Analysis of the canopy spectrum and water content of desert plants

Plant water is one of the main factors affecting plant photosynthesis, respiration, biomass, and other physiological and biochemical indices. Investigation of the water content of plants is an important part in vegetation research. Study of the relationship between water content and canopy spectrum of typical desert plants is of considerable significance to remote sensing monitoring of vegetation in desert areas. In this study, the canopy spectral curves of 10 desert plants were determined using ASD portable terrestrial spectrometers. Correlation coefficient and vegetation index methods were used to analyze the spectral characteristics of different desert plants and their relationship with canopy water content. The following results were obtained, 1) The reflectance spectrum of desert plants had the general characteristics of green plants in the visible-near infrared band, and had an obvious “green peak” and “red-edge effect.” 2) The three bands of 954-973, 1 184-1 198, and 1 440-1 462 nm showed an obvious water absorption valley in desert plants. In the 1440-1462 nm band, the spectral reflectance and water content correlation coefficient is greater than 0.8, and the two parameters showed a strong linear correlation. 3) There was significant correlations between water band index, normalized difference water index, normalized difference infrared index, moisture stress index, and plant water content (P<0.05), and the canopy water content index was consistent with the measured value of vegetation water, which could reflect changes in the water content of desert vegetation.