Monthly variation of production of key range species in central arid rangeland, Case study: Saveh-Markazi Province, Iran

     Forage production of rangelands differs during different times of grazing season and in the same month of different years. In range management projects, grazing capacity calculated once during the grazing season, which coincides with the maximum production of rangeland species. This may cause more livestock entry into the rangeland during the grazing season, leading to more degradation. Therefore, it is necessary to measure forage production during the months of grazing season over a few years, based on which the long-term grazing capacity of key range species could be estimated. Production variations of the key species, namely Artemisia sieberi, Salsola laricina, and Stipa hohenackeriana were investigated in Khoshkerood-e-Saveh site in growth and grazing season over the course of three years. For this purpose, the production of each species measured in a one-hectare exclosure with one month intervals until the growth dormancy. After air-drying, forage production was analyzed by SAS software. Based on the results, due to the high variability of monthly and annual precipitation in the region, forage production of key range species had significant differences at P ≤5% level. The maximum and minimum mean production (543 and 388 kg/ha) belonged to 2009 and 2008, respectively. According to the production fluctuation in different years, it is recommended that range management plans account for the long-term average of good production.