Comparison of three modeling approaches for simulating denitrification and nitrous oxide emissions from loam‐textured arable soils

Abstract

[1] Soil denitrification fluxes and nitrous oxide (N 2 O) emissions from the soil surface simulated by a Water and Nitrogen Management Model (WNMM), with three different gas modules, are compared to measurement data sets from two irrigated wheat-maize systems at two locations in the North China Plain (NCP) (2 years of measurement at the Luancheng site and 1 year of measurement at the Fengqiu site). The three gas modules are the WNMM gas module, the DAYCENT gas module, and the DNDC gas module. The term gas module used in this paper refers to the model component which simulates N 2 O emission from the processes of soil nitrification and denitrification. Soil water, temperature, organic matter decomposition, other nitrogen (N) transformations, such as mineralization and immobilization, and crop growth are simulated by the WNMM platform. For the 2-year data set from Luancheng, the three gas modules generate similar soil mineral N dynamics in the 0-20 cm topsoil. The daily time step, simply structured WNMM gas module consistently performs the best among the three gas modules for predicting soil denitrification fluxes (R 2 = 0.28, n = 39, p = 0.0006) and N 2 O emissions (R 2 = 0.45, n = 36, p < 0.0001). Up to 73, 43, and 22% of total N 2 O emissions are nitrification-induced as simulated by the DNDC, DAYCENT, and WNMM gas modules respectively, in this well-drained loam soil during the 2-year simulation. When applied to the 1-year data set at the Fengqiu site, the WNMM gas module consistently performs better in estimating N 2 O emissions (R 2 = 0.54, n = 35, p < 0.0001) compared to the other two modules. Simulations using the DNDC and DAYCENT gas modules explain over 40% of the temporal variation of N 2 O emission from the soil. Further testing on different soils and different agroecosystems is needed to confirm the superior performance of the WNMM gas module observed in this simulation study.

Testing DNDC model for simulating soil respiration and assessing the effects of climate change on the CO2 gas flux from Irish agriculture

“…Reduced tillage has the advantage of sequestering C in the soils (Six et al, 2004;Li et al, 2005;Chatskikh and Olesen, 2007). Residue management also has an influence on the availability of organic matter, the quantity of micro-organisms and their activity (Doran et al, 1998;Frank et al, 2006).…”

Modelling nitrous oxide and carbon dioxide emission from soil in an incubation experiment

“…Denitrification could occur at water contents below DUL because of anaerobic microsites, and occur at WFPS ranging from 0.55 to 0.90 (de Klein and van Logtestijn, 1996;Dobbie and Smith, 2001;Linn and Doran, 1984;Weier et al, 1993). In soils with high clay content, denitrification may occur at WFPS around 0.40 (Li et al, 2005b;Mosier et al, 1996;Parton et al, 1996;Robertson et al, 1993).…”

Modelling spatial and inter-annual variations of nitrous oxide emissions from UK cropland and grasslands using DailyDayCent

“…This has been seen in other studies including Abdalla et al (2010) and Rafique et al (2011). Differences in daily values can be attributed to time lags in simulated emissions after N fertiliser application (Li et al, 2005;Del Grosso et al, 2010) and the effect of soil freezing and thawing, especially in winter months (Fitton et al, 2014a;Lit et al, 2010). In addition the processes governing an uptake of N 2 O on actively managed grass or croplands are not properly understood , therefore as models tend assume/simulate a net release of N 2 O this is another source of potential model error (Houska et al, 2017).…”