土壤中溶解性有机质对不同类型堆肥的响应差异

Different Responses of Soil Dissolved Organic Matter to Different Types of Compost

为探究不同类型堆肥施用对土壤溶解性有机质(DOM)的影响,以空白土壤为对照,采用紫外、荧光光谱并结合平行因子分析对分别添加不同比例的牛粪堆肥、餐厨垃圾堆肥和污泥堆肥土壤中DOM进行分析,探究DOM结构变化特征及其驱动因素.结果表明,3种堆肥施用后土壤中AN、NH^(+)_(4)-N、DOC和SOM含量均显著提高,SOM和DOC含量随堆肥添加量的增加而增加;施用牛粪和餐厨垃圾堆肥更有利于土壤中AN、NO^(-)_(3)-N和DOC含量的提高,而施用污泥堆肥土壤中NH^(+)_(4)-N和SOM含量更高.堆肥施用后DOM结构特性的改变主要表现为共轭苯环结构、疏水性组分、醌基和显色组分含量显著提高,不饱和有机分子π→π*的跃迁更为活跃,DOM分子量增大,腐殖化程度增强.堆肥低剂量添加(5%)时,餐厨垃圾堆肥更有利于DOM的芳构化和腐殖化;堆肥较高剂量添加(10%和20%)时,牛粪堆肥更能驱动DOM结构变化;污泥堆肥对DOM结构影响最弱.堆肥施用后土壤DOM荧光组分相对含量发生改变,小分子类腐殖质相对含量增加,类蛋白相对含量降低.二维相关光谱表明,施用牛粪和餐厨垃圾堆肥土壤中DOM荧光组分变化顺序为:类蛋白>大分子类富里酸>小分子类腐殖质;而施用污泥堆肥土壤中表现为:大分子类富里酸>类蛋白>小分子类腐殖质.DOM结构变化受多种因素共同影响,影响程度表现为:堆肥种类>添加比例>理化因子>培养时间.DOC和AN含量的增加是引起DOM腐殖化程度增强和类蛋白相对含量降低的重要因素,小分子类腐殖质相对含量与NO^(-)_(3)-N含量显著正相关,DOM中大分子类富里酸相对含量因外源SOM的输入而增加.

This study explored the responses of soil dissolved organic matter (DOM) to the application of different types of compost using a soil sample without compost as a control.Ultraviolet and fluorescence spectrum technology and EEM-PARAFAC was used to analyze DOM structure and driving factors in soil added with different proportion of cow dung compost (SCC),food and kitchen waste compost (SFC),and sludge compost (SCC).Compared with the control group,contents of AN,NH^(+)_(4)-N,DOC,and SOM in soil added with compost were significantly increased,and contents of SOM and DOC increased with the increasing of compost amount.When added compost in the same proportion,contents of AN,NO^(-)_(3)-N,and DOC in SCC and SFC were significantly higher than those in SSC,while contents of NH^(+)_(4)-N and SOM were higher in SSC.The results of spectral analysis showed that the structure of conjugated benzene ring,hydrophobic component,quinone group,and chromogenic component in DOM of soil added with compost were significantly increased,the transition of unsaturated organic molecule (π→π*) was more active,the molecular weight of DOMincreased,and the degree of humification was enhanced.When the amount of compost added is 5%,the influence of food and kitchen waste compost on DOM structure was greatest among three types of compost.At 10%and 20%,sludge compost had the greatest impact on DOM structure.The results of EEM-PARAFAC analysis showed that the relative content of fulvic acid-like substances with low molecular in DOM of soil added with compost was increased,while the relative content of proteoid-like substances decreased.2D-COSanalysis showed that compost affected the change order of fluorescence components in DOM.SCC and SFC were as follows:proteoidlike>fulvic acid-like>humus-like;in SSC,it was fulvic acid-like>proteoid-like>humus-like.The enhance of humification and the decrease of relative content of protein-like substances in DOM were related to increased DOC and AN,the relative content of humuslike in low molecular weight was positively correlated with the content of NO^(-)_(3)-N,and the relative content of macromolecule fulvic acid-like was increased due to the input of SOM from compost.