Estimating Crop and Reference Evapotranspiration and Crop Factor and Some Growth Indicators for Wheat and Barley in Dhi Qar Governorate Using the CropWat Program

Abstract

Information about the average water consumption or evapotranspiration of crops is the basis for scheduling irrigation and the water requirements of plants, and choosing the appropriate crops for the region in light. This experiment was carried out to evaluate and calculate the ability of the CropWat program to estimate evapotranspiration rates, and plant consumptive water use for strategic crops in Iraq, including wheat and barley in Dhi Qar Governorate. The results of the study showed that the maximum root depth ranged between 1.20 m, and 1.10 m in the distance between the vegetative growth and flowering stages for wheat and barley crops, respectively. It was also noted that the crop evapotranspiration (ETc) values decreased at the beginning of the growing season, ranging from 0.79 mm day–1 to 1.57 mm day–1 for wheat and barley crops, respectively. Then, the values increased with the progress of the growing season and the increase of the vegetative mass of the plants, reaching 3.72 mm day–1 and 3.46 mm day–1 for wheat and barley crops, respectively. The reference evapotranspiration (ETo) values were also low in the first months of the year and were around 2.1 mm day–1 at the beginning, then gradually increased with the progress of the months of the year, reaching the maximum reference evapotranspiration values of 10.5 mm day–1 in the