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DOM是土壤中一种活跃的组分,研究其组成、分布和腐殖化特点对揭示土壤地球化学环境行为特征具有重要意义。蔬菜大棚作为一种特殊的土地利用类型,受人类活动影响较为强烈,长期人类活动的作用会影响其土壤中DOM构成和土壤腐殖化过程的空间分布。但关于蔬菜大棚土壤DOM特征的研究鲜见报道。基于此,利用三维荧光图谱技术,结合PARAFAC模型,解析具有长期种植年限的北方典型蔬菜种植基地土壤DOM的特征。结果显示,蔬菜大棚土壤DOM主要由类富里酸(C1)、类胡敏酸(C2)和类蛋白(C3)物质组成,以C1组分为主。空间分布特征显示:在垂直方向上,随着剖面深度的增加,C1和C2组分都明显减少,而C3组分先增后减,DOM的腐殖化程度从0~20到30~40cm明显降低,到40~50cm又有所增加;在水平方向上,C2组分的含量在每层的空间变异均较大,C1组分在每层的空间变化均较小,C3组分介于上述二者之间,土壤的腐殖化指数在每层的空间变异均较大。上述结果表明,蔬菜大棚土壤的腐殖化进程在表层较快,此外,腐殖化进程具有较大的空间变异特性。本研究的意义在于:(1)通过三维荧光光谱揭示了了北方蔬菜大棚土壤DOM的组成及其空间异质性特点;(2)将PARAFAC模型用于土壤DOM的分析中,并成功对其DOM的组分特征进行定量表征,对土壤DOM的研究提供了新的思路。
DOM is an active component in soils, and its composition, distribution and humification are very important to reveal the characteristics of soil geochemical environment. As a special type of land use, greenhouses are more affected by human activities. The effect of long-term human activities will affect the spatial distribution of DOM and soil humification in soil. However, there are few reports about the characteristics of DOM in vegetable greenhouse. Based on this, the characteristics of soil DOM in northern typical vegetable planting base with long-term planting years were analyzed by using three-dimensional fluorescence spectroscopy combined with PARAFAC model. The results showed that DOM in vegetable greenhouse mainly consisted of class C1, humic acid (C2) and protein (C3). The spatial distribution shows that in the vertical direction, the C1 and C2 components decrease obviously with the increase of the profile depth, while the C3 components increase first and then decrease, the degree of DOM humification is obvious from 0 ~ 20 to 30 ~ 40cm In the horizontal direction, the content of C2 component in each layer has a larger spatial variation, the C1 component in each layer of space changes are small, C3 components in the above Between the two, the soil humification index in each layer spatial variability are larger. The above results show that the soil humification process in vegetable greenhouse is faster on the surface, in addition, the humification process has larger spatial variability. The significance of this study lies in: (1) Reveal the composition and spatial heterogeneity of DOM in the northern vegetable greenhouse by three-dimensional fluorescence spectroscopy; (2) PARAFAC model was applied to the analysis of soil DOM, and its DOM The characteristics of the components of the quantitative characterization of soil DOM research provides a new way of thinking.