Assessing crop model improvements through comparison of sorghum (sorghum bicolor L. moench) simulation models: A case study of West African varieties

Akinseyea, F M and Adam, M and Agele, S O and Hoffmann, M P and Traore, P C S and Whitbread, A M (2017) Assessing crop model improvements through comparison of sorghum (sorghum bicolor L. moench) simulation models: A case study of West African varieties. Field Crops Research, 201. pp. 19-31. ISSN 0378-4290

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Abstract

Better defining niches for the photoperiod sensitive sorghum (Sorghum bicolor L. Moench) varieties of West Africa into the local cropping system might help to improve the resilience of food production in the region. In particular, crop models are key tools to assess the growth and development of such varieties against climate and soil variability. In this study, we compared the performance of three process-based crop models (APSIM, DSSAT and Samara) for prediction of diverse sorghum germplasm having widely varying photoperiod sensitivity (PPS) using detailed growth and development observations from field trials conducted in West Africa semi-arid region. Our results confirmed the capability of each selected model to reproduce growth and development for varieties of diverse sensitivities to photoperiod. Simulated phenology and morphology organs during calibration and validation were within the closet range of measured values with the evaluation of model error statistics (RMSE and R2). With the exception of highly sensitive variety (IS15401), APSIM and Samara estimates indicate the lowest value of RMSE (<7days) against the observed values for phenology events (flowering and maturity) compared to DSSAT model. Across the varieties, there was over-estimation for simulated leaf area index (LAI) while total leaf number (TLN) fitted well with the observed values. Samara estimates were found to be the closet with the lowest RMSE values (<3 leaves for TLN and <1.0 m2/m2 for LAI) followed by DSSAT and APSIM respectively. Prediction of grain yield and biomass was less accurate for both calibration and validation. The predictions using APSIM were found to be closest to the observed followed by DSSAT and Samara models respectively. Based on detailed field observations, this study showed that crop models captured well the phenology and leaf development of the photoperiod sensitive (PPS) varieties of West Africa, but failed to estimate accurately partitioning of assimilates during grain filling. APSIM and SAMARA as more mechanistic crop models, have a higher sensitivity of the adjustment of key parameters, notably the specific leaf area for APSIM in low PPS varieties, while SAMARA shows a higher response to parameters changes for high PPS varieties.

Item Type: Article
Divisions: Research Program : Innovation Systems for the Drylands (ISD)
Research Program : West & Central Africa
CRP: CGIAR Research Program on Dryland Cereals
CGIAR Research Program on Dryland Systems
Uncontrolled Keywords: Sorghum bicolor L. moench; Photoperiod sensitivity; APSIM; DSSAT; Samara
Subjects: Others > Crop Physiology
Mandate crops > Sorghum
Others > West Africa
Depositing User: Mr Ramesh K
Date Deposited: 23 Dec 2016 05:30
Last Modified: 05 Apr 2017 06:11
URI: http://oar.icrisat.org/id/eprint/9818
Official URL: http://dx.doi.org/10.1016/j.fcr.2016.10.015
Projects: UNSPECIFIED
Funders: UNSPECIFIED
Acknowledgement: This work constitutes part of doctoral research studies funded byWASCAL Graduate research programme. Experimental work wassupported by ICRISAT, Mali and funded through the CGIAR Coop-erative Research Programs, Dryland Systems and Dryland Cereals.The authors thank Dr. Neil Huth for his assistance during calibrationof the varieties in APSIM and also Dr. Benoit Clerget for permis-sion to use part of his data reported on sorghum physiology projectexperiments in West Africa for the validation of the models.
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