Magnitude and Edaphic Controls of Nitrous Oxide Fluxes in Natural Forests at Different Scales

Forest nitrous oxide (N2O) emission plays an important role in the greenhouse gas budget of forest ecosystems. However, spatial variability in N2O fluxes complicates the determination of key factors of N2O fluxes at different scales. Based on an updated database of N2O fluxes and the main edaphic factors of global forests, the magnitude of N2O fluxes from forests and the relationships between edaphic factors and N2O fluxes at different scales were analyzed. According to the results, the average annual N2O flux of the global forest was 142.91 ± 14.1 mg N m−2 year−1. The range of total forest estimated N2O emission was 4.45–4.69 Tg N in 2000. N2O fluxes from forests with different leaf traits (broadleaved and coniferous) have significant differences in magnitude, whereas the leaf habit (evergreen and deciduous) was an important characteristic reflecting different patterns of N2O seasonal variations. The main factors affecting N2O fluxes on the global scale were ammonium (NH4+) and nitrate (NO3−) concentrations. With an increasing scale (from the site scale to the regional scale to the global scale), the explanatory power of the five edaphic factors to N2O flux decreased gradually. In addition, the response curves of N2O flux to edaphic factors were diversified among different scales. At both the global and regional scales, soil hydrothermal condition (water filled pore space (WFPS) and soil temperature) might not be the main spatial regulation for N2O fluxes, whereas soil nutrient factors (particularly NO3− concentration) could contribute more on N2O flux spatial variations. The results of site-control analysis demonstrated that there were high spatial heterogeneity of the main N2O controls, showing N2O fluxes from low latitude forests being more likely associated with soil WFPS and temperature. Thus, our findings provide valuable insights into the regulatory edaphic factors underlying the variability in N2O emissions, when modeling at different scales.

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Nitrous oxide emission from highland winter wheat field after long-term fertilization

Biogeosciences Discussions ◽

10.5194/bgd-7-4539-2010 ◽

2010 ◽

Vol 7 (3) ◽

pp. 4539-4563 ◽

Cited By ~ 2

Author(s):

X. R. Wei ◽

M. D. Hao ◽

X. H. Xue ◽

P. Shi ◽

A. Wang ◽

...

Keyword(s):

Nitrous Oxide ◽

Winter Wheat ◽

N2o Emission ◽

N Fertilizer ◽

N2o Emissions ◽

N2o Flux ◽

Mineral N ◽

Wheat Field ◽

N2o Fluxes ◽

Nitrogen Phosphorus

Abstract. Nitrous oxide (N2O) is an important greenhouse gas. N2O emissions from soils vary with fertilization and cropping practices. The response of N2O emission to fertilization of agricultural soils plays an important role in global N2O emission. The objective of this study was to assess the seasonal pattern of N2O fluxes and the annual N2O emissions from a rain-fed winter wheat (Triticum aestivum L.) field in the Loess Plateau of China. A static flux chamber method was used to measure soil N2O fluxes from 2006 to 2008. The study included 5 treatments with 3 replications in a randomized complete block design. Prior to initiating N2O measurements the treatments had received the same fertilization for 22 years. The fertilizer treatments were unfertilized control (CK), manure (M), nitrogen (N), nitrogen + phosphorus (NP), and nitrogen + phosphorus + manure (NPM). Soil N2O fluxes in the highland winter wheat field were highly variable temporally and thus were fertilization dependent. The highest fluxes occurred in the warmer and wetter seasons. Relative to CK, M slightly increased N2O flux while N, NP and NPM treatments significantly increased N2O fluxes. The fertilizer induced increase in N2O flux occurred mainly in the first 30 days after fertilization. The increases were smaller in the relatively warm and dry year than in the cold and wet year. Combining phosphorous and/or manure with mineral N fertilizer partly offset the nitrogen fertilizer induced increase in N2O flux. N2O fluxes at the seedling stage were mainly controlled by nitrogen fertilization, while fluxes at other plant growth stages were influenced by plant and environmental conditions. The cumulative N2O emissions were always higher in the fertilized treatments than in the non-fertilized treatment (CK). Mineral and manure nitrogen fertilizer enhanced N2O emissions in wetter years compared to dryer years. Phosphorous fertilizer offset 0.78 and 1.98 kg N2O ha−1 increases, while manure + phosphorous offset 0.67 and 1.64 kg N2O ha−1 increases by N fertilizer for the two observation years. Our results suggested that the contribution of single N fertilizer on N2O emission was larger than that of NP and NPM and that manure and phosphorous had important roles in offsetting mineral N fertilizer induced N2O emissions. Relative to agricultural production and N2O emission, manure fertilization (M) should be recommended while single N fertilization (N) should be avoided for the highland winter wheat due to the higher biomass and grain yield and less N2O flux and annual emission in M than in N.

