Decomposition process and scientific management of yak dung on alpine meadow in the eastern QinghaiTibetan Plateau

Ruminant dung fertilization is one of important ways to impact grassland ecosystems, especially for highaltitude ecosystem nutrient cycling. In this study, characteristics and decomposition dynamics of nutrients of yak dung were determined and scientific management strategy of yak dung was explored through calculating nutrient demands of plant growth and input amounts of yak dung on the alpine meadow of the eastern QinghaiTibetan Plateau. The results indicated that released nitrogen and phosphorus from yak dung on a typical alpine meadow were 79.4 and 11.8 kgha-1 a-1, respectively. After 85 d decomposition in summer, most of the major nutrients were degraded (approximately 0.48%-6.98% of the initial state), while in autumn the decomposition rate was much lower (approximately 13.44%-40.06% of the initial state). It was estimated that the input amount of fresh yak dung on the study area was approximately 4.08105 kg per household. If 3.08105 kg and 8.93104 kg of fresh dung were used for maintenance of soil fertilization and daily life per household respectively, there was only 2.5% of total fresh yak dung remaining per year. Based on these calculations, yak dung for commercial use was not recommended on the alpine meadow.