荧光是由具有芳香结构或共轭生色团以及未饱和脂肪链的物质产生的, 可以评价土壤腐殖化程度。 该技术广泛用于检测土壤腐殖质水溶液荧光, 很少用于直接检测土壤固体表面荧光。 本文选取乌梁素海周围盐角草、 碱蓬、 盐爪爪和苦豆子群落的土壤作为研究对象, 分别采集0～20, 20～40和40～60 cm的12个混合土样, 分析土壤固体表面荧光光谱特征, 提出一个基于固体表面荧光光谱的土壤腐殖化指数(HIXSSF), 并与I400/I360, I465/I399和A4/A1等常规腐殖化指数有显著的线性正相关。 盐角草和碱蓬群落的HIXSSF比盐爪爪和苦豆子群落的小, 并且随土层深度变化小。 腐殖化指数与土壤盐度有显著的线性负相关, 土壤腐殖化程度随盐度的减小而增强。 HIXSSF不仅表征土壤腐殖化程度, 而且表征土壤盐碱化进程.

Fluorescence spectroscopy relies on the fluorescence emitted by rigid conjugated systems and thus has been increasingly used to assess the soil organic matter (SOM) humification. This technique is widely applied to solution samples of humic substances, and so far no information exists about its applicability to solid-phase soil samples. Composite soil samples of different depths (0-20, 20-40 and 40-60 cm) were collected from four different halophyte communities along a saline-impact gradient, namely, Comm. Salicornia europaea (CSE), Comm. Suaeda glauca (CSG), Comm. Kalidium foliatum (CKF) and Comm. Sophora alopecuroides (CSA) located around Wuliangsuhai Lake. A humification index based on solid surface fluorescence spectroscopy (HIXSSF) was proposed, and compared with conventional humification indices I400/I360, I470/I360, I465/I399 and A4/A1. There were close positive linear correlations between HIXSSF and I400/I360, I465/I399 and A4/A1, but a poor positive linear correlation existed between the HIXSSF and I470/I360. The results indicated that HIXSSF can be taken as a tool to assess the soil humification. The HIXSSF of the CSE and CSG varied inappreciably within soil profiles and there was no trend with depth. However the HIXSSF varied appreciably in the CKF and CSA, and the HIXSSF of the bottom soil profile was higher than that of the other profiles. As a whole, the soil humification degree was low around Wuliangsuhai Lake, and the ecological environment was relatively fragile. The salinity showed a strong negative linear relationship with the I400/I360, I470/I360, I465/I399 and A4/A1, but a good negative linear relationship with the HIXSSF. The results indicated that the degree of the SOM humification increased with the drop in the salinity. The HIXSSF can be an indicator not only of the degree of SOM humification, but also of the process of the salinisation.