It is of great significance to study the root characteristics of rice to improve water and nitrogen (N) use efficiency and reduce environmental pollution. This study investigated whether root traits and architecture of rice influence grain yield, as well as water and N utilization efficiency. An experiment was conducted using the upland rice cultivar Zhonghan 3 (a japonica cultivar) and paddy rice cultivar Huaidao 5 (also a japonica cultivar) using three N levels, namely, 2 g urea/pot (low amount, LN), 3 g urea/pot (normal amount, NN), and 4 g urea/pot (high amount, HN), and three soil water potentials (SWPs, namely, well-watered (0 kPa), mildly dried (–20 kPa) and severely dried (–40 kPa). The results showed that with decreasing SWP, the percentage of upland rice roots increased in the 0–5 cm tillage layer, and decreased in the 5–10 and 10–20 cm tillage layers, whereas paddy rice roots showed the opposite trend. With increasing amounts of N, the yield of upland and paddy rice increased, and the percentage of root volume ratios of the two rice cultivars in the 0–5 and 5–10 cm tillage layers increased, whereas that in the 10–20 cm tillage layer decreased. The roots of upland rice are mainly distributed in the 10–20 cm tillage layer, whereas most paddy rice roots are in the 0–5 cm tillage layer. These results indicate that the combination of –20 kPa SWP and NN in upland rice and 0 kPa SWP and LN in paddy rice promotes the growth of the root system during the middle and late stages, which in turn may decrease the requirements for water and N fertilizer and increase rice yield.

研究水稻的根系特征，对于提高水和氮（N）的利用效率，减少环境污染具有重要意义。本研究调查了水稻的根系特性和结构是否会影响谷物的产量以及水分和氮的利用效率。实验用高地水稻品种中旱图3（a进行粳稻栽培品种）和水稻品种坏道5（也是粳稻而大多数水稻的根系在0-5厘米的耕作层中。这些结果表明，旱稻中–20 kPa SWP和NN以及水稻中0 kPa SWP和LN的组合促进了中后期的根系生长，进而降低了对水和氮的需求。施肥和增加水稻产量。