| چکیده انگلیسی مقاله |
Background and Objectives: Following excessive exploitation of natural areas, particularly forests, soil fertility has declined, and production sustainability has been disrupted. Therefore, understanding the condition of forest soils and examining the effects of various activities on soil characteristics play a vital role in forest management. This study aimed to evaluate the physical, chemical, and biological characteristics of soil in the habitat of the Juniper tree species (Juniperus excelsa M.Bieb) in the Galouchar region of Rabar, Kerman Province.
Materials and Methods: Soil sampling was conducted using a selective method in J. excelsa forest habitats and a control area (without vegetation cover). For this purpose, 25 J. excelsa trees with similar trunk diameters and canopy cover were selected. Soil samples were taken from a depth of 0 to 25 cm, and then every five soil samples from under adjacent trees were mixed, and a composite sample was obtained for soil tests. In order to reduce the effect of interfering environmental factors, an effort was made to ensure that all selected trees and sampling points had relatively uniform conditions in terms of altitude, slope, and geographical direction. After transferring the samples to the laboratory, they were prepared and measured using standard methods to determine physical (soil texture), chemical [i.e., pH, electrical conductivity (EC), calcium carbonate equivalent (CCE), organic carbon (OC), total nitrogen (TN), available phosphorus (P), available potassium (K), exchangeable calcium (Ca), exchangeable magnesium (Mg)], Micronutrient characteristics [i.e., iron (Fe), zinc (Zn), copper (Cu), manganese (Mn) and sodium (Na)] and biological [i.e., basal and substrate-induced respiration (SMR and SIR), microbial biomass carbon (MBC), potential nitrification (PN)] parameters. Subsequently, the data obtained from soil samples under tree canopies were statistically compared with the data related to the control area (without vegetation cover) using an independent t-test.
Results: The results showed that under the Juniper tree canopy, the soil silt percentage significantly increased, but no significant statistical difference was observed in other soil texture components. Also, the values of soil chemical characteristics such as pH, EC, CCE, OC, TN, and K significantly increased under the Juniper canopy compared to the control area, while available calcium, P, and Mg did not show significant statistical differences. Micronutrients (except Cu) significantly increased in the soil under the Juniper canopy compared to the control area. Furthermore, soil biological indicators such as SMR, SIR, MBC and PN also showed a significant increase under the Juniper canopy, confirming the positive effect of this tree species on soil microbial activity.
Conclusion: Overall, the findings of this research demonstrate the positive and significant effect of the J. excelsa tree species on improving soil chemical and biological indices, including a substantial increase in basal and induced microbial respiration, microbial biomass carbon, and nitrification potential under tree canopies. This confirms the strong stimulation of microbial activity resulting from the accumulation of organic matter and the improvement of microclimatic conditions in the vicinity of the canopy cover of this species. Based on the results obtained, it is suggested that to preserve and enhance soil fertility and health in mountainous areas with poor soils, the use of J. excelsa species be considered in afforestation and habitat restoration programs. |