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选用华南亚热带地区常见阔叶树种木荷和针叶树种湿地松的新近凋落叶,在野外分解0、30、60、90、150、210、240、365 d,分析溶出的溶解性有机质(DOM)浓度、组成和性质的变化,以及对土壤可溶性有机碳(DOC)的影响.结果表明:随着分解的进行,尽管木荷叶片的DOM浓度高于松针,但是2种凋落叶DOM浓度、性质和物质组成变化规律一致;2种凋落叶的DOM浓度均呈下降趋势,芳香化程度和分子量增大,富里酸、腐殖酸类物质逐渐增多,可降解的简单芳烃蛋白(如酪氨酸)逐渐减少.在分解初期,DOM主要由亲水中性和酸性部分组成,易分解、易迁移,对表层土壤DOC影响不显著;在分解后期,DOM主要为腐殖酸和富里酸类物质,吸附性强,表层土壤DOC浓度显著下降.
The freshly litter leaves of Schima superba and Pinus sylvestris var.mongolica, which are common hardwood species in the subtropical region of China, were selected to decompose in the field for 0, 30, 60, 90, 150, 210, 240 and 365 days. The dissolved organic matter (DOM) Composition and properties of soil litter and the effect on soil dissolved organic carbon (DOC) were studied.The results showed that with the decomposition of DOM, the concentration of DOM in two litter leaves was higher than that of pine needles, The DOM concentrations of two kinds of litter showed a decreasing trend. The degree of aromatization and molecular weight increased. The contents of fulvic acid and humic acid gradually increased, and the content of degradable simple aromatic hydrocarbons (such as tyrosine) decreased gradually. In the early stage of decomposition, DOM mainly consisted of hydrophilic neutral and acidic components, easily decomposed and easily migrated, and had insignificant effect on topsoil DOC. In the later stage of decomposition DOM was mainly humic acid and fulvic acid, The surface soil DOC concentration decreased significantly.