Impact of some soil physic-chemical properties on drought resistance Plantation of Arizona cypress in East of Isfahan

In recent years, Arizona cypress plantations located in East Isfahan are increasingly drying. Water deficit and frequent drought are allegedly considered as the main reasons. Nevertheless, the wilting trees are not evenly dispersed across the plantations, leading to existing associate factors. The present research Consider that the effect of soil chemo-physical characteristics on the wilting rate. Preliminary research work showed that the forest area studied can be classified on the basis of environmental stresses related to four separate regions. One area due to its proximity to population centers , the two , proximity to roads , the three, with a maximum distance from the areas with high stress potential and the due to the proximity to the industrial zone four were selected. In each plot, all trees, including health, are drying up, dried, and even recently cut trees were counted, as well as Soil samples were taken from each plot up to a depth of 30 cm and then analyzed in the laboratory. Soil texture, pH, electrical conductivity, sodium concentrations in treated, Concentrations of calcium, sodium adsorption ratio, cation exchange capacity, total nitrogen and phosphorus and Potassium absorbable parameters were measured. Wilting rate was increased significantly in more salty and more conductive soils. Soils made ​ up of particles of all sizes were more resistant to drought. The results also showed that overuse chemical fertilizers decreased the trees’ survival in severe drought conditions.