University of Tehran Press Iranian Journal of Soil and Water Research 2008-479X 57 4 2026 06 22 The Effect of Air Relative Humidity on the Crop Water Requirement of Basil in the Greenhouse The Effect of Air Relative Humidity on the Crop Water Requirement of Basil in the Greenhouse 827 845 107493 10.22059/ijswr.2026.412822.670119 FA Amirhosein Asadi Department of Water Engineering and Management, Faculty of Agriculture, Tarbiat Modares University, Tehran, Iran 0009-0009-8727-4787 Ahmad Ahmadinik Department of Water Engineering and Management, Faculty of Agriculture, Tarbiat Modares University, Tehran, Iran 0000-0002-1724-3899 Journal Article 2026 04 16 Due to strategic location in the vicinity of the sea, Iran has a unique capacity to benefit from this great potential for development in different fields. In the field of agricultural development in coastal areas, various ideas have been developed in the world, one of the successful examples of which is the coastal greenhouse system. This system, by simulating the hydrological cycle, enables the simultaneous production of crops and freshwater. In this regard, in the present study, by simulating the functional principles of the coastal greenhouse system, a physical modeling of a similar cultivation media was conducted with smart equipment. The main aim of this study is to evaluate the effect of high air relative humidity (more than 80%) on the crop water requirement and crop yield of Basil in greenhouses cultivation media and compare it with the corresponding values in controlled cultivation media with normal relative humidity, such as conventional greenhouse conditions. In this study, plant cultivation was carried out by randomized complete block design in pots, and the crop water requirement were determined using the micro-lysimeter method. By the results, the crop yield by wet weight in the conventional and coastal greenhouse cultivation medias was 15.98 and 15.83, by dry weight was 1.62 and 1.53 grams, respectively. However, the total and average of Basil water requirement during the cultivation period were 45.20 mm and 1.33 mm/day in the coastal greenhouse, and 87.66 mm and 2.58 mm/day in the conventional greenhouse, respectively. Due to strategic location in the vicinity of the sea, Iran has a unique capacity to benefit from this great potential for development in different fields. In the field of agricultural development in coastal areas, various ideas have been developed in the world, one of the successful examples of which is the coastal greenhouse system. This system, by simulating the hydrological cycle, enables the simultaneous production of crops and freshwater. In this regard, in the present study, by simulating the functional principles of the coastal greenhouse system, a physical modeling of a similar cultivation media was conducted with smart equipment. The main aim of this study is to evaluate the effect of high air relative humidity (more than 80%) on the crop water requirement and crop yield of Basil in greenhouses cultivation media and compare it with the corresponding values in controlled cultivation media with normal relative humidity, such as conventional greenhouse conditions. In this study, plant cultivation was carried out by randomized complete block design in pots, and the crop water requirement were determined using the micro-lysimeter method. By the results, the crop yield by wet weight in the conventional and coastal greenhouse cultivation medias was 15.98 and 15.83, by dry weight was 1.62 and 1.53 grams, respectively. However, the total and average of Basil water requirement during the cultivation period were 45.20 mm and 1.33 mm/day in the coastal greenhouse, and 87.66 mm and 2.58 mm/day in the conventional greenhouse, respectively. https://ijswr.ut.ac.ir/article_107493_3d9636a7d2fe6df44eca21e18c8e8c5d.pdf