Response of spectral reflectance and quantitative characteristics inversion accuracy to the change in coverage of Seriphidium transiliense

The aim of this study was to explore the influence of the change in coverage on plant spectral reflectance and achieve high-precision inversion of coverage and biomass, taking Seriphidium transiliense as the object. We obtained the spectral reflectance of plants under different coverages through indoor controlled experiments; processed the data using maximum normalization; used first-order differential and second-order differential processing to analyze the changes in reflectivity; and the normalized difference vegetation index (NDVI), ration vegetation index (RVI), enhanced vegetation index (EVI), and soil-adjusted vegetation index (SAVI) were used to invert the coverage and biomass data. The response of inversion accuracy to coverage variation is discussed. The results showed that the spectral reflectance of the canopy of S. transiliense gradually decreased with the increase in coverage in the visible band and gradually increased in the near-infrared band. A characteristic plant red edge effect was formed at 680 nm, and the maximum normalization and differential transformation highlighted the spectral characteristics of the plants. The spectral reflectance difference was basically stable with an increase in coverage in the visible band. When the vegetation index was used to invert coverage and biomass step by step, the accuracy increased with increased coverage. When the land use and land coverage changed the coverage inversion, the inversion accuracy of the quantitative characteristics of the S. transiliense population with a coverage greater than 20% was improved, and the best vegetation index was SAVI.