Research Center for Environmental Ecology and Engineering, School of Environmental Ecology and Biological Engineering, Wuhan Institute of Technology, Wuhan, China.
Laboratorio de Biodiversidad y Funcionamiento Ecosistémico, Instituto de Recursos Naturales y Agrobiología de Sevilla (IRNAS), CSIC, Sevilla, Spain.
Glob Chang Biol. 2024 Sep;30(9):e17502. doi: 10.1111/gcb.17502.
Priming effects of soil organic matter decomposition are critical to determine carbon budget and turnover in soil. Yet, the overall direction and intensity of soil priming remains under debate. A second-order meta-analysis was performed with 9296-paired observations from 363 primary studies to determine the intensity and general direction of priming effects depending on the compound type, nutrient availability, and ecosystem type. We found that fresh carbon inputs induced positive priming effects (+37%) in 97% of paired observations. Labile compounds induced larger priming effects (+73%) than complex organic compounds (+33%). Nutrients (e.g., N, P) added with organic compounds reduced the intensity of priming effects compared to compounds without N and P, reflecting "nutrient mining from soil organic matter" as one of the main mechanisms of priming effects. Notably, tundra, lakebeds, wetlands, and volcanic soils showed much larger priming effects (+125%) compared to soils under forests, croplands, and grasslands (+24…+32%). Our findings highlight that positive priming effects are predominant in most soils at a global scale. Optimizing strategies to incorporate fresh organic matter and nutrients is urgently needed to offset the priming-induced accelerated organic carbon turnover and possible losses.
土壤有机质分解的激发效应对于确定土壤碳收支和周转至关重要。然而，土壤激发的总体方向和强度仍存在争议。通过对 363 项主要研究中的 9296 对观测值进行二次荟萃分析，根据化合物类型、养分供应和生态系统类型，确定激发效应的强度和总体方向。我们发现，新鲜碳输入在 97%的配对观测中诱导出正激发效应（+37%）。易变化合物比复杂有机化合物（+33%）诱导出更大的激发效应（+73%）。与不含氮和磷的化合物相比，添加有机化合物的养分（如 N、P）会降低激发效应的强度，这反映了“从土壤有机质中矿化养分”是激发效应的主要机制之一。值得注意的是，与森林、农田和草原下的土壤相比（+24…+32%），苔原、湖底、湿地和火山土壤的激发效应大得多（+125%）。我们的研究结果表明，在全球范围内，大多数土壤中存在正向激发效应。迫切需要优化策略，将新鲜有机物质和养分纳入其中，以抵消激发诱导的加速有机碳周转和可能的损失。
