Characteristics of nutrient uptake and root system distribution in super early and super late rice

In order to elucidate the mechanisms involved in high yield of rice and provide guidance for fertilization in rice farming, the characteristics of nutrient uptake and root distribution in both super early rice and super late rice were studied under field conditions. The average uptake of nitrogen, phosphorus (P), and potassium (K) was 170.04, 21.97 and 107.48 kg/ha, respectively, by super early rice, and was 224.90, 39.88 and 144.47 kg/ha, respectively, by super late rice. Except for super early rice zhuliangyou819, the nutrient uptakes of super rice were higher than those of control rice cultivars. The total amount of nutrient uptakes from panicle initiation to heading were positively correlated with the grain yield of super rice. Compared to the control cultivars, super rice had a larger root system and higher dry root weight, but the nutrient requirement for per 100 kg of grain production was 10% less. The dry root weights of super rice at 15 d or 20 d post-heading were positively correlated with grain yield. Furthermore, only the root weight in 5-10 cm deep soil exhibited significant correlation with super rice's nutrient uptake. In general, these observations suggest that a higher grain yield of super early and late rice is mainly due to the higher uptake of nitrogen, phosphorus, and potassium from panicle initiation to heading, and a larger root system.