Table 4.
VIF of each independent variable for each crop area.
| Crop Area | β 1 | β 2 | β 3 | γ |
|---|---|---|---|---|
| Double-cropping rice area in South China | 1.1945 | 8.2247 | 8.6717 | 1.1898 |
| Single- and double-cropping rice areas in Central China | 2.4871 | 2.2701 | 2.9919 | 1.1801 |
| Single- and double-cropping rice areas on the Southwest Plateau of China | 3.6948 | 2.0385 | 3.0412 | 1.4064 |
| Single-cropping rice area in North China | 1.8717 | 1.2607 | 1.6227 | 1.1130 |
| Early-maturing, single-cropping rice area in Northeast China | 2.5946 | 31.3800 | 25.0936 | 1.0502 |
| Single-cropping rice area in dry area of Northwest China | 1.9516 | 1.3012 | 1.8670 | 1.3341 |
| Japan rice area | 11.4393 | 9.3500 | 6.6507 | 1.0939 |
| Korea rice area | 26.2476 | 17.9801 | 4.1156 | 1.0629 |
| Winter wheat (autumn sowing) area in northern China | 2.2262 | 1.4196 | 2.3437 | 1.1729 |
| Winter wheat (autumn sowing) area in southern China | 2.4213 | 2.7505 | 4.2112 | 1.6201 |
| Spring wheat (spring sowing) area of China | 1.3803 | 4.5462 | 4.6765 | 1.1909 |
| Winter and spring sowing wheat areas of China | 1.9761 | 1.0311 | 1.9356 | 1.0335 |
| Japan wheat area | 6.7006 | 1.4523 | 6.6055 | 1.1486 |
| Korea wheat area | 8.1970 | 4.6529 | 3.5710 | 1.0648 |
| Spring maize area in northern China | 2.4236 | 11.7103 | 9.0062 | 1.2765 |
| Summer maize area in the Huang-Huai-Hai Plain | 5.1883 | 8.7393 | 3.0180 | 1.0175 |
| Maize area in the Southwest China Mountains | 4.6703 | 6.2971 | 2.6591 | 1.1282 |
| Maize area in hilly southern China | 13.1194 | 7.6808 | 4.8837 | 1.3908 |
| Irrigated maize area in Northwest China | 1.6665 | 9.8974 | 14.1108 | 1.8945 |
| Mazie area on the Qinghai–Tibetan Plateau of China | 1.4767 | 2.1175 | 1.8110 | 1.3394 |
| Japan maize area | 9.0438 | 3.1719 | 6.3990 | 1.0870 |
| Korea maize area | 4.1217 | 2.2174 | 3.6954 | 1.1033 |