Nitrous oxide emission from the littoral zones of the Miyun Reservoir near Beijing, China

Large dams may be substantial contributors to greenhouse gas emissions. Nitrous oxide (N2O) is the third most important greenhouse gas but studies on N2O emission from reservoirs are limited. We measured N2O emissions and environmental factors including atmospheric pressure, wind speed, air and soil/sediment temperature, biomass, soil water content and organic matter, total nitrogen, NH4+-N and NO3−-N of soil, from the littoral zones of the Miyun Reservoir, near Beijing, China, in January, May, June, August, and October during 2009 and 2010. Using the static chamber method we investigated the seasonal and spatial variation, relating it to environmental factors. Spatial and temporal variations in N2O flux appeared to be influenced by several environmental factors, working singly or in conjunction, including soil water depth, soil nutrition, biomass, and wind speed. In winter and spring, high N2O emissions (up to 1.9 ± 0.6 mg N2O m−2 h−1) were recorded at both eulittoral and infralittoral zones, while the flux from the supralittoral zone was low during all the seasons (from −0.04 to 0.01 mg N2O m−2 h−1). This study suggests that the littoral zone is a substantial source of N2O. However, its spatiotemporal variation and environmental drivers are still not clear.

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Toward Modeling of Nitrous Oxide Emissions Following Precipitation, Urine, and Feces Deposition on Beef Cattle Feedyard Surfaces

Transactions of the ASABE ◽

10.13031/trans.13847 ◽

2020 ◽

Vol 63 (5) ◽

pp. 1371-1384

Author(s):

David B. Parker ◽

Kenneth D. Casey ◽

Kristin E. Hales ◽

Heidi M. Waldrip ◽

Byeng Min ◽

...

Keyword(s):

Nitrous Oxide ◽

Beef Cattle ◽

Greenhouse Gas ◽

Empirical Modeling ◽

Nitrous Oxide Emissions ◽

N2o Emissions ◽

List Type ◽

Equivalent Mass ◽

Fresh Feces ◽

Feces Deposition

HighlightsNitrous oxide is a greenhouse gas emitted from feedyard pen surfaces.Experiments were conducted to quantify nitrous oxide emissions from precipitation, urine, and feces.Nitrous oxide emissions from urine were about 30% of those from equal amounts of precipitation.Regression equations were developed for empirical modeling of emissions.Abstract. The amount of moisture deposited annually as urine (~320 mm) and feces (~95 mm) on typical semi-arid Texas beef cattle feedyard pens is considerable compared to the regional 470 mm mean annual precipitation. Precipitation is a primary factor affecting nitrous oxide (N2O) emissions from manure, but specific effects of urine and feces deposition are unknown. The objectives of this research were to (1) quantify N2O emissions following precipitation, urine, and feces deposition on a dry feedyard manure surface, and (2) develop equations for future empirical modeling of these emissions. Four experiments (Exp.) were conducted using recirculating flux chambers to quantify N2O emissions. Exp. 1 had treatments (TRT) of water (W), artificial urine (AU), and two urines collected from beef cattle fed high-quality forage (FU) or corn-based concentrate (CU). Exp. 2 had TRT of W, AU, and two feces levels (Fx1 and Fx2). In Exp. 3, N2O emissions were quantified from fresh feces pats. In Exp. 4, the effect of rainfall pH on N2O emissions was evaluated. Results from Exp. 1 showed that the W TRT had the highest mean cumulative N2O emission, while AU, FU, and CU ranged from 31.0% to 70.0% of W on an equal volume-applied basis. There was little correlation between N2O emissions and urine or water nitrogen (N) content. In Exp. 2, W again had the highest cumulative N2O. Cumulative N2O emissions expressed per unit of water added were 29.0, 3.8, 4.5, and 5.1 mg N kg-1 water added for W, AU, Fx1, and Fx2, respectively. In Exp. 3, fresh feces pats emitted no direct N2O, but N2O originated from the dry manure beneath the feces pat due to wetting. In Exp. 4, the highest N2O emissions occurred at pH 5 and pH 8, with lower emissions at pH 6 and pH 7. This research has shown that the addition of moisture to the pen surface from urine and feces contributes considerably to N2O emissions as compared to precipitation alone. The following recommendations were developed for future empirical modeling purposes: (1) N2O emissions from urine should be calculated as 32.7% of those emissions from the equivalent mass deposition of water, and (2) N2O emissions resulting from the mass of water in feces should be calculated as 15.6% of those emissions from the equivalent mass deposition of water. Keywords: Beef cattle, Greenhouse gas, Manure, Nitrous oxide, Urine, Precipitation.

