Investigation on soil and water salinity effects on weakness and mortality of Arizona Cypress (Cupressus arizonica G.) in Qom

A research project was carried out from 2004 to 2006 to survey the dieback causes of Arizona Cupressus trees, in Gadir park, located nine kilometers south of Qom. In this project some quantitative and qualitative properties of the trees were surveyed. The collected data and different information of soil, water and plant were divided into four groups, according to different rate of trees dryness and were analyzed as random complete block by four replication. Results showed that based on ANOVA table, there is a significant difference in trees freshness, Cl, B, Cu and Zn amount (1%) and P, K and Fe (5%) between four groups of trees. The results of leaf analysis showed that Cl, B and Zn were highest in the trees with less score of survival. Therefore, unsuitable soil and salinity of water were detected the most important causes of Cupressus's dryness in this research. The salinity of water and soil in addition to the aggregation of substances and their absorption with the trees had caused nutritional and physiologic disorders and consequently, the weakness and dryness of trees. The analysis of tree's leaves showed that a large amount of Na and Cl were absorbed by the plants which had caused a toxicity of these elements. There was also a high density of Fe, Zn, Mn and Cu which shows nutritional imbalance due to the salinity. Due to the fact of weakening and intensifying of unfavorable conditions, secondary factors like fungus Nattrassia mangiferae affect the plant and have made faster the process of dryness.