Table 4 Natural and purchased emergy input in major maize planting areas of China
From: The creation of “Ecosystem Core” hypothesis to explain ecosystem evolution
Ecological zones | Natural emergy input (× 1014 sej/ha/year) | Purchased emergy input (× 1014 sej/ha/year) | Natural emergy input ratio (%) | Purchased emergy input ratio (%) |
|---|---|---|---|---|
Northwest of China | 8.32 | 47.19 | 15 | 85 |
Huang-Huai-Hai Plain | 6.82 | 28.08 | 20 | 80 |
Loess Plateau | 10.16 | 35.84 | 22 | 78 |
Southwest of China | 11.48 | 35.65 | 25 | 75 |
Northeast of China | 10.99 | 25.97 | 30 | 70 |