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Nitrous oxide emission from highland winter wheat field after long-term fertilization

Biogeosciences ◽

10.5194/bg-7-3301-2010 ◽

2010 ◽

Vol 7 (10) ◽

pp. 3301-3310 ◽

Cited By ~ 30

Author(s):

X. R. Wei ◽

M. D. Hao ◽

X. H. Xue ◽

P. Shi ◽

R. Horton ◽

...

Keyword(s):

Nitrous Oxide ◽

Winter Wheat ◽

N2o Emission ◽

N Fertilizer ◽

N2o Emissions ◽

N2o Flux ◽

Mineral N ◽

Wheat Field ◽

N2o Fluxes ◽

Nitrogen Phosphorus

Abstract. Nitrous oxide (N2O) is an important greenhouse gas. N2O emissions from soils vary with fertilization and cropping practices. The response of N2O emission to fertilization of agricultural soils plays an important role in global N2O emission. The objective of this study was to assess the seasonal pattern of N2O fluxes and the annual N2O emissions from a rain-fed winter wheat (Triticum aestivum L.) field in the Loess Plateau of China. A static flux chamber method was used to measure soil N2O fluxes from 2006 to 2008. The study included 5 treatments with 3 replications in a randomized complete block design. Prior to initiating N2O measurements the treatments had received the same fertilization for 22 years. The fertilizer treatments were unfertilized control (CK), manure (M), nitrogen (N), nitrogen + phosphorus (NP), and nitrogen + phosphorus + manure (NPM). Soil N2O fluxes in the highland winter wheat field were highly variable temporally and thus were fertilization dependent. The highest fluxes occurred in the warmer and wetter seasons. Relative to CK, m slightly increased N2O flux while N, NP and NPM treatments significantly increased N2O fluxes. The fertilizer induced increase in N2O flux occurred mainly in the first 30 days after fertilization. The increases were smaller in the relatively warm and dry year than in the cold and wet year. Combining phosphorous and/or manure with mineral N fertilizer partly offset the nitrogen fertilizer induced increase in N2O flux. N2O fluxes at the seedling stage were mainly controlled by nitrogen fertilization, while fluxes at other plant growth stages were influenced by plant and environmental conditions. The cumulative N2O emissions were always higher in the fertilized treatments than in the non-fertilized treatment (CK). Mineral and manure nitrogen fertilizer enhanced N2O emissions in wetter years compared to dryer years. Phosphorous fertilizer offset 0.50 and 1.26 kg N2O-N ha−1 increases, while manure + phosphorous offset 0.43 and 1.04 kg N2O-N ha−1 increases by N fertilizer for the two observation years. Our results suggested that the contribution of single N fertilizer on N2O emission was larger than that of NP and NPM and that manure and phosphorous had important roles in offsetting mineral N fertilizer induced N2O emissions. Relative to agricultural production and N2O emission, manure fertilization (M) should be recommended while single N fertilization (N) should be avoided for the highland winter wheat due to the higher biomass and grain yield and lower N2O flux and annual emission in m than in N.

