Table 2 The formulas used to derive the indices, and their references

1

Salinity index - SI1

SI1 = sqrt(green² + red²)

Douaoui et al. (2006)

2

Salinity index - SI2

SI2 = sqrt(green × red)

Douaoui et al. (2006)

3

Salinity index - SI3

SI3 = sqrt(blue × red)

Khan et al. (2001)

4

Salinity index - SI4

SI4 = (red × NIR)/green

Abbas and Khan (2001)

5

Salinity index - SI5

SI5 = blue/red

Abbas and Khan (2001)

6

Normalized Difference Salinity Index (NDSI)

NDSI = (red − NIR)/(red + NIR)

Khan et al. (2001)

7

Normalized Difference Vegetation Index (NDVI)

NDVI = (NIR − red)/(red + NIR)

Khan et al. (2001)

8

Soil Adjusted Vegetation Index (SAVI) (L = 0.5)

SAVI = (1 + L) × NIR − red/L + NIR + red

Alhammadi and Glenn (2008)

9

Vegetation Soil Salinity Index (VSSI)

VSSI = 2 × green − 5 × (red + NIR)

Dehni and Lounis (2015)