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Multi-site Sensitivity analysis of DNDCv.Can model to predict N2O emissions from German croplands with maize, rapeseed and wheat

10.5194/egusphere-egu21-16306 ◽

2021 ◽

Author(s):

Jarno Rouhiainen ◽

Dorothee Neukam ◽

Rene Dechow ◽

Rima Rabah Nasser ◽

Henning Kage

Keyword(s):

Nitrous Oxide ◽

Greenhouse Gas ◽

Nitrogen Fertilizers ◽

Sensitivity Analyses ◽

Nitrous Oxide Emissions ◽

Model Parameters ◽

N2o Emissions ◽

Natural Conditions ◽

Data Set ◽

Process Based Models

<div> <div> <div> <p>Nitrous oxide is an important greenhouse gas. In Germany, around 50% of annual nitrous oxide emissions originate from managed agricultural land. Among other options, the mitigation of nitrous oxide emissions from arable land is one important measure to reduce greenhouse gas emissions of the agricultural sector. Several mitigation options have been examined including reduced application of nitrogen fertilizers, timing of fertilizer applications, crop residue management, pH management or application of nitrification inhibitors. Depending on the underlying natural conditions (soil, climate), these measures vary in their mitigation efficiency.</p> <p>Suitable methods are required to evaluate and quantify mitigation strategies for nitrous oxide emissions at a regional and national scale. For this purpose, several model approaches have been developed ranging from simple stochastic equations to sophisticated process-based models. Because of their reduced input requirements, stochastic approaches like emission factor approaches are common to quantify nitrous oxide emissions and mitigation effects while process based models are promising tools to describe interactions of natural conditions and anthropogenic activities. They have the potential to be more accurate and informative.</p> <p>However, due to the complex nature of N2O producing processes in croplands and the high spatial and temporal variability of N2O fluxes the portability of model developments from one site to another site or the validity of upscaling methods are questionable. We collected available field experimental data measuring nitrous oxide emissions to improve and analyze the prediction accuracy of model approaches in Germany, recently with data of 19 sites and 1251 site years in total and focus on the crop types wheat, maize and rape.</p> <p>Here, we present this data set and show results of model applications and a multi-site sensitivity analyses with the process based model DNDCv.Can. Contrary to other DNDC versions, DNDCvCAN allows to modify a range of internal parameters.</p> <p>We performed sensitivity analyses based on the Morris method by varying 45 model parameters. Each participating site was modeled for a three years period and the simulations were repeated for each parameter 500 times, resulting to 23000 simulations per site. Highest impact on N2O emissions were caused by soil concentrations of humads, humus and black carbon and their related C/N ratios. Surprisingly, N2O emissions showed only minor sensitivites in general on hydrological parameters and</p> </div> </div> </div><div> <div> <div> <p>on parameters related to N cycling in soil profile. Parameters controling macropore flow, nitrifier growth and denitrifier growth made here an exception. Sets of ranked most sensitive parameters varied between sites showing that multi-site sensitivity analyses might be helpful to identify global and local parameters for model calibration and help to assess regional mitigation effects.</p> </div> </div> </div>

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Emissions of nitrous oxide, ammonia and methane from Australian layer-hen manure storage with a mitigation strategy applied

Animal Production Science ◽

10.1071/an15584 ◽

2016 ◽

Vol 56 (9) ◽

pp. 1367 ◽

Cited By ~ 6

Author(s):

T. A. Naylor ◽

S. G. Wiedemann ◽

F. A. Phillips ◽

B. Warren ◽

E. J. McGahan ◽

...

