1. The dry season in the north is long, from 1 1 to April of the following year.

2. The northern rice-growing areas (including plain areas and northern lowlands) have a large population and large paddy fields.

3. The north is densely populated and rich in labor.

4. Planting in the north has a long history, with traditional experience of intensive cultivation, and local people have a hobby of eating rice.

The yield of rice in the north is high, and planting rice can alleviate the population's demand for food.