凋落物C/N对土壤有机碳矿化的影响  

The Influence of Litter C/N Ratios on Soil Organic Carbon Mineralization

作　　者：李天 苗淑杰[1] 余洁 赵玉蝶 乔云发[1] LI Tian;MIAO Shujie;YU Jie;ZHAO Yudie;QIAO Yunfa(School of Ecology and Applied Meteorology,Nanjing University of Information Science&Technology,Nanjing 210044,P.R.China)

机构地区：[1]南京信息工程大学生态与应用气象学院,江苏南京210044

出　　处：《生态环境学报》2024年第11期1686-1695,共10页Ecology and Environmental Sciences

基　　金：国家自然科学基金项目(42177279,42130506);江苏省碳达峰碳中和科技创新专项(BE2022425)。

摘　　要：凋落物输入会影响土壤有机碳(SOC)矿化过程,其影响程度主要受凋落物C/N、土壤肥力和温度条件的影响,然而,这三因素的综合影响仍不清楚。以低肥力土壤(LF)和高肥力土壤(HF)为研究对象,分别添加7种不同C/N的凋落物,并设置培养温度为23℃和33℃,进行恒温避光培养,期间动态监测CO_(2)排放的变化,以揭示SOC矿化过程应对三因子的响应机制。结果显示,凋落物添加显著增加CO_(2)峰值排放速率,且与C/N>30的凋落物相比,添加C/N<30的凋落物对CO_(2)的峰值排放速率的促进作用更显著。CO_(2)峰值排放速率同时受土壤肥力和培养温度影响,HF-33℃条件下的CO_(2)峰值排放速率最高。添加C/N<30的凋落物显著增加了CO_(2)累积排放量,在LF-23℃、LF-33℃、HF-23℃和HF-33℃条件下,最大增幅分别为407%、304%、345%和160%。相关分析显示,SOC矿化率与凋落物C/N间呈负相关关系,这说明低质量凋落物会抑制SOC矿化。在LF-23℃、LF-33℃、HF-23℃和HF-33℃处理下,与凋落物C/N最低的CN1相比,添加C/N最高的CN7后,SOC矿化率的降幅分别达3.53、3.04、1.71和2.06倍。土壤肥力影响SOC矿化,HF的SOC矿化率较LF高1.29-2.66倍。培养温度对SOC矿化的影响在HF中表现出显著差异,与CK相比,在HF中添加凋落物显著降低了SOC矿化温度敏感性(Q10)。综合PLS-PM模型可知,SOC矿化是凋落物C/N、土壤肥力和培养温度综合作用的结果。其中,凋落物的C/N比对SOC矿化产生显著的负效应,土壤肥力则对SOC矿化产生主要的正效应,而温度的正效应则相对较小。研究结果有助于进一步理解不同土壤肥力和温度背景下,C/N不同的外源有机物输入对SOC矿化的影响及其背后的综合效应。Litter input influences the soil organic carbon(SOC)mineralization process,with its effect primarily governed by litter C/N,soil fertility,and temperature conditions.However,the combined impact of these three factors remains unclear.This study used low-fertility soil(LF)and high-fertility soil(HF),adding seven different C/N ratio litters and setting incubation temperatures of 23℃and 33℃,with constant temperature and no light exposure.CO_(2) emissions were dynamically monitored to investigate how SOC mineralization responds to the three factors.Results showed that litter addition significantly increased peak CO_(2) emission rates,and litter with a C/N ratio less than 30 had a more pronounced effect on peak CO_(2) emission rates compared to litter with a C/N ratio greater than 30.The peak CO_(2) emission rate was also affected by soil fertility and incubation temperature,with the highest peak CO_(2) emission rate observed under the HF-33℃condition.Litter with a C/N ratio below 30 significantly increased cumulative CO_(2) emissions,with maximum increases of 407%,304%,345%and 160%under LF-23℃,LF-33℃,HF-23℃and HF-33℃conditions,respectively.Correlation analysis showed a negative relationship between SOC mineralization rate and litter C/N ratio,suggesting that lower-quality litter inhibits SOC mineralization.Under LF-23℃,LF-33℃,HF-23℃and HF-33℃conditions,compared to litter with the lowest C/N ratio(CN1),adding litter with the highest C/N ratio(CN7)reduced SOC mineralization rates by 3.53,3.04,1.71 and 2.06 times,respectively.Soil fertility influenced SOC mineralization,with the SOC mineralization rate in HF being 1.29 to 2.66 times higher than in LF.The effect of incubation temperature on SOC mineralization showed significant differences in HF,and compared to the CK,litter addition in HF significantly reduced the temperature sensitivity(Q10)of SOC mineralization.Using the PLS-PM model,the study concluded that SOC mineralization results from the combined effects of litter C/N,soil fertility,and incu

关 键 词：凋落物输入 凋落物碳氮比 有机碳矿化 CO_(2)释放速率 室内培养 温度敏感性 

分 类 号：S153[农业科学—土壤学] X171.1[农业科学—农业基础科学] X144[环境科学与工程—环境科学]