Keyword(s):

Nitrous Oxide ◽

Greenhouse Gas ◽

Emission Factors ◽

Control Treatment ◽

N2o Emissions ◽

Gaseous Emissions ◽

Total N ◽

Volatile Solids ◽

Manure Storage ◽

The Relationship

Greenhouse gas and ammonia emissions are important environmental impacts from manure management in the layer-hen industry. The present study aimed to quantify emissions of nitrous oxide (N2O), methane (CH4) and ammonia (NH3) from layer-hen manure stockpiles, and assess the use of an impermeable cover as an option to mitigate emissions. Gaseous emissions of N2O, CH4 and NH3 were measured using open-path FTIR spectroscopy and the emission strengths were inferred using a backward Lagrangian stochastic model. Emission factors were calculated from the relationship between gaseous emissions and stockpile inputs over a 32-day measurement period. Total NH3 emissions were 5.97 ± 0.399 kg/t (control) and 0.732 ± 0.116 kg/t (mitigation), representing an 88% reduction due to mitigation. Total CH4 emissions from the mitigation stockpile were 0.0832 ± 0.0198 kg/t. Methane emissions from the control and N2O emissions (control and mitigation) were below detection. The mass of each stockpile was 27 820 kg (control) and 25 120 kg (mitigation), with a surface area of ~68 m2 and a volume of ~19 m3. Total manure nitrogen (N) and volatile solids (VS) were 25.2 and 25.8 kg/t N, and 139 and 106 kg/t VS for the control and mitigation stockpiles respectively. Emission factors for NH3 were 24% and 3% of total N for the control and mitigation respectively. Methane from the mitigation stockpile had a CH4 conversion factor of 0.3%. The stockpile cover was found to reduce greenhouse gas emissions by 74% compared with the control treatment, primarily via reduced NH3 and associated indirect N2O emissions.

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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 hotspots from organic soils in Europe

Biogeosciences Discussions ◽

10.5194/bgd-11-9135-2014 ◽

2014 ◽

Vol 11 (6) ◽

pp. 9135-9182

Author(s):

T. Leppelt ◽

R. Dechow ◽

S. Gebbert ◽

A. Freibauer ◽

A. Lohila ◽

...

Keyword(s):

Nitrous Oxide ◽

Greenhouse Gas ◽

Ph Value ◽

A Priori ◽

Emission Factors ◽

Organic Soils ◽

N2o Emissions ◽

The European Union ◽

Study Results ◽

N2o Fluxes

Abstract. Organic soils are a main source of direct nitrous oxide (N2O) emissions, an important greenhouse gas (GHG). Observed N2O emissions from organic soils are highly variable in space and time which causes high uncertainties in national emission inventories. Those uncertainties could be reduced when relating the upscaling process to a priori identified key drivers by using available N2O observations from plot scale in empirical approaches. We used the empirical fuzzy modelling approach MODE to identify main drivers for N2O and utilize them to predict the spatial emission pattern of European organic soils. We conducted a meta study with a total amount of 659 annual N2O measurements which was used to derive separate models for different land use types. We applied our models to available, spatial explicit input driver maps to upscale N2O emissions on European level and compared the inventory with recently published IPCC emission factors. The final statistical models explained up to 60% of the N2O variance. Our study results showed that cropland and grasslands emitted the highest N2O fluxes 0.98 ± 1.08 and 0.58 ± 1.03 g N2O-N m−2 a−1, respectively. High fluxes from cropland sites were mainly controlled by low soil pH-value and deep drained groundwater tables. Grassland hotspot emissions were strongly related to high amount of N-fertilizer inputs and warmer winter temperatures. In contrast N2O fluxes from natural peatlands were predominantly low (0.07±0.27 g N2O-N m−2 a−1) and we found no relationship with the tested drivers. The total inventory for direct N2O emissions from organic soils in Europe amount up to 149.5 Gg N2O-N a−1, which included also fluxes from forest and peat extraction sites and exceeds the inventory calculated by IPCC emission factors of 87.4 Gg N2O-N a−1. N2O emissions from organic soils represent up to 13% of total European N2O emissions reported in the European Union (EU) greenhouse gas inventory of 2011 from only 7% of the EU area. Thereby the model demonstrated that with up to 85% the major part of the inventory is induced by anthropogenic management, which shows the significant reduction potential by rewetting and extensivation of agricultural used peat soils.

