SQI) showed ACP and dehydrogrnase, OC, pH, available phosphorous as MDS had the highest effect on studied soils quality among evaluated properties. SQI in forest land use (1.92) was significantly more than orchard (1.71) and agronomic (1.41) land uses. It is calculated that land use has high effect on soil enzyme activity and typically in intact ecosystems (forest) soil enzyme activity is high which can be related to sustanability of these ecosystems.