Salinity Index (SI) detects salt accumulation in soils by analyzing spectral signatures influenced by saline content. It helps identify areas at risk of soil degradation, reduced fertility, or crop stress due to salinity. Higher SI values indicate elevated soil salinity, while lower values represent healthier soils. It is useful for managing soil health in arid and semi-arid regions.

Firefly = (B062-B118)/(B062+B118)
Sentinel = (B04-B08)/(B04+B08)
Landsat 8-9 = (red-nir08)/(red+nir08)