Abstract: (1 Views)
Introduction and Objective: The water scarcity crisis and the high share of agriculture in water consumption have made improving irrigation efficiency a key pillar of water resource management policies. The agricultural sector, as the largest consumer of fresh water, accounts for more than 70% of global water resources and is at the center of this crisis. In Iran, about 80% of groundwater resources have been consumed, and the extraction index has exceeded 90%, far beyond the permissible limit of 40%. In such circumstances, the concept of water productivity as a key indicator for measuring the efficiency of water consumption in agriculture becomes doubly important, and irrigation efficiency, as one of the most determining factors affecting water productivity, plays a central role. The Tajan Basin in Mazandaran Province, as one of the most important agricultural hubs in the north of the country, faces water stress and groundwater depletion. A review of previous studies shows that most of them have either been limited to analyzing the effect of a specific irrigation method on a particular crop or have merely examined the physical aspects of water productivity, and less attention has been paid to the simultaneous analysis of cropping pattern, economic water productivity, and farmers' risk-averse behavior within a multi-criteria decision-making framework. Therefore, this study aimed to analyze the effect of improving irrigation efficiency on cropping pattern and economic water productivity in the Tajan Basin using the Positive Multi-Attribute Utility Programming (PMAUP) model.
Materials and Methods: To achieve the research objective, the PMAUP model was used, which allows for the simultaneous consideration of expected gross profit and risk aversion in farmers' decision-making. The utility function was considered as Cobb-Douglas type, and the calibration method proposed by Gutiérrez-Martín was used by equating the Marginal Rate of Substitution (MRS) with the Marginal Rate of Transformation (MRT) to extract the utility function parameters. The required data, including cultivated area, yield, prices, and production costs of selected irrigated crops, were collected from reliable sources of the Ministry of Agriculture-Jihad for the 2022-2023 crop year. After calibrating the model, the effect of increasing irrigation efficiency under scenarios of 10% to 30% on cropping pattern composition, gross profit, average water consumption per hectare, and economic water productivity was examined.
Results: The calibration results showed that the model could well reproduce the observed cropping pattern in the region, indicating the validity of the model in representing farmers' decision-making behavior. Based on the calibration results, the weight of the profit criterion (0.73) was much higher than the weight of the risk criterion (0.27), indicating the higher importance of profit in farmers' decision-making in the region. The results showed that improving irrigation efficiency creates significant changes in the cropping pattern of the region. In the base scenario, high-quality rice with a share of 45.6% of irrigated land was the dominant crop in the region. With a 10% increase in irrigation efficiency, the area under high-quality rice decreased to 34.2%, while high-yield rice increased to 38.8% and soybean to 9.5%. In the 20% scenario, high-yield rice with a share of 45.6% replaced high-quality rice as the dominant crop, and soybean reached 22.1%. Finally, in the 30% scenario, the cropping pattern reached a new equilibrium in which high-yield rice with 46.5%, soybean with 24.7%, and high-quality rice with 26.6% formed the three main crops, and wheat and canola were almost eliminated from the cropping pattern. The complete elimination of canola in this scenario can be interpreted as a logical consequence of the model, as canola with lower gross profit and similar water requirement to soybean is considered a suboptimal option. From the perspective of economic indicators and productivity, gross profit in the 30% scenario increased by 15.88% compared to the base scenario, reaching 730.810 million rials per hectare. Average water consumption per hectare decreased by 15.17% to 6873.328 cubic meters, and economic water productivity increased by 36.62% to 0.1063 million rials per cubic meter. The notable point is that the reduction in water consumption per hectare was accompanied by an increase in profit, creating a win-win situation for farmers and water resource management. However, the expansion of water-intensive crops such as high-yield rice and soybean revealed a rebound effect, whereby part of the water savings from improved efficiency was offset through the expansion of water-intensive crop cultivation.
