Pedosphere 34(6): 1051--1065, 2024
ISSN 1002-0160/CN 32-1315/P
©2024 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Arsenic mobilization and nitrous oxide emission modulation by different nitrogen management strategies in a flooded ammonia-enriched paddy soil |
Feng WANG1, Jing ZHANG4, Yanqiong ZENG1, Honghui WANG4, Xiyu ZHAO1, Yilin CHEN1, Huanhuan DENG1, Liyun GE1, Randy A. DAHLGREN1,3, Hui GAO2 , Zheng CHEN1,4 |
1 Zhejiang Provincial Key Laboratory of Watershed Science & Health, Wenzhou Medical University, Wenzhou 325035 (China);
2 Key Laboratory of Fertility Preservation and Maintenance of Ministry of Education, Ningxia Medical University, Yinchuan 750004 (China);
3 Department of Land, Air & Water Resources, University of California, Davis (UC Davis), Davis CA 95616 (USA);
4 School of Environmental Science & Engineering, Tan Kah Kee College, Xiamen University, Zhangzhou 363105 (China) |
| ABSTRACT |
| Elevated arsenic (As) mobilization and increased nitrous oxide (N2O) emission are two primary environmental concerns existing in flooded paddy soils. In this study, dissolved As(III), N isotope-labeled Na15NO3, and/or 14NH4Cl were incorporated into a microcosm incubation to determine the effects of N fertilization regimes on As mobilization and N2O emission in a flooded paddy soil. Because nitrate had a higher redox potential and comprised a higher proportion of N substrate, As(V) was preferentially formed due to enhanced nitrate-dependent microbial As(III) oxidation. Thus, As availability was correspondingly attenuated due to the improved production of less mobile and toxic As(V). After 2-d incubation, more than 90% and 98% of soluble As(III) were immobilized in the As + NH4+ -N + NO3- -N and As + NO3- -N treatments, respectively. Following nitrate depletion (after 2 d), microbial As(V) and Fe(III) reductions were gradually enhanced, which was attributed to stimulation of anaerobic ammonium oxidation (anammox) coupled to Fe(III) reduction, known as Feammox, by the abundance of NH4+ . By the end of the incubation period (10 d), the As + NO3- -N treatment led to higher As immobilization of originally added As(III) (ca. 61%) than the As + NH4+ -N + NO3- -N treatment (42%). The As + NH4+ -N + NO3- -N treatment prominently mitigated N2O emission compared to the As + NO3- -N treatment, which was ascribed to anammox, inducing accumulation of byproducts from incomplete denitrification. High-throughput sequencing indicated that the relative abundances of denitrifiers (e.g., Azoarcus, Ochrobactrum, and Thiobacillus denitrificans) increased in the As + NO3- treatment, whereas quantitative polymerase chain reaction results indicated higher 16S rRNA gene copy numbers for anammox and Feammox (Acidimicrobiaceae bacterium A6) bacteria in the As + NH4+ + NO3- treatment. Collectively, the experimental results demonstrated that N fertilization can be a feasible As remediation strategy while providing an effective strategy for mitigating N2O emission from paddy soils at the same time. |
| Key Words: anammox bacteria,Feammox bacteria,flooded paddy soil,microbe,15N-isotope tracing technique,redox reaction |
| Citation: Wang F, Zhang J, Zeng Y Q, Wang H H, Zhao X Y, Chen Y L, Deng H H, Ge L Y, Dahlgren R A, Gao H, Chen Z. 2024. Arsenic mobilization and nitrous oxide emission modulation by different nitrogen management strategies in a flooded ammonia-enriched paddy soil. Pedosphere. 34(6): 1051-1065. |
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