Table 5.

SAR values based on general irrigation water category (Source: [20]).

SAR	Category	Description of category	Precaution and management suggestions
0–10	1	Low Na water	Little danger
10–18	2	Medium Na water	Problems on fine texture soils and sodium sensitive plants, especially under low-leaching conditions. Soils should have good permeability
18–24	3	High Na water	Problems on most soils. Good salt tolerant plants are required along with special management such as the use of gypsum
>24	4	Very high Na water	Unsatisfactory except with high salinity (>2.0 dS/m), high calcium levels, and the use of gypsum