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Greenhouse gas emissions from dung, urine and dairy pond sludge applied to pasture. 1. Nitrous oxide emissions

Animal Production Science ◽

10.1071/an15595 ◽

2018 ◽

Vol 58 (6) ◽

pp. 1087 ◽

Cited By ~ 7

Author(s):

G. N. Ward ◽

K. B. Kelly ◽

J. W. Hollier

Keyword(s):

Nitrous Oxide ◽

Greenhouse Gas Emissions ◽

Greenhouse Gas ◽

Nitrification Inhibitor ◽

Emission Factors ◽

Nitrous Oxide Emissions ◽

Cow Dung ◽

N2o Emissions ◽

Active Ingredients ◽

Gas Emissions

Nitrous oxide (N2O) from excreta deposited by grazing ruminants is a major source of greenhouse gas emissions in Australia. Experiments to measure N2O emissions from dairy cow dung, urine and pond sludge applied to pasture, and the effectiveness of the nitrification inhibitor nitrapyrin in reducing these emissions, were conducted in south-western Victoria, Australia. In Experiment 1, emissions from urine, with and without nitrapyrin, and from dung were measured. Treatments applied in September 2013 resulted in cumulative emissions (245 days) of 0.60, 5.35, 4.15 and 1.02 kg N2O-nitrogen (N)/ha for the nil, urine (1000 kg N/ha), urine (1000 kg N/ha) + nitrapyrin (1 kg active ingredients/ha), and dung (448 kg N/ha) treatments, respectively, giving emission factors of 0.47% and 0.09% for urine and dung respectively. Nitrapyrin reduced N2O emissions from urine for 35 days, with an overall reduction in emissions of 25%. In Experiment 2, sludge, with and without nitrapyrin, was applied in May 2014, and dung was applied in May, August, November 2014 and January 2015. Cumulative emissions (350 days) were 0.19, 0.49, 0.31 and 0.39 kg N2O-N/ha for the nil, sludge (308 kg N/ha), sludge (308 kg N/ha) + nitrapyrin (1 kg active ingredients/ha), and dung (total 604 kg N/ha) treatments, respectively, giving emission factors of 0.10% and 0.03% for sludge and dung. Nitrapyrin reduced N2O emissions from sludge for 60 days, with an overall reduction in emissions of 59%. A third experiment on two soil types compared emissions from urine and dung, with and without nitrapyrin, applied in different seasons of the year. Emissions were highly seasonal and strongly related to soil water status. Emission factors (90 days) ranged from 0.02% to 0.19% for urine and 0.01% to 0.12% for dung. Nitrapyrin reduced emissions from urine by 0–35% and had little effect on emissions from dung. Overall, the experiments found that nitrapyrin was an effective tool in reducing emissions from urine, dung and sludge applied to pasture, but the magnitude varied across the year, with nitrapyrin being most effective when soils had >70% water-filled pore space when major emissions occurred.

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The Effects of System Changes in Grazed Dairy Farmlet Trials on Greenhouse Gas Emissions

Animals ◽

10.3390/ani8120234 ◽

2018 ◽

Vol 8 (12) ◽

pp. 234 ◽

Cited By ~ 6

Author(s):

Tony van der Weerden ◽

Pierre Beukes ◽

Cecile de Klein ◽

Kathryn Hutchinson ◽

Lydia Farrell ◽

...

