Importance of annual and seasonal precipitation variations for the sustainable use of rangelands in semi arid regions with high altitude

Precipitation is one of the most important factors which can determine the type and productivity of rangeland vegetation in arid and semi arid regions. In the present study, a widely used drought analysis index, Standard Precipitation Index (SPI), was used considering an eighty–year precipitation data set belonging to Erzurum province. Data was analysed in order to estimate the length, magnitude and severity of drought period in Erzurum province. According to the results of the present study, it was found that long term average precipitation was normal or close to normal in 56 years (70%), 11 years (13.75%) were moderately dry, one year (1.25%) was severely dry while the number of moderately, severely and extremely wet years was 3 (3.75%), 7 (8.75%) and 2 (2.5%) respectively.