Evaluation of relationship between topographic and climatic factors with Sablan rangeland forage production

This study is conducted to identify relationship between the amount of forage production with topographic (elevation, slope and aspect) and climatic (rainfall and minimum, maximum and mean temperature parameters) variables in Sabalan’s rangelands. Using digital elevation model, rainfall, slope and aspect classes maps was prepared environment. In preparing rainfall and temperature parameters classes maps, data of weather stations and derived relavant gradient were used. Then, by considering vegetation types and different elevations, slopes, aspects, rainfall, and temprature parameter classes in the maximum vegetative growing stage, annual production using one square meter plots by cutting and weighting method was harvested. Topographic and climatic variables for plots was derived using prepared maps. To determine the most important affective environmental factor or factors in production vaiation, principal component analysis method used. Results show that from the selected environmental factors based on the firest two components, elevation, rainfall, mean temperature and slope have the most effect on the production of Sabalan’s, which the first component 68.13% and the second component 14.96% of changes and the two components totally 83.09% were covered of the changes. Moreover, results of correlation analysis show that the mean of temperature has negative effect and other factors have positive effect on the changes of production. Therefore, in the assessment of production and grazing capacity such as Sabalan rangeland, topographic and climatic factors should be considered.