Fluorescence Spectrum Characteristic of the Extracted Humic Substances in Soil from Shannan Developed Area

Contents of extracted humic substances in soil growed with different crops were determined, and the fluorescence spectra features of extracted humic substances in the same sampling point in different soil layers was analyzed. The results showed that contents of extracted humic substances in soil growed with different crops are different, there is no obvious rule. For different soil layers of the same sampling point, the distribution of extracted humic substances is not the same, mostly show that: the surface (0 similar to 20cm)> the middle (40 similar to 60cm)> the lower (80 similar to 100cm). The excited state fluorescence spectra of extracted humic substances in soil of different land types have similar fluorescence characteristics, peak obvious presents in about 390nm and 455nm. The fluorescence emission spectra are all broadband peak without obvious features, emission wavelength is about 500nm.