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Chen Q, Long C, Bao Y, Men X, Zhang Y, Cheng X. The dominant genera of nitrogenase (nifH) affects soil biological nitrogen fixation along an elevational gradient in the Hengduan mountains. Chemosphere 2024; 347:140722. [PMID: 37972867 DOI: 10.1016/j.chemosphere.2023.140722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 11/01/2023] [Accepted: 11/12/2023] [Indexed: 11/19/2023]
Abstract
Biological nitrogen (N) fixation by diazotrophic microbes is an essential process for the N input. However, the patterns of biological N fixation and its biological or environmental mechanism along an elevational gradient in mountain ecosystems are not fully understood. In this study, a field experiment was conducted in the Hengduan Mountains to investigate the biological N fixation associated with the diversity and abundance of the nifH gene. Our results showed that both the abundance of the nifH gene and the biological N fixation displayed hump-shaped trends along an elevation gradient in the wet and dry seasons. However, the diversity of the nifH gene showed an inverse unimodal trend along an elevation gradient. We observed that biological N fixation was jointly associated with the abundance of the nifH gene, especially dominant genera, as well as soil chartacteristics. Among them, clay content played a preeminent role in the regulation of N fixation potentially through the formation of microaggregates and microenvironments. In general, our results revealed that biological N fixation was correlated with the abundance of microorganisms, especially dominant genera, and soil texture. These results highlighted the importance of dominant genera, which should be considered in the modeling and forecasting of N cycling under future environmental change.
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Affiliation(s)
- Qiong Chen
- Key Laboratory of Soil Ecology and Health in Universities of Yunnan Province, School of Ecology and Environmental Sciences, Yunnan University, Kunming 650500, PR China
| | - Chunyan Long
- Key Laboratory of Soil Ecology and Health in Universities of Yunnan Province, School of Ecology and Environmental Sciences, Yunnan University, Kunming 650500, PR China
| | - Yong Bao
- Key Laboratory of Soil Ecology and Health in Universities of Yunnan Province, School of Ecology and Environmental Sciences, Yunnan University, Kunming 650500, PR China
| | - Xiuxian Men
- Key Laboratory of Soil Ecology and Health in Universities of Yunnan Province, School of Ecology and Environmental Sciences, Yunnan University, Kunming 650500, PR China
| | - Yong Zhang
- Key Laboratory of Soil Ecology and Health in Universities of Yunnan Province, School of Ecology and Environmental Sciences, Yunnan University, Kunming 650500, PR China
| | - Xiaoli Cheng
- Key Laboratory of Soil Ecology and Health in Universities of Yunnan Province, School of Ecology and Environmental Sciences, Yunnan University, Kunming 650500, PR China.
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2
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Elrys AS, Abo El-Maati MF, Dan X, Wen Y, Mou J, Abdelghany AE, Uwiragiye Y, Shuirong T, Yanzheng W, Meng L, Zhang J, Müller C. Aridity creates global thresholds in soil nitrogen retention and availability. Glob Chang Biol 2024; 30:e17003. [PMID: 37943245 DOI: 10.1111/gcb.17003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 10/12/2023] [Accepted: 10/12/2023] [Indexed: 11/10/2023]
Abstract
Identifying tipping points in the relationship between aridity and gross nitrogen (N) cycling rates could show critical vulnerabilities of terrestrial ecosystems to climate change. Yet, the global pattern of gross N cycling response to aridity across terrestrial ecosystems remains unknown. Here, we collected 14,144 observations from 451 15 N-labeled studies and used segmented regression to identify the global threshold responses of soil gross N cycling rates and soil process-related variables to aridity index (AI), which decreases as aridity increases. We found on a global scale that increasing aridity reduced soil gross nitrate consumption but increased soil nitrification capacity, mainly due to reduced soil microbial biomass carbon (MBC) and N (MBN) and increased soil pH. Threshold response of gross N production and retention to aridity was observed across terrestrial ecosystems. In croplands, gross nitrification and extractable nitrate were inhibited with increasing aridity below the threshold AI ~0.8-0.9 due to inhibited ammonia-oxidizing archaea and bacteria, while the opposite was favored above this threshold. In grasslands, gross N mineralization and immobilization decreased with increasing aridity below the threshold AI ~0.5 due to decreased MBN, but the opposite was true above this threshold. In forests, increased aridity stimulated nitrate immobilization below the threshold AI ~1.0 due to increased soil C/N ratio, but inhibited ammonium immobilization above the threshold AI ~1.3 due to decreased soil total N and increased MBC/MBN ratio. Soil dissimilatory nitrate reduction to ammonium decreased with increasing aridity globally and in forests when the threshold AI ~1.4 was passed. Overall, we suggest that any projected increase in aridity in response to climate change is likely to reduce plant N availability in arid regions while enhancing it in humid regions, affecting the provision of ecosystem services and functions.