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Nitrate and dissolved nitrous oxide in groundwater within cropped fields and riparian buffers

Biogeosciences Discussions ◽

10.5194/bgd-6-651-2009 ◽

2009 ◽

Vol 6 (1) ◽

pp. 651-685 ◽

Cited By ~ 17

Author(s):

D.-G. Kim ◽

T. M. Isenhart ◽

T. B. Parkin ◽

R. C. Schultz ◽

T. E. Loynachan

Keyword(s):

Nitrous Oxide ◽

N2o Emission ◽

Riparian Buffers ◽

Riparian Buffer ◽

N2o Emissions ◽

Cool Season ◽

N2o Flux ◽

Crop Fields ◽

Ipcc Methodology ◽

Cool Season Grass

Abstract. Transport and fate of dissolved nitrous oxide (N2O) in groundwater and its significance to nitrogen dynamics within agro-ecosystems are poorly known in spite of significant potential of N2O to global warming and ozone depletion. Increasing denitrification in riparian buffers may trade a reduction in nitrate (NO3−) transport to surface waters for increased N2O emissions resulting from denitrification-produced N2O dissolved in groundwater being emitted into the air when groundwater flows into a stream or a river. This study quantifies the transport and fate of NO3− and dissolved N2O moving from crop fields through riparian buffers, assesses whether groundwater exported from crop fields and riparian buffers is a significant source of dissolved N2O emissions, and evaluates the Intergovernmental Panel on Climate Change (IPCC) methodology to estimate dissolved N2O emission. We measured concentrations of NO3−; chloride (Cl−); pH; dissolved N2O, dissolved oxygen (DO), and organic carbon (DOC) in groundwater under a multi-species riparian buffer, a cool-season grass filter, and adjacent crop fields located in the Bear Creek watershed in central Iowa, USA. In both the multi-species riparian buffer and the cool-season grass filter, concentrations of dissolved N2O in the groundwater did not change as it passed through the sites, even when the concentrations of groundwater NO3− were decreased by 50% and 59%, respectively, over the same periods. The fraction of N lost to leaching and runoff (0.05) and the modified N2O emission factor, [ratio of dissolved N2O flux to N input (0.00002)] determined for the cropped fields indicate that the current IPCC methodology overestimates dissolved N2O flux in the sites. A low ratio between dissolved N2O flux and soil N2O emission (0.0003) was estimated in the cropped fields. These results suggest that the riparian buffers established adjacent to crop fields for water quality functions (enhanced denitrification) decreased NO3− and were not a source of dissolved N2O. Also, the flux of dissolved N2O from the cropped field was negligible in comparison to soil N2O emission in the crop fields.

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Nitrous oxide fluxes from tropical peat with different disturbance history and management

Biogeosciences Discussions ◽

10.5194/bgd-8-5423-2011 ◽

2011 ◽

Vol 8 (3) ◽

pp. 5423-5450 ◽

Cited By ~ 3

Author(s):

J. Jauhiainen ◽

H. Silvennoinen ◽

R. Hämäläinen ◽

K. Kusin ◽

S. Limin ◽

...

Keyword(s):

