Evaluation of two process-based models to estimate soil N2O emissions in Eastern Canada

Process-based models play an important role in the estimation of soil N2O emissions from regions with contrasting soil and climatic conditions. A study was performed to evaluate the ability of two process-based models, DAYCENT and DNDC, to estimate N2O emissions, soil nitrate- and ammonium-N levels, as well as soil temperature and water content. The measurement sites included a maize crop fertilized with pig slurry (Quebec) and a wheat-maize-soybean rotation as part of a tillage-fertilizer experiment (Ontario). At the Quebec site, both models accurately simulated soil temperature with an average relative error (ARE) ranging from 0 to 2%. The models underpredicted soil temperature at the Ontario site with ARE from −5 to −7% for DNDC and from −5 to −13% for DAYCENT. Both models underestimated soil water content particularly during the growing season. The DNDC model accurately predicted average seasonal N2O emissions across treatments at both sites whereas the DAYCENT model underpredicted N2O emissions by 32 to 58% for all treatments excluding the fertilizer treatment at the Quebec site. Both models had difficulty in simulating the timing of individual emission events. The hydrology and nitrogen transformation routines need to be improved in both models before further enhancements are made to the trace gas routines. Key words: Nitrous oxide, process-based model, DNDC, greenhouse gas emissions, soil

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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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Benchmarking nitrous oxide emissions in deciduous tree cropping systems

Soil Research ◽

10.1071/sr15326 ◽

2016 ◽

Vol 54 (5) ◽

pp. 500 ◽

Cited By ~ 7

Author(s):

Nigel Swarts ◽

Kelvin Montagu ◽

Garth Oliver ◽

Liam Southam-Rogers ◽

Marcus Hardie ◽

...

Keyword(s):

Nitrous Oxide ◽

Soil Temperature ◽

Water Content ◽

Nutrient Use Efficiency ◽

Nitrous Oxide Emissions ◽

Deciduous Tree ◽

N2o Emissions ◽

Tree Line ◽

Tree Crops ◽

Eastern Australia

Nitrous oxide (N2O) emissions contribute 6% of the global warming effect and are derived from the activity of soil-based microorganisms involved in nitrification and denitrification processes. There is a paucity of greenhouse gas emissions data for Australia’s horticulture industry. In this study we investigated N2O flux from two deciduous fruit tree crops, apples and cherries, in two predominant growing regions in eastern Australia, the Huon Valley in southern Tasmania (Lucaston – apples and Lower Longley – cherries), and high altitude northern New South Wales (Orange – apples and Young – cherries). Estimated from manual chamber measurements over a 12-month period, average daily emissions were very low ranging from 0.78gN2O-Nha–1day–1 in the apple orchard at Lucaston to 1.86gN2O-Nha–1day–1 in the cherry orchard in Lower Longley. Daily emissions were up to 50% higher in summer (maximum 5.27gN2O-Nha–1day–1 at Lower Longley) than winter (maximum 2.47gN2O-Nha–1day–1 at Young) across the four trial orchards. N2O emissions were ~40% greater in the inter-row than the tree line for each orchard. Daily flux rates were used as a loss estimate for annual emissions, which ranged from 298gN2O-Nha–1year–1 at Lucaston to 736gN2O-Nha–1year–1 at Lower Longley. Emissions were poorly correlated with soil temperature, volumetric water content, water filled porosity, gravimetric water content and matric potential – with inconsistent patterns between sites, within the tree line and inter-row and between seasons. Stepwise linear regression models for the Lucaston site accounted for less than 10% of the variance in N2O emissions, for which soil temperature was the strongest predictor. N2O emissions in deciduous tree crops were among the lowest recorded for Australian agriculture, most likely due to low rates of N fertiliser, cool temperate growing conditions and highly efficient drip irrigation systems. We recommend that optimising nutrient use efficiency with improved drainage and a reduction in soil compaction in the inter-row will facilitate further mitigation of N2O emissions.

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Testing the DNDC model using N2O emissions at two experimental sites in Canada

Canadian Journal of Soil Science ◽

10.4141/s01-048 ◽

2002 ◽

Vol 82 (3) ◽

pp. 365-374 ◽

Cited By ~ 50

Author(s):

W N Smith ◽

R L Desjardins ◽

B. Grant ◽

C. Li ◽

R. Lemke ◽

...

