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Timilsina A, Neupane P, Yao J, Raseduzzaman M, Bizimana F, Pandey B, Feyissa A, Li X, Dong W, Yadav RKP, Gomez-Casanovas N, Hu C. Plants mitigate ecosystem nitrous oxide emissions primarily through reductions in soil nitrate content: Evidence from a meta-analysis. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 949:175115. [PMID: 39084361 DOI: 10.1016/j.scitotenv.2024.175115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Revised: 06/26/2024] [Accepted: 07/27/2024] [Indexed: 08/02/2024]
Abstract
Nitrous oxide (N2O) is a potent greenhouse gas (GHG) and an ozone-depleting substance. The presence of plants in an ecosystem can either increase or decrease N2O emissions, or play a negligible role in driving N2O emissions. Here, we conducted a meta-analysis comparing ecosystem N2O emissions from planted and unplanted systems to evaluate how plant presence influences N2O emissions and examined the mechanisms driving observed responses. Our results indicate that plant presence reduces N2O emissions while it increases dinitrogen (N2) emissions from ecosystems through decreases in soil nitrate concentration as well as increases in complete denitrification and mineral N immobilization. The response of N2O emissions to plant presence was universal across major terrestrial ecosystems - including forests, grassland and cropland - and it did not vary with N fertilization. Further, in light of the potential mechanisms of N2O formation in plant cells, we discussed how plant presence could enhance the emission of N2O from plants themselves. Improving our understanding of the mechanisms driving N2O emissions in response to plant presence could be beneficial for enhancing the robustness for predictions of our GHG sinks and sources and for developing strategies to minimize emissions at the ecosystem scale.
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Affiliation(s)
- Arbindra Timilsina
- Hebei Key Laboratory of Soil Ecology, Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Shijiazhuang 050021, China; Texas A&M AgriLife Research Center, Vernon 76384, TX, USA; DOE Center for Advanced Bioenergy and Bioproducts Innovation, University of Illinois, Urbana-Champaign, IL, USA
| | - Pritika Neupane
- Department of Plant Breeding and Genetics, Institute of Agriculture and Animal Science, Tribhuvan University, Nepal
| | - Jinzhi Yao
- Hebei Key Laboratory of Soil Ecology, Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Shijiazhuang 050021, China; University of Chinese Academy of Sciences, 19AYuquan Road, Beijing 100049, China
| | - Md Raseduzzaman
- Hebei Key Laboratory of Soil Ecology, Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Shijiazhuang 050021, China; University of Chinese Academy of Sciences, 19AYuquan Road, Beijing 100049, China
| | - Fiston Bizimana
- Hebei Key Laboratory of Soil Ecology, Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Shijiazhuang 050021, China; University of Chinese Academy of Sciences, 19AYuquan Road, Beijing 100049, China
| | - Bikram Pandey
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan 650201, China
| | - Adugna Feyissa
- Texas A&M AgriLife Research Center, Vernon 76384, TX, USA; DOE Center for Advanced Bioenergy and Bioproducts Innovation, University of Illinois, Urbana-Champaign, IL, USA; Key Laboratory of Soil Ecology and Health in Universities of Yunnan Province, School of Ecology and Environmental Sciences, Yunnan University, Kunming 650091, China; Institute of International Rivers and Eco-security, Yunnan University, Kunming 650091, China
| | - Xiaoxin Li
- Hebei Key Laboratory of Soil Ecology, Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Shijiazhuang 050021, China.
| | - Wenxu Dong
- Hebei Key Laboratory of Soil Ecology, Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Shijiazhuang 050021, China
| | | | - Nuria Gomez-Casanovas
- Texas A&M AgriLife Research Center, Vernon 76384, TX, USA; DOE Center for Advanced Bioenergy and Bioproducts Innovation, University of Illinois, Urbana-Champaign, IL, USA; Rangeland, Wildlife & Fisheries Management Department, Texas A&M, TX, USA.
| | - Chunsheng Hu
- Hebei Key Laboratory of Soil Ecology, Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Shijiazhuang 050021, China; University of Chinese Academy of Sciences, 19AYuquan Road, Beijing 100049, China.
