Effect of degradation intensity of wooded rangelands on root characteristics and soil ecochemical activities of Mirkola Region of Nowshahr

Background and objectives: Mountain habitats, due to their climatic conditions, are considered to be very sensitive areas and generally have less plant diversity compared to the lower elevations. Unfortunately, in the past years, due to human attacks, parts of these areas have been destroyed and now some areas are either devoid of vegetation or have very little vegetation. Since Crataegus and Berberis comprise the majority of the shrub cover in the mountainous habitats of the north of the country, this study will study the effect of different intensities of degradation of these vegetation covers on soil biological indicators. Methodology: For this purpose, areas with a percentage of cover between 90-100, 70-60, 40-30 and 10-0 percent, as non-degraded site and the habitats with degradation intensities of light, moderate and heavy, respectively, in Mirkola region of Kojoor district located in Mazandaran Province was elected. Three plots of one hectare (100 m × 100 m) were considered in each of these habitats. Inside each of these plots, there are 5 soil samples (from the four corners and the center of the plots) from the depths of 0-10, 10-20 and 20-30 cm and on a surface of 30 cm × 30 cm were taken. In total, 45 soil samples from each of these habitats were transferred to the laboratory. Results: The highest amounts of soil coarse and fine roots biomass were observed in non-degraded habitats. The highest values ​​of carbon content were observed in the coarse roots of the habitats without degradation. Habitats without degradation as well as habitats with low degradation intensity had the highest values ​​of nitrogen and phosphorus content in roots. The highest amounts of calcium were observed in the fine roots of the habitats without degradation and with low degradation, while the habitat without degradation had the highest calcium values ​​in the coarse roots. The lowest amounts of magnesium were observed in the coarse and fine roots of habitats with heavy degradation. The highest activity of urease enzyme was observed in habitats without degradation and upper soil layers, and the activity of this enzyme decreased significantly with increasing intensity of degradation. The highest activity of soil acid phosphatase enzyme was observed in habitats without degradation and the lowest values ​​were observed in habitats with heavy degradation. In habitats with medium degradation intensity, the amount of acid phosphatase enzyme activity in different soil depths did not show a statistically significant difference. The increase in degradation intensity caused a significant decrease in the activity of arylsulfatase and invertase enzymes in the soil. The soil depth of 0-10 cm had the highest amounts of soil arylsulfatase and invertase in habitats without degradation and light, moderate and heavy degradation intensities, respectively. Conclusion: The results of the current research indicate that different intensities of vegetation degradation have a significant effect on soil biological indicators. In fact, it can be mentioned that protection of vegetation can have positive effects on the activity of underground soil components. Therefore, the findings of this research support the protection of natural vegetation to increase the quality characteristics and health of the soil. The results of this research can provide valuable information to natural resource managers regarding the evaluation of the ecological capacity and nutrient cycle of natural vegetation in the mountainous areas of northern Iran.