Modelling uncertainty for nitrate leaching and nitrous oxide emissions based on a Swedish field experiment with organic crop rotation

• High uncertainties are common in detailed quantification of the N budget of agricultural cropping systems. The process-based CoupModel, integrated with the parameter calibration method known as Generalized likelihood uncertainty estimation (GLUE), was used here to define parameter values and estimate an N budget based on experimental data from an organic farming experiment in south-west Sweden. Data on nitrate (NO3-) leaching and nitrous oxide (N2O) emissions were used as a basis for quantifying N budget pools. A complete N budget with uncertainties associated with the different components of the N cycle compartments for two different fields (B2 and B4) is presented. Simulated N2O emissions contributed 1-2% of total N output, which corresponded to 7% and 8.7% of total N leaching for B2 and B4, respectively. Measured N2O emissions contributed 3.5% and 10.3% of total N leaching from B2 and B4, respectively. Simulated N inputs (deposition, plant N fixation and fertilisation) and outputs (emissions, leaching and harvest) showed a relatively small range of uncertainty, while the differences in N storage in the soil exhibited a larger range of uncertainty. One-fifth of the GLUE-calibrated parameters had a significant impact on simulated NO3- leaching and/or N2O emissions data. Emissions of N2O were strongly associated with the nitrification process. The high degree of equifinality indicated that a simpler model could be calibrated to the same field data.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Naturresursteknik -- Annan naturresursteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Environmental Engineering -- Other Environmental Engineering (hsv//eng)

LANTBRUKSVETENSKAPER  -- Lantbruksvetenskap, skogsbruk och fiske -- Jordbruksvetenskap (hsv//swe)

AGRICULTURAL SCIENCES  -- Agriculture, Forestry and Fisheries -- Agricultural Science (hsv//eng)

NATURVETENSKAP  -- Biologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences (hsv//eng)

NATURVETENSKAP  -- Geovetenskap och miljövetenskap (hsv//swe)

NATURAL SCIENCES  -- Earth and Related Environmental Sciences (hsv//eng)

Nyckelord

Agriculture

N budget

N-2 fixation

soil

CoupModel

Calibration

Uncertainty estimations

Environmental engineering

Miljöteknik

Agricultural engineering

Jordbruksteknik

Agriculture

N budget

N2 fixation soil

CoupModel Calibration

Uncertainty estimations

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