Document Type : Research Paper
Authors
Water Engineering Department, Agriculture Faculty, Urmia University, Urmia, Iran
Abstract
Keywords
Main Subjects
In the world, most of the freshwater resources are used for agricultural activities, but the reduction of these resources in the recent years has led to a significant focus on water efficiency in this sector. Nowadays, the agriculture sector has increasingly entered to competitive space with other sectors in obtaining more water with low price, especially during the peak consumption time. It is clear that, farmers economically need to achieve the most optimal crop yield per unit of consumed water by increasing irrigation efficiency. Therefore, developing the best irrigation scheduling to the crop pattern is essential so that the farmers can accurately be enable to estimate the required water for their fields. It is mentioned that the fundamental factor in achieving the best irrigation planning is to calculate the accurate volume of required water. For this purpose, measuring the water requirement or estimating crop evapotranspiration (ET) has vital role for water conservation in watershed level. Evapotranspiration is a phenomenon in which water losses are a combination of two processes including evaporation (directly from the soil) and transpiration (from plants). This process depends on the several factors including type of vegetation cover, soil characteristics, climate, topography, and land use. Therefore, estimating ET for a large and vast region is faced with important and significant challenge. In recent years, remote sensing technology has become an efficient tool for data collection and developing high-precision evapotranspiration estimation techniques which is as one of the most important factors in agricultural water resource management. This study aims to determine the actual evapotranspiration of the pressurized irrigation of Dryas and Tootaghaj network using the SEBAL algorithm. In this direction, the water requirement and irrigation efficiency of the study area was evaluated.
This study was conducted in the pressurized irrigation network of Daris and Toot Aghaj in the southwest of the Lake Urmia basin. The crops in the study area include apple, pear, alfalfa, wheat, peach, apricot, cherry, plum, and sour cherry. In this research, 7 different Landsat 8 satellite images were utilized. The actual evapotranspiration in the study area was estimated using the SEBAL algorithm and the processed images were used with ENVI software.
The results of estimating actual evapotranspiration values in the study area indicate that the highest level of water loss through evapotranspiration was happened during the middle stages of the growing season, which corresponds to the period from mid-May to mid-July. The highest daily evapotranspiration value corresponds to the date of July 18, 2022, equal to 12.39 mmday-1. Based on the results of this study, the highest amount of seasonal evapotranspiration is related to the apple with a value of 773.934 mm, after that peach with a value of 763.714 mm and alfalfa with a value of 701.778 mm in the study area. have. Based on estimates and calculations, the total water requirement within the study area is 2,060,000 cubic meters. However, due to the entry of approximately 2,500,000 m3 of water into the network and the unauthorized use of wells within the studied area, a significant amount of water resources is being loosed due to unsuitable management. Therefore, a review of land water resource management in the Daryas and Toot Aghaj plains is crucial.
In this study, an attempt was made to evaluate the water consumption and management of pressurized irrigation networks in Daryas and Tootaghaj plains using remote sensing methods. The actual evapotranspiration of this network in 2022 was estimated to be approximately 2,060,000 m3, which is 18% higher compared to the water delivered to the network, which was 2,500,000 m3. It should be noted that changes in cropping patterns in the recent years have led to increase the extraction of groundwater by farmers, which could potentially cause irreparable damage to environmental, economic, and social areas in the face of the country's water crisis in the future. Finally, the results obtained from remote sensing technology and satellite images showed that monitoring and assessing the agricultural land status at large scales using this method has been reasonably accurate. It is possible to improve the distribution and efficiency of water in irrigation and drainage networks by creating maps of evapotranspiration and water productivity.
Z.E.: Writing – original draft, Formal analysis, Conceptualization, Data curation, Methodology, Validation, Writing – review & editing. J.B.: Writing – review & editing. V. R.: Writing – review & editing.
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The authors would like to thank Urmia University and West Azerbayjan province Jahad Keshavarzi for their kindley supports.
The study was approved by the Ethics Committee of the Urmia University. The authors avoided data fabrication, falsification, plagiarism, and misconduct.
The author declares no conflict of interest.
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