Survey of the impact of the form and growth stage on forage quality of nine range species in central Alborz (case study: Taleghan)

For assessing of rangelands and programming for supply of feedstock requirement of livestock depends to growth season and calculation of grazing capacity, the knowing of forage quality information of the key plants is necessary. This research was done in watershed of Taleghan, Nine species belonged to three life forms during three stage of growth assessed in this research including: Bromus tomentellus، Agropyron intermedium، Dactylis glomerata from family of Poaceae and Artemisia aucheri,، Achillea millefolium, Centaurea virgata، Scariola orientalis from family Asteraceae and Thymus kotschyanus from family of Lamiatae and Coronilla varia from family of Fabaceae. Samples from species were collected randomly in three phenological stages (Vegetative growth, flowering and seeding). For each species 3 replicates and for each replicate five stands of plant were selected and cut from 1 cm above surface for grasses and forbs and current year growth for shrubs. The samples were dried in 70° oven for 24 hours. Then chemical analysis was accomplished for determination of: crude protein (CP), acid detergent fiber (ADF), digestible dry matter (DMD) and metabolic energy (ME). Analysis of variance was applied for data analysis. The results indicated that crude protein was decreased by development of growth in all species while acid detergent fiber increased. The highest amount of forage quality was related to Coronilla varia and in vegetative growth. While the lowest one is related to Centaurea virgata and in maturity growth. Also the results showed that there are significant differences between life forms and between species within life forms and between phenological stages (p ≤ 0. 1). Also there were significant differences interaction effects species in phenological stages for total studied traits (p ≤ 0. 1). Considering difference of forage quality of species and effect of phenological stages based on plant composition and time of grazing daily requirement of livestock will be different.