Study on Spectral Features of Soil Fe_2O_3

The study of soil spectral reflectance features is the physical basis for soil remote sensing.Soil Fe_2O_3 content is one of the main factors which influence the soil spectral reflectance.On the basis of predecessor studies,this article tried to construct different spectral indicators to predict the Fe_2O_3 content of soil samples.Three kinds of spectral variable were mainly discussed,which are spectral reflectance as well as its various transformations,variables based on spectral absorption features and vegetation index variables.In this paper,one hundred and seventy-four soil samples were collected from the top five centimeters of soil from the study area to represent the range of aspect,slope,and elevation and parent materials within the area.Field spectral measurements were taken with the ASD Pro FR and multivariate statistical analysis was applied.On the basis of data analysis,some conclusions were drawn.The soil Fe_2O_3 content has negative correlation with soil reflectance.It is the same as SOM which manifest the soil reflectance will decrease with the increasing of soil Fe_2O_3 content.But the prediction effect of Fe_2O_3 is not as good as SOM or moisture.The Soil Ferric Oxide Index(SFOI) which consists of the logarithm of average red band and blue band reflectance has good correlation with soil Fe_2O_3.It is more sensitive than the spectral variable composed by O1DLA(Order 1 Derivative of the Logarithm of Albedo).SFOI possesses of application potential in imaging spectral data interpreting.Correlation analysis is also used between absorption peak around 870 nm and Fe_2O_3 and the results show that they have no correlation.