Effects Of Fertilization On Leaf N And P Resorption In An Alpine Meadow Of The Tibetan Plateau

Anthropogenic activities have indeed increased nitrogen and phosphorus deposition. The alpine meadow ecosystem of Tibetan Plateau is one of the major parts of the biogeochemical cycle. It is very fragile and is sensitive to the human activities due to its special geographic environment. However, the most studies were focused on the effects of N inputs on community composition, species richness and biomass. And few data regarding how N or P inputs affect the N and P resorption in plants and the community level. Here, we conducted a 5-years N and P addition experiment to explore the responses of three dominant species(Kobresia capillifolia, Elymus nutans and Anemone rivularis) and the community level under fertilization.Our results showed:1. Nitrogen addition increased mature leaf N concentration and senesced leaf N and P concentrations(except Kobresia capillifolia which showed a decline of P in senesced leaf). Across all levels, plant N and P resorption proficiency and efficiency decreased with increasing N addition rates(except Kobresia capillifolia which PRE increased).2. P fertilization increased two of three species mature and senesced leaf P concentration, but did not affect the N concentration in mature and senesced leaf of Anemone rivularis. Meanwhile P addition caused decreased in P resorption proficiency and efficiency in Kobresia capillifolia and Elymus nutans, but had no effect on N resorption proficiency and efficiency of Anemone rivularis. At the community level, P addition had no effect on NRP and PRP, but declined NRE and PRE.In all, under N fertilization, the NRE and PRE of plants were interrelated may due to the plant internal stoichiometric ratio. And when massive P inputs, plant NRE was not related to PRE, and NRE was not affected by P addition. When facing with different fertilizations, the species and community would adopt diverse strategies to adapt and then have significant impact on plant nutrients cycle and biogeochemical cycle.