Discrimination soil salinization distribution in the middle region of Heihe River basin using TM data

A preliminary study has been conducted to test the effectiveness of the stepwise canonical discriminant approach to making spatial discrimination of salt-affected soil surfaces, using the Landsat TM data taken in the middle reaches of the Heihe River, China. We regard a saline area as being composed of salt-affected patches differ in degree and try to make discrimination of salt-affected soil surfaces by stepwise canonical discriminant approach. Five indices (B₄, Wetness, SI, NDSI, Fe₂O₃) were selected as discriminating variables, and two canonical discriminant functions (y₁, y₂) were determined for the three groups using these five discriminating variables. When group centroids and individual cases were plotted on the plane determined by two canonical discriminant functions y₁ and y₂, the groups were quite distinct and their centroids were well separated. These results suggest that the stepwise canonical discriminant approach is promising for spatial discrimination of salt-affected soil surfaces.