Keyword(s):

Nitrous Oxide ◽

Management Practices ◽

Agricultural Soils ◽

Nitrous Oxide Emissions ◽

N2o Emissions ◽

Western Canada ◽

Dndc Model ◽

Eastern Canada ◽

Ipcc Methodology ◽

Key Words Nitrous Oxide

Measured data from two experimental sites in Canada were used to test the ability of the DeNitrification and DeComposition model (DNDC) to predict N2O emissions from agricultural soils. The two sites, one from eastern Canada, and one from western Canada, provided a variety of crops, management practices, soils, and climates for testing the model. At the site in eastern Canada, the magnitude of total seasonal N2O flux from the seven treatments was accurately predicted with a slight average over-prediction (ARE) of 3% and a coefficient of variation of 41%. Nitrous oxide emissions based on International Panel for Climate Change (IPCC) methodology had a relative error of 62% for the seven treatments. The DNDC estimates of total yearly emissions of N2O from the field site in western Canada showed an underestimation of 8% for the footslope landscape position and an overestimation of 46% for the shoulder position. The data input for the DNDC model were not of sufficient detail to characterize the moisture difference between the landscape positions. The estimates from IPCC guidelines showed an underestimation of 54% for the footslope and an overestimation of 161% for the shoulder. The results indicate that the DNDC model was more accurate than IPCC methodology at estimating N2O emissions at both sites. Key words: Nitrous oxide, DNDC, soil model, greenhouse gas, testing

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Dynamics of the soil respiration response to soil reclamation in a coastal wetland

Scientific Reports ◽

10.1038/s41598-021-82376-0 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Xiliang Song ◽

Yihao Zhu ◽

Weifeng Chen

Keyword(s):

Soil Respiration ◽

Soil Temperature ◽

Soil Carbon ◽

Water Content ◽

Coastal Wetlands ◽

Positive Relationship ◽

Soil Reclamation ◽

Diurnal Changes ◽

Seasonal Scale ◽

Study Sites

AbstractThe soil carbon (C) pools in coastal wetlands are known as “blue C” and have been damaged extensively owing to climate change and land reclamation. Because soil respiration (RS) is the primary mechanism through which soil carbon is released into the atmosphere at a global scale, investigating the dynamic characteristics of the soil respiration rate in reclaimed coastal wetlands is necessary to understand its important role in maintaining the global C cycle. In the present study, seasonal and diurnal changes in soil respiration were monitored in one bare wetland (CK) and two reclaimed wetlands (CT, a cotton monoculture pattern, and WM, a wheat–maize continuous cropping pattern) in the Yellow River Delta. At the diurnal scale, the RS at the three study sites displayed single-peak curves, with the lowest values occurring at midnight (00:00 a.m.) and the highest values occurring at midday (12:00 a.m.). At the seasonal scale, the mean diurnal RS of the CK, CT and WM in April was 0.24, 0.26 and 0.79 μmol CO2 m−2 s−1, and it increased to a peak in August for these areas. Bare wetland conversion to croplands significantly elevated the soil organic carbon (SOC) pool. The magnitude of the RS was significantly different at the three sites, and the yearly total amounts of CO2 efflux were 375, 513 and 944 g CO2·m−2 for the CK, CT and WM, respectively. At the three study sites, the surface soil temperature had a significant and positive relationship to the RS at both the diurnal and seasonal scales, and it accounted for 20–52% of the seasonal variation in the daytime RS. The soil water content showed a significant but negative relationship to the RS on diurnal scale only at the CK site, while it significantly increased with the RS on seasonal scale at all study sites. Although the RS showed a noticeable relationship to the combination of soil temperature and water content, the synergic effects of these two environment factors were not much higher than the individual effects. In addition, the correlation analysis showed that the RS was also influenced by the soil physico-chemical properties and that the soil total nitrogen had a closer positive relationship to the RS than the other nutrients, indicating that the soil nitrogen content plays a more important role in promoting carbon loss.

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Nitrous Oxide Emissions in Pineapple Cultivation on a Tropical Peat Soil

Sustainability ◽

10.3390/su13094928 ◽

2021 ◽

Vol 13 (9) ◽

pp. 4928

Author(s):

Alicia Vanessa Jeffary ◽

Osumanu Haruna Ahmed ◽

Roland Kueh Jui Heng ◽

Liza Nuriati Lim Kim Choo ◽

Latifah Omar ◽

...

