The significant role of inorganic matters in preservation and stability of soil organic carbon in the Baoji and Luochuan loess/paleosol profiles, Central China
The significant role of inorganic matters in preservation and stability of soil organic carbon in the Baoji and Luochuan loess/paleosol profiles, Central China
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DOI：
10.1016/j.catena.2013.04.001
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发表时间：
2013-10
期刊：
影响因子：
6.2
通讯作者：
Chao Wang;Fuchun Li;Huanzhi Shi;Zhangdong Jin;Xuhui Sun;Fei Zhang;Feng Wu;S. Kan
中科院分区：
文献类型：
--
作者：
Chao Wang;Fuchun Li;Huanzhi Shi;Zhangdong Jin;Xuhui Sun;Fei Zhang;Feng Wu;S. Kan
土壤有机碳的保存和稳定机制是评价土壤碳库容量和可持续利用潜力的重要因素。为了解埋藏条件下土壤有机碳的保存时间和机制，研究了宝鸡和洛川两个黄土-古土壤剖面中有机碳(TOC)和稳定有机碳(STOC)的分布及其与粘土、粘土矿物和不同形态铁氧化物含量的关系。观察到了以下四个事实。(1)黄土和古土壤中不稳定的有机碳在形成375年后基本分解，最稳定的有机碳得以保存。在埋藏条件下，无论是在黄土中还是在古土壤中，斯托克都可以保存至少762kyr。(2)土壤有机碳含量与土壤粘粒含量呈正相关，相关系数宝鸡为0.72，洛川为0.63。(3)TOC、STOC、矿物保护有机碳(MOC)、顽固性有机碳(ROC)与高岭石呈正相关，宝鸡相关系数分别为0.93、0.72、0.52、0.81，洛川相关系数分别为0.78、0.58、0.50、0.49，均与高岭石呈正相关。(4)TOC与复合铁(FEP)、无定形氧化铁(FeO)的相关系数分别为0.90(宝鸡)和0.82(洛川)。其中，高岭石主要受吸附和络合作用的影响，而高岭石则兼具化学和物理作用。这些系数的大小进一步突出了无机物对有机碳固定的贡献大小顺序为高岭石>；FEP>；FeO。
The preservation and stability mechanisms of soil organic carbon (SOC) are the important factors to evaluate the capacity of soil carbon pool and the potential of sustainable utilization. To understand the preservation time and mechanisms of SOC under burial conditions, in the present study, the distributions of total organic carbon (TOC) and stable organic carbon (StOC), and their correlations with the contents of clays and clay minerals and different forms of iron oxides were investigated in the Baoji and Luochuan loess–paleosol profiles. Four facts were observed as the followings. (1) The labile SOC almost was decomposed and the mostly stable SOC was preserved in the loess and paleosol after 375kyr since their formation. StOC could be preserved at least 762kyr in both loess and paleosol under burial condition. (2) The TOC was positively correlated with clay contents, with correlation coefficients of 0.72 (Baoji) and 0.63 (Luochuan). (3) The TOC, StOC, mineral-protected organic carbon (MOC), and recalcitrant organic carbon (ROC) were positively correlated with kaolinite, with correlation coefficients of 0.93, 0.72, 0.52, 0.81 (Baoji) and 0.78, 0.58, 0.50, 0.49 (Luochuan), respectively, both with neither illite nor vermiculite. (4) The TOC was highly correlated with complex iron (Fep) with correlation coefficients of 0.90 (Baoji) and 0.82 (Luochuan), so with amorphous oxides of iron (Feo) as well. Among them, Feomainly affected by sorption and Fepby complexation on SOC preservation, whereas kaolinite had both chemical and physical effects. The values of coefficients further highlight that the contributions of inorganic matters to the fixation of organic carbon were ranked to an order of kaolinite>Fep>Feo.