桉树林和天然次生林土壤溶解性有机质的荧光特性研究

利用三维荧光光谱结合平行因子分析法对桉树林和天然次生林土壤溶解性有机质(Dissolved Organic Matter,DOM)的组成成分和结构特征进行分析,同时利用荧光指数(Fluorescence Index,FI)、生物源指数(Biological Index,BIX)和腐殖化指数(Humification Index,HIX)解析土壤中DOM的来源特征。结果表明,桉树林和天然次生林土壤的DOM均包含4个荧光组分,为2种类腐殖质(C1、C2)和2种类蛋白组分(C3、C4)。在0~30 cm土壤层,桉树林和天然次生林土壤中的DOM主要成分是类腐殖质,桉树林土壤中的类腐殖质含量高于天然次生林,2种森林表层土壤的DOM来自陆源输入和微生物的共同作用,其中桉树林土壤中DOM的陆源输入多于天然次生林。在30~60 cm土壤层,桉树林和天然次生林土壤的DOM主要成分是类蛋白,其来源是陆源输入和微生物的共同作用。在60~100 cm土壤层,桉树林和天然次生林土壤的DOM主要成分是类蛋白,表现出腐殖化程度弱,微生物作用影响明显。

Comparative study between eucalyptus forest and natural grown secondary fluorescence-featured forest in abundant organism dissolved soil

The present paper intends to analyze the spectral composition and the structural features of the soil dissolved organic matters( SDOM) of eucalyptus and natural secondary forest by the 3-D fluorescence excitation emission matrix( EEM)and the parallel factor analysis( PARAFAC). At the same time,we have also analyzed the source original features of the SDOM,the fluorescence index( FI),the biological index( BIX) and the humification index( HIX). The results of the above analysis show that both the eucalyptus forests and natural secondary forests contain the SDOM in the 2 humic-like components( C1,C2) and the 2 protein-like components( C3,C4). The humiclike components can be found both in the main components of the SDOM in the eucalyptus forest and the natural secondary forest on the top soil( uppermost 30 cm),which can mainly result from the fact that litter and plant roots are mostly concentrated at the top soil whereas the humus has been accumulated at the top of the soil and formulated as a result of the decomposition of litter. However,the humic-like components( C1,C2) of the eucalyptus forest soil turn to be higher than that of the natural secondary forest. And,then,both of the SDOM in the 2 kinds of soil turn to be originated from the combination and constitution of the terrestrial input and microbially production,though the proportion of the terrestrial input of SDOM in the eucalyptus forest tends to be higher than that in the natural secondary forest. On the other hand,the main components of SDOM in the eucalyptus forest and the natural secondary forest suggest protein-like components while the SDOM is also originated from the interaction of the terrestrial input and the microbial activity in the middle layer of the soil( 30-60 cm). However,the main components of SDOM in the eucalyptus forest and the natural secondary forest have been found both to be of protein-like components in the lower strata of the soil( 60-100 cm). Nevertheless,the humification degree turns to be relatively inadequate with the microbial activities given a strong influence on the SDOM compositions at the said soil layer. Therefore, since the humic-like components( C1,C2) serve as an important component of DOM,they may still produce direct impact on the soil level of humic-like component in the form of the DOM. Therefore,it can be concluded that the eucalyptus planting can influence the soil’s dissolved organic matter,which can be taken as a theoretical basis for the rational use of eucalyptus plantation to create their due economic benefit and a certian promotive role in the growth of eucalyptus forest and natural secondary forest.