Soil Carbon, Nitrogen and Phoshorus Dynamics in Response to Warming and Grazing in Alpine Meadow Ecosystem of the Tibet plateau

Abstract

Ongoing global climate change is predicted to substantially impact on terrestrial ecosystems. The Qinghai-Tibet plateau is very sensitive to climate change. Alpine meadows, one of the major ecosystems on the Qinghai-Tibet Plateau, is very vulnerable and can be sensitive to both climate change and human disturbance. Grazing is the main land use mode of the alpine meadow ecosystem. Soil carbon (C), nitrogen (N), and phosphorus (P) availability are key to ecosystem productivity, while the alterations in soil C, N and P dynamics can affect ecosystem substantially. Investigation on the response of soil C, N and P cycling and the associated functional microorganisms in the alpine meadow can provide insights into soil function under warming and grazing conditions and sustainable management of the ecosystem. In this thesis, the study was conducted based on a controlled warming-grazing experiment in the Haibei Alpine Meadow Ecosystem Station, Chinese Academy of Sciences (CAS). A free-air temperature enhancement (FATE) system and a moderate grazing intensity were applied to simulate the effects of warming and grazing. Four treatments including no warming with no grazing (NWNG), no warming with grazing (NWG), warming with no grazing (WNG) and warming with grazing (WG) were applied.