生产力稳定性是草原生态系统稳定性的基础。时间稳定性和抵抗力是生产力稳定性两个重要方面，明确二者的协同作用关系是揭示环境变化对生产力稳定性影响的关键环节。氮沉降通过降低物种多样性而改变生产力时间稳定性和对极端气候的抵抗力。然而，多数相关研究仅考虑了时间稳定性或抵抗力单方面的变化，对它们协同关系及驱动机制并不清楚。本项目拟以内蒙古典型草原生态系统为研究对象，基于氮素添加（10和40 g N m-2 a-1）和模拟生长季中期极端降雨的控制实验，探明氮沉降背景下草原生态系统生产力的时间稳定性、抵抗力以及它们协同关系对极端降雨的响应规律。同时，通过对土壤理化性状、植物物种多样性、物种非同步性等关键生物和非生物环境指标的同步测定，阐明生产力时间稳定性和抵抗力协同作用关系的响应机制。本研究结果将有助于多维度深化对草原生态系统生产力稳定性的认知，也为预测极端降雨和氮沉降对草原生态系统的影响提供理论依据。

Productivity stability is the basis of grassland ecosystem stability. Temporal stability and resistance are two important aspects of productivity stability, and to clarify the synergistic relationship between them is the key to reveal the impact of environmental changes on productivity stability. Nitrogen deposition can alter the temporal stability of productivity and resistance to extreme climates by reducing species diversity. However, most of the relevant studies only considered the alteration in temporal stability or resistance, however, it is not clear that their covary relationship and driving mechanism. This project, based on the nitrogen addition (10 and 40 g N m-2 a-1) and simulating the extreme rainfall in the middle of the growing season in typical grassland ecosystems in Inner Mongolia, discuss that the temporal stability and resistance of the productivity of the grassland ecosystem under the background of nitrogen deposition, as well as the response law of their synergic relationship to the extreme rainfall, are investigated. At the same time, we would measure the simultaneous determination of key biological and abiotic environmental indicators such as soil physical and chemical properties, plant species diversity and species asynchrony, to elucidate the influence mechanism on the synergistic relationship between productivity temporal stability and resistance. Our study will help to furthur understand the synergic relationship of productivity stability of grassland ecosystem, and provide a theoretical basis for predicting the impact of extreme rainfall and nitrogen deposition on grassland ecosystem.