Alpine meadow,with limited plant-available nitrogen (N) by decomposition constraints,may be quite capable of retaining additional N.However,plant will control the quantity of N retained,which have potential implications for system N fluxes.We examined the retention and allocation of 15N three years after labeling an alpine meadow ecosystem in the Tibetan plateau based on a 15N labeling experiment,the plant community of which is a mixture of graminoids,cyperaceaes and forbs.