Spectral Characteristics of Biological Soil Crusts under the Different Types in the Water-Wind Erosion Crisscross Region on the Loess Plateau

The study on spectral characteristics of biological soil crust in the water-wind erosion crisscross region in the Loess Plateau has important scientific value for the identification of biological soil crust based on remote sensing technology at regional scale, also provides important technical support for estimating the effect of biological soil crust on regional soil erosion control. The spectra of higher vegetation as well as the biological soil crust of algae with different coverage and different types of mosses were measured and quantified by Surface Species Spectrometry. The results are as follows, the algal bio-soil crust has similar spectral characteristics with soil in the water-wind erosion crisscross region in the Loess Plateau, and there is no obvious "peak valley" characteristic in the spectral curve. The reflectivity was reduced by the increasing coverage of the biological soil crust. Compared with the bare area, the spectral reflectance normalized mean of algae biological soil crust deceased 8. 64%, 15. 80% and 23. 09% respectively in the coverage of 10% to 20%, 30% to 40% and 50% to 60% in the visible area. The absorption characteristic at 680 nm (Chlorophyll) became increasingly obvious and the absorption valley at 2 200 nm (secondary mineral) became smaller as the coverage of algae biological soil crust increased. The spectral curve of moss biological soil crust showed the reflection peak of the green band, the absorption valley of the red light band and the high reflection of the near infrared band, which is similar with the vegetation. In the range of 760 similar to 930 nm, the slope of moss biological soil crust was 2. 5 to 4. 5 timed higher than that of vegetation. The study can provide some theoretical basis and technical support for the identification of biological soil crust.