Estimating the Climate Water Budget and Water Consumption of the Wheat Crop in Salah Al-Din Governorate for the Period 1990-2022

Abstract

This study utilizes Community Water Model - CWatM to calculate reference evapotranspiration and estimate the climate water budget using field data and remote sensing data obtained from three different stations in For Salah ad-Din Governorate in Iraq. The evapotranspiration calculation in CWatM is based on the FAO method, which necessitates input data that obtained from climate stations as well as the utilization of satellite images and remote sensing technology. The results showed obvious a pronounced deficit at Tikrit and Touz stations during the wheat growing season as well as high water consumption. Conversely, the Baiji station showed a water surplus during winter season across all years except for 1994, which exhibited a water deficit. During the spring season, Baiji station consistently records a water deficit.

Furthermore, there is a noticeable decrease in water consumption during the wheat growing season at Baiji compared to Tikrit and Touz stations, indicating a shift of suitable regions for wheat cultivation towards the north of the study area. The Evapotranspiration record showed a general trend towards decrease, with February being the highest for consecutive negative changes for all three stations.

As for water consumption, a general trend towards decrease was recorded during most of the growth season months, including February for both Baiji and Tuz stations, respectively. However, Tikrit station recorded the lowest directional coefficient in January. Regarding positive changes, both evaporation/production and water consumption showed a trend towards increase due to rising temperatures during April for all three stations consecutively. Meanwhile, the CWB recorded May as having the highest positive change across all study stations.