Document Type : Research Paper
Authors
1 Assistant Professor of Forests, Rangelands and Watershed Management Engineering, Kohgiluyeh and Boyerahmad Agricultural and Natural Resources Research and Education Center, Agricultural Research, Education and Extension Organization, Kohgiluyeh and Boyerahmad, Iran
2 Assistant Professor, Soil Conservation and Watershed Management Research Institute, Agricultural Research, Education and Extension Organization, Tehran, Iran
Abstract
Introduction
The role of water in agricultural development and economic growth is undeniable. The imbalance between water supply and demand in Iran has created a challenge for the management of water resources, especially in agriculture. Paying serious attention to water productivity and improving it through appropriate methods and policies is one of the most effective solutions to address the water crisis and enhance the quantity and quality of agricultural production. The concept of water productivity is to produce the best and most products with the least amount of water. Agricultural water productivity has received serious attention in recent years from scientific societies related to irrigation and agriculture. The variation in water productivity for different crops at the local level and in comparison with other countries with similar climatic conditions indicates the potential for increasing agricultural water productivity. In the present research, the productivity of agricultural and horticultural products was investigated through field surveys, field measurements, and remote sensing analyses.
Materials and methods
First, the status of water resources in the aquifer, including changes in groundwater levels and programmable water, was investigated. Then, the water consumption of agricultural plants was calculated using the difference between effective rainfall and plant water requirement (evaporation-transpiration). In the next step, the cultivated area of Basht Aquifer was examined using Sentinel-2 satellite images in Google Earth Engine software. Yield, dates of planting and harvesting, and irrigation times for agricultural products were verified through questionnaires completed by farmers and experts. After that, the water requirement of the current cultivation pattern was calculated using the FAO Penman-Monteith method. Finally, the productivity of different products was determined by evaluating the products in terms of productivity.
Results and discussion
The area of the alluvial aquifer was 45.5 km², with an average length of about 25 km and a width of 5 km. The total volume of discharge and extraction from groundwater resources was 39.723 MCM. The infiltration amount of the Basht alluvial aquifer was calculated to be 7.905 MCM. By joining the outflow streams, including transfer streams through different elevations, the aquifer was recharged with a total of 20.377 MCM. Calculations using the FAO Penman-Monteith method showed that the water requirements of the dominant crops in the aquifer, including citrus fruits, wheat, barley, corn, canola, watermelon, rice, legumes, and alfalfa, were 9170, 5630, 4821, 7863, 5411, 9291, 20234, 5225, and 14083 m³, respectively. In total, the amount of water consumed by the agricultural products of Basht Aquifer was nearly 45 MCM, which was approximately equivalent to 1 m³m⁻² of the cultivated area. This is 2.64 times higher than the amount of water that can be programmed for agriculture (17 MCM).
Conclusion
The cultivation pattern will be influenced by parameters such as the climatic compatibility of products, the potentials of water and soil resources, regional needs, customs and interests of local people, and economic evaluation and income from production. Any change in the cultivation pattern should consider all social, economic, and environmental factors. However, given the existing conditions of the water sources, any cultivation pattern (even those considering high income) that increases discharge compared to the aquifer's recharge sources will be dangerous for future sustainability and will cause groundwater salinization and aquifer subsidence. Cultivation of high water-consumption plants such as seed corn should be stopped due to the severe water conditions of the region, and more investment should be made in developing crops such as canola, which are better adapted to the region's climate.
Keywords
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