| Abstrakt: |
Background and Objectives: Arid and semi-arid regions are characterized by sensitive and fragile ecosystems that are highly susceptible to fires. Understanding the impact of fire is crucial for making informed modifications to the vegetation composition in these habitats. This study aimed to investigate the effects of fire on the soil characteristics of Tamarix aphylla (L.) Karst habitats in the Niatak area of Sistan and Baluchistan province. Materials and Methods: The statistical design employed in this study was a completely randomized design, and the sampling method utilized a sample line approach. Following a thorough survey of the area, stands that had experienced fire for a duration of 10 years, as well as a control stand, were selected. Within each stand, a randomly chosen one-hectare area with dimensions of 100×100 m was identified. Approximately 50 m from the linear sides of the square, sampling locations were designated. Plots measuring 5×5 m were then selected, with a spacing of approximately 50 m between each plot. This resulted in three sample lines, each consisting of three sample plots, amounting to a total of nine sample plots. Within each sample plot, five soil samples were obtained from the four corners and the center, at a depth of 0-30 cm. These samples were combined to form a composite sample, which was subsequently transferred to the laboratory for analysis. The analysis aimed to determine the physical properties (moisture content and bulk density) as well as the chemical properties (sodium, exchangeable potassium, phosphorus, nitrogen, organic carbon, electrical conductivity, and pH) of the soil. Statistical analysis of the physical and chemical aspects of the soil was conducted using the t-test and the non-parametric Mann-Whitney U test. Results: The findings revealed notable differences between the control and burnt stands. The number of trees per ha in the control stand was 93, while in the burnt stand it was 56. Additionally, 11 saplings under one meter were observed in the control stand, whereas the burnt stand had 25 saplings. Furthermore, 2% of trees in the control stand were in the form of sprouts, compared to 30% in the burnt stand. The analysis indicated a decrease in soil moisture due to the fire, with a value of 32.77±0.99 compared to 37±1.38 in the control stand. In contrast, the bulk density increased in the burnt stand, measuring 1.46±0.03. It was also found that the control stand exhibited higher percentages of soil nitrogen (0.08±0.01), absorbable phosphorus (11.99±0.63), exchangeable potassium (400.23±20.05), and soil organic carbon (0.9±0.02) compared to the burnt stand (P≤0.05). The acidity variable did not show a significant difference between the burnt plots and the control (P≥0.05). However, the electrical conductivity in the burnt stand (9.8±0.57) was higher than that of the control stand (5.05). Conclusion: It is evident that fire has significant effects on vegetation density, reproduction, and soil physicochemical properties. Despite the passage of 10 years since the fire, the ecosystem of Tamarix aphylla still exhibits notable differences in soil characteristics compared to the control stand. The physicochemical properties of the soil, as well as vegetation density, continue to display disparities between the burnt and control plots. This indicates that the stand has not fully recovered to its original state. Therefore, there are signs of reproduction and the presence of new sprouts in the stand, which suggest a potential return to its original state. It is recommended to focus on soil improvement measures and expedite the evolution of vegetation by introducing native species through reforestation efforts in these forests. [ABSTRACT FROM AUTHOR] |
