نوع مقاله : مقاله کامل علمی پژوهشی
نویسندگان
1 دانشجوی دکتری علوم زیستی جنگل، دانشکده کشاورزی، دانشگاه ایلام، ایلام، ایران
2 دانشیار، گروه علوم جنگل، دانشکده کشاورزی، دانشگاه ایلام، ایلام، ایران
3 استاد ، گروه علوم جنگل، دانشکده کشاورزی، دانشگاه ایلام، ایلام، ایران
4 دکتری علوم زیستی جنگل، دانشکده کشاورزی، دانشگاه ایلام، ایلام، ایران
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Background and Objective: Pinus eldarica Medw species is effective on physical and chemical properties and soil quality index. However, the extent of these effects varies depending on factors such as climate, planting age, and soil depth. The aim of the present study is to investigate the short-term (20-year) and medium-term (30-year) effects of pine afforestation on soil properties.
Materials and Methods: Based on the Demarton index, two representative regions of semi-arid and Mediterranean climates were selected in Ilam province. Two 20- and 30-year-old plantations of P. eldarica were used for this study. Soil sampling was carried out using a completely randomized design in each region
at two depths of 0-10 and 10-20 cm with five replications. For data analysis, three-way analysis of variance (GLM) based on a factorial design was used to determine the significant effects of treatments and their interactions on physical (soil texture, bulk density, and soil moisture) and chemical (pH, electrical conductivity, organic carbon, total nitrogen, available potassium, available phosphorus, and lime) properties and soil quality index. Comparison of means was performed using Duncan's test at a 5% probability level. Principal component analysis (PCA) was used to examine the relationships between soil properties and explain the patterns of change between different treatments.
Results: The results showed that soil depth had a significant effect on the clay, sand, moisture, and bulk density. While the climate had a significant effect on soil moisture and the age of the plantations on moisture and bulk density, the soil moisture in 30-year-old plantations was about 1.5 times that of 20-year-old plantations. Also, climate had a significant effect on total nitrogen, phosphorus, and potassium and soil quality index. Stand age and soil depth had a significant effect on most chemical properties. In addition, the interaction between age and soil depth had a significant effect on organic carbon, total nitrogen, available potassium, and soil quality index. The organic carbon content in the surface layer of 30-year-old trees was 3 to 3.5 times higher, total nitrogen was 2.5 to 3 times higher, available potassium was 1.8 to 1.5 times higher, soil quality index was 1.15 and 1.14 times higher, and electrical conductivity was lower than in 20-year-old plantations. These differences were observed in semi-arid and Mediterranean regions, respectively.
Conclusion: Afforestation with the non-native species of Tehran pine in degraded lands, plays an important role in soil conservation, water resource conservation, carbon storage, and landscape restoration. Although soil quality index has improved in the Mediterranean climate due to higher organic matter input, more favorable climatic conditions, and greater water holding capacity, a gradual trend of soil properties improvement in older stands is also observed in the semi-arid region. These stands play an effective role in soil improvement and stability under water-limited conditions by increasing carbon and nitrogen content and reducing electrical conductivity. Therefore, the continuation of afforestation programs using non-native pine species should be accompanied by long-term monitoring and rigorous comparative studies with native species, in order to meaningfully contribute to sustainable natural resource management and the restoration of ecological balance in vulnerable ecosystems.
کلیدواژهها [English]
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