Determination of nitrogen dilution curves of corn, canola, and spring wheat in Canada using classical and Bayesian approaches

Jégo G., Sansoulet Julie, Pattey E., Beaudoin Nicolas, Bélanger G., Ziadi Noura, Tremblay N., Grant C., Tremblay G., O'Donovan J., Harker K.N., Blackshaw R., Johnson E., Justes Eric. 2022. Determination of nitrogen dilution curves of corn, canola, and spring wheat in Canada using classical and Bayesian approaches. European Journal of Agronomy, 135:126481, 15 p.

https://doi.org/10.1016/j.eja.2022.126481

Article de revue ; Article de recherche ; Article de revue à facteur d'impact

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Résumé : Determining the dynamics of crop nitrogen (N) uptake is essential to optimize N management and increase the sustainability of crop production. The concept of critical N concentration helps to achieve this goal by defining the minimum shoot N concentration required to produce the maximum aerial biomass at a given time during the crop cycle. The objective of this study was to determine new critical N dilution curves of the main annual field crops used in Canada (spring wheat, canola and corn) using a classical approach well established and a new Bayesian approach and compare these curves with the curves previously published. A total of 557 data for the three crops were used, covering a wide range of pedoclimatic conditions, crop management and cultivars across Canada. These data were processed following a classical statistical approach involving two steps to determine critical points used to calculate the parameters of the critical N dilution curve and then validate these curves against N limiting and non-limiting points. Data were also processed with a new one step Bayesian approach which allows estimating the 95% credibility intervals of the calculated critical curves. For spring wheat, our analysis confirmed the results of a previous study showing that the critical N curve established for winter wheat was not adequate for spring wheat. The critical N dilution curve determined with the classical approach (Nc = 4.14 W−0.51) performed well in separating the N limiting to the N non-limiting data of the validation dataset. The use of a larger dataset than in the previous study conducted for spring wheat in eastern Canada allowed us to demonstrate that new critical, minimum and maximum N dilution curves for spring wheat has a larger domain of validity than suggested by results of previous studies. Our study shows the strong interaction between plant N and water status, and that N dilution concept allowed us to reveal the occurrence of interaction between water and N stresses for crops in Western Canada, explaining the lower efficiency of N fertilizer in western than in eastern regions. For corn, the refined critical N dilution curve was very close to the critical N dilution curve determined in France and in eastern Canada, but the Bayesian approach allowed to propose a specific critical N curve for Canada (Nc = 3.07 W−0.40). In addition, minimum and maximum N dilution curves for corn were determined in Canada's pedoclimatic conditions. For canola, the new critical (Nc = 4.26 W−0.26), minimum and maximum curves determined in this study were close to the curves found in previous studies during the vegetative stages. In addition, a new critical N curve valid after the flowering stage was determined.

Mots-clés Agrovoc : blé de printemps, biomasse, fertilisation, Zea mays, agroécosystème

Mots-clés géographiques Agrovoc : France, Canada

Mots-clés libres : Tritricum aestivum L., Brassica campestris L., Brassica rapa L., Zea mays L

Champ stratégique Cirad : CTS 2 (2019-) - Transitions agroécologiques

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