Research Article
Study on Irrigation Water Quality in the Rift Valley Areas of Awash River Basin, Ethiopia
Table 9
Classification of irrigation water quality.
| Parameter | Range | Classification | References |
| pH | <6.5 | Acidic | [20, 21] | 6.5–8.4 | Permissible | >8.4 | Alkaline |
| EC (dS/m) | <0.25 | Low saline (totally safe) | [15, 19, 20, 24, 25] | 0.25–0.75 | Moderately saline (safe) | 0.75–2.25 | Medium-to-high salinity (leaching required) | 2.25–4 | High salinity (unsafe) | 4–6 | Very high salinity (unsafe) | >6 | Excessive salinity (severe) |
| SAR | <10 | Low (excellent) | [15, 19, 24, 25] | 10–18 | Medium (good) | 18–26 | High (doubtful) | >26 | Very high (unsuitable) |
| HCO3− | <1.5 | Normal | [25] | 1.5–8.5 | Slight to moderate | >8.5 | Severe |
| Cl− | <2 | None (generally safe for all plants) | [15, 20, 25] | 2–4 | Slight to moderate (sensitive plants usually show slight to moderate injury) | 4–10 | High (moderately tolerant plants usually show slight to substantial injury) | >10 | Very high (can cause severe problems) |
| RSC (meq/L) | <1.25 | Safe | [15, 25] | 1.25–2.5 | Marginal | >2.5 | Unsuitable |
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