Introduction
Wheat is the most important strategic crop both globally and nationally. It is one of the most critical staple crops in Iran, playing a vital role in food security and economic stability. However, its production is highly sensitive to climatic fluctuations, including temperature changes, precipitation variability, and extreme weather events. In semi-arid and arid regions such as Khorasan Razavi province, where agriculture is heavily dependent on climatic conditions, understanding yield trends and their underlying drivers is crucial for optimizing production and ensuring sustainability. This study aims to analyze the spatiotemporal variations in irrigated and rainfed wheat yield in Khorasan Razavi over an 11-year period (2011–2021) across 29 counties and identify key climatic and management-related factors influencing these changes. The findings provide essential insights into the spatial and temporal patterns of yield fluctuations and help inform adaptive strategies for mitigating agroclimatic risks.
Materials and Methods
The study was conducted in Khorasan Razavi province, located in northeastern Iran, covering 29 counties with diverse climatic and agronomic conditions. The data for this study were obtained from the Agricultural Jihad Organization's website, including annual yield records for irrigated and rainfed wheat. To model the yield trends, polynomial functions were employed. Linear, quadratic, and cubic regression models were applied, and the best-fitting model was selected using the Akaike Information Criterion (AIC). Based on yield trends, counties were classified into four classes: (1) Increasing, where yield has shown a significant and consistent upward trend; (2) Stagnating, where yield has remained relatively stable with no substantial increase or decrease; (3) Never Improved, where no significant improvement in yield was observed throughout the study period; and (4) Collapsed, where a sharp decline in yield occurred. The spatial distribution of yield variations was also analyzed to identify regional patterns.
Results and Discussion
The results of the study showed that in Khorasan Razavi province, the average irrigated wheat yield increased by about 1000 kilograms per hectare (kg ha-1) over an 11-year period. However, this increase was not uniformly distributed across all counties; in half of the counties, an improvement in yield was observed, while in the other half, stagnation or no improvement in yield was observed. Furthermore, only one county experienced a significant decrease in yield. Regarding rainfed wheat, the average yield over the 11-year period increased by about 800 kilograms per hectare (kg ha-1), indicating the product's sensitivity to environmental and management factors in different regions of the province. Spatial analysis revealed that the pattern of wheat yield changes across the province was heterogeneous; central counties such as Torbat Heydarieh, Fariman, and Nishapur experienced yield improvements, while areas like Khushab and some northern and southern counties faced decreases, stagnation, or no improvement in yield. Temporal variation charts showed that both types of wheat (irrigated and rainfed) were influenced by long-term climatic and management changes. Overall, management practices in the province have led to yield improvements, but in some counties, climatic changes and severe weather fluctuations, especially in the final year of the study, neutralized the positive effects of agricultural management, resulting in stagnation or no improvement in wheat yield. This study investigates the variations in precipitation and temperature over the agricultural years 2011 to 2021, with precipitation ranging from 60 to 430 mm and mean temperature varying between 10°C and 22.5°C. Significant fluctuations in both factors are highlighted, particularly the severe drought in 2020-2021 (the final year of the study), which had a notable impact on agricultural productivity. This suggests that even with improved farming techniques, climate adaptation measures including changes in sowing date, drought-resistant cultivars, soil moisture conservation techniques, and enhanced irrigation systems are necessary to sustain long-term productivity. Also, several counties classified as Collapsed, Stagnating or Never Improved may require additional investment in agricultural extension services, farmer training, and climate-smart agricultural practices to bridge the yield gap.
Conclusion
The results emphasize the need for adaptive management strategies to enhance wheat yield stability in Khorasan Razavi. Although agronomic improvements have led to yield increases in many areas, the effects of climate fluctuations remain a major challenge. Policymakers and agricultural planners should prioritize climate adaptation measures, such as changes in sowing date, improved irrigation techniques, using drought-resistant crop varieties, and precision agriculture, to mitigate climate-related yield losses and ensure sustainable wheat production in the region. |
