Research Article
Trends in Moisture Index, Farmland Area, and Their Combined Effects on Grain Production in Northern China
Table 6
Factors that affect grain yield.
| County | Year | Unit grain yield (kg/ha) | Cropping index | Chemical fertilizer applied (kg/ha) | Total power of agricultural machinery (W/ha) | Percentage of irrigated area (%) |
| Juxian | 1989 | 4,635 | 1.22 | 304.3 | 2,648.2 | 53.9 | 2008 | 6,382.6 | 0.78 | 1455.5 | 10,166.2 | 50.0 |
| Yuxian | 1989 | 809.8 | 0.75 | 65.1 | 688.3 | 25.4 | 2008 | 911.0 | 0.73 | 106.9 | 3,453.0 | 35.0 |
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