عنوان مقاله [English]
Effect of edaphic and geomorphologic factors on the growth promotion or restriction of the planted seedlings of Cupressus sempervirens var. horizontalis Mill., Cupressus sempervirens var. arizonica Greene., Pinus brutia Elwes Henry., Pinus eldarica Medw., Ailanthus glandulosa Desff., Robinia pesudoacacia L., Quercus brantii var. persica Zohary., Fraxinus rotundifolia Mill. and Elaeagnus angustifolia L. was studied in a pilot project at the Kamfirooz research station in Fars province. The statistical design was completely randomized block with 3 replications. As in a previous 10-years study in the same area with the same species, significant differences had been observed among replications, we designed this problem oriented study to pinpoint the edaphic and geomorphologic factors, which might have influenced the performance of these species. Soil map units (SMU) were differentiated on the basis of topographical and geomorphological aspects. In each SMU, morphological characteristics of soil profiles (depth to the lithic contact) were studied, and three units A, B and C wee separated. Subunits were selected on the basis of factors that prohibit or improve plant growth. It was hypothesized that the presence or absence and the degree of cementation of marl stratum in the subsoil, and the degree of slope and amount of stones in the rooting zone, were the growth limiting factors. Moreover, soil physical and chemical characteristics were considered as the effective growth-modifying factors. The growth was evaluated visually and numerically from 1 (the best) to 5 (the worst). Also the 4 years average of survival rates in each replication were used to evaluated the relationship between plant growths and soil factors. We strongly believe that the morphology followed in our study is superior to the currently used evaluation techniques, as it takes into account those factors which heavily affect plant growth in our area.