[Ecosystem carbon uptake was co-limited by nitrogen and phosphorus in alpine meadow on the Qinghai-Tibet Plateau]

Alpine grassland is threatened by the import of chemicals, fertilizers and other external resources with increasing human activities on the Qinghai-Tibet Plateau. It is unclear how carbon cycle of alpine grasslands is affected by the inputs of external resources such as nitrogen, phosphorus, and potassium (N, P, K) and their interactions. We conducted a 3 year experiment on the interactive addition of N, P and K with alpine grassland as the research object to clarify ecosystem carbon exchange process in response to resource addition by measuring community coverage and ecosystem carbon exchange. The results showed the alpine meadow was represented by carbon sequestration during the growing season. The mean value of net ecosystem CO随着人类活动加剧,青藏高原高寒草地面临外来资源输入的威胁,而外源资源输入如氮、磷、钾(N、P、K)及其交互作用如何影响高寒草地生态系统碳循环尚不明确。本研究在藏北高寒草甸进行了连续3年N、P、K元素交互的添加试验,测定群落盖度和生态系统碳交换等数据,旨在阐明资源添加对高寒草甸生态系统碳交换过程的影响。结果表明: 在植物生长季,高寒草甸生态系统总体表现为碳汇,对照下NEE均值为-13.0 μmol·m