Estimation of Livestock Available Forage Yield Based on Condition, Trend and Soil Erosion in Taleghan Rangelands (Case study: Varkesh, Khodkavand and Orazan sub-basins)

It is essential to have correct information to determine short-term and long-term capacity of rangelands. Total forage yield cannot be used by livestock due to allowed utilization limit and palatability of species. Varkesh, Khodkavand and Orazan sub- basins of Taleghan region were selected for this research and within key region of each vegetation type, sampling was conducted based on randomized- systematic approach. Four transects of 100 m length was established in each type along and in vertical direction to the slope. Based on vegetation type and uniformity, 10 random plots of 1m2 area were considered and then by clipping and weighting method and considering palatability and allowed utilization limit, available forage yield was calculated. The results showed that among 10 existing types, five types do not have grazing suitability due to weak condition and high sensitivity to soil erosion and were not considered for calculating available forage yield which is mostly related to mountainous and steep slope of the region, low palatability of some class III species (Centaurea virgata and Astragalus aegobromus), sensitivity of soil to erosion and also existence of poisonous species in the region.