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2
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Carreras Pereira KA, Wolf AA, Kou-Giesbrecht S, Akana PR, Funk JL, Menge DNL. Allometric relationships for eight species of 4-5 year old nitrogen-fixing and non-fixing trees. PLoS One 2023; 18:e0289679. [PMID: 37603572 PMCID: PMC10441808 DOI: 10.1371/journal.pone.0289679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 07/25/2023] [Indexed: 08/23/2023] Open
Abstract
Allometric equations are often used to estimate plant biomass allocation to different tissue types from easier-to-measure quantities. Biomass allocation, and thus allometric equations, often differs by species and sometimes varies with nutrient availability. We measured biomass components for five nitrogen-fixing tree species (Robinia pseudoacacia, Gliricidia sepium, Casuarina equisetifolia, Acacia koa, Morella faya) and three non-fixing tree species (Betula nigra, Psidium cattleianum, Dodonaea viscosa) grown in field sites in New York and Hawaii for 4-5 years and subjected to four fertilization treatments. We measured total aboveground, foliar, main stem, secondary stem, and twig biomass in all species, and belowground biomass in Robinia pseudoacacia and Betula nigra, along with basal diameter, height, and canopy dimensions. The individuals spanned a wide size range (<1-16 cm basal diameter; 0.24-8.8 m height). For each biomass component, aboveground biomass, belowground biomass, and total biomass, we determined the following four allometric equations: the most parsimonious (lowest AIC) overall, the most parsimonious without a fertilization effect, the most parsimonious without canopy dimensions, and an equation with basal diameter only. For some species, the most parsimonious overall equation included fertilization effects, but fertilization effects were inconsistent across fertilization treatments. We therefore concluded that fertilization does not clearly affect allometric relationships in these species, size classes, and growth conditions. Our best-fit allometric equations without fertilization effects had the following R2 values: 0.91-0.99 for aboveground biomass (the range is across species), 0.95 for belowground biomass, 0.80-0.96 for foliar biomass, 0.94-0.99 for main stem biomass, 0.77-0.98 for secondary stem biomass, and 0.88-0.99 for twig biomass. Our equations can be used to estimate overall biomass and biomass of tissue components for these size classes in these species, and our results indicate that soil fertility does not need to be considered when using allometric relationships for these size classes in these species.
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Affiliation(s)
- K. A. Carreras Pereira
- Department of Ecology, Evolution and Environmental Biology, Columbia University, New York, New York, United States of America
| | - Amelia A. Wolf
- Department of Integrative Biology, University of Texas Austin, Austin, Texas, United States of America
| | - Sian Kou-Giesbrecht
- Department of Ecology, Evolution and Environmental Biology, Columbia University, New York, New York, United States of America
- Canadian Centre for Climate Modelling and Analysis, Victoria, British Columbia, Canada
- Department of Earth and Environmental Sciences, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Palani R. Akana
- Department of Ecology, Evolution and Environmental Biology, Columbia University, New York, New York, United States of America
| | - Jennifer L. Funk
- Department of Plant Sciences, University of California, Davis, Davis, California, United States of America
| | - Duncan N. L. Menge
- Department of Ecology, Evolution and Environmental Biology, Columbia University, New York, New York, United States of America
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3
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Feng J, Song Y, Zhu B. Ecosystem-dependent responses of soil carbon storage to phosphorus enrichment. THE NEW PHYTOLOGIST 2023; 238:2363-2374. [PMID: 36960561 DOI: 10.1111/nph.18907] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Accepted: 03/14/2023] [Indexed: 05/19/2023]
Abstract
Phosphorus deposition can stimulate both plant carbon inputs and microbial carbon outputs. However, how P enrichment affects soil organic carbon (SOC) storage and the underlying mechanisms remain unclear. We conducted a meta-analysis of 642 SOC observations from 213 field P addition experiments world-wide and explored the regulations of plant inputs, microbial outputs, plant characteristics, and environmental and experimental factors on SOC responses. We found that, globally, P addition stimulated SOC by 4.0% (95% CI: 2.0-6.0%), but the stimulation only occurred in forest and cropland rather than in grassland. Across sites, the response of SOC correlated with that of plant aboveground rather than belowground biomass, suggesting that the change in plant inputs from aboveground was more important than that from belowground in regulating SOC changes due to P addition. Among multiple factors, plant N fixation status and mean annual temperature were the best predictors for SOC responses to P addition, with SOC stimulation being higher in ecosystems dominated by symbiotic nitrogen fixers and ecosystems in high-temperature regions like tropical forests. Our findings highlight the differential and ecosystem-dependent responses of SOC to P enrichment and can contribute to accurate predictions of soil carbon dynamics in a P-enriched world.