Nitrous Oxide ◽

Greenhouse Gas ◽

N2o Emissions ◽

Monitoring Methods ◽

N2o Flux ◽

Swamp Forest ◽

Closed Chamber ◽

Tropical Peat ◽

C Stocks ◽

N2o Fluxes

Abstract. Tropical peatlands are one of the most important terrestrial ecosystems in terms of C stocks, and greenhouse gas emissions following disturbances such as deforestation, drainage or wildfire. Nitrous oxide dynamics in tropical peat systems is still poorly known. We quantified in situ N2O fluxes using closed chamber methods and compared them with CO2 and CH4 fluxes at sites representing differing land uses and land use change intensities, i.e. non-drained and drained selectively logged peat swamp forest, clear-felled drained recovering forest, deforested drained and burned peat, and agriculture on peat. The mean N2O flux rates (N2O-N ± SD, mg m−2 h−1) varied as follows: drained forest (0.112 ± 0.293) > agricultural peat in Kalampangan site (0.012 ± 0.026) > drained burned peat (0.011 ± 0.018) > agricultural peat in Marang site (0.0072 ± 0.028) > nondrained forest (0.0025 ± 0.053) > clear-felled drained recovering forest (0.0022 ± 0.021). Most N2O fluxes were < 0.05 mg N2O-N m−2 h−1 efflux, but some modest peat N2O influx readings were also detected. Many very high flux rates (deviating markedly from the majority of observations) occurred both spatially and over time, and further studies using continuous flux monitoring methods are needed to better understand the contribution of these to cumulative emissions. The widest N2O flux amplitude was detected in the drained forest with moderately drained peat (max. 2.312 and min. −0.043 mg N2O-N m−2 h−1. At the other sites the flux amplitude remained about 10 × smaller. Annual cumulative peat surface N2O emissions expressed as CO2 equivalents as a percentage of the total greenhouse gas (N2O, CO2 and CH4) emissions was at the highest 9.2 %, but typically ~1 %.

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Nitrous oxide emission factor from cattle urine and dung in native grassland of the Pampa biome, South Brazil

Soil Research ◽

10.1071/sr19095 ◽

2020 ◽

Vol 58 (2) ◽

pp. 198 ◽

Cited By ~ 1

Author(s):

Janquieli Schirmann ◽

Diego Fernandes de Bastos ◽

Douglas Adams Weiler ◽

Murilo G. Veloso ◽

Jeferson Dieckow ◽

...

Keyword(s):

Nitrous Oxide ◽

Emission Factor ◽

Live Weight ◽

N2o Emission ◽

N2o Emissions ◽

Native Grassland ◽

Tier 1 ◽

N2o Fluxes ◽

The Impact ◽

South Brazil

Native grassland supports extensive livestock production in the Pampas of South America, but the impact of cattle excreta on nitrous oxide (N2O) emissions remains unknown in this biome. The objective of this study was to determine the N2O emission factor (EF-N2O, % of N applied that is emitted as N2O) for urine and dung from beef cattle grazing on native grasslands. A field trial was conducted under low and moderate forage allowances (FA4 and FA12; i.e. 4 and 12 kg dry matter/100 kg live weight respectively) during the 30th year of a long-term grassland experiment on a Typic Paleudult in South Brazil. Urine and dung were applied onto separate patches, at rates equivalent to one average urination or defecation; and N2O fluxes were monitored with closed static chambers over 338 days. In adjacent microplots receiving the same excreta treatment, water-filled pore space, nitrate, ammonium and extractable dissolved organic carbon were monitored in the top 0.1 m of soil. Averaged across the forage allowances, daily soil N2O fluxes were low in the control without excreta (1.3 g N ha–1), but increased upon application of dung (3.8 g N ha–1) and urine (66 g N ha–1). The annual N2O emission and the EF-N2O for urine were greater under FA12 than FA4, but no difference was observed for dung. The positive relationships between N2O-N emissions and ammonium intensity and nitrate intensity suggest that N2O may have been produced concurrently by nitrification, nitrifier/denitrification and denitrification. On average, the EF-N2O was almost 10 times higher for urine than for dung (0.74% vs 0.08%), both much lower than the IPCC’s Tier 1 default value of 2%. Our findings reinforce the need for disaggregating the EF-N2O for urine and dung and of revising the IPCC’s Tier 1 EF-N2O.

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Nitrous oxide emissions from crop rotations including wheat, rapeseed and dry pea

Biogeosciences Discussions ◽

10.5194/bgd-9-9289-2012 ◽

2012 ◽

Vol 9 (7) ◽

pp. 9289-9314 ◽

Cited By ~ 4

Author(s):

M. H. Jeuffroy ◽

E. Baranger ◽

B. Carrouée ◽

E. de Chezelles ◽

M. Gosme ◽

...

