Single-season rice is a rice planting system, and only one season of rice is planted every year. Double-cropping rice is a rice planting system, in which two crops of rice are planted and harvested in the same rice field. Similarly, three-season rice is to plant and harvest three-season rice in the same paddy field in one year. As early as the middle of19th century, three-season rice was planted in Taiwan Province Province and introduced to some areas south of Nanling, Chinese mainland.

The safe growth period of indica rice (the interval between the initial period when the daily average temperature is stable at 10℃ and the final period at ≥22℃) is 2 12 ~ 253 days; Japonica rice (the interval from the beginning of daily average temperature ≥ 10℃ to the end of ≥20℃) is 235 ~ 273 days. Paddy fields are mainly distributed in river plains and hilly valleys, which are suitable for the growth of double cropping rice. Safe growth period: indica rice 180 days, japonica rice 235 days. Paddy fields are mainly distributed in river valleys, and the upper limit of planting height is altitude 1800 ~ 2400 meters. In most places, only one season of rice is planted a year, and the main pests and diseases are bacterial blight and Chilo suppressalis. In the future, it is necessary to improve irrigation conditions, increase multiple cropping, improve soil and change the habit of extensive rotation.