Items | Equations | Classifications | References |
SAR |
| Excellent, Good, Permissible, Doubtful | Richards (1954) |
Na (%) |
| Excellent, Good, Permissible, Doubtful, Unsuitable | Wilcox (1954) |
RSC |
| Good, Medium, Bad | Richards (1954) |
PI |
| Excellent, Good, Unsuitable | Doneen (1964) |
SSP |
| Excellent, Good, Fair, poor | Joshi (2009) |
MH |
| Suitable, Unsuitable | Paliwal (1972) |
Kelly’s Ratio |
| Permissible, Non-Permissible | Kelly (1963) |
PS |
| Excellent to Good, Good to Injurious, Injurious to Unsatisfactory | Doneen (1954, 1962) |