Effects of water and nitrogen on growth, development and yield of rice in cold area of Northeast China

To understand the effects of water and nitrogen (N) fertilizer on growth, development and yield of rice, experiments with three irrigation treatments (rainfed, intermittent, continued flooding) and three N applications (0 kg/hm², 112—135 kg/hm², 142—173 kg/ hm²) were implemented in a randomized complete block design at Jiansanjiang experimental station in Heilongjiang province from 2010 to 2011. The results showed that crop development stages of panicle initiation, flowing and mature under rainfed treatment were 1—5 days shorter, and growth index and yield were significantly decreased, while that for intermittent irrigation were not significant, compared to continued flooding irrigation. Compared to convential N application (112—135 kg/hm²), crop development stages of panicle initiation, flowing and mature were 2—5 days shorter for treatment without N, but those stages were prolonged 2—4 days at high N application. Crop yield and growth index were increased significantly with N dose. Under low nitrogen input, water stress was obvious, while high nitrogen input could compensate crop growth due to loss by water stress. Effective panicle number and grain number per panicle were significantly increased with N and water supply. Intermittent irrigation and high N application showed a potential to achieve high yield and high resource use efficiency. This study could provide a theoretical basis for irrigation and fertilization of rice in cold area.