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Affiliation(s)
- Ahmed S Elrys
- College of Tropical Crops, Hainan University, Haikou, China
- Soil Science Department, Faculty of Agriculture, Zagazig University, Zagazig, Egypt
- Liebig Centre for Agroecology and Climate Impact Research, Justus Liebig University, Giessen, Germany
| | - Mohamed F Abo El-Maati
- Agriculture Biochemistry Department, Faculty of Agriculture, Zagazig University, Zagazig, Egypt
| | - Xiaoqian Dan
- College of Tropical Crops, Hainan University, Haikou, China
| | - YuHong Wen
- College of Tropical Crops, Hainan University, Haikou, China
| | - Jinxia Mou
- College of Tropical Crops, Hainan University, Haikou, China
| | - Ahmed Elsayed Abdelghany
- Key Laboratory of Agricultural Soil and Water Engineering in Arid and Semiarid, Areas of Ministry of Education, Northwest A&F University, Yangling, China
- Water Relation and Field Irrigation Department, Agriculture and Biological Institute, National Research Centre, Cairo, Egypt
| | - Yves Uwiragiye
- Department of Agriculture, Faculty of Agriculture, Environmental Management and Renewable Energy, University of Technology and Arts of Byumba, Byumba, Rwanda
- School of Geography, Nanjing Normal University, Nanjing, China
| | - Tang Shuirong
- College of Tropical Crops, Hainan University, Haikou, China
| | - Wu Yanzheng
- College of Tropical Crops, Hainan University, Haikou, China
| | - Lei Meng
- College of Tropical Crops, Hainan University, Haikou, China
| | - JinBo Zhang
- College of Tropical Crops, Hainan University, Haikou, China
- Liebig Centre for Agroecology and Climate Impact Research, Justus Liebig University, Giessen, Germany
- School of Geography, Nanjing Normal University, Nanjing, China
| | - Christoph Müller
- Liebig Centre for Agroecology and Climate Impact Research, Justus Liebig University, Giessen, Germany
- Institute of Plant Ecology, Justus Liebig University Giessen, Giessen, Germany
- School of Biology and Environmental Science and Earth Institute, University College Dublin, Dublin, Ireland
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3
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Chen X, Thomas BR, Pattison S, An Z, Chang SX. Pulp mill biosolids mitigate soil greenhouse gas emissions from applied urea and improve soil fertility in a hybrid poplar plantation. J Environ Manage 2023; 344:118474. [PMID: 37364496 DOI: 10.1016/j.jenvman.2023.118474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 06/04/2023] [Accepted: 06/19/2023] [Indexed: 06/28/2023]
Abstract
Pulp mill biosolids (hereafter 'biosolids') could be used as an organic amendment to improve soil fertility and promote crop growth; however, it is unclear how the application of biosolids affects soil greenhouse gas emissions and the mechanisms underlying these effects. Here, we conducted a 2-year field experiment on a 6-year-old hybrid poplar plantation in northern Alberta, Canada, to compare the effects of biosolids, conventional mineral fertilizer (urea), and urea + biosolids on soil CO2, CH4 N2O emissions, as well as soil chemical and microbial properties. We found that the addition of biosolids increased soil CO2 and N2O emissions by 21 and 17%, respectively, while urea addition increased their emissions by 30 and 83%, respectively. However, the addition of urea did not affect soil CO2 emissions when biosolids were also applied. The addition of biosolids and biosolids + urea increased soil dissolved organic carbon (DOC) and microbial biomass C (MBC), while urea addition and biosolids + urea addition increased soil inorganic N, available P and denitrifying enzyme activity (DEA). Furthermore, the CO2 and N2O emissions were positively, while the CH4 emissions were negatively associated with soil DOC, inorganic N, available phosphorus, MBC, microbial biomass N, and DEA. In addition, soil CO2, CH4 and N2O emissions were also strongly associated with soil microbial community composition. We conclude that the application of the combination of biosolids and chemical N fertilizer (urea) could be a beneficial approach for both the disposal and use of pulp mill wastes, by reducing greenhouse gas emissions and improving soil fertility.
