نوع مقاله: مقاله پژوهشی
نویسندگان
1 1دانش آموخته کارشناسی ارشد گروه مهندسی خاک و آب، دانشگاه ایلام
2 استادیار گروه مهندسی خاک و آب، دانشگاه ایلام
3 استادیار گروه علوم خاک دانشکده کشاورزی دانشگاه ایلام
چکیده
کلیدواژه‌ها
عنوان مقاله [English]
نویسندگان [English]
Abstract
Background and objectives: Fire is a major threat for natural resources in the world and is an important factor in changing physical and chemical properties of soil. Knowledge of the positive or negative effects of fire on soil properties can be a great importance for the management of natural resources. This study was conducted with the aim of the effect of fire on physical and chemical properties of soil in rangelands of Badreh area in Ilam provice and comparison with non-fire areas (control).
Materials and methods: After field studies in Badreh area in the eastern of Ilam province, soil samples were taken from 0-5 and 5- 20cm depths and collected randomly and transferred to the laboratory. Physical analysis (soil texture, mean weight aggregate diameter, saturation moisture and bulk density) and chemical (organic matter, total nitrogen, phosphorus available, potassium available, calcium and magnesium exchangeable, cation exchange capacity) were carried out on soil samples.
Results: The highest amount of sand (46.4%) and soil silt (24.4%) were found in burned pasture and the highest clay content (39%) was found in control rangelands. Fire decreased the stability of aggregates and soil porosity in burned rangelands compared to unprocessed rangelands (14.28 and 8.68%) significantly (α= 0.05). The bulk density of the burned pasture was 9.1% higher than that of the control pasture. In the soil surface layer, the soil moisture content increased 16.98% compared to the control treatment. The fire decreased the amount of soil organic matter from 2.66% in control pasture to 2.19% in burned pasture (α= 0.05). Soil acidity increased significantly in burned pasture (pH=7.45) compared to control pasture (pH=7.07). The highest cation exchange capacity (24.82 cmol kg-1) and the lowest (18.98 cmol kg-1) were obtained in control and burned rangelands respectively. Also, with an increase in soil depth, the cation exchange capacity of soil decreased to 14.10%. The most available phosphorus, magnesium and calcium were obtained in burned pasture at the soil surface. Fire had no significant effect in the subsoil layer, on the amount of soil phosphorus, magnesium and calcium exchangeable.
Conclusion: In general, the results indicate that fire in rangelands of Badreh area in Ilam province affected physical and chemical properties of soil. In most cases, soil quality is decreased chemically (decreasing organic matter, nitrogen, cation exchange capacity) and physically (soil texture changing, soil aggregate stability, porosity and bulk density), and in some cases, fire caused to release the nutrient elements such as phosphorus, calcium and magnesium in the soil and improved the nutrient cycling nutrients in the soil.
کلیدواژه‌ها [English]
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