Tian Qiuxiang, He Hongbo, Cheng Weixin, Bai Zhen, Wang Yang, Zhang Xudong
State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China.
Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan 430074, China.
Sci Rep. 2016 Jan 6;6:18783. doi: 10.1038/srep18783.
Changes in soil organic carbon (SOC) stability may alter carbon release from the soil and, consequently, atmospheric CO2 concentration. The mean annual temperature (MAT) can change the soil physico-chemical characteristics and alter the quality and quantity of litter input into the soil that regulate SOC stability. However, the relationship between climate and SOC stability remains unclear. A 500-day incubation experiment was carried out on soils from an 11 °C-gradient mountainous system on Changbai Mountain in northeast China. Soil respiration during the incubation fitted well to a three-pool (labile, intermediate and stable) SOC decomposition model. A correlation analysis revealed that the MAT only influenced the labile carbon pool size and not the SOC stability. The intermediate carbon pool contributed dominantly to cumulative carbon release. The size of the intermediate pool was strongly related to the percentage of sand particle. The decomposition rate of the intermediate pool was negatively related to soil nitrogen availability. Because both soil texture and nitrogen availability are temperature independent, the stability of SOC was not associated with the MAT, but was heavily influenced by the intrinsic processes of SOC formation and the nutrient status.
土壤有机碳（SOC）稳定性的变化可能会改变土壤中的碳释放，进而影响大气中的二氧化碳浓度。年均温度（MAT）会改变土壤的物理化学特性，并改变输入土壤的凋落物的质量和数量，而这些因素会调节SOC的稳定性。然而，气候与SOC稳定性之间的关系仍不明确。在中国东北长白山一个具有11°C温度梯度的山区系统的土壤上进行了为期500天的培养实验。培养期间的土壤呼吸与一个三库（易分解、中等稳定性和稳定）SOC分解模型拟合良好。相关性分析表明，MAT仅影响易分解碳库的大小，而不影响SOC的稳定性。中等稳定性碳库对累积碳释放的贡献最大。中等稳定性碳库的大小与砂粒百分比密切相关。中等稳定性碳库的分解速率与土壤氮有效性呈负相关。由于土壤质地和氮有效性均与温度无关，因此SOC的稳定性与MAT无关，而是受到SOC形成的内在过程和养分状况的严重影响。