Keyword(s):

Oilseed Rape ◽

Ghg Emissions ◽

Global Scale ◽

N2o Emission ◽

Nitrous Oxide Emissions ◽

N2o Emissions ◽

N Fixation ◽

Biological Fixation ◽

Mineral N ◽

N2o Fluxes

Abstract. Approximately 65% of anthropogenic emissions of N2O, a potent greenhouse gas, originate from soils at global scale, and particularly after N fertilisation of the main crops in Europe. Thanks to their capacity to fix atmospheric N2 through biological fixation, legumes allow to reduce N fertilizer use, and possibly N2O emission. Nevertheless, the decomposition of crop organic matter during the crop cycle and during the residue decomposition, and possibly the N fixation process itself, could lead to N2O emissions. The objective of this study was to quantify N2O emissions from a dry pea crop (Pisum sativum, harvested at maturity) and from the subsequent crops in comparison with N2O emissions from wheat and oilseed-rape crops, fertilized or not, in various rotations. A field experiment was conducted during 4 consecutive years, aiming at comparing the emissions during the pea crop, in comparison with those during the wheat (fertilized or not) or oilseed rape crops, and after the pea crop, in comparison with other preceding crops. N2O fluxes were measured using static chambers. In spite of low N2O fluxes, mainly linked with the site soil characteristics, fluxes during the crop were significantly lower for pea and unfertilized wheat than for fertilized wheat and oilseed rape. The effect of the preceding crop was not significant, while soil mineral N at harvest was higher after pea. These results, combined with the emission reduction allowed by the production and transport of the N fertiliser not applied on the pea crop, should be confirmed in a larger range of soil types. Nevertheless, they demonstrate the absence of N2O emission linked to the symbiotic N fixation process, and allow us to estimate the decrease of N2O emissions to 20–25% by including one pea crop in a three-year rotation. At a larger scale, this reduction of GHG emissions at field level has to be cumulated with the reduction of GHG emissions linked with the lower level of production and transport of the N fertiliser not applied on the pea crop.

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Management matters: testing a mitigation strategy for nitrous oxide emissions using legumes on intensively managed grassland

Biogeosciences ◽

10.5194/bg-15-5519-2018 ◽

2018 ◽

Vol 15 (18) ◽

pp. 5519-5543 ◽

Cited By ~ 21

Author(s):

Kathrin Fuchs ◽

Lukas Hörtnagl ◽

Nina Buchmann ◽

Werner Eugster ◽

Val Snow ◽

...

Keyword(s):

