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Fig. 2.

Fig. 3.

Fig. 4.

Fig. 5.

Fig. 6.

Fig. 7.

Fig. 8.

Descriptive statistical results of vegetation indices
| Indices | Mean | Std | Var | Median | Skewness | Kurtosis | Q25 | Q75 |
|---|---|---|---|---|---|---|---|---|
| NDVI | 0.702038 | 0.083245 | 0.006930 | 0.723672 | –0.071365 | 2.045454 | 0.642460 | 0.756097 |
| NDWI | –0.538684 | 0.026957 | 0.000727 | –0.549065 | 1.081511 | 3.079622 | –0.554977 | –0.531618 |
| SAVI | 0.940731 | 0.120926 | 0.014623 | 0.986801 | –1.529100 | 4.264492 | 0.929660 | 1.006785 |
| EVI | 0.505570 | 0.088888 | 0.007901 | 0.491353 | –0.698589 | 4.182447 | 0.460148 | 0.579817 |
Variable importance estimates from multivariate analysis
| Variable | Estimate | Std. error | p-value | 95% CI |
|---|---|---|---|---|
| NDVI | 18.827 | 6.659 | 0.022* | (3.470, 34.184) |
| EVI | 7.855 | 8.227 | 0.368 | (–11.115, 26.826) |
| NDWI | 7.797 | 16.349 | 0.646 | (–29.905, 45.499) |
| Slope | –0.289 | 0.242 | 0.266 | (–0.846, 0.268) |
SHAP variable importance
| Variable | Mean (SHAP) | Direction |
|---|---|---|
| NDVI | 1.567 | Positive |
| EVI | 0.698 | Positive |
| Slope | 0.680 | Negative |
| NDWI | 0.210 | Positive |
| Elevation | 0.186 | Positive |
| Total. protein | 0.173 | Positive |
Summary of hayfield yield and forage quality (Bornuur)
| Variable | Min | Max | Mean (approx.) |
|---|---|---|---|
| Area (ha) | 10.3 | 6 000 | – |
| Yield (g/m2) | 54.1 | 132.9 | 93 |
| Moisture (%) | 4.92 | 7.69 | 5.9 |
| Dry matter (%) | 92.31 | 95.08 | 94.1 |
| Crude protein (%) | 9.12 | 16.56 | 11.9 |
| Fibre (%) | 22.8 | 36.96 | 30.1 |
| Digestibility (%) | 55.66 | 68.59 | 61.7 |
| Energy (MJ) | 8.02 | 9.87 | 8.8 |
Descriptive statistical results of Land surface factors
| Land surface factor | Mean | Std | Var | Median | Skewness | Kurtosis | Q25 | Q75 |
|---|---|---|---|---|---|---|---|---|
| Elevation | 1 114.7 | 84.1 | 7 060.9 | 1133.0 | –0.6 | 3.3 | 1 050.8 | 1 159.5 |
| Aspect | 166.6 | 118.6 | 14 076.4 | 160.2 | 0.1 | 1.8 | 58.3 | 250.1 |
| Slope | 7.1 | 2.4 | 5.5 | 6.9 | –0.2 | 2.9 | 5.7 | 8.7 |
Model comparison results
| Model | RMSE | MAE | R2 |
|---|---|---|---|
| FULL | 0.853 | 0.653 | 0.879 |
| LASSO | 0.889 | 0.677 | 0.869 |