Optimization of combining controlled-release urea of different release period and normal urea improved rice yield and nitrogen use efficiency

ABSTRACT

Controlled-release urea (CRU) and normal urea have been shown to improve yield and nitrogen use efficiency (NUE) in rice. However, the effects of combined fertilizers (CRU and normal urea, at different N ratios) on rice yield, temperature and solar radiation utilization efficiency (TSRUE) and NUEs remain unclear. In this study, CRU with release periods of 60 days and 100 days were mixed with urea at N ratios of 7:3, 6:4, 5:5, 4:6 and 3:7 and applied during the rice-growing season in a rice-wheat cropping system. Rice yield, dry matter accumulation (DMA), TSRUE and NUEs were investigated. The yields under one-time fertilization mode 2 (OFM2) and OFM8 were 5.36%-9.70% higher than that of farmer fertilization practices (FFP) on average across 2018 and 2019. The NUEs under OFM2 and OFM8 was 3.87%-35.56% and 6.26%-58.56% higher than that under FFP, respectively, across 2018 and 2019. Correlation analysis showed that TSRUE were significantly positively correlated with yield, DMA and NUEs. The higher TSRUE under OFM2 and OFM8 contributed to the synergistic improvement of yield and NUEs. Both OFM2 and OFM8 improved rice yields and NUEs compared to FFP while having lower fertilizer and labor costs; therefore, these treatments are worthy of promotion and application.

KEYWORDS:

• Rice
• controlled-release urea
• yield
• N use efficiency
• temperature and solar radiation utilization efficiency

Acknowledgements

The authors thank Miss Jialin Hou and Mr. Lingtian Zhao for their assistance with the experiments.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplementary material

Supplemental data for this article can be accessed here.

Additional information

Funding

This research was financially supported by the Natural Science Foundation of China (32001469), the National Key Research and Development Program (2018YFD0300802), the Key Research Program of Jiangsu Province, China (BE2020319, BE2019377, BE2018362), the priority academic program development of Jiangsu higher education institutions (PAPD).