Natural Burning Effects on Some Vegetation and Soil Characteristics of Rangeland (Case Study: Pir Gol Sorkh Behbahan Rangeland)

This study was conducted to explore the effects of natural fires on vegetation and soil characteristics in Pir Golsorkh rangeland of Behbahan. Samples were collected in two areas which were burned and unburned by random- systematic method. In each plot percentage of total cover, percentage of bare soil, percentage of gravel and rocks, percentage of litter, percentage of vegetation according to their growth, the amount of production were measured and the condition of pasture was determined. Five profiles dug and soil samples were collected from two depths (0-20 and 20-40 centimeters) in each area and analyzed. The amount of nitrogen, potassium, carbon and phosphor were determined. Results show that in the area where fire took place the percentage of vegetation class III more than vegetation of class III of unburned area. While class I vegetation in unburned area was more than vegetation class I in the fire place. The percentage of vegetation in the burned area is qualitatively increased and the amount of grass is decreased. Percentage of vegetation and amount of grass in the burned place has a meaningful increase compare to unburned place. Soil factors analysis show no meaningful differences in nitrogen, carbon, potassium or phosphor between these two areas. Therefore, when there is fire along with drought, this can cause an increase in unpalatable grass and then it will become a suitable place for the upcoming fire.