Pedosphere 35(2): 364--372, 2025
ISSN 1002-0160/CN 32-1315/P
©2025 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Effects of straw incorporation on biological nitrogen fixation under continuous and intermittent flooding irrigation in a rice cropping system |
Yanhui ZHANG1,3, Jing WANG2, Qi LIU2, Haihou WANG3,7, Tianlong HU4, Hui WANG4, Zhe CHEN4, Liangzuo SHU5, Elrys S. AHMED6, Zubin XIE4 |
1 School of Geography, Nanjing Normal University, Nanjing 210023 (China)
2 Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing 210037 (China)
3 Suzhou Academy of Agricultural Sciences, Institution of Agricultural Sciences Taihu Lake District, Suzhou 215155 (China)
4 State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China)
5 Zhejiang Provincial Key Laboratory of Plant Evolutionary and Conservation, School of Life Science, Taizhou University, Taizhou 318000 (China)
6 Soil Science Department, Faculty of Agriculture, Zagazig University, Zagazig 44511 (Egypt)
7 National Soil Quality Observation and Experimental Station in Xiangcheng, Suzhou 215131 (China) |
| ABSTRACT |
| Both straw incorporation and irrigation practices affect biological nitrogen (N) fixation (BNF), but it is still unclear how straw incorporation impacts BNF under continuous (CFI) or intermittent (IFI) flooding irrigation in a rice cropping system. A 15N2-labeling chamber system was placed in a rice field to evaluate BNF with straw incorporation under CFI or IFI for 90 d. The nifH (gene encoding the nitrogenase reductase subunit) DNA and cDNA in soil were amplified using real-time quantitative polymerase chain reaction, and high-throughput sequencing was applied to the nifH gene. The total fixed N in the straw incorporation treatment was 14.3 kg ha-1 under CFI, being 116% higher than that under IFI (6.62 kg ha-1). Straw incorporation and CFI showed significant interactive effects on the total fixed N and abundances of nifH DNA and cDNA. The increase in BNF was mainly due to the increase in the abundances of heterotrophic diazotrophs such as Desulfovibrio, Azonexus, and Azotobacter. These results indicated that straw incorporation stimulated BNF under CFI relative to IFI, which might ultimately lead to a rapid enhancement of soil fertility. |
| Key Words: heterotrophic diazotrophs,irrigation practices,15N2-labeling experiment,nifH cDNA,nifH DNA,soil fertility,water management |
| Citation: Zhang Y H, Wang J, Liu Q, Wang H H, Hu T L, Wang H, Chen Z, Shu L Z, Ahmed E S, Xie Z B. 2025. Effects of straw incorporation on biological nitrogen fixation under continuous and intermittent flooding irrigation in a rice cropping system. Pedosphere. 35(2): 364-372. |
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