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Affiliation(s)
- Xinli Chen
- Department of Renewable Resources, University of Alberta, 442 Earth Sciences Building, Edmonton, AB, T6G 2E3, Canada
| | - Barb R Thomas
- Department of Renewable Resources, University of Alberta, 442 Earth Sciences Building, Edmonton, AB, T6G 2E3, Canada
| | - Sarah Pattison
- Department of Renewable Resources, University of Alberta, 442 Earth Sciences Building, Edmonton, AB, T6G 2E3, Canada
| | - Zhengfeng An
- Department of Renewable Resources, University of Alberta, 442 Earth Sciences Building, Edmonton, AB, T6G 2E3, Canada
| | - Scott X Chang
- Department of Renewable Resources, University of Alberta, 442 Earth Sciences Building, Edmonton, AB, T6G 2E3, Canada.
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Xia N, Du E, Tang Y, Guo H. A distinctive latitudinal trend of nitrogen isotope signature across urban forests in eastern China. Glob Chang Biol 2023; 29:5666-5676. [PMID: 37555694 DOI: 10.1111/gcb.16899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2023] [Revised: 07/19/2023] [Accepted: 07/20/2023] [Indexed: 08/10/2023]
Abstract
Rapid urbanization has greatly altered nitrogen (N) cycling from regional to global scales. Compared to natural forests, urban forests receive much more external N inputs with distinctive abundances of stable N isotope (δ15 N). However, the large-scale pattern of soil δ15 N and its imprint on plant δ15 N remain less well understood in urban forests. By collecting topsoil (0-20 cm) and leaf samples from urban forest patches in nine large cities across a north-south transect in eastern China, we analyzed the latitudinal trends of topsoil C:N ratio and δ15 N as well as the correlations between tree leaf δ15 N and topsoil δ15 N. We further explored the spatial variation of topsoil δ15 N explained by corresponding climatic, edaphic, vegetation-associated, and anthropogenic drivers. Our results showed a significant increase of topsoil C:N ratio towards higher latitudes, suggesting lower N availability at higher latitudes. Topsoil δ15 N also increased significantly at higher latitudes, being opposite to the latitudinal trend of soil N availability. The latitudinal trend of topsoil δ15 N was mainly explained by mean annual temperature, mean annual precipitation, and atmospheric deposition of both ammonium and nitrate. Consequently, tree leaf δ15 N showed significant positive correlations with topsoil δ15 N across all sampled plant species and functional types. Our findings reveal a distinctive latitudinal trend of δ15 N in urban forests and highlight an important role of anthropogenic N sources in shaping the large-scale pattern of urban forest 15 N signature.
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Affiliation(s)
- Nan Xia
- State Key Laboratory of Earth Surface Processes and Resource Ecology, Faculty of Geographical Science, Beijing Normal University, Beijing, China
- School of Natural Resources, Faculty of Geographical Science, Beijing Normal University, Beijing, China
| | - Enzai Du
- State Key Laboratory of Earth Surface Processes and Resource Ecology, Faculty of Geographical Science, Beijing Normal University, Beijing, China
- School of Natural Resources, Faculty of Geographical Science, Beijing Normal University, Beijing, China
| | - Yang Tang
- State Key Laboratory of Earth Surface Processes and Resource Ecology, Faculty of Geographical Science, Beijing Normal University, Beijing, China
- School of Natural Resources, Faculty of Geographical Science, Beijing Normal University, Beijing, China
| | - Hongbo Guo
- State Key Laboratory of Earth Surface Processes and Resource Ecology, Faculty of Geographical Science, Beijing Normal University, Beijing, China
- School of Natural Resources, Faculty of Geographical Science, Beijing Normal University, Beijing, China
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5
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Chen C, Wang G, Li J, Jia Y, Chen Z. Examination of the negative correlation between leaf δ 15N and the N:P ratio across a northeast-southwest transect in China. Sci Total Environ 2023; 885:163843. [PMID: 37137362 DOI: 10.1016/j.scitotenv.2023.163843] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 04/23/2023] [Accepted: 04/26/2023] [Indexed: 05/05/2023]
Abstract
Nitrogen (N) and phosphorus (P) are two crucial limiting mineral elements for terrestrial plants. Although the leaf N:P ratio is extensively used to indicate plant nutrient limitations, the critical N:P ratios cannot be universally applied. Some investigations have suggested that leaf nitrogen isotopes (δ15N) can provide another proxy for nutrient limitations along with the N:P ratio, but the negative relationships between N:P and δ15N were mainly limited to fertilization experiments. It will obviously benefit the study of the nature of nutrient limitations if the relationship could be explained more generally. We analyzed leaf δ15N, N, and P contents across a northeast-southwest transect in China. Leaf δ15N was weakly negatively correlated with leaf N:P ratios for all plants, while there was no correlation between them for various plant groups, including different growth forms, genera, and species across the entire N:P range. This suggests that the use of leaf δ15N in indicating the shift of nutrient limitations across the whole N:P range still requires more validated field investigations. Notably, negative relationships between δ15N and N:P hold for plants with N:P ratios between 10 and 20 but not for plants with N:P ratios lower than 10 or higher than 20. That is, changes in leaf δ15N along with the N:P ratio of plants that are co-limited by N and P can exhibit variations in plant nutrient limitations, whereas plants that are strictly limited by N and P cannot. Moreover, these relationships are not altered by vegetation type, soil type, MAP, or MAT, indicating that the use of leaf δ15N in reflecting shifts in nutrient limitations, depending on the plant nutrient limitation range, is general. We examined the relationships between leaf δ15N and the N:P ratio across an extensive transect, providing references for the widespread use of leaf δ15N in reflecting shifts in nutrient limitation.
