Effect of surface fire on dynamic of some chemico-physical properties of forest soil, Sardasht, West Azarbayjan

This study was conducted to investigate the effect of fire on some soil chemical properties in Northwestern oak forests of Iran. The study area was selected 30 km from Sardasht city in West Azerbaijan province which was burnt in September of 2017. The control or unburned area was selected with the same conditions adjacent to the burn area. After surveying forest conditions in each area, 9 plots, each with an area of 500 m2 and a total of 18 plots were sampled using systematic random method and 100 × 100 m grids. Soil samples were collected at the center of each plot at a depth of 0-10 cm at three times: 1 - immediately after the fire 2 - three months after the fire and 3 - six months after the fire. The pH, EC, K, P, OC, Mg, N factors were measured. The results showed that the soil elements in the burned area were slightly higher than the unburned soils but these increases were not statistically significant. The results of repeated measures analysis showed that the effect of time on the acidity (pH), calcium and magnesium in the burned and unburned area was statistically significant. The largest change in the value of the three above mentioned variables was observed three months after the fire. Overall, the low intensity of surface fire in the area did not have a significant effect on soil chemical properties, so that six months after the fire, most of the elements returned to their pre-existing levels.