Keyword(s):

Nitrous Oxide ◽

Soil Temperature ◽

Peat Soil ◽

Farming Systems ◽

N2o Emission ◽

Nitrous Oxide Emissions ◽

Natural State ◽

N2o Emissions ◽

Wet Season ◽

Peat Soils

Farming systems on peat soils are novel, considering the complexities of these organic soil. Since peat soils effectively capture greenhouse gases in their natural state, cultivating peat soils with annual or perennial crops such as pineapples necessitates the monitoring of nitrous oxide (N2O) emissions, especially from cultivated peat lands, due to a lack of data on N2O emissions. An on-farm experiment was carried out to determine the movement of N2O in pineapple production on peat soil. Additionally, the experiment was carried out to determine if the peat soil temperature and the N2O emissions were related. The chamber method was used to capture the N2O fluxes daily (for dry and wet seasons) after which gas chromatography was used to determine N2O followed by expressing the emission of this gas in t ha−1 yr−1. The movement of N2O horizontally (832 t N2O ha−1 yr−1) during the dry period was higher than in the wet period (599 t N2O ha−1 yr−1) because of C and N substrate in the peat soil, in addition to the fertilizer used in fertilizing the pineapple plants. The vertical movement of N2O (44 t N2O ha−1 yr−1) was higher in the dry season relative to N2O emission (38 t N2O ha−1 yr−1) during the wet season because of nitrification and denitrification of N fertilizer. The peat soil temperature did not affect the direction (horizontal and vertical) of the N2O emission, suggesting that these factors are not related. Therefore, it can be concluded that N2O movement in peat soils under pineapple cultivation on peat lands occurs horizontally and vertically, regardless of season, and there is a need to ensure minimum tilling of the cultivated peat soils to prevent them from being an N2O source instead of an N2O sink.

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Modeling soil temperature using air temperature features in diverse climatic conditions with complementary machine learning models

Computers and Electronics in Agriculture ◽

10.1016/j.compag.2021.106158 ◽

2021 ◽

Vol 185 ◽

pp. 106158

Author(s):

Maryam Bayatvarkeshi ◽

Suraj Kumar Bhagat ◽

Kourosh Mohammadi ◽

Ozgur Kisi ◽

M. Farahani ◽

...

Keyword(s):

Machine Learning ◽

Soil Temperature ◽

Air Temperature ◽

Climatic Conditions ◽

Learning Models ◽

Machine Learning Models

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Microbial CO2 production from surface and subsurface soil as affected by temperature, moisture, and nitrogen fertilisation

Soil Research ◽

10.1071/sr07144 ◽

2008 ◽

Vol 46 (3) ◽

pp. 273 ◽

Cited By ~ 12

Author(s):

Xiaobin Jin ◽

Shenmin Wang ◽

Yinkang Zhou

Keyword(s):

Soil Temperature ◽

Water Content ◽

Soil Water ◽

Soil Water Content ◽

Sanjiang Plain ◽

Co2 Production ◽

The Sanjiang Plain ◽

Subsurface Soil ◽

C Mineralisation ◽

Q10 Values

The Sanjiang Plain of north-east China is presently the second largest freshwater marsh in China. The drainage and use of marshes for agricultural fields occurred in the past 50 years, resulting in the increase in cultivated land from about 2.9 × 108 m2 in 1893 to 4.57 × 1010 m2 in 1994. Under human disturbance in the past half century, the environment in Sanjiang Plain has had significant change. We hypothesised that environmental factors such as soil moisture, soil temperature, and soil N levels affect the rates of soil organic C mineralisation and the nature of the controls on microbial CO2 production to change with depth through the soil profile in the freshwater marsh in the Sanjiang Plain. In a series of experiments, we measured the influence of soil temperature, soil water content, and nitrogen additions on soil microbial CO2 production rates. The results showed that Q10 values (the factor by which the CO2 production rate increases when the temperature is increased by 10°C) significantly increased with soil depth through the soil profile (P < 0.05). The average Q10 values for the surface soils were 2.7 (0–0.2 m), significantly lower than that (average Q10 values 3.3) for the subsurface samples (0.2–0.6 m) (P < 0.05), indicating that C mineralisation rates were more sensitive to temperature in subsurface soil horizons than in surface horizons. The maximum respiration rate was measured at 60% water hold capacity for each sample. The quadratic equation function adequately describes the relationship between soil respiration and soil water content, and the R2 values were > 0.80. The sensitivity of microbial CO2 production rate response to soil water content for surface soils (0–0.2 m) was slightly lower than for subsurface soils (0.2–0.6 m). The responses of actual soil respiration rates to nitrogen fertilisation were different for surface and subsurface soils. In the surface soils (0–0.2 m), the addition of N caused a slight decreased in respiration rates compared with the control, whereas, in the subsurface soils (0.2–0.6 m), the addition of N tended to increase microbial CO2 production rates, and the addition of 10 µg N/g soil treatment caused twice the increase in C mineralisation rates of the control. Our results suggested that the responses of microbial CO2 production to changes in soil moisture, soil temperature, and soil N levels varied with soil depth through the profile, and subsurface soil organic C was more sensitive to temperature increase and nitrogen inputs in the freshwater marsh of the Sanjiang Plain.

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