| چکیده انگلیسی مقاله |
Background and objectives: Achieving sustainable development and ensuring food security of the country will not be possible without preserving and reclamation of natural areas. Soil is the basis of the health of rangeland ecosystems, so the consequences of land management on its productivity and quality should be evaluated. The use of restoration operations in rangelands and exclosures have long been used as strategies to improve the condition of vegetation cover and soil. Past studies show the significant importance of management decisions on vegetation and soil in natural ecosystems. The purpose of this research is to know the effect of rangeland management on changes in the main characteristics of soil health and quality, for this purpose, Khamesan representative watershed was selected from the sub-watersheds of Sirvan. The restoration operation of the rangelands of Khamesan region, including mechanical operations (construction of banket and pitting), biological operations (pit-seeding and intercropping) since 2006, and exclosure by the General Department of Natural Resources of Kurdistan province, since 2007, in order to preserve and restore the rangelands.
Materials and methods: Khamesan watershed, 35 km from Kamyaran city in Kurdistan province with an area of 4193 hectares, with three types of management including restoration management, exclosure and livestock grazing area, was selected for the study. In each type of management, three homogeneous areas with similar physiographic conditions were selected and five profiles (one profile in the center and four additional ones around it) were dug in each of them. Soil sampling was done from a depth of 0-30 cm and the factors of Bulk density, soil texture, porosity, average particle diameter, electrical conductivity, acidity, phosphorus, potassium, lime, nitrogen, organic carbon, carbon to nitrogen ratio, Basal respiration, stimulated respiration, carbon of microbial biomass, nitrogen of carbon biomass, ratio of carbon to nitrogen of microbial biomass, microbial metabolic coefficient were measured and analyzed by SPSS 19 software.
Results: The role of management is very effective on the physicochemical and biological characteristics of the soil, so that among the investigated factors, the physical characteristics of the soil (silt percentage, clay percentage, bulk density, porosity percentage and average particle diameter), chemical (organic carbon, phosphorus, soil carbon-nitrogen ratio) and biological (basal respiration, stimulated respiration, microbial biomass carbon, microbial biomass nitrogen, microbial biomass carbon-nitrogen ratio, microbial biomass carbon-nitrogen ratio and microbial ratio) have been affected by the type of management. Biological indicators of soil in the studied area have been affected more than other characteristics by the restoration operations and exclosure, so that the highest amount of basic respiration in the part under livestock grazing is 0.93 (mgCO2g-1dm24h-1), and Its lowest is in the modified section, 0.57 (mgCO2g-1dm24h-1). The highest bulk density (1.69 (gr/cm3)) was in the area under livestock grazing, and the lowest (1.57 (gr/cm3)) was related to the areas with restoration operations. The carbon-nitrogen ratio of the soil in the modified pasture is 12.18 and in the grazed area, it is 6.91.
Conclusion: Soil is the bed of life in ecosystems. Preservation of vegetation and biodiversity in nature depends on preservation of all ecosystem components, especially soil. long period over grazing usually takes place in the rangelands, therefore, a significant level of the rangelands needs to be managed and change the level of protection. Among the characteristics of soil, biological indicators are more sensitive to management and environmental changes than other indicators and can be used in the assessment of soil health of ecosystems. restoration operations and correct management, by improving vegetation cover, helping soil granulation and improving soil structure, increasing carbon input, increasing soil microbial population, and improve soil health and quality. The result of the conducted study shows the positive effect of restoration operations and exclosure on the improvement of the soil condition.
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