The effect of composition on stability (C-14 activity) of soil organic matter fractions from the albic and black soils
The effect of composition on stability (C-14 activity) of soil organic matter fractions from the albic and black soils
复制标题
成分对白土和黑土土壤有机质组分稳定性（C-14 活性）的影响
DOI：
10.1016/j.scitotenv.2015.09.041
复制
发表时间：
2016
影响因子：
9.8
通讯作者：
Xing Baoshan
中科院分区：
文献类型：
--
作者：
Jin Jie;Sun Ke;Wang Ziying;Han Lanfang;Wu Fengchang;Xing Baoshan
土壤有机质（SOM）组成对碳(C)循环的重要性仍存在争议。本文采用单一土壤源，考察其组成对SOM组分稳定性（14C活性）的具体影响，同时限制其他影响碳周转的因素，如矿物、气候和植物输入。从两种土壤样品中分离出4种腐植酸、2种腐植酸、非水解碳和脱矿部分。我们使用固态13c核磁共振（NMR）和热分析检测了SOM馏分的同位素比例与组成（如脂肪族和芳香族C含量）的关系。从白土（SOM - a）和黑土（SOM - b）分离出的有机质组分的Δ14C值与其分解峰温度和一半总反应热产生的温度呈负相关，表明有机质组分的热稳定性与生物地球化学稳定性之间存在潜在的联系。13c NMR测定的SOMs-A的芳基C含量与δ 15n值成反比，与δ 13c值成正相关，表明SOMs-A的部分芳基C可能是火衍生的。SOMs-A的Δ14C值与脂肪族C含量呈正相关，与芳香族C含量呈负相关。因此，我们得出结论，在SOMs-A中，火衍生的芳香族C似乎比微生物衍生的脂肪族C更稳定。SOMs-B组分的更大分解削弱了它们的Δ14C值与烷基和芳基C含量的关系。因此，SOM组分组成在调节稳定性中的作用可能取决于特定C形式的来源及其分解阶段。
The importance of the composition of soil organic matter (SOM) for carbon (C) cycling is still under debate. Here a single soil source was used to examine the specific influence of its composition on stability (14C activity) of SOM fractions while constraining other influential C turnover factors such as mineral, climate and plant input. The following SOM fractions were isolated from two soil samples: four humic acids, two humins, non-hydrolyzable carbon, and the demineralized fraction. We examined the isotope ratios of SOM fractions in relation to composition (such as aliphatic and aromatic C content) using solid state13C nuclear magnetic resonance (NMR) and thermal analysis. The Δ14C values of the fractions isolated from both an albic soil (SOMs-A) and a black soil (SOMs-B) correlated negatively with their peak temperature of decomposition and the temperature where half of the total heat of reaction was evolved, implying a potential link between thermal and biogeochemical stability of SOM fractions. Aryl C contents of SOMs-A determined using13C NMR varied inversely withδ15N values and directly withδ13C values, suggesting that part of aryl C of SOMs-A might be fire-derived. The Δ14C values of SOMs-A correlated positively with aliphatic C content and negatively with aromatic C content. We therefore concluded that fire-derived aromatic C in SOMs-A appeared to be more stable than microbially-derived aliphatic C. The greater decomposition of SOMs-B fractions weakened the relationship of their Δ14C values with alkyl and aryl C contents. Hence, the role of the composition of SOM fractions in regulating stability might be dependent on the source of specific C forms and their stage of decomposition.