Nitrous Oxide ◽

N2o Emission ◽

Mitigation Strategy ◽

Nitrous Oxide Emissions ◽

Plant Residues ◽

N2o Emissions ◽

Fixed Nitrogen ◽

Biomass Yields ◽

N2o Fluxes ◽

Intensively Managed

Abstract. Replacing fertiliser nitrogen with biologically fixed nitrogen (BFN) through legumes has been suggested as a strategy for nitrous oxide (N2O) mitigation from intensively managed grasslands. While current literature provides evidence for an N2O emission reduction effect due to reduced fertiliser input, little is known about the effect of increased legume proportions potentially offsetting these reductions, i.e. by increased N2O emissions from plant residues and root exudates. In order to assess the overall effect of this mitigation strategy on permanent grassland, we performed an in situ experiment and quantified net N2O fluxes and biomass yields in two differently managed grass–clover mixtures. We measured N2O fluxes in an unfertilised parcel with high clover proportions vs. an organically fertilised control parcel with low clover proportions using the eddy covariance (EC) technique over 2 years. Furthermore, we related the measured N2O fluxes to management and environmental drivers. To assess the effect of the mitigation strategy, we measured biomass yields and quantified biologically fixed nitrogen using the 15N natural abundance method. The amount of BFN was similar in both parcels in 2015 (control: 55±5 kg N ha−1 yr−1; clover parcel: 72±5 kg N ha−1 yr−1) due to similar clover proportions (control: 15 % and clover parcel: 21 %), whereas in 2016 BFN was substantially higher in the clover parcel compared to the much lower control (control: 14±2 kg N ha−1 yr−1 with 4 % clover in DM; clover parcel: 130±8 kg N ha−1 yr−1 and 44 % clover). The mitigation management effectively reduced N2O emissions by 54 % and 39 % in 2015 and 2016, respectively, corresponding to 1.0 and 1.6 t ha−1 yr−1 CO2 equivalents. These reductions in N2O emissions can be attributed to the absence of fertilisation on the clover parcel. Differences in clover proportions during periods with no recent management showed no measurable effect on N2O emissions, indicating that the decomposition of plant residues and rhizodeposition did not compensate for the effect of fertiliser reduction on N2O emissions. Annual biomass yields were similar under mitigation management, resulting in a reduction of N2O emission intensities from 0.42 g N2O-N kg−1 DM (control) to 0.28 g N2O-N kg−1 DM (clover parcel) over the 2-year observation period. We conclude that N2O emissions from fertilised grasslands can be effectively reduced without losses in yield by increasing the clover proportion and reducing fertilisation.

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Management matters: Testing a mitigation strategy for nitrous oxide emissions on intensively managed grassland

10.5194/bg-2018-192 ◽

2018 ◽

Cited By ~ 2

Author(s):

Kathrin Fuchs ◽

Lukas Hörtnagl ◽

Nina Buchmann ◽

Werner Eugster ◽

Valerie Snow ◽

...

Keyword(s):

Nitrous Oxide ◽

N2o Emission ◽

Mitigation Strategy ◽

Nitrous Oxide Emissions ◽

Environmental Drivers ◽

Plant Residues ◽

N2o Emissions ◽

Biomass Yields ◽

N2o Fluxes ◽

Intensively Managed

Abstract. Replacing fertilizer nitrogen with biological nitrogen fixation (BNF) through legumes has been suggested as a strategy for nitrous oxide (N2O) mitigation from intensively managed grasslands. While current literature provides evidence for an N2O emission reduction effect due to reduced fertilizer input, little is known about the effect of increased legume proportions potentially offsetting these reductions, i.e. by increased N2O emissions from plant residues and root exudates. In order to assess the overall effect of this mitigation strategy on permanent grassland, we performed an in-situ experiment to quantify net N2O fluxes and biomass yields in two differently managed grass-clover mixtures. We measured N2O fluxes in an unfertilized parcel with high clover proportions vs. a fertilized control parcel with low clover proportions using the eddy–covariance (EC) technique over two years. Furthermore, we related the measured N2O fluxes to management and environmental drivers. To assess the effect of the mitigation strategy, we measured biomass yields and quantified biologically fixed nitrogen using the 15N natural abundance method. The mitigation management effectively reduced N2O emissions by 54 % and 39 % in 2015 and 2016, respectively. These reductions in N2O emissions can be attributed to the absence of fertilization on the clover parcel. Differences in clover proportions during periods with no recent management showed no measurable effect on N2O emissions, indicating that decomposition of plant residues and rhizodeposition did not compensate the effect of fertilizer reduction on N2O emissions. Annual biomass yields were similar under mitigation management, resulting in a reduction of N2O emission intensities from 0.42 g N2O-N kg−1 DM (control) to 0.28 g N2O-N kg−1 DM (clover parcel) over the two years observation period. We conclude that N2O emissions from fertilized grasslands can be effectively reduced without losses in yield by increasing the clover proportion and reducing fertilization.

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Nitrous oxide fluxes from tropical peat with different disturbance history and management

Biogeosciences ◽

10.5194/bg-9-1337-2012 ◽

2012 ◽

Vol 9 (4) ◽

pp. 1337-1350 ◽

Cited By ~ 25

Author(s):

J. Jauhiainen ◽

H. Silvennoinen ◽

R. Hämäläinen ◽

K. Kusin ◽

S. Limin ◽

...

