Crop water productivity mapping using aster imagery for irrigated fields of Al-Kharj region in Eastern province of Saudi Arabia

Overwhelming emphasis of this study was to develop comprehensive sets of simplified methods and protocols for water productivity mapping (WPM) using high spatial resolution satellite images (ASTER), based on combination of crop classification, yield, and water use (actual evapotranspiration) computation for crops using thermal band data and surface energy balance models. The study used satellite images for the year 2012 and focused on Water Productivity Mapping (WPM) of wheat, alfalfa, corn and Rhodes grass fields under centre pivot sprinkler irrigated system at Todhia Arable Farm of the Al-Kharj region, in Eastern province of Saudi Arabia. Crop water productivity map (WPM) was generated for the whole farm by dividing the crop productivity map (CPM) with water use map (WUM). The water used by different crops varied considerably depending on the crop growing season in seasonal crops (wheat and corn) and the harvesting/cutting schedules in alfalfa and Rhodes grass, which are multi-cut crops. The highest water productivity (t/ha mm) was observed in corn (1.24), followed by Rhodes grass (0.55) wheat (0.4) and alfalfa (0.38).