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Uttam Kumar
Department of Agricultural Research for Northern Sweden, Swedish University of Agricultural Science, 90183 Umeå, Sweden

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Journal article
Published: 26 February 2021 in Plants
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Phenology algorithms in crop growth models have inevitable systematic errors and uncertainties. In this study, the phenology simulation algorithms in APSIM classical (APSIM 7.9) and APSIM next generation (APSIM-NG) were compared for spring barley models at high latitudes. Phenological data of twelve spring barley varieties were used for the 2014–2018 cropping seasons from northern Sweden and Finland. A factorial-based calibration approach provided within APSIM-NG was performed to calibrate both models. The models have different mechanisms to simulate days to anthesis. The calibration was performed separately for days to anthesis and physiological maturity, and evaluations for the calibrations were done with independent datasets. The calibration performance for both growth stages of APSIM-NG was better compared to APSIM 7.9. However, in the evaluation, APSIM-NG showed an inclination to overestimate days to physiological maturity. The differences between the models are possibly due to slower thermal time accumulation mechanism, with higher cardinal temperatures in APSIM-NG. For a robust phenology prediction at high latitudes with APSIM-NG, more research on the conception of thermal time computation and implementation is suggested.

ACS Style

Uttam Kumar; Julien Morel; Göran Bergkvist; Taru Palosuo; Anne-Maj Gustavsson; Allan Peake; Hamish Brown; Mukhtar Ahmed; David Parsons. Comparative Analysis of Phenology Algorithms of the Spring Barley Model in APSIM 7.9 and APSIM Next Generation: A Case Study for High Latitudes. Plants 2021, 10, 443 .

AMA Style

Uttam Kumar, Julien Morel, Göran Bergkvist, Taru Palosuo, Anne-Maj Gustavsson, Allan Peake, Hamish Brown, Mukhtar Ahmed, David Parsons. Comparative Analysis of Phenology Algorithms of the Spring Barley Model in APSIM 7.9 and APSIM Next Generation: A Case Study for High Latitudes. Plants. 2021; 10 (3):443.

Chicago/Turabian Style

Uttam Kumar; Julien Morel; Göran Bergkvist; Taru Palosuo; Anne-Maj Gustavsson; Allan Peake; Hamish Brown; Mukhtar Ahmed; David Parsons. 2021. "Comparative Analysis of Phenology Algorithms of the Spring Barley Model in APSIM 7.9 and APSIM Next Generation: A Case Study for High Latitudes." Plants 10, no. 3: 443.

Journal article
Published: 02 May 2020 in Agronomy
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APSIM Next Generation was used to simulate the phenological development and biomass production of silage maize for high latitudes (i.e., >55°). Weather and soil data were carefully specified, as they are important drivers of the development and growth of the crop. Phenology related parameters were calibrated using a factorial experiment of simulations and the minimization of the root mean square error of observed and predicted phenological scaling. Results showed that the model performed well in simulating the phenology of the maize, but largely underestimated the production of biomass. Several factors could explain the discrepancy between observations and predictions of above-ground dry matter yield, such as the current formalization of APSIM for simulating the amount of radiation absorbed by the crop at high latitudes, as the amount of diffuse light and intercepted light increases with latitude. Another factor that can affect the accuracy of the predicted biomass is the increased duration of the day length observed at high latitudes. Indeed, APSIM does not yet formalize the effects of extreme day length on the balance between photorespiration and photosynthesis on the final balance of biomass production. More field measurements are required to better understand the drivers of the underestimation of biomass production, with a particular focus on the light interception efficiency and the radiation use efficiency.

ACS Style

Julien Morel; David Parsons; Magnus A. Halling; Uttam Kumar; Allan Peake; Göran Bergkvist; Hamish Brown; Mårten Hetta. Challenges for Simulating Growth and Phenology of Silage Maize in a Nordic Climate with APSIM. Agronomy 2020, 10, 645 .

AMA Style

Julien Morel, David Parsons, Magnus A. Halling, Uttam Kumar, Allan Peake, Göran Bergkvist, Hamish Brown, Mårten Hetta. Challenges for Simulating Growth and Phenology of Silage Maize in a Nordic Climate with APSIM. Agronomy. 2020; 10 (5):645.

Chicago/Turabian Style

Julien Morel; David Parsons; Magnus A. Halling; Uttam Kumar; Allan Peake; Göran Bergkvist; Hamish Brown; Mårten Hetta. 2020. "Challenges for Simulating Growth and Phenology of Silage Maize in a Nordic Climate with APSIM." Agronomy 10, no. 5: 645.