The dynamics of soil biochemistry and microbiology in various land management of the Western Hyrcanian region

Land use change is one of the major human interactions in natural ecosystems that affect ecosystem processes, especially soils. In the present study, the effect of land use change on the dynamics of microbial and enzymatic activities in the Gerdkooh-Safak area of ​​Mazandaran province was investigated. For this purpose, soil sampling was carried out by systematic-random method from two depths of 0-5 and 5-10 cm. Totally, 240 soil samples were collected from six land uses (i.e. natural forests of hornbeam-ironwood, degraded natural forest, alder plantation, sequia plantation, improved follow and home garden), in four seasons of spring, summer, autumn and winter. According to the results, alder plantation and natural forest had the highest basal (0.49 and 0.44 mg CO2-C g−1 day−1) and substrate induced respirations (1.40 and 1.40 mg CO2-C g−1 day−1); in contrast, the sequia plantaion and improved follow had the least basal (0.21 and 0.24 mg CO2-C g−1 day−1) and substrate induced respirations (1.02 and 1.07 mg CO2-C g−1 day−1). Alder plantation and natural forest had the highest amount of nitrogen microbial biomass (70.20 and 67.38 mg kg-1), nitrate (32.92 and 30.49 mg kg-1) and ammonium (30.04 and 27.95 mg kg-1). The highest levels of enzymes activity of urease, phosphatase, arylsulphatase and invertase were found in alder plantation and natural forest (145.8, 144.8 µg NH4+–N g−1 2 h−1, 651.2, 629.6 µgPNP g−1 h−1, 142.4, 141.4 µg PNP g−1 h−1 and 217, 214.8 µg Glucose g−1 3 h−1) respectively and the least activity was detected under improved follow, degraded sites and sequia planation (127.22, 128.86, 128.08 µg NH4+–N g−1 2 h−1, 273.2, 261.2, 272.8 µgPNP g−1 h−1, 107.2, 109.6, 108/8 µg PNP g−1 h−1 and 151.4, 155.4, 158.8 µg Glucose g−1 3 h−1). Due to the variability of soil microbial and enzymatic characteristics in different seasons of the year and the proposed depths, the highest values ​​of these characteristics were allocated to the seasons of summer and spring and the upper layer of soil. According to the evaluation of land uses and following the natural forest, the establishment of the alder species in the degraded forest areas of the northern Iran can be considered as the selected species for land uses with similar conditions to improve the soil quality and health.