Keyword(s):

Nitrous Oxide ◽

New Zealand ◽

Greenhouse Gas ◽

Production Systems ◽

Current System ◽

Ghg Emissions ◽

N Leaching ◽

N2o Emissions ◽

System Changes ◽

Emissions Intensity

An important challenge facing the New Zealand (NZ) dairy industry is development of production systems that can maintain or increase production and profitability, while reducing impacts on receiving environments including water and air. Using research ‘farmlets’ in Waikato, Canterbury, and Otago (32–200 animals per herd), we assessed if system changes aimed at reducing nitrate leaching can also reduce total greenhouse gas (GHG) emissions (methane and nitrous oxide) and emissions intensity (kg GHG per unit of product) by comparing current and potential ‘improved’ dairy systems. Annual average GHG emissions for each system were estimated for three or four years using calculations based on the New Zealand Agricultural Inventory Methodology, but included key farmlet-specific emission factors determined from regional experiments. Total annual GHG footprints ranged between 10,800 kg and 20,600 kg CO2e/ha, with emissions strongly related to the amount of feed eaten. Methane (CH4) represented 75% to 84% of the total GHG footprint across all modelled systems, with enteric CH4 from lactating cows grazing pasture being the major source. Excreta deposition onto paddocks was the largest source of nitrous oxide (N2O) emissions, representing 7–12% of the total GHG footprint for all systems. When total emissions were represented on an intensity basis, ‘improved’ systems are predicted to generally result in lower emissions intensity. The ‘improved’ systems had lower GHG footprints than the ‘current’ system, except for one of the ‘improved’ systems in Canterbury, which had a higher stocking rate. The lower feed supplies and associated lower stocking rates of the ‘improved’ systems were the key drivers of lower total GHG emissions in all three regions. ‘Improved’ systems designed to reduced N leaching generally also reduced GHG emissions.

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Effect of variability in soil properties plus model complexity on predicting topsoil water content and nitrous oxide emissions

Soil Research ◽

10.1071/sr18080 ◽

2018 ◽

Vol 56 (8) ◽

pp. 810 ◽

Cited By ~ 2

Author(s):

Iris Vogeler ◽

Rogerio Cichota

Keyword(s):

Nitrous Oxide ◽

Soil Properties ◽

Water Content ◽

Soil Water ◽

Soil Water Content ◽

Soil Profile ◽

Nitrous Oxide Emissions ◽

Soil Types ◽

N2o Emissions ◽

Silt Loam

Despite the importance of soil physical properties on water infiltration and redistribution, little is known about the effect of variability in soil properties and its consequent effect on contaminant loss pathways. To investigate the effects of uncertainty and heterogeneity in measured soil physical parameters on the simulated movement of water and the prediction of nitrous oxide (N2O) emissions, we set up the Agricultural Production Systems sIMulator (APSIM) for different soil types in three different regions of New Zealand: the Te Kowhai silt loam and the Horotiu silt loam in the Waikato region, and the Templeton silt loam in the Canterbury region, and the Otokia silt loam and the Wingatui silt loam in the Otago region. For each of the soil types, various measured soil profile descriptions, as well as those from a national soils database (S-map) were used when available. In addition, three different soil water models in APSIM with different complexities (SWIM2, SWIM3, and SoilWat) were evaluated. Model outputs were compared with temporal soil water content measurements within the top 75mm at the various experimental sites. Results show that the profile description, as well as the soil water model used affected the prediction accuracy of soil water content. The smallest difference between soil profile descriptions was found for the Templeton soil series, where the model efficiency (NSE) was positive for all soil profile descriptions, and the RMSE ranged from 0.055 to 0.069m3/m3. The greatest difference was found for the Te Kowhai soil, where only one of the descriptions showed a positive NSE, and the other two profile descriptions overestimated measured topsoil water contents. Furthermore, it was shown that the soil profile description highly affects N2O emissions from urinary N deposited during animal grazing. However, the relative difference between the emissions was not always related to the accuracy of the measured soil water content, with soil organic carbon content also affecting emissions.

