1. Nitrate has a stronger rhizobacterial-based effect on rice growth and nitrogen use than ammonium in acidic paddy soil.
- Author
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Xiao, Xun, Liu, Zeng Tai, Shen, Ren Fang, and Zhao, Xue Qiang
- Subjects
RICE ,ACID soils ,LIMING of soils ,IRON oxidation ,SOIL acidity ,AMMONIUM ,COMMUNITIES - Abstract
Background and Aims: Suitable N source supply is critical to improve plant growth and N uptake, but the importance of nitrate (NO
3 − ) for rice (Oryza sativa L.) and microbiota is often neglected in acidic paddy soils where ammonium (NH4 + ) is dominant. This study aimed to explore the differential effects of NH4 + and NO3 − on rice growth, fertilizer nitrogen recovery efficiency (FNRE), and rhizosphere bacterial community in acid soil. Methods: Two rice varieties, Kasalath (Al-sensitive indica) and Koshihikari (Al-tolerant japonica), were exposed to different N sources with or without lime in an acid soil. Results: Liming and NO3 − application solely improved the growth and FNRE of the Al-sensitive rice, namely, by increasing soil pH and alleviating Al toxicity. Compared with liming and rice variety, N source had a more pronounced influence on rhizobacterial community composition. Of the two sources, NO3 − had a stronger effect on the rhizobacterial community than NH4 + . Remarkably, rice plants fed with NH4 + specifically recruited Desulfosporosinus and Desulfitobacterium associated with ferric NH4 + oxidation in the rhizosphere, whereas those exposed to NO3 − recruited Alicyclobacillus with NO3 − -reducing iron oxidation ability. Three keystone taxa were identified in a rhizobacterial co-occurrence network analysis: Alicyclobacillus, which was positively associated with rice growth and FNRE, and Acidobacteriales and WPS-2, both with negative associations. Conclusion: Compared with NH4 + , NO3 − enhances the growth and FNRE of Al-sensitive rice and exerts dominant effects on the rhizobacterial community, which indicates the importance of NO3 − for rice and has instructive implications for N management in acid soil. [ABSTRACT FROM AUTHOR]- Published
- 2023
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