An investigation of preference value of important range plants in Saraliabad Gorgan Rangelands in different phenological stages

Determining the preference value of range plant species and its variation during the grazingseason is one of the factors affecting the grazing capacity of rangeland. This study was conducted in semi steppe rangelands of Saraliabad Gorgan, located 45 km far from south Gorgan. Saraliabad rangelands have important role because of providing required forage especially at the times that all plain lands of the province are under planting of agricultural products. This research was aimed to determine the preference value of rangeland species for four years and during the three months of livestock presence on rangeland through estimating the consumption rate. Data were analyzed by SPSS software and mean comparison was performed by Duncan's Multiple Range Test. Results showed that there were significant differences between the preference index of species, years and months (P<0.01). According to the consumption percentage, the preference value of the most species was medium (class II), except Cousinia glaucopsis, classified as a non-palatable species (class III). The highest preference value was recorded for Medicago lupulina, Achillea millefolium, Galium verum and Medicago sativa, respectively and the lowest was obtained for Cousinia glaucopsis.