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.  
Highlights
The objectives of this study are: 1) To compare the grain yield, yield components, and rice quality between direct-seeded rice and hand-transplanted rice under different nitrogen application rates to investigate the effects on rice production in Zhejiang Province, Eastern China; and 2) to elucidate the optimum nitrogen rate and nitrogen management for direct-seeded rice
ADS, HT, represent direct seeding, hand-transplantation, respectively. bWithin a column in each method, means followed by the same letters are not significantly different according to least significant difference (LSD) (0.05).Low-case and upper-case letters indicate comparisons among three different nitrogen treatments and between two rice establish methods
ADS, HT, represent direct seeding, hand-transplantation, respectively. b Within a column in each method, means followed by the same letters are not significantly different according to LSD (0.05).Low-case and upper-case letters indicate comparisons among three different nitrogen treatments and between two rice establish methods
Summary
Since the 1990s, the economic growth has been rapid in China, and many labourers have transferred from rural areas to cities, in the Zhejiang Province, which is located in Yangtze River Delta economic zone in Eastern China This phenomenon has caused the labor costs for crop production to rise significantly. In order to reduce labour costs and maintain profit margins, many farmers in China have chosen to directly-seed rice instead of using the traditional hand-transplantation method (Liu et al, 2014; Zhang et al, 2018; Ladha et al, 2009), as direct-seeded rice is considered to be a more labour- and resource-effective rice cultivation method compared to traditional hand-transplantation (Sun et al, 2015). The area of direct-seeded rice continues to increase with each passing year (Mao et al, 2018; Wang, 2015)
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