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Affiliation(s)
- Jiguang Feng
- Institute of Ecology, College of Urban and Environmental Sciences, and Key Laboratory for Earth Surface Processes of the Ministry of Education, Peking University, Beijing, 100871, China
| | - Yanjun Song
- University of Bordeaux, INRAE, BIOGECO, Pessac, 33615, France
| | - Biao Zhu
- Institute of Ecology, College of Urban and Environmental Sciences, and Key Laboratory for Earth Surface Processes of the Ministry of Education, Peking University, Beijing, 100871, China
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4
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Jager EA, Quebbeman AW, Wolf AA, Perakis SS, Funk JL, Menge DNL. Symbiotic nitrogen fixation does not stimulate soil phosphatase activity under temperate and tropical trees. Oecologia 2023; 201:827-840. [PMID: 36877257 DOI: 10.1007/s00442-023-05339-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 02/17/2023] [Indexed: 03/07/2023]
Abstract
Symbiotic nitrogen (N)-fixing plants can enrich ecosystems with N, which can alter the cycling and demand for other nutrients. Researchers have hypothesized that fixed N could be used by plants and soil microbes to produce extracellular phosphatase enzymes, which release P from organic matter. Consistent with this speculation, the presence of N-fixing plants is often associated with high phosphatase activity, either in the soil or on root surfaces, although other studies have not found this association, and the connection between phosphatase and rates of N fixation-the mechanistic part of the argument-is tenuous. Here, we measured soil phosphatase activity under N-fixing trees and non-fixing trees transplanted and grown in tropical and temperate sites in the USA: two sites in Hawaii, and one each in New York and Oregon. This provides a rare example of phosphatase activity measured in a multi-site field experiment with rigorously quantified rates of N fixation. We found no difference in soil phosphatase activity under N-fixing vs. non-fixing trees nor across rates of N fixation, though we note that no sites were P limited and only one was N limited. Our results add to the literature showing no connection between N fixation rates and phosphatase activity.
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Affiliation(s)
- Emily A Jager
- Department of Ecology, Evolution, and Environmental Biology, Columbia University, New York, NY, USA
| | - Andrew W Quebbeman
- Department of Ecology, Evolution, and Environmental Biology, Columbia University, New York, NY, USA
| | - Amelia A Wolf
- Department of Integrative Biology, University of Texas at Austin, Austin, TX, USA
| | - Steven S Perakis
- Forest and Rangeland Ecosystem Science Center, US Geological Survey, Corvallis, OR, USA
| | - Jennifer L Funk
- Department of Plant Sciences, University of California, Davis, CA, USA
| | - Duncan N L Menge
- Department of Ecology, Evolution, and Environmental Biology, Columbia University, New York, NY, USA.
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5
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Zheng J, Sakata T, Fujii K. Deciphering nitrous oxide emissions from tropical soils of different land uses. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 862:160916. [PMID: 36526175 DOI: 10.1016/j.scitotenv.2022.160916] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2022] [Revised: 12/08/2022] [Accepted: 12/09/2022] [Indexed: 06/17/2023]
Abstract
Tropical regions are hotspots of increasing greenhouse gas emissions associated with land-use change. Although many field studies have quantified soil fluxes of nitrous oxide (N2O; a potent greenhouse gas) from various land uses, the driving mechanisms remain uncertain. Here, we used tropical soils of diverse land uses and actively manipulated the soil moisture (35%, 60%, and 95% water-filled pore space [WFPS]) and substrate supply (control, nitrate, and nitrate plus glucose) to investigate the responses of N2O emissions with short-term incubations. We then identified key factors regulating N2O emissions out of a series of soil physicochemical and biological factors and explored how these factors interacted to drive N2O emissions. Land-use changes from primary forest to oil palm or Acacia plantation risks emitting more N2O, whereas low emissions could be maintained by conversion to Macaranga forest or Imperata grassland; these laboratory observations were corroborated by a literature synthesis of field N2O measurements across tropical regions. Soil redox potential (Eh) and labile organic nitrogen (LON; amino acid mixture, arginine, and urea) mineralization were among the factors with greatest influence on N2O emissions. In contrast to common understandings, the control of WFPS over N2O emissions was largely indirect, and acted through Eh. The mineralization of LON, particularly arginine, potentially played multiple roles in N2O production (e.g., bottlenecks of nitrifier-denitrification or simultaneous nitrification-denitrification versus substrate competition for co-denitrification). Structural equation models suggest that soil-environmental factors of different levels (from distal including land use, soil moisture, and pH to proximal such as LON mineralization) drive N2O emissions through cascading interactions. Overall, we show that, despite identical initial soil conditions, land conversion can substantially alter the N2O emission potential. Also, collectively considering soil-environmental regulators and their interactions associated with land conversion is crucial to predict and design mitigation strategies for N2O emissions from land-use change.
