Table 2.
Statistical evaluation of the uncalibrated and calibrated APSIM model performance in simulating corn and soybean yields by N rate across 16-years.
| Uncalibrated | Calibrated/Validated | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Corn | Soybean | Corn | Soybean | |||||||
| N rate | CC | SC | SC_val1 | SC | SC_val | CC | SC | SC_val1 | SC | SC_val |
| RMSE (kg ha-1) | ||||||||||
| 0 | 1412 | 946 | 1365 | 631 | 1337 | 1283 | 920 | 1829 | 560 | 789 |
| 67 | 1255 | 806 | 1996 | 689 | 1275 | 1284 | 718 | 1892 | 663 | 619 |
| 134 | 1627 | 1324 | 2269 | 672 | 1264 | 1085 | 1466 | 1259 | 662 | 599 |
| 201 | 1870 | 1586 | 2528 | 726 | 1320 | 1084 | 1365 | 1367 | 783 | 716 |
| 268 | 1806 | 1611 | 2353 | 723 | 1288 | 946 | 1387 | 1452 | 884 | 608 |
| Mean | 1611 | 1287 | 2019 | 689 | 1297 | 1136 | 1171 | 1560 | 722 | 666 |
| RRMSE (%) | ||||||||||
| 0 | 39.4 | 14.7 | 20.0 | 21.5 | 43.5 | 30.8 | 12.2 | 22.9 | 16.6 | 22.2 |
| 67 | 17.8 | 8.8 | 20.7 | 23.4 | 41.1 | 15.7 | 6.6 | 16.9 | 19.5 | 17.3 |
| 134 | 18.0 | 13.3 | 20.8 | 22.9 | 40.9 | 10.2 | 15.6 | 9.9 | 19.5 | 16.8 |
| 201 | 19.6 | 15.2 | 22.4 | 25 | 41.1 | 9.7 | 11.2 | 10.4 | 23.4 | 19.3 |
| 268 | 18.2 | 15.4 | 20.6 | 24.8 | 39.7 | 8.1 | 12.3 | 10.9 | 26.4 | 16.3 |
| Mean | 20.6 | 14.4 | 20.3 | 23.5 | 41.3 | 14.9 | 11.6 | 14.2 | 21.1 | 18.3 |
1Dataset used for model validation.
Root mean square error, RRMSE; relative root mean square error, RRMSE; continuous corn, CC; corn and soybean phases over the corn-soybean rotation (SC), part of the SC phase-years used for validation (SC_val).