Relationship between nitrogen accumulation and nitrogen use efficiency of rice under different urea types and management methods

ABSTRACT

We aimed to clarify the effectiveness of polyaspartic acid (PASP)-urea on nitrogen (N) accumulation and N use efficiency in rice. We compared PASP-urea with conventional urea with two N management methods (farmer’s fertilizer practice and optimized N management) in Wenjiang, Sichuan Province, China, in 2014 and 2015. N recovery efficiency (NRE), N agronomic efficiency (NAE), and N partial factor productivity (PFP) decreased with increasing N uptake by the shoot and the stem plus sheath at 14 days after transplanting (DAT), while they were positively related to N uptake of the shoot, leaf lamina, and stem plus sheath at the middle and later stages. N use efficiency and N uptake differed according to urea type and N management. PASP-urea increased N accumulation of the shoot by improving N uptake of the leaf lamina and stem plus sheath from DAT 27, contributing to the significant improvement in NRE, NAE, and PFP. PASP-urea with optimized N management markedly improved the N uptake of each organ at the middle and latter stages, leading to increased final N uptake of the shoot, NRE, NAE, and PFP. Using PASP-urea with ONM method is a suitable way for improving both N accumulation and N use efficiency.

KEYWORDS:

• Nitrogen accumulation
• nitrogen management
• nitrogen use efficiency
• PASP-urea
• rice

Acknowledgments

We thank the students and farmers involved in the experiment.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Ministry of Science and Technology of the People’s Republic of China; under Grant [number 2016YFD0300506]; and the Science and Technology Department of Sichuan Province under Grant [number 2016NYZ0051].