Fiber Performance of Introduced Huacaya Alpacas Grazing on Sown Pasture Effects of Stipa bungeana on Soil Water Contents and Nutrients of Sloping Lands in Loess Plateau of China Study on Utilization Pattern of Sown Pasture-based Sheep Grazing and Cutting Effect of Grazing Intensity on Community Character and Aboveground Present Biomass of Alpine Mixed-sown Pasture