Projection and Zoning the Frequency of Adverse temperature extreme events Wheat crop in western Iran

Background and Objective: Climate change poses a significant global threat to human health and impacts various sectors of society, including water security and agricultural production. Wheat, as one of the most important crops worldwide, plays a vital role in ensuring food security and the livelihoods of farmers. With an annual production exceeding 600 million tons, it ranks as the third largest crop after maize and rice. Given that most wheat is grown in rainfed areas, the impacts of climate change on these crops are particularly significant. This research aims to examine the effects of climate change on wheat yield in different regions and provide strategies to reduce its vulnerability to these changes. The study seeks to analyze climatic data and use simulation models to investigate the challenges facing wheat due to rising temperatures and changing precipitation patterns.
 
Materials and Methods: This study utilized climatic and agricultural data from several regions where wheat is cultivated. In this context, maximum and minimum temperature data from 16 synoptic stations were collected, quality controlled, analyzed, and simulated for the future using the RCP 5.8 scenario. The frequency of adverse temperature phenomena was calculated based on the B.H.H agroclimatic index and interpolated across the entire study area using co-kriging. Analyses were conducted using statistical software and advanced models to identify the relationship between climatic variables and wheat yield.
 
Results and Discussion: Using linear regression modeling, the results indicated that in some stations, the slopes of maximum and minimum temperatures were negative, while in others, the slopes were positive. These changes were particularly evident in mountainous stations. The results showed an increasing trend in temperatures, especially minimum temperatures, and a significant rise in the risk of thermal stress for wheat. The findings indicated that rising temperatures significantly affect the reduction of the wheat growing season, with this impact being more pronounced in elevated areas. The likelihood of adverse maximum temperature events for wheat ranges from one to 23 occurrences for the mid-future scenario. The most vulnerable areas are located at higher latitudes within the study area, particularly regions where wheat cultivation is more prevalent, such as Dehgolan, Qorveh, and around Hamadan. Subsequently, the study area was classified into four distinct zones. The analysis of variance test showed significant differences among classes with a statistic of 10754.91 and a p-value of 0.000. Approximately 38% of the western country will face severe exposure to adverse maximum temperature events for wheat, with frequencies ranging from 15 to 23 occurrences.
 
Conclusion: Based on the findings of this research, it can be concluded that climate change represents a serious threat to wheat production, necessitating that farmers and policymakers consider appropriate strategies to reduce the vulnerability of this crop. Such strategies may include selecting temperature-resistant varieties and adjusting planting times. This research clearly demonstrates that, despite the challenges posed by climate change, implementing suitable measures can improve wheat yield and enhance the sustainability of its production.