Active Restoration of Carbon Poor Degraded Grassland Accelerated Subsoil Carbon Accumulation and Turnover

The study, conducted in Zoige County on the eastern Qinghai–Tibet Plateau, examined three alpine grassland types differing in initial soil organic carbon (SOC) content (C-rich, C-middle, and C-poor) under non-restored, passively restored, and actively restored conditions. In August 2022, vegetation surveys measured species composition, coverage, height, and aboveground biomass, while soil samples were collected from 0–10 cm and 20–30 cm depths for physico-chemical analyses, bulk density, and microbial biomass measurements. Additional soil cores were taken for belowground biomass. Active restoration involved sowing locally adapted grass species, whereas passive restoration relied on natural recovery with grazing exclusion. Laboratory analyses determined plant nutrients, SOC, total C and N, and microbial biomass C and N. Soil incubation experiments at three temperatures (5 °C, 15 °C, 25 °C) assessed SOC mineralization rates and temperature sensitivity (Q₁₀), with CO₂ release monitored over 28 days.本研究于青藏高原东部若尔盖县开展，针对初始土壤有机碳（Soil Organic Carbon, SOC）含量存在差异的3类高寒草原类型（富碳、中碳、贫碳），设置了未修复、被动修复与主动修复3种干预条件。2022年8月，研究团队开展植被调查，测定了物种组成、盖度、高度及地上生物量；同时采集0~10 cm与20~30 cm土层的土壤样品，用于理化分析、容重测定及微生物生物量检测，并额外采集土壤柱样以获取地下生物量。主动修复措施为播种当地适生草本物种，被动修复则依托封禁放牧实现自然恢复。实验室分析测定了植物养分、SOC、总碳与总氮，以及微生物生物量碳与氮。设置5℃、15℃、25℃三个温度梯度开展土壤培养实验，以评估SOC矿化速率及其温度敏感性（Q₁₀），并在28天的实验周期内持续监测二氧化碳（Carbon Dioxide, CO₂）释放量。