文献类型： 外文期刊

作者： Xiaochuang Cao;Chao Ma;Qingxu Ma;Ruohui Lu;Haimin Kong;Yali Kong;Lianfeng Zhu;Chunquan Zhu;Wenhao Tian;Qianyu Jin;Lianghuan Wu;Junhua Zhang

作者机构：

关键词： 13C,15N-glycine;13C-PLFA;AWD;ON uptake;Optimum fertilization

期刊名称： Field Crops Research

ISSN： 0378-4290

年卷期： 2025 年 328 卷

页码：

收录情况： SCIE（2025版）

摘要： Context: Alternate wetting-drying (AWD) combined with controlled-release/stable fertilizers demonstrate promising potential for enhancing rice yield and N uptake. However, current research paradigms predominantly focus on inorganic N, while the critical role of soil organic N (ON) utilization within rice-microbe-soil continuum remains unexplored. Objective: This study aims to investigate the shifts in soil N pools composition and availability, along with the underlying mechanism through ON partitioning within the rice-microbial system and its key microbial communities under different fertilization and irrigation regimes. Methods: Based on the five-year field experiment with two irrigation (flood irrigation, FI; AWD) and five N fertilization treatments (zero N, N0; conventional N, PUN100; 80 % of conventional N, PUN80; 80 % of conventional N applied as controlled-release N and urea, CRN80; and 80 % of conventional N applied as stable compound N and urea, SFN80), an incubation experiment was performed to investigate ON utilization by rice and microbes, using 13C,15N-labelled glycine and 13C-phospholipid fatty acids (PLFA) techniques. Results: Compared to FI, AWD combined with SFN80 and CRN80 significantly enhanced rice yield, N uptake and N use efficiency through optimized soil fertility and microbial activity. This improvement was demonstrated by increased soil nitrification rate, extractable total N (ETN), NO3- and free amino acids (FAAs), along with elevated microbial carbon and N entropy (qMBC, qMBN). Furthermore, enzyme activities, including β-glucosidase (BG), invertase (Inv), N-acetyl-β-D-glucosaminidase (NAG) and urease (SUE) were also significantly enhanced. 15N uptake analysis revealed significantly higher values in CRN80 and SFN80 compared to PUN100 and PUN80, with AWD promoting the assimilation of both intact and mineralized N forms by rice and microbes. Notably, AWD increased the proportion of 15N-glycine uptake by rice while reducing its utilization by microbes. Subsequent correlation analysis established positive relationships between rice yield/NUE and glycine uptake parameters. The synergistic effect of AWD and optimized fertilization increased total 13C-PLFA contents and Fungi:Bacteria ratio, while reducing the Gram-positive:Gram-negative ratio. Gram-positive and Gram-negative bacteria, and general FAME (fatty acid methyl ester) groups have been identified as primary competitors with rice for soil ON. Redundancy analysis highlighted NO3-, FAAs, and qMBN as key drivers governing microbial composition and ON partitioning within the rice-microbial system. Conclusions: This study demonstrated that AWD enhanced soil N availability and rice competitive advantage for ON uptake over soil microbes, particularly in CRN80 and SFN80. The improved soil bacterial community and Fungi:Bacteria ratio, together with increased nitrification rate and FAAs contents, created the optimal condition for ON utilization in rice-microbial system, which simultaneously improves soil N availability and ultimately enhances both rice yield and NUE. Implications: This study highlights the importance of distinct N allocation strategy within rice-microbial system and ON utilization for rice growth under optimized fertilization and irrigation management. However, the accurate quantification of soil ON availability over long-term cultivation, as well as the functional mechanisms of specific microbial communities, warrant further investigation.

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