利用分子生物标志物法揭示种植芭蕉的农业土壤中有机质的来源与降解

Organic Matter Source and Degradation as Revealed by Molecular Biomarkers in Agricultural Soils of Plantain Cropping

采集并比较两类不同耕作活动下的土壤(BJ和YS),利用分子生物标志物法对其中土壤有机质(SOM)的组成、分布特征和降解状态进行分析比较,以研究不同耕作活动对SOM的影响。土壤总碳含量从1.75%(YS)降低至1.58%(BJ),表明BJ中SOM的含量显著下降;脂肪酸的含量从127.22 mg g^(-1) C(YS)增大至345.09 mg g^(-1) C(BJ),长链烷烃C29、C31,以及芭蕉叶和茎中未检测到的烷醇在BJ中大量出现,表明芭蕉来源有机质的大量输入。C/N值从14.94(YS)降低至11.47(BJ),烷烃的ACLFA值从23.87(YS)增大至24.97(BJ),3,5-DHBA/V值从0.52(YS)增大至0.64(BJ),表明BJ的降解程度高于YS。短链烷烃和木质素V类可能来自原始土壤中的有机无机复合体。以上结果证明:人为耕作活动加速了SOM在土壤中的周转。广泛了解人为耕作活动对SOM的影响,将会为土壤经营管理以及估算受人为干扰的生态系统中的碳循环提供重要的信息。

Two soil samples（BJ and YS） with different tillage activities were collected and their soil organic matter（SOM） composition, distribution characteristics and degradation status were compared by a biomarker method in order to analyze the effects of tillage activities on SOM. The total carbon content decreased from 1.75%（YS） to 1.58%（BJ）,indicating that the content of SOM in BJ decreased significantly. The content of aliphatic acids increased from 127.22 mg g^-1 C（YS） to 345.09 mg g^-1 C（BJ）. The long chain alkanes C29 and C31 and the alkanols were undetected in the plantain leaves and stems in BJ, suggesting a large quantity input of plantain fractions. The ratio of C/N decreased from 14.94（YS） to 11.47（BJ）, as well as the ACLFA value of alkanes and the 3,5-DHBA/V value, respectively,increased from 23.87（YS） to 24.97（BJ） and from 0.52（YS） to 0.64（BJ）, indicating that the degradation status of BJ was higher than that of YS. Short-chain alkanes and the V class of lignin might be derived from the organic-mineral complexes in the original soil. The results showed that the human tillage activities accelerated the turnover of SOM.Understanding SOM behavior would provide important information for soil management and carbon cycling evaluation in human-affected ecological systems.