为了研究长期施用堆肥对潮土剖面土壤水溶性有机物(DOM)的来源和组分特征的影响, 研究以河北省曲周实验站长期施用堆肥的试验田为研究对象, 利用三维荧光光谱技术研究了在长期施用高量生物堆肥(EMI)、 常量生物堆肥(EMII)、 高量传统堆肥(TCI)、 常量传统堆肥(TCII)和化肥(CF)下不同深度土壤水溶性有机物在来源和组成的差异。 研究结果表明, 不同施肥处理的土壤水溶性有机碳(DOC)含量在土壤剖面的分布规律有较大差异, 堆肥使0～20和60～80 cm土层的DOC分别显著提高了81.94%～171.33%和61.18%～152.18%。 荧光光谱指数表明, DOM来源为微生物和植物混合源, 堆肥施用量的增加使DOM腐殖化程度加强, 造成表层土壤中DOM由陆源向生物源迁移, 随着土壤深度的增加, DOM由陆源向生物源迁移。 三维荧光光谱和荧光区域积分表明, 生物堆肥和传统堆肥增加了类腐殖酸物质的含量, 且随着施用量的增加而增加; 高量生物堆肥和传统堆肥增加了类富里酸物质和类溶解性微生物代谢产物的含量; 施用化肥和堆肥均降低了类色氨酸的含量。 类腐殖酸含量、 类富里酸含量和类溶解性微生物代谢产物数量随着土壤深度的增加整体呈降低趋势; 类酪氨酸随着土壤深度的增加呈增加趋势; 类色氨酸随着土壤深度增加整体呈先增加后降低趋势, 且在20～40 cm含量最高。 相关性分析表明, 全磷(TP)、 全氮(TN)、 阳离子交换量(CEC)、 速效钾(AK)、 有机碳(SOC)和DOC等土壤理化指标与类酪氨酸物质呈显著负相关, 与类富里酸、 类溶解性微生物产物和类腐殖酸含量呈显著正相关, 硝态氮(NO-3-N)、 TN、 pH、 SOC与类色氨酸物质呈显著正相关。 总之, 长期施用堆肥增加了潮土表层DOM的含量, 显著改变了土壤中DOM的组成和剖面上的分布特征。

In order to study the effects of the long-term application of compost on the source and composition characteristics of soil DOM in fluvo-aquic soil, this study took the experimental field of long-term application of compost at Quzhou Experimental Station in Hebei Province as the research object. It used three-dimensional fluorescence spectroscopy to explore the differences of the source and composition characteristics of DOM in the soil profile under long-term application of the high dosage of bio-compost (EMI), the conventional dosage of bio-compost (EMII), high dosage of traditional compost (TCI), the conventional dosage of traditional compost (TCII) and chemical fertilizers (CF). The results showed that the distribution of soil dissolved organic carbon (DOC) in soil profiles under different fertilization treatments was quite different, and the application of compost significantly increased the DOC in the 0~20 and 60~80 cm soil layers by 81.94%~171.33% and 61.18%~152.18%, respectively. The fluorescence spectrum index showed that the source of DOM is a mixed source of microorganisms and plants. The increase of compost dosage will increase the degree of DOM’s humification, causing the surface soil’s DOM to migrate from land source to biological source. As the soil depth increased, DOM migrated from land to biological sources. Three-dimensional fluorescence spectroscopy and fluorescence area integration showed that bio-compost and traditional compost increased the content of humic acid-like substances, which increased with the increase of application rate. High-dosage bio-compost and traditional compost increased fulvic acid-like and soluble microbial byproduct-like substances. The application of chemical fertilizers and compost reduced the content of tryptophan-like. The contents of humic acid-like, fulvic acid-like, and soluble microbial byproduct-like substances showed an overall decreasing trend with soil depth; Tyrosine-like protein increased with soil depth; Tryptophan-like substance first increased and then decreased with the increase of soil depth, and the content of tryptophan-like substance was the highest in 20~40 cm. Correlation analysis showed that soil physical and chemical indexes such as TP, TN, CEC, AK, SOC and DOC were negatively correlated with tyrosine-like substances, positively correlated with fulvic acid-like substances, soluble microbial products and humic acid-like substances. Moreover, NO-3-N, TN, pH and SOC were significantly positively correlated with tryptophan-like substances. In a word, long-term application of compost increased the DOM content in the surface layer of fluvo-aquic soil and significantly changed the composition of DOM in the soil and the distribution characteristics on the profile.