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

From: Soil salinity assessment by using near-infrared channel and Vegetation Soil Salinity Index derived from Landsat 8 OLI data: a case study in the Tra Vinh Province, Mekong Delta, Vietnam

No.IndicesFormulaSources
1Salinity index - SI1SI1 = sqrt(green2 + red2)Douaoui et al. (2006)
2Salinity index - SI2SI2 = sqrt(green × red)Douaoui et al. (2006)
3Salinity index - SI3SI3 = sqrt(blue × red)Khan et al. (2001)
4Salinity index - SI4SI4 = (red × NIR)/greenAbbas and Khan (2001)
5Salinity index - SI5SI5 = blue/redAbbas and Khan (2001)
6Normalized Difference Salinity Index (NDSI)NDSI = (red − NIR)/(red + NIR)Khan et al. (2001)
7Normalized Difference Vegetation Index (NDVI)NDVI = (NIR − red)/(red + NIR)Khan et al. (2001)
8Soil Adjusted Vegetation Index (SAVI) (L = 0.5)SAVI = (1 + L) × NIR − red/L + NIR + redAlhammadi and Glenn (2008)
9Vegetation Soil Salinity Index (VSSI)VSSI = 2 × green − 5 × (red + NIR)Dehni and Lounis (2015)