| Annual K-fertilizer rate (kg K ha−1) | 3-year average seedcotton yield (kg∙ha−1) | Cumulative (3-year) K rate (kg K ha−1) | Total 3-year yield seedcotton yield (kg∙ha−1) |
| 0 | 2940 | 0 | 8720 |
| 27.9 | 3061 | 83.7 | 9184 |
| 55.8 | 3196 | 167.3 | 9600 |
| 83.7 | 3353 | 251.0 | 10,060 |
| 111.6 | 3289 | 334.7 | 9868 |
| 139.4 | 3438 | 418.3 | 10,316 |