An investigation of preference value of summer rangelands species in Blumann (Zagheh) in Lorestan By filming method

Knowledge of preference value of plant species is one of the essential requirements for determining forage available and consequently, calculation of grazing capacity for rangeland habitats. This project was investigated in 36 species including of 21 perennials and 15 annuals species. For this purpose, during four-years period (2007-2010) in each month of the growing season (spring and summer) film was taken from a non-pregnant and non -lactating unit adult ewes (Lori)for at least 1800 seconds with an average weight of 50 kg inside the flock which were grazing in rangeland. Results indicated that annual grasses such as Boissiera squarrosa, Bromus danthonia, Bromus tectorum, Heteranthelium piliferum had the highest grazing time with a total duration of 3083 seconds compared to other species. Subsequent species including of Agropyron trichophorum with 2594 seconds, Bromus tomentellus with 1232 seconds, Onobrychis melanotricha with 681 seconds, broadleaf herbaceous annual such as Helianthemum ledifolhum, Viciea peregerina, Diplotaxis erucoides, talaspi perfoliatum, Minuartia obtusiloba with 670 second and Hordeum bulbosum with 565 second were ranked in the next. Finally, it was found that annual grasses and shrubs in May, perennial grasses in June, and broadleaf herbaceous annual in July have quite palatable and located in Class I. Also, total grasses and perennial forbs in July, annual forbs and shrubs in May and June have fairly palatable respectively which have located in class (II) and vegetative forms have palatable class III in other months.