Investigation of Rice Yields and Critical N Losses from Paddy Soil under Different N Fertilization Rates with Iron Application

Weishou Shen; Yaou Long; Zijian Qiu; Nan Gao; Yoko Masuda; Hideomi Itoh; Hirotomo Ohba; Yutaka Shiratori; Adharsh Rajasekar; Keishi Senoo

doi:10.3390/ijerph19148707

Investigation of Rice Yields and Critical N Losses from Paddy Soil under Different N Fertilization Rates with Iron Application

Int J Environ Res Public Health. 2022 Jul 17;19(14):8707. doi: 10.3390/ijerph19148707.

Authors

Weishou Shen¹, Yaou Long¹, Zijian Qiu¹, Nan Gao², Yoko Masuda³, Hideomi Itoh⁴, Hirotomo Ohba⁵, Yutaka Shiratori⁵, Adharsh Rajasekar¹, Keishi Senoo^{3

6}

Affiliations

¹ Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, School of Environmental Science and Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China.
² National Engineering Research Center for Biotechnology, School of Biological and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211816, China.
³ Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan.
⁴ Microbial Ecology and Technology Research Group, Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Toyohira-ku, Sapporo 062-8517, Japan.
⁵ Agro-Environment Research Division, Niigata Agricultural Research Institute, Nagaoka 940-0826, Japan.
⁶ Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, Tokyo 113-8657, Japan.

Abstract

The application of iron powder stimulated the growth of iron-reducing bacteria as a respiratory substrate and enhanced their nitrogen (N)-fixing activity in flooded paddy soils. High N fertilization (urea) in the flooded paddy soils has caused adverse environmental impacts such as ammonia (NH₃) volatilization, nitrous oxide (N₂O) emissions, and nitrate (NO₃^-) leaching. This study aims to investigate the effects of N fertilization rates in combination with an iron amendment on rice yields and N losses from flooded paddy fields. We performed a 2-year field plot experiment with traditional rice-wheat rotation in China's Yangtze River Delta. The investigation consisted of seven treatments, including 100%, 80%, 60%, and 0% of the conventional N (urea and commercial organic manure) fertilization rate, and 80%, 60%, and 0% of the conventional N with the iron powder (≥99% purity) amendment. The rice yields decreased with a reduction in the conventional N fertilization rate, whereas they were comparable after the iron application under the 80% and 60% conventional N rate. The critical N losses, including NH₃ volatilization, N₂O emissions, and NO₃^- and NH₄⁺ leaching, generally decreased with a reduction in the conventional N fertilization rate. These N losses were significantly greater after the iron amendment compared with the non-amended treatments under the 80% and 60% conventional N fertilization rate in the first rice-growing season. However, it was comparable between the iron-amended and the non-amended treatments in the second season. Furthermore, NO₃^- leaching was the most significant N loss throughout the two rice seasons, followed by NH₃ volatilization. The iron amendment significantly increased soil Fe²⁺ content compared with the non-amended treatments irrespective of N fertilization, suggesting the reduction of amended iron by iron-reducing bacteria and their simultaneous N fixation. A combination of the iron application with 60-80% of the conventional N fertilization rate could maintain rice yields similar to the conventional N fertilization rate while reducing the critical N losses in the flooded paddy field tested in this study. Our study leads to the establishment of novel and practical rice cultivation, which is a step towards the development of green agriculture.

Keywords: NO3− leaching; ammonia volatilization; iron-reducing bacteria; nitrogen fixation; nitrous oxide emissions.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Agriculture
Fertilization
Fertilizers / analysis
Iron
Nitrogen / analysis
Nitrous Oxide / analysis
Oryza* / chemistry
Powders
Soil* / chemistry
Urea

Substances

Fertilizers
Powders
Soil
Urea
Iron
Nitrous Oxide
Nitrogen

Grants and funding

This research was funded by the Jiangsu Agricultural Science and Technology Innovation Fund (CX(21)3183), National Natural Science Foundation of China (41771291), JSPS KAKENHI (JP20H05679), and JST-Mirai Program (JPMJMI20E5).