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Affiliation(s)
- Jinsen Zheng
- Forestry and Forest Products Research Institute, Tsukuba 305-8687, Japan.
| | - Tadashi Sakata
- Forestry and Forest Products Research Institute, Tsukuba 305-8687, Japan
| | - Kazumichi Fujii
- Forestry and Forest Products Research Institute, Tsukuba 305-8687, Japan.
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6
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Li M, Gu H, Lam SS, Sonne C, Peng W. Deposition-mediated phytoremediation of nitrogen oxide emissions. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 308:119706. [PMID: 35798191 DOI: 10.1016/j.envpol.2022.119706] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 06/06/2022] [Accepted: 06/29/2022] [Indexed: 06/15/2023]
Abstract
The growing global population and use of natural resources lead to significant air pollution. Nitrogen oxide emissions is a potential killer threatening human health requiring focus and remediation using vegetation being efficient and cheap. Here we review the mechanisms of removing nitrogen oxides by dry deposition of plants, discussing the principle of leaf absorption of pollutants and factors affecting the removal of nitrogen oxides providing a theoretical basis for the selection of urban greening vegetation.
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Affiliation(s)
- Mengzhen Li
- Henan Province International Collaboration Lab of Forest Resources Utilization, School of Forestry, Henan Agricultural University, Zhengzhou 450002, China
| | - Haping Gu
- Henan Province International Collaboration Lab of Forest Resources Utilization, School of Forestry, Henan Agricultural University, Zhengzhou 450002, China
| | - Su Shiung Lam
- Universiti Malaysia Terengganu, Higher Institution Centre of Excellence (HICoE), Institute of Tropical Aquaculture and Fisheries; 21030 Kuala Nerus, Terengganu, Malaysia
| | - Christian Sonne
- Aarhus University, Department of Bioscience, Arctic Research Centre (ARC), Frederiksborgvej 399, PO Box 358, DK-4000 Roskilde, Denmark
| | - Wanxi Peng
- Henan Province International Collaboration Lab of Forest Resources Utilization, School of Forestry, Henan Agricultural University, Zhengzhou 450002, China.
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7
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Yang G, Huang L, Shi Y. Magnitude and determinants of plant root hydraulic redistribution: A global synthesis analysis. FRONTIERS IN PLANT SCIENCE 2022; 13:918585. [PMID: 35937319 PMCID: PMC9355616 DOI: 10.3389/fpls.2022.918585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 06/27/2022] [Indexed: 06/15/2023]
Abstract
Plant root hydraulic redistribution (HR) has been widely recognized as a phenomenon that helps alleviate vegetation drought stress. However, a systematic assessment of the magnitude of HR and its drivers at the global scale are lacking. We collected 37 peer-reviewed papers (comprising 47 research sites) published in 1900-2018 and comprehensively analyzed the magnitude of HR and its underlying factors. We used a weighting method to analyze HR magnitude and its effect on plant transpiration. Machine learning algorithms (boosted regression trees) and structural equation modeling were used to determine the influence of each factor on HR magnitude. We found that the magnitude of HR was 0.249 mm H2O d-1 (95% CI, 0.113-0.384) and its contribution to plant transpiration was 27.4% (3-79%). HR varied significantly among different terrestrial biomes and mainly occurred in forests with drier conditions, such as temperate forest ecosystems (HR = 0.502 mm H2O d-1), where HR was significantly higher than in other ecosystems (p < 0.01). The magnitude of HR in angiosperms was significantly higher than that in gymnosperms (p < 0.05). The mean magnitude of HR first increased and then decreased with an increase in humidity index; conversely, the mean magnitude of HR decreased with an increase in water table depth. HR was significantly positively correlated with root length and transpiration. Plant characteristics and environmental factors jointly accounted for 61.0% of the variation in HR, and plant transpiration was the major factor that directly influenced HR (43.1% relative importance; p < 0.001), and soil texture was an important indirect driver of HR. Our synthesis offers a comprehensive perspective of how plant characteristics and environmental factors influence HR magnitude.
