The Effect of Forest Land Use Change on Soil Quality Characteristics and Carbon Dioxide Emission

Changing land use is one of the most important human interactions in natural ecosystems that affect ecosystem processes, especially soils. In the present study, the effects of forest (natural forest and oak plantation) and non-forest (garden, rangeland and agriculture) land sues on the variability of soil quality indices and carbon dioxide emission dynamics have been considered. In each of the proposed land uses, 16 soil samples (0-10 cm depth) were collected and transferred to the laboratory. According to the results, the highest amounts of soil organic matter were allocated to forest habitats and the highest bulk density was belonged to rangeland and agricultural areas. However, the variation of soil particle density among the various land uses was not significant, but the highest soil porosity was found under oak plantation. The natural forest has the most stable aggregates, and following deforestation and the land use change, their stability was significantly reduced. The highest amount of sand was belonged to rangelands and the highest amount of clay was allocated to natural forest, while the content of silt did not show significant differences among different land uses. The highest amount of coarse root biomass was observed in the natural forest and oak plantation, while the fine root biomass in the natural forest was the highest amount. Greater amounts of soil moisture content were found in the forest habitats (especially in winter and autumn), while the highest soil temperature was assigned to agriculture and rangeland areas (especially in summer). The emission of carbon dioxide from the soil was highest during the summer, under the oak plantation. According to the PCA output, the amount of soil organic matter, moisture content and porosity in the oak plantation have had an important role in increasing carbon dioxide emission from the soil of this type of land use compared to other sites. The results of this study confirm the protection of natural forests in order to increase the soil quality characteristics and health.