Abstract:

In the study, the effects of nitrogen levels and transplanting densities on yield and nitrogen agronomic efficiency of rice were studied, and the economic benefits of different treatments were analyzed, aiming to provide practical information for rice breeding and production in future. The high yield and high quality hybrid rice ‘Changyou 4’, which bred by Changshu Institute of Agricultural Science and approved by the National Crop Variety Approval Committee of China, was used as the test material. A randomized block design experiment was conducted. The two factors of nitrogen application rate and transplanting density were set up, the nitrogen application rate was 330, 180, 0 kg/hm ², and the density was 45×10⁴, 30×10⁴, 18×10⁴ seedlings/hm², respectively. The grain yield and economic benefit and nitrogen agronomic efficiency of ‘Changyou 4’ were analyzed. The results show that the nitrogen application and transplanting density have significant influence on the grain yield, yield component and nitrogen agronomic efficiency. The grain yield increases with the increase of nitrogen level and transplanting density. The nitrogen agronomic efficiency decreases with the increase of nitrogen level and transplanting density. However, the grain yield significantly decreases when the nitrogen level is more than N 180 kg/hm ². The increase of N significantly raises the benefits, however, transplanting density does not change the benefit significantly. Under the conditions of this experiment, the best treatment for ‘Changyou 4’ is A2B3, when the nitrogen application is N 180 kg/hm ² and transplanting density is 18×10⁴ seedlings/hm², the grain yield is 9919.2 kg/hm², the economic benefit is 12542.2 yuan/hm²and the nitrogen agronomic efficiency is 19.87 kg/kg, respectively.

Key words: rice, nitrogen fertilizer, density, grain yield, economic benefit, nitrogen agronomic efficiency