Table 2 Test set prediction errors for years 2017 and 2018 of ML models for benchmark and hybrid cases.
From: Coupling machine learning and crop modeling improves crop yield prediction in the US Corn Belt
ML model | Benchmark (no APSIM variable) | Hybrid simulation—ML (all 22 APSIM variables included) | % decrease in RMSE | ||||||
|---|---|---|---|---|---|---|---|---|---|
RMSE (kg/ha) | RRMSE (%) | MBE (kg/ha) | R2 (%) | RMSE (kg/ha) | RRMSE (%) | MBE (kg/ha) | R2 (%) | % | |
Test set: 2018 | |||||||||
LASSO | 1160 | 9.5 | 559 | 24.5 | 1094 | 8.9 | 206 | 32.8 | 5.7 |
XGBoost | 1482 | 12.1 | − 879 | − 23.3 | 1172 | 9.6 | − 581 | 22.8 | 20.9 |
LightGBM | 1067 | 8.7 | − 549 | 36.1 | 883 | 7.2 | − 89 | 56.2 | 17.3 |
Random forest | 1259 | 10.3 | − 717 | 11.1 | 1055 | 8.6 | − 567 | 37.5 | 16.1 |
Linear regression | 1095 | 8.9 | 589 | 32.7 | 955 | 7.8 | 100 | 48.8 | 12.7 |
Optimized weighted ens | 1033 | 8.4 | − 485 | 40.1 | 909 | 7.4 | − 192 | 53.6 | 12.0 |
Average ensemble | 959 | 7.8 | − 200 | 48.4 | 938 | 7.7 | − 186 | 50.7 | 2.2 |
Stacked regression ens | 1140 | 9.3 | − 705 | 27.1 | 943 | 7.7 | − 23 | 50.1 | 17.3 |
Stacked LASSO ensemble | 1128 | 9.2 | − 685 | 28.5 | 941 | 7.7 | − 29 | 50.3 | 16.6 |
Stacked Random f. ens | 1363 | 11.1 | − 355 | − 4.2 | 1002 | 8.2 | 49 | 43.6 | 26.5 |
Stacked LightGBM ens | 1365 | 11.2 | − 366 | − 4.6 | 995 | 8.1 | 43 | 44.4 | 27.1 |
Test set: 2017 | |||||||||
LASSO | 835 | 7.0 | − 192 | 67.0 | 771 | 6.5 | 63 | 71.9 | 7.6 |
XGBoost | 957 | 8.0 | − 256 | 56.7 | 946 | 7.9 | − 236 | 57.7 | 1.2 |
LightGBM | 914 | 7.7 | − 437 | 60.5 | 916 | 7.7 | − 64 | 60.3 | − 0.2 |
Random forest | 1004 | 8.4 | − 544 | 52.3 | 841 | 7.1 | − 276 | 66.5 | 16.2 |
Linear regression | 858 | 7.2 | − 333 | 65.2 | 830 | 7.0 | 271 | 67.4 | 3.3 |
Optimized weighted ens | 885 | 7.4 | − 404 | 62.9 | 787 | 6.6 | − 8 | 70.7 | 11.1 |
Average ensemble | 859 | 7.2 | − 352 | 65.1 | 762 | 6.4 | − 48 | 72.5 | 11.3 |
Stacked regression ens | 940 | 7.9 | − 495 | 58.2 | 810 | 6.8 | 96 | 68.9 | 13.8 |
Stacked LASSO ensemble | 935 | 7.9 | − 486 | 58.7 | 809 | 6.8 | 100 | 69.0 | 13.4 |
Stacked Random f. ens | 993 | 8.3 | − 331 | 53.4 | 888 | 7.5 | 63 | 62.7 | 10.6 |
Stacked LightGBM ens | 921 | 7.7 | − 288 | 59.8 | 838 | 7.0 | 98 | 66.8 | 9.1 |