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Affiliation(s)
- Guisen Yang
- Shapotou Desert Research and Experiment Station, Northwest Institute of Eco-Environmental Resources, Chinese Academy of Sciences, Lanzhou, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Lei Huang
- Shapotou Desert Research and Experiment Station, Northwest Institute of Eco-Environmental Resources, Chinese Academy of Sciences, Lanzhou, China
| | - Yafei Shi
- Shapotou Desert Research and Experiment Station, Northwest Institute of Eco-Environmental Resources, Chinese Academy of Sciences, Lanzhou, China
- University of Chinese Academy of Sciences, Beijing, China
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8
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Qiu Q, Mgelwa AS, Jin S, Hu Y. Nitrogen-Induced Changes in Soil Environmental Factors Are More Important Than Nitrification and Denitrification Gene Abundance in Regulating N 2O Emissions in Subtropical Forest Soils. FRONTIERS IN PLANT SCIENCE 2022; 13:950367. [PMID: 35903223 PMCID: PMC9315429 DOI: 10.3389/fpls.2022.950367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/22/2022] [Accepted: 06/14/2022] [Indexed: 06/15/2023]
Abstract
Subtropical regions are currently experiencing a dramatic increase in nitrogen (N) deposition; however, the contributions of nitrification and denitrification processes to soil N2O emissions and the underlying mechanisms under increasing N deposition remain unclear. Therefore, a 15N-tracing laboratory experiment with four N application rates (0, 12.5, 25, and 50 μg 15N g-1 soil) was conducted to investigate the response of nitrification- and denitrification-derived N2O to N additions in an evergreen broad-leaved forest (BF) and a Pinus forest (PF) in the Wuyi Mountains in southeastern China. Moreover, the abundance of functional genes related to nitrification (amoA), denitrification (nirK, nirS, and nosZ), and soil properties were measured to clarify the underlying mechanisms. Results showed that nitrification-derived N2O emissions were generally decreased with increasing N input. However, denitrification-derived N2O emissions were a non-linear response to N additions, with maximum N2O emissions at the middle N application rate. Denitrification-derived N2O was the dominant pathway of N2O production, accounting for 64 to 100% of the total N2O fluxes. Soil NH4 +-N content and pH were the predominant factors in regulating nitrification-derived N2O emissions in BF and PF, respectively. Soil pH and the nirS abundance contributed the most to the variations of denitrification-derived N2O emissions in BF and PF, respectively. Our results suggest that N application has the potential to increase the contribution of denitrification to N2O production in subtropical forest soils. Changes in soil chemical properties induced by N addition are more important than the abundance of nitrification and denitrification functional genes in regulating soil nitrification- and denitrification-derived N2O emissions.
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Affiliation(s)
- Qingyan Qiu
- Forest Ecology and Stable Isotope Center, College of Forestry, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Abubakari Said Mgelwa
- College of Natural Resources Management and Tourism, Mwalimu Julius K. Nyerere University of Agriculture and Technology, Musoma, Tanzania
| | - Shaofei Jin
- Department of Geography, Minjiang University, Fuzhou, China
| | - Yalin Hu
- Forest Ecology and Stable Isotope Center, College of Forestry, Fujian Agriculture and Forestry University, Fuzhou, China
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9
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Bytnerowicz TA, Akana PR, Griffin KL, Menge DNL. Temperature sensitivity of woody nitrogen fixation across species and growing temperatures. NATURE PLANTS 2022; 8:209-216. [PMID: 35115725 DOI: 10.1038/s41477-021-01090-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 12/15/2021] [Indexed: 06/14/2023]
Abstract
The future of the land carbon sink depends on the availability of nitrogen (N)1,2 and, specifically, on symbiotic N fixation3-8, which can rapidly alleviate N limitation. The temperature response of symbiotic N fixation has been hypothesized to explain the global distribution of N-fixing trees9,10 and is a key part of some terrestrial biosphere models (TBMs)3,7,8, yet there are few data to constrain the temperature response of symbiotic N fixation. Here we show that optimal temperatures for N fixation in four tree symbioses are in the range 29.0-36.9 °C, well above the 25.2 °C optimum currently used by TBMs. The shape of the response to temperature is also markedly different to the function used by TBMs (asymmetric rather than symmetric). We also show that N fixation acclimates to growing temperature (hence its range of optimal temperatures), particularly in our two tropical symbioses. Surprisingly, optimal temperatures were 5.2 °C higher for N fixation than for photosynthesis, suggesting that plant carbon and N gain are decoupled with respect to temperature. These findings may help explain why N-fixing tree abundance is highest where annual maximum temperatures are >35 °C (ref. 10) and why N-fixing symbioses evolved during a warm period in the Earth's history11,12. Everything else being equal, our findings indicate that climate warming will probably increase N fixation, even in tropical ecosystems, in direct contrast to past projections8.
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Affiliation(s)
- Thomas A Bytnerowicz
- Department of Ecology, Evolution and Environmental Biology, Columbia University, New York, NY, USA.
- Department of Integrative Biology, University of Texas at Austin, Austin, TX, USA.
| | - Palani R Akana
- Department of Ecology, Evolution and Environmental Biology, Columbia University, New York, NY, USA
| | - Kevin L Griffin
- Department of Ecology, Evolution and Environmental Biology, Columbia University, New York, NY, USA
- Department of Earth and Environmental Sciences, Columbia University, Palisades, NY, USA
| | - Duncan N L Menge
- Department of Ecology, Evolution and Environmental Biology, Columbia University, New York, NY, USA
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10
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Kou-Giesbrecht S, Funk JL, Perakis SS, Wolf AA, Menge DNL. N supply mediates the radiative balance of N 2 O emissions and CO 2 sequestration driven by N-fixing vs. non-fixing trees. Ecology 2021; 102:e03414. [PMID: 34041747 DOI: 10.1002/ecy.3414] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 04/05/2021] [Accepted: 05/10/2021] [Indexed: 11/11/2022]
Abstract
Forests are a significant CO2 sink. However, CO2 sequestration in forests is radiatively offset by emissions of nitrous oxide (N2 O), a potent greenhouse gas, from forest soils. Reforestation, an important strategy for mitigating climate change, has focused on maximizing CO2 sequestration in plant biomass without integrating N2 O emissions from soils. Although nitrogen (N)-fixing trees are often recommended for reforestation because of their rapid growth on N-poor soil, they can stimulate significant N2 O emissions from soils. Here, we first used a field experiment to show that a N-fixing tree (Robinia pseudoacacia) initially mitigated climate change more than a non-fixing tree (Betula nigra). We then used our field data to parameterize a theoretical model to investigate these effects over time. Under lower N supply, N-fixers continued to mitigate climate change more than non-fixers by overcoming N limitation of plant growth. However, under higher N supply, N-fixers ultimately mitigated climate change less than non-fixers by enriching soil N and stimulating N2 O emissions from soils. These results have implications for reforestation, suggesting that N-fixing trees are more effective at mitigating climate change at lower N supply, whereas non-fixing trees are more effective at mitigating climate change at higher N supply.
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Affiliation(s)
- Sian Kou-Giesbrecht
- Department of Ecology, Evolution, and Environmental Biology, Columbia University, New York, New York, 10027, USA
| | - Jennifer L Funk
- Department of Plant Sciences, University of California, Davis, California, 95616, USA
| | - Steven S Perakis
- Forest and Rangeland Ecosystem Science Center, United States Geological Survey, Corvallis, Oregon, 97331, USA
| | - Amelia A Wolf
- Department of Integrative Biology, University of Texas, Austin, Texas, 78712, USA
| | - Duncan N L Menge
- Department of Ecology, Evolution, and Environmental Biology, Columbia University, New York, New York, 10027, USA
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11
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Kou-Giesbrecht S, Menge DNL. Nitrogen-fixing trees increase soil nitrous oxide emissions: a meta-analysis. Ecology 2021; 102:e03415. [PMID: 34042181 DOI: 10.1002/ecy.3415] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 04/30/2021] [Accepted: 05/10/2021] [Indexed: 01/15/2023]
Abstract
Nitrogen-fixing trees are an important nitrogen source to terrestrial ecosystems. While they can fuel primary production and drive carbon dioxide sequestration, they can also potentially stimulate soil emissions of nitrous oxide, a potent greenhouse gas. However, studies on the influence of nitrogen-fixing trees on soil nitrous oxide emissions have not been quantitatively synthesized. Here, we show in a meta-analysis that nitrogen-fixing trees more than double soil nitrous oxide emissions relative to non-fixing trees and soils. If planted in reforestation projects at the global scale, nitrogen-fixing trees could increase global soil nitrous oxide emissions from natural terrestrial ecosystems by up to 4.1%, offsetting climate change mitigation via reforestation by up to 4.4%.
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Affiliation(s)
- Sian Kou-Giesbrecht
- Department of Ecology, Evolution and Environmental Biology, Columbia University, New York, New York, 10027, USA
| | - Duncan N L Menge
- Department of Ecology, Evolution and Environmental Biology, Columbia University, New York, New York, 10027, USA
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