Understanding and modelling compound climate and weather events and their impacts on oilseed rape

MD Rafique Ahasan Chawdhery

Doctoral thesis

Abstract:

Winter oilseed rape (Brassica napus L., WOSR) is the most essential source of vegetable oil in Europe. Compound agrometeorological events (CEs) are considered to be one of the main factors controlling crop growth and yields under changing climate conditions. To increase the WOSR yield per unit area, utilizing appropriate farming management and sustainable adaptation strategies is now a growing concern. The complex interaction of temperature and precipitation events has major influences on the growth and yield of WOSR. The main focus of the study was to assess the simulation performance of the CSM-CROPGRO-Canola model (incorporated in the Decision Support System for Agrotechnology Transfer (DSSAT) program) for the first time in the Czech Republic. Based on the observed growth and yield parameters of WOSR in the growing seasons 2020–2021 (dry conditions) and 2021–2022 (normal conditions), the study was carried out using three WOSR varieties (Architect, Temptation, and Sněžka) in three different climatic regions (Chrastava, Staňkov, and Vysoká). These varieties were added to the DSSAT crop variety database as new varieties, and their parameters were supplemented based on the experimental field data. Model calibration and evaluation were performed based on the root mean square errors (RMSEs) for each variety. For the Architect, Temptation, and Sněžka, the performance agreement between the observed and simulated yields revealed lower RMSE values of 0.26 t ha-1, 0.04 t ha-1, and 0.07 t ha-1, respectively. Regarding seed oil content, Architect, Temptation, and Sněžka had corresponding RMSEs of 1.18%, 0.67%, and 1.19%, respectively. These results were used to evaluate the model's calibration accuracy and performance, and it was found to be well enough for simulating the selected WOSR varieties for experimental activities. Temperature variations have an impact on the growth and development of WOSR, and the warm temperature region of Chrastava has lower leaf area index (LAI) values for Architect, Temptation, and Sněžka, 3.75, 3.69, and 3.57 m2 m-2, respectively. On the other hand, Vysoká exhibited higher growth and LAI values as a normal temperature region, with LAI values for Architect, Temptation, and Sněžka of 4.73, 4.78, and 4.69 m2 m-2, respectively. Under the projected temperature scenario, the highest simulated maximum LAI was recorded from the Vysoká location with the Sněžka variety, while the Chrastava location showed the lowest simulated maximum LAI with the Architect variety. In addition, the frequency of occurrence of CEs (heat stress during flowering and grain filling stages, black frost, water logging during seeding, and floral bud development) was quantified and evaluated. Projections of CE occurrence for the periods 2021–2040 and 2041–2060 showed that the hot and wet scenarios will experience an increase in heat stress and water logging conditions during flowering and grain-filling stages in all experimental locations. However, the cold and dry scenario will be more vulnerable to a significant rise in the black frost event. Based on the evaluation of the climatic condition, Sněžka and Temptation varieties were found to be the most potential varieties for seed and oil yield, respectively. Moreover, the Vysoká location indicated the most suitable cropping location for WOSR. The findings of this doctoral study will contribute to our understanding of complex interactions among compound events and WOSR crop production dynamics. By utilizing the CSM-CROPGRO-Canola model as a tool to address these effects, we can improve WOSR management strategies.

Keywords

Winter oilseed rape (WOSR), compound events, CSM-CROPGRO-Canola model, climate change, crop simulation, growth, yield, oil

Language used: English

Date on which the thesis was submitted / produced: 27. 8. 2023

Thesis defence

• Supervisor: doc. Dr. Mgr. Vera Potopová
• Reader: Jan Haberle, externi, Jan Mikulka, externi, Petr Hlavinka, externi

Czech University of Life Sciences Prague

Faculty of Agrobiology, Food and Natural Resources

Doctoral programme:
Plant Sciences