黑土长期定位施肥土壤富里酸的荧光特性研究

摘要

选取哈尔滨长期定位施肥对照处理(CK)、施用氮磷钾化肥( NPK)、有机肥马粪(OM)及有机肥与无机肥混施(MNPK)四个不同处理的土壤样品,利用荧光检测技术对土壤富里酸(Fulvic acid,FA)组分进行分析.荧光发射、激发与同步扫描主要特征峰及三维荧光图谱Peaka,b,c均显示:与CK比较,NPK处理均出现明显蓝移,而OM与MNPK出现不同程度红移,表明NPK可使土壤FA结构趋于简单化,OM与MNPK处理则使FA结构趋于复杂.通过对不同处理土壤FA荧光指数f450/500与A1370～412nm/A370～600nm,A4538～600nm/A70～600nm,A4/A1荧光面积积分比值等参数比较分析,进一步说明NPK处理土壤FA芳构化程度较低,而OM与MNPK长期施肥均使FA缩合度与芳构化程度升高.%In order to investigate the effect of long-term located fertilization on soil fulvic acid (FA), in this study, four soil samples were taken from black soil with long-term located fertilization (about 30 year) in Harbin, Heilongjiang province. The fertilization treatments included control (CK), N, P and K fertilization (NPK), horse manure (OM), combination of organic manure and chemical fertilizations (MNPK). Soil FA was extracted from the samples and purified. The excitation, emission, synchronous, and three-dimensional-excitation emission matrix fluorescence spectroscopy (3DEEM) characteristics of the FA were determined. The excitation, emission and synchronous scan spectra all indicated that the main peaks of FA in the NPK treatment exhibited a significantly blue shift compared with CK, while those of MNPK, OM treatment caused a red shift to some extent. 3DEEM spectra of FA in all treatments exhibited four peaks (peak a, peak b, peak c, and peak d), compared with FA in CK, the wavelengths shift tendency of peak a, peak b, and peak c of FA 3DEEM in NPK, MNPK and OM treatments were similar to that of traditional spectra in FA. In order to provide quantitative information of FA humification degree in different treatments, we investigated the fluorescence index f450/500(FI), area integration (A370～600nm, A1370～412nm A4538～600nm,). Compared with CK, the f450/500, ratio of A1 /A in NPK and A4/A in MNPK treatment increased by 4. 62%, 6. 12%, 7. 22%, respectively. Howev-er, the f450/500, the ratio of A1 /A in MNPK and A4 /A in NPK treatment decreased by 3. 86 %, 15.31%, and 7. 22% respectively. This indicated that NPK application gave a lower degree of FA humification, and combination of organic manure and chemical fertilizations would lead to a greater degree of FA aromatization in black soil with long-term located fertilization than CK.