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Influence of pore size distribution and soil water content on nitrous oxide emissions

Soil Research ◽

10.1071/sr11112 ◽

2012 ◽

Vol 50 (2) ◽

pp. 125 ◽

Cited By ~ 61

Author(s):

Tony J. van der Weerden ◽

Francis M. Kelliher ◽

Cecile A. M. de Klein

Keyword(s):

Nitrous Oxide ◽

Pore Size Distribution ◽

Pore Size ◽

Water Content ◽

Size Distribution ◽

Soil Water ◽

Gas Diffusion ◽

Field Conditions ◽

Nitrous Oxide Emissions ◽

N2o Emissions

Nitrous oxide (N2O) emissions from agricultural soils have been estimated to comprise about two-thirds of the biosphere’s contribution of this potent greenhouse gas. In pasture systems grazed by farmed animals, where substrate is generally available, spatial variation in emissions, in addition to that cause by the patchiness of urine deposition, has been attributed to soil aeration, as governed by gas diffusion. However, this parameter is not readily measured, and the soil’s water-filled pore space (WFPS) has often been used as a proxy, despite gas diffusion in soils depending on the volumetric fractions of water and air. With changing water content, these fractions will reflect the soil’s pore size distribution. The aims of this study were: (i) to determine if the pore size distribution of two pastoral soils explains previously observed differences in N2O emissions under field conditions, and (ii) to assess the most appropriate soil water/gas diffusion metric for estimating N2O emissions. The N2O emissions were measured from intact cores of two soils (one classified as well drained and one as poorly drained) that had been sampled to a depth of 50 mm beneath grazed pasture. Nitrogen (N, 500 kg N/ha) was applied to soil cores as aqueous nitrate solution, and the cores were drained under controlled conditions at a constant temperature. The poorly drained soil had a larger proportion of macropores (23.5 v. 18.7% in the well-drained soil), resulting in more rapid drainage and increased pore continuity, thereby reducing the duration of anaerobicity, and leading to lower N2O emissions. Emissions were related to three soil water proxies including WFPS, volumetric water content (VWC), and matric potential (MP), and to relative diffusion (RD). All parameters showed highly significant relationships with N2O emissions (P < 0.001), with RD, WFPS, VWC, and MP accounting for 59, 72, 88, and 93% of the variability, respectively. As VWC is more readily determined than MP, the former is potentially more suitable for estimating N2O emission from different soils across a range of time and space scales under field conditions.

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Nitrous oxide emissions from subtropical horticultural soils: a time series analysis

Soil Research ◽

10.1071/sr11100 ◽

2012 ◽

Vol 50 (7) ◽

pp. 596 ◽

Cited By ~ 8

Author(s):

Xiaodong Huang ◽

Peter Grace ◽

Keith Weier ◽

Kerrie Mengersen

Keyword(s):

Time Series ◽

Nitrous Oxide ◽

Soil Temperature ◽

Water Content ◽

Soil Water ◽

Soil Water Content ◽

Regression Models ◽

N2o Emissions ◽

Time Series Regression ◽

Custard Apple

Time series regression models were used to examine the influence of environmental factors (soil water content and soil temperature) on the emissions of nitrous oxide (N2O) from subtropical soils, by taking into account temporal lagged environmental factors, autoregressive processes, and seasonality for three horticultural crops in a subtropical region of Australia. Fluxes of N2O, soil water content, and soil temperature were determined simultaneously on a weekly basis over a 12-month period in South East Queensland. Annual N2O emissions for soils under mango, pineapple, and custard apple were 1590, 1156, and 2038 g N2O-N/ha, respectively, with most emissions attributed to nitrification. The N2O-N emitted from the pineapple and custard apple crops was equivalent to 0.26 and 2.22%, respectively, of the applied mineral N. The change in soil water content was the key variable for describing N2O emissions at the weekly time-scale, with soil temperature at a lag of 1 month having a significant influence on average N2O emissions (averaged) at the monthly time-scale across the three crops. After accounting for soil temperature and soil water content, both the weekly and monthly time series regression models exhibited significant autocorrelation at lags of 1–2 weeks and 1–2 months, and significant seasonality for weekly N2O emissions for mango crop and for monthly N2O emissions for mango and custard apple crops in this location over this time-frame. Time series regression models can explain a higher percentage of the temporal variation of N2O emission compared with simple regression models using soil temperature and soil water content as drivers. Taking into account seasonal variability and temporal persistence in N2O emissions associated with soil water content and soil temperature may lead to a reduction in the uncertainty surrounding estimates of N2O emissions based on limited sampling effort.

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