Comparison effect of prescribed heat on some chemical properties of soil under Persian oak (Quercus brantii Lindl.) in laboratory conditions

Fire is one of the most important natural disturbances in forest ecosystems, and it has significant effects on soil properties depending on its severity and duration. The aim of this study was to compare the properties of forest soil beneath Iranian oak (Quercus brantii Lindl.) on northern and southern slopes that were heated under laboratory conditions. To collect soil samples, northern and southern slopes were selected in the forest area of Baneh. A transect was established on the counter lines of both slopes. On each transect, the closest tree to the transect was selected, and the next seven trees were chosen at 30-meter intervals. In total, sixteen soil samples were taken from a depth of 0-5 cm. The soil samples were divided into four parts in the laboratory (unburned soil and three treatments heated at 200, 400, and 600°C). The amount of organic carbon did not change at 200°C but decreased after that. The amount of nitrogen increased at a temperature of 200°C and then decreased to 0.05 and 0.02 at 600°C in the soil of the northern and southern slopes, respectively. The pH and phosphorus levels decreased initially and then increased. The electrical conductivity was 1093 and 838 μS/cm at 600°C in the soil of the northern and southern slopes, respectively. The amount of magnesium increased in treatments of 200 and 400°C but decreased in treatments of 600°C. The amount of phosphorus, potassium, calcium, and electrical conductivity in the soil of the southern slope was 75%, 32%, 32%, and 100% higher than that of the northern slope at 600°C treatment, respectively. In conclusion, it can be inferred that the soil properties of southern aspects can be more affected than those of northern aspects by heat of fire with moderate to high severity.