**6.1 Periodical monitoring and assessment by salinity mapping**

Various natural and anthropogenic factors which increase the deterioration, and severity of saline soil in order to reduce adverse effect, continuous monitoring and prediction is needed. Various quantitative and qualitative mapping done through multi-temporal and multi-spectral information from remote sensing is needed. Hyper spectral remote sensing: it is having number of narrow and continuous band provide a precise information about difference in halophytes and non halophytes and used to distinguish various salinity classes [20–22].

Number of indices used for measure salinity.

$$\text{NDVI}\left(\text{normalized}\,\text{difference\\_salt}\,\text{intex}\right) = \frac{\left(R - \text{NIR}\right)}{\left(R + \text{NIR}\right)}\tag{1}$$

$$\begin{aligned} \text{Brightness index} &= \sqrt{\text{R} \, 2 + \text{NIR}} \\\\ \text{Sability index} &= \sqrt{B \times R} \end{aligned} \tag{2}$$

where NIR, near infrared reflectance; R, red band; B, blue band.
