Document Type : Research Paper - Modeling
Authors
1 Department of Production Engineering and Plant Genetics, Faculty of Agriculture, Khorramabad, Iran
2 Department of Agronomy and Plant Breeding, Faculty of Agriculture, Lorestan University, Khorramabad, Iran.
3 Department of Agroecology, Environmental Sciences Research Institute, Shahid Beheshti University, Tehran, Iran
Abstract
Introduction: Canola is a crucial industrial crops in the country's oil production in order to produce high-quality edible oil. However, the challenges related to water allocation to the spring crops at the end of the autumn canola growth period have become one of the obstacles to achieving optimal production levels for this crop. Addressing this challenge is essential for enhancing the productivity and sustainability of rapeseed farming in the country.
Materials and Methods: This research aimed to evaluation the effect of withholding irrigation treatments on different growth stages of autumn canola production. It also seeks to identify the suitable canola cultivar and the optimal growth stage for implementing withholding irrigation through a long-term simulation experiment using the APSIM-canola simulation model. It was carried out in four counties of Lorestan province including Khorramabad, Pol-e Dokhtar, Kuhdasht and Aleshtar in Faculty of Agriculture, Lorestan University. For this purpose, in the first step, the model was evaluated using two independent data sets. The cultivars included Hyola308, Hyola401 and RGS003 (early, mid and late maturity cultivars, respectively), and the irrigation treatments of the study included full irrigation, withholding irrigation at the flowering stage, withholding irrigation at the pod initiation stage, and withholding irrigation at the grain filling stage.
Results and Discussion: The evaluation of the APSIM-canola simulation model demonstrated that this model has a good capability to accurately predict autumn canola grain yield evidenced by an estimation error (nRMSE) of 18%. The results showed that the variability of the autumn canola grain yield across all of the studied locations, different treatments of withholding irrigation and cultivars was significant. Notably, the highest yield was recorded at 4.49 t ha-1 in Khorramabad, while the lowest was 1.96 t ha-1 in Aleshtar. Furthermore, the analysis of dry matter production indicated a considerable variability across different locations and treatments in a way that the highest and lowest amount of dry matter between location belonged to Khorramabad and Aleshtar (17.80 and 8.89 t ha-1, respectively). The research findings highlighted the crucial role of climatic conditions, particularly air temperature, in informing management practices such as cultivar selection and irrigation strategies. Based on this, the use of Hyola401 mid maturity cultivar in Pol-e Dokhtar, Khorramabad and Kuhdasht counties along with full irrigation throughout the growing season resulted in the highest grain yields of 5.38, 5.36, and 4.49 t ha-1, respectively. It was while in Aleshtar (with cooler temperature condition compared to other locations) employing the early maturity cultivar of Hyola308 coupled with withholding of irrigation before the end of the growing season led to the highest amount of grain yield (2.64 t ha-1) in this region.
Conclusion: The findings of this research indicate that in the cultivation of autumn canola, it is crucial to consider climatic factors, particularly air temperature, as well as the accessibility of water resources when selecting the appropriate cultivar. Specifically, under conditions where water availability is restricted, opting for early-maturing and mid-maturing cultivars can serve as an effective strategy. This approach not only mitigates the adverse impacts of water scarcity but also contributes to the sustainable production of canola in various regions. By aligning cultivar selection with the specific climatic and water conditions of an area, farmers can enhance crop resilience and ensure a more stable yield, ultimately supporting the agricultural sustainability of their communities.
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