The process-based crop-soil models that integrate biogeochemical processes such as crop growth, organic matter decomposition, and nitrification and denitrification are effective tools for assessing the transport and transformation of carbon and nitrogen nutrients in the crop and soil systems, and provide important solutions for the efficient use of on-land nutrients. The denitrification-decomposition (DNDC) model has been successfully used to simulate crop growth, soil temperature and water movement, soil carbon and nitrogen dynamics, and greenhouse gas emissions. However, few studies have systematically analyzed the response of crop yields and soil N2O emissions of diverse corn rotation systems to long-term climate variability using the DNDC model.

The objectives of this study were to calibrate and evaluate the DeNitrification-DeComposition (DNDC) model using measurements of yields, nitrogen (N) uptake, soil inorganic N levels, soil temperature, soil moisture and nitrous oxide (N2O) emissions under long-term fertilized continuous corn (CC) and corn-oats-alfalfa-alfalfa (COAA) rotation systems in southwest Ontario, Canada, from 1959 to 2015, and to explore the impacts of four diverse rotation systems (CC, COAA, corn-soybean-corn-soybean (CSCS) and corn-soybean-winter wheat (CSW)) on corn yields and annual N2O emissions under long-term climate variability. The results show that DNDC had a “good” performance in simulating corn, oats and alfalfa yield. The model provided “fair” to “good” simulations for corn N uptake and soil inorganic N, and also daily soil temperature and soil moisture. The model also had a “good” performance in estimating daily and cumulative N2O emissions from both the continuous and rotational corn. The highest corn yields were from COAA, followed by CSW, CSCS, then CC. The lowest N2O emissions were from COAA followed by CSCS, CSW then CC.

Simulated and measured values of corn yields, soil moisture and daily N2O emissions under both monoculture and rotation systems

The research results were published in the international academic journal Science of the Total Environment (IF 7.963). Jiang Rong, a postdoctoral researcher at the Institute of Agricultural Resources and Regional Planning (IARRP) of the Chinese Academy of Agricultural Sciences (CAAS), is the first author. Research fellow He Ping from IARRP, CAAS, and research fellow Yang Jingyi from Agriculture and Agri-Food Canada are the co-corresponding authors. This research was funded by the National Key Research and Development Program of China (No. 2016YFD0200101), the dispatch project of the Postdoctoral International Exchange Program (No. 20180027), and Agriculture and Agri-Food Canada.

Rong Jiang, J.Y. Yang*, C.F. Drury, Wentian He, W.N. Smith, B.B. Grant, Ping He*, Wei Zhou. Assessing the impacts of diversified crop rotation systems on yields and nitrous oxide emissions in Canada using the DNDC model. Science of the Total Environment. 2021. 759, 143433.

https://doi.org/10.1016/j.scitotenv.2020.143433