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Affiliation(s)
- Chongjuan Chen
- School of Earth System Science, Tianjin University, Tianjin 300072, China
| | - Guoan Wang
- Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, Department of Environmental Sciences and Engineering, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China
| | - Jiazhu Li
- Institute of Desertification Studies, Chinese Academy of Forestry, Beijing 100091, China; Institute of Ecological Conservation and Restoration, Chinese Academy of Forestry, Beijing 100091, China.
| | - Yufu Jia
- Center for Soil Protection and Landscape Design, Chinese Academy of Environmental Planning, Beijing 100012, China
| | - Zixun Chen
- Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, Department of Environmental Sciences and Engineering, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China
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6
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Wang Y, Niu G, Wang R, Rousk K, Li A, Hasi M, Wang C, Xue J, Yang G, Lü X, Jiang Y, Han X, Huang J. Enhanced foliar 15 N enrichment with increasing nitrogen addition rates: Role of plant species and nitrogen compounds. Glob Chang Biol 2023; 29:1591-1605. [PMID: 36515451 DOI: 10.1111/gcb.16555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2022] [Revised: 12/08/2022] [Accepted: 12/09/2022] [Indexed: 05/28/2023]
Abstract
Determining the abundance of N isotope (δ15 N) in natural environments is a simple but powerful method for providing integrated information on the N cycling dynamics and status in an ecosystem under exogenous N inputs. However, whether the input of different N compounds could differently impact plant growth and their 15 N signatures remains unclear. Here, the response of 15 N signatures and growth of three dominant plants (Leymus chinensis, Carex duriuscula, and Thermopsis lanceolata) to the addition of three N compounds (NH4 HCO3 , urea, and NH4 NO3 ) at multiple N addition rates were assessed in a meadow steppe in Inner Mongolia. The three plants showed different initial foliar δ15 N values because of differences in their N acquisition strategies. Particularly, T. lanceolata (N2 -fixing species) showed significantly lower 15 N signatures than L. chinensis (associated with arbuscular mycorrhizal fungi [AMF]) and C. duriuscula (associated with AMF). Moreover, the foliar δ15 N of all three species increased with increasing N addition rates, with a sharp increase above an N addition rate of ~10 g N m-2 year-1 . Foliar δ15 N values were significantly higher when NH4 HCO3 and urea were added than when NH4 NO3 was added, suggesting that adding weakly acidifying N compounds could result in a more open N cycle. Overall, our results imply that assessing the N transformation processes in the context of increasing global N deposition necessitates the consideration of N deposition rates, forms of the deposited N compounds, and N utilization strategies of the co-existing plant species in the ecosystem.
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Affiliation(s)
- Yinliu Wang
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, The Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Guoxiang Niu
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
| | - Ruzhen Wang
- School of Life Sciences, Hebei University, Baoding, China
| | - Kathrin Rousk
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Ang Li
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, The Chinese Academy of Sciences, Beijing, China
| | - Muqier Hasi
- College of Grassland, Resources and Environment, Inner Mongolia Agricultural University, Hohhot, China
| | - Changhui Wang
- Grassland College, Shanxi Agriculture University, Taigu, China
| | - Jianguo Xue
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, The Chinese Academy of Sciences, Beijing, China
| | - Guojiao Yang
- Erguna Forest-Steppe Ecotone Research Station, CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, China
- College of Ecology and Environment, Hainan University, Haikou, China
| | - Xiaotao Lü
- Erguna Forest-Steppe Ecotone Research Station, CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, China
| | - Yong Jiang
- School of Life Sciences, Hebei University, Baoding, China
| | - Xingguo Han
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, The Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Jianhui Huang
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, The Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
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