Abstract

In order to clarify whether the shift from hand-transplanting seedlings to direct seeding will bring negative effects to rice production and to find optimal nitrogen management for direct-seeded rice in Eastern China, research has been conducted in Quzhou City, in the Zhejiang Province of China in the year 2017 and 2018. One indica inbred rice variety, “Zhongjiazao-17” was planted by two different rice establishment methods (direct seeding and hand-transplantation), and five different nitrogen application rates were set as experimental treatments (0, 120 and 180 kg ha-1 in 2017 and 0, 165 and 195 kg ha-1 in 2018). The grain yield, economic profit, and rice quality were compared between direct-seeded rice and hand-transplanted rice under different nitrogen rates. Our results indicate that the direct-seeded rice showed no obvious disadvantages in grain yield compared to the hand-transplanted rice, but improved economic profit significantly. The highest grain yield and production profit were achieved at 180 kg N ha-1 in direct-seeded rice while the hand-transplanted rice achieved highest grain yield and profit at 165 kg ha-1. The direct-seeded rice showed lower physical quality but higher cooking and tasting quality than the hand-transplanted rice. Increasing the nitrogen rate improved the physical quality but decreased cooking and tasting quality in both the direct-seeded rice and hand-transplanted rice. Hence, direct-seeded rice has the potential to be promoted in Eastern China, and 180 kg ha-1 is the optimal nitrogen rate. In addition, applying sufficient nitrogen at panicle initiation is necessary to increase the grain yield of direct-seeded rice.

Key words: Direct seeding, hand-transplantation, grain yield, nitrogen management, physical quality, cooking and tasting quality.