Effect of Climate Change on Water Requirement of Rice Crop in the Tajan Watershed

Document Type : Research Paper


1 Watershed Management, Department of Watershed Management, Faculty of Natural Resources and Marine Sciences, Tarbiat Modares University, Noor, Iran.

2 Department of Watershed Management, Faculty of Natural Resources and Marine Sciences, Tarbiat Modares University

3 Department of Water Management and Engineering, Faculty of Agriculture, Tarbiat Modares University, Tehran, Iran.


Climate change has greatly challenged the management of water resources by affecting the water needs of crops. In this research, the effect of climate change on the water requirement of the rice crops was simulated in the study area of the Tajen watershed and its changes until 2060 were studied. Lars-WG software and HadGEM2 model outputs under climate scenarios (RCP 2.6) and (RCP 8.5) have been used to investigate climate change. To evaluate the impact of climate change in the next 40 years on water demand, using CROPWAT 8.0 software, the amount of potential and actual evapotranspiration and effective rainfall for the future period was calculated and the water demand of the crop was determined and compared with the water demand of the current period. took The results showed that the average water requirement of rice in the RCP 2.6 scenario in 2021-2040 and 2041-2060 is equal to 658.27 and 658.46 mm, respectively, and in RCP 8.5 scenario in 2021-2040 and 2041-2060, It is expected to be 672.93 and 673 mm, respectively. Therefore, according to both climate scenarios, the water requirement has increased in all time periods compared to the historical period, which is about 648 mm. Climate change by affecting the amount of evaporation and transpiration and effective rainfall causes the increasing trend of rice water requirement in both climate scenarios in the future period (2060-2021). The increase in water demand in future period (2041-2060) compared to the near future time period (2021-2040) is more than the historical period.


Main Subjects

  • Receive Date: 05 February 2023
  • Revise Date: 16 July 2023
  • Accept Date: 13 September 2023
  • Publish Date: 13 September 2023