Evaluation influece of wildfire on the chemical properties of forest soil at the top and toe slope in Sarvabad, Kurdistan province

Soil properties can be greatly affected by both topography and fire. Topography is one of the factors affecting the fire intensity. The aim of this study was to compare the effect of fire on chemical soil properties at top and toe of hillside slope. In order to sampling, one week after fire, three transects were installed with a length of approximately 100 meters from top to toe and interval of 20 meters from each other on the western slope in each area (burned and unburned) where the fire occurred in the summer of 2018 in Sarvabad area. Totally, 36 soil samples were collected and some properties were measured including: carbon, nitrogen, phosphorus, pH, EC, potassium, calcium and magnesium.The results showed that all chemical soil parameters were lower in the upper position than in the toe position slope in control area. However, the pH and electrical conductivity and calcium of soil increased more at the top than toe position of the slope in the burned area. Also, the amount of carbon and nitrogen of soil has increased at the top less than toe of the slope. The amount of soil phosphorus showed significantly difference in the burned soil at the top of the slope in comparision to the control. In general, the intensity of fire in these two positions can indirectly measure by comparison soil properties at top and toe of slope in burned area. Because of changes on soil chemical properties in the burned area, it seems that the fire intensity was higher at the top of the slope due to heat transfer from the bottom to the top of the slope.