Combination of remote sensing and meteorological data for estimation of crop water requirements in the irrigated perimeter of Tadla in Morocco

In arid and semi-arid regions, agriculture is an important element of the national economy, but this sector is a large consumer of water. In a context of high pressure on water resources (climate change, population growth, desertification, etc.), an appropriate management is required. The development of remote sensing tools: temporal, spatial and spectral resolution offers a better opportunity for hydro-agricultural management. The main objective of this study is to combine climate data with that of optical remote sensing in order to estimate crop water requirements in the irrigated perimeter of Tadla. In semi-arid regions, such as Tadla Plain, a large quantity of water is lost by evapotranspiration (ET). The objective of this study is to use a scientific approach based on the modulation of evaporative demand for the estimation of crop water requirements. This approach is based on the FAO-56 method using image data from the Sentinel-2A and Landsat-8 satellites, and climate data: surface temperature, air humidity, wind speed, global solar radiation and precipitation. It also allowed the spatialization of crop water requirements on a large area of irrigated crops during the 2016–2017 agricultural season. Maps of water requirements have been developed. They show the variability over time of crop development and their estimated water requirements. The results obtained constitute an important indicator of how water should be distributed over the area in order to improve irrigation efficiency and protection of water resources.