Impacts of management practices on soil organic carbon in degraded alpine meadows on the Tibetan Plateau

[摘要] Grassland soil organic carbon (SOC) is sensitive to anthropogenic activities.Increased anthropogenic disturbance related to overgrazing has led towidespread alpine grassland degradation on the Tibetan Plateau. The degradedgrasslands are considered to have great potential for carbon sequestrationafter adoption of improved management practices. Here, we calibrated andemployed the Century model to investigate the effects of overgrazing andimproved managements on the SOC dynamics in alpine meadows. We calibratedthe Century model against plant productivity at the Haibei Research Station. SOCstocks for validation were obtained in 2009–2010 from degraded alpinemeadows in two communes. We found that Century model can successfully capturegrassland SOC changes. Overall, our simulation suggests that degraded alpinemeadow SOC significantly increased with the advent of restoration managementfrom 2011 to 2030. Carbon sequestration rates ranged between 0.04 Mg C ha⁻¹ yr⁻¹ in lightly degraded winter grazing grasslands and2.0 Mg C ha⁻¹ yr⁻¹ in moderately degraded summer grazinggrasslands. Our modelling work also predicts that improve management in degraded Tibetan grasslands will contribute to an annual carbon sink of0.022–0.059 Pg C yr⁻¹. These results imply that restoration ofdegraded grasslands in theTibetan Plateau has great potential for soil carbonsequestration to mitigate greenhouse gases.

[学科分类] 地球化学与岩石