Effects of plant growth and precipitation changes on the rangeland production in semi-steppe areas (Case study: Mashkin-Shahr Rangeland)

Knowing the ecological characteristics of plants and consequently changes in forage production during the season of grazing for grazing management is essential. Therefore, understanding the annual and monthly production of different rangeland types is essential for efficient and effective forage management. Consequently, relationships between forage production and climatic variables should be considered. For this purpose, the annual forage production was measured in the research exclosure of Arshaq Site rangelands in Ardabil province during 2007-2010 by clipping and weighing method. The monthly rainfall in this period was calculated using Mashkin-Shahr synoptic station data and then the amount of cumulative rainfall in winter and spring of each year was calculated. Afterward, the relationship between production and winter and spring rainfall as well as rainfall of different months of winter and spring was studied separately. Statistical analysis was performed using SAS software. According to the results, the average forage production during four years was calculated of which 28.95% belonged to Artemisia fragrans, 26.35% to Kochia prostrate, 19.55% to Stipa hohenackeriana, 4.77% to Astragalus brachyodonuts and 20.38% to the other species. Analysis of variance showed that the production of species among years were significant (P<0.01). In terms of stability (interactions of year × month), Artemisia fragrans and Kochia prostrata were stable, with a high yield; however, Astragalus brachyodonuts and Stipa hohenackeriana were stable with a low yield.