Keyword(s):

Nitrous Oxide ◽

Greenhouse Gas ◽

Nitrogen Availability ◽

N2o Emissions ◽

Forest Site ◽

N2o Flux ◽

Water Tables ◽

Tropical Peatlands ◽

Peat Surface ◽

N2o Fluxes

Abstract. Tropical peatlands are one of the most important terrestrial ecosystems in terms of impact on the atmospheric greenhouse gas composition. Currently, greenhouse gas emissions from tropical peatlands following disturbances due to deforestation, drainage or wildfire are substantial. We quantified in situ nitrous oxide (N2O) fluxes during both dry and wet seasons using a closed chamber method at sites that represented differing land uses and land use change intensities in Central Kalimantan, Indonesia. Cumulative N2O fluxes were compared with carbon dioxide (CO2) and methane (CH4) fluxes. The mean N2O flux rates (N2O-N &plusmn: SD, mg m−2 h−1) varied as follows: drained forest (0.112 ± 0.293) > agricultural peat at the Kalampangan site (0.012 ± 0.026) > drained burned peat (0.011 ± 0.018) > agricultural peat at the Marang site (0.0072 ± 0.028) > undrained forest (0.0025 ± 0.053) > clear-felled, drained, recovering forest (0.0022 ± 0.021). The widest N2O flux range was detected in the drained forest (max. 2.312 and min. −0.043 mg N2O-N m−2 h−1). At the other flux monitoring sites the flux ranges remained at about one tenth that of the drained forest site. The highest N2O emission rates were observed at water tables close to the peat surface where also the flux range was widest. Annual cumulative peat surface N2O emissions (expressed in CO2 equivalents as a percentage of the total greenhouse gas (N2O, CO2 and CH4) emissions) were 9.2 % at highest, but typically ~1 %. Average N2O fluxes and also the total of monitored GHG emissions were highest in drainage-affected forest which is characterized by continuous labile nitrogen availability from vegetation, and water tables typically below the surface.

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Warming Increases Nitrous Oxide Emission from the Littoral Zone of Lake Poyang, China

Sustainability ◽

10.3390/su12145674 ◽

2020 ◽

Vol 12 (14) ◽

pp. 5674

Author(s):

Junxiang Cheng ◽

Ligang Xu ◽

Mingliang Jiang ◽

Jiahu Jiang ◽

Yanxue Xu

Keyword(s):

Nitrous Oxide ◽

Soil Moisture ◽

Littoral Zone ◽

Abiotic Factors ◽

Growing Season ◽

N2o Emission ◽

N2o Emissions ◽

N2o Flux ◽

Lake Poyang ◽

Littoral Wetlands

Littoral wetlands are globally important for sustainable development; however, they have recently been identified as critical hotspots of nitrous oxide (N2O) emissions. N2O flux from subtropical littoral wetlands remains unclear, especially under the current global warming environment. In the littoral zone of Lake Poyang, a simulated warming experiment was conducted to investigate N2O flux. Open-top chambers were used to raise temperature, and the static chamber-gas chromatograph method was used to measure N2O flux. Results showed that the littoral zone of Lake Poyang was an N2O source, with an average flux rate of 8.9 μg N2O m−2 h−1. Warming significantly increased N2O emission (13.8 μg N2O m−2 h−1 under warming treatment) by 54% compared to the control treatment. N2O flux in the spring growing season was also significantly higher than that of the autumn growing season. In addition, temperature was not significantly related to N2O flux, while soil moisture only explained about 7% of N2O variation. These results imply that N2O emission experiences positive feedback effect on the ongoing warming of the climate, and abiotic factors (e.g., soil temperature and soil moisture) were not main controls on N2O variation in this littoral wetland.

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