اثر تاج تک درختان بنه (Pistacia atlantica Desf.) بر میزان عناصر مغذی خاک جنگل (منطقه سروآباد استان کردستان)

Trees crown can be regarded as main factor contributing to the conservation and support of soil in many ecosystems including semiarid forests in Zagross. The aim of this study was to find out the effect of tree crown of pictachio (Pistacia atlantica Desf) on N, OC, P, pH, EC and the texture of the soil. Soil samples were collected in and outside the crown of 5 single pistachio trees on four directions of each tree in a northern slope from the 0-5 cm depth of soil in the Sarvabad region, Kurdistan. The results of this study showed that the amount of the soil organic carbon was decreased from 6.71% in the soil inside tree crowns to 4.73% in the soils outside the tree canopies. The soil inside trees had a higher concentration of soil nitrogen (0.406%) than the one outside (0.224%) the tree crown; the concentration of phosphorus was measured to be 32.7 mg/kg in the soil inside canopy, while it was 21.1 mg/kg in the soil of outside the tree canopy. EC under the tree crowns was more than that outside the canopy. The results, therefore, showed that soil texture was lighter inside the canopy, as compared to outside; however, the acidity of the soil was not affected by tree crowns and no significant differences were observed in different areas of the crown. Therefore, Persian turpentine trees have positive impacts on the soil properties in Zagros forests and eliminating them will lead to the significant loss of soil fertility and greater soil erosion.