Conclusion: Based on the findings of this study, it is recommended that policymakers and water resource managers prioritize investment in improving irrigation efficiency at levels of 10% to 20%, as the economic return of these levels is higher than higher levels. Since improving irrigation efficiency alone cannot lead to a reduction in total water consumption at the basin level, it is necessary that these policies be accompanied by simultaneous management of cropping patterns and cultivated area, and that economic instruments such as water pricing, compensatory payments, and water quota allocation be used. Special support policies are also needed to maintain the production of strategic crops such as wheat and canola, and encouraging farmers to cultivate soybean instead of part of the high-quality rice area can maintain farmers' profit while reducing water consumption.
Materials and Methods: To achieve the research objective, the PMAUP model was used, which allows for the simultaneous consideration of expected gross profit and risk aversion in farmers' decision-making. The utility function was considered as Cobb-Douglas type, and the calibration method proposed by Gutiérrez-Martín was used by equating the Marginal Rate of Substitution (MRS) with the Marginal Rate of Transformation (MRT) to extract the utility function parameters. The required data, including cultivated area, yield, prices, and production costs of selected irrigated crops, were collected from reliable sources of the Ministry of Agriculture-Jihad for the 2022-2023 crop year. After calibrating the model, the effect of increasing irrigation efficiency under scenarios of 10% to 30% on cropping pattern composition, gross profit, average water consumption per hectare, and economic water productivity was examined.
Results: The calibration results showed that the model could well reproduce the observed cropping pattern in the region, indicating the validity of the model in representing farmers' decision-making behavior. Based on the calibration results, the weight of the profit criterion (0.73) was much higher than the weight of the risk criterion (0.27), indicating the higher importance of profit in farmers' decision-making in the region. The results showed that improving irrigation efficiency creates significant changes in the cropping pattern of the region. In the base scenario, high-quality rice with a share of 45.6% of irrigated land was the dominant crop in the region. With a 10% increase in irrigation efficiency, the area under high-quality rice decreased to 34.2%, while high-yield rice increased to 38.8% and soybean to 9.5%. In the 20% scenario, high-yield rice with a share of 45.6% replaced high-quality rice as the dominant crop, and soybean reached 22.1%. Finally, in the 30% scenario, the cropping pattern reached a new equilibrium in which high-yield rice with 46.5%, soybean with 24.7%, and high-quality rice with 26.6% formed the three main crops, and wheat and canola were almost eliminated from the cropping pattern. The complete elimination of canola in this scenario can be interpreted as a logical consequence of the model, as canola with lower gross profit and similar water requirement to soybean is considered a suboptimal option. From the perspective of economic indicators and productivity, gross profit in the 30% scenario increased by 15.88% compared to the base scenario, reaching 730.810 million rials per hectare. Average water consumption per hectare decreased by 15.17% to 6873.328 cubic meters, and economic water productivity increased by 36.62% to 0.1063 million rials per cubic meter. The notable point is that the reduction in water consumption per hectare was accompanied by an increase in profit, creating a win-win situation for farmers and water resource management. However, the expansion of water-intensive crops such as high-yield rice and soybean revealed a rebound effect, whereby part of the water savings from improved efficiency was offset through the expansion of water-intensive crop cultivation.
Conclusion: Based on the findings of this study, it is recommended that policymakers and water resource managers prioritize investment in improving irrigation efficiency at levels of 10% to 20%, as the economic return of these levels is higher than higher levels. Since improving irrigation efficiency alone cannot lead to a reduction in total water consumption at the basin level, it is necessary that these policies be accompanied by simultaneous management of cropping patterns and cultivated area, and that economic instruments such as water pricing, compensatory payments, and water quota allocation be used. Special support policies are also needed to maintain the production of strategic crops such as wheat and canola, and encouraging farmers to cultivate soybean instead of part of the high-quality rice area can maintain farmers' profit while reducing water consumption.
Keywords: Positive Multi-Attribute Utility Programming (PMAUP), Farmers', Risk Aversion, Water Rebound Effect, Agricultural Water Productivity, Mazandaran.
Type of Study: Research |
Received: 2026/09/27 | Accepted: 2026/10/13
Received: 2026/09/27 | Accepted: 2026/10/13
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