Variability of soil chemical characteristics in Oak stands with different dieback

Determination of soil chemical properties variability that affected tree tolerance to stresses can help to manage this environmental phenomenon. In this investigation, for detection of this variation trend, area of affected decline oak trees divided to four groups of control (without Oak decline), slight, middle and severe Oak decline based on tree and branch number per soil surface unit. In each study group, soil sampling was done with four replications. After soil sampling operation and preparation, experimental properties such as calcium carbonate, available phosphour (P), potassium (K), and zinc (Zn) were determined by three replications. Data were analyzed by Statistical Analysis System (SAS) program v 9.2 and comparisons among means were done by Duncans, multiple range test (DMRT) at p<0.05. Analysis of variation of data indicated that a TNV content that has high effect on availability of nutrient elements had increase trend from without toward severe Oak decline locations. In addition, with change in location from without oak decline to sever decline, available phosphorus concentration had a decreasing trend. Concentration of this nutrient decreased from 18.1 mg kg-1 in depth of 0-25 cm in whitout oak decline to 13.0 mg kg-1 in severe oak decline lication. In other hand, decrease trend of available potassium and zinc concentrations were observed. Therefore, higher Oak decline in locations with lower P, K and Zn, cause to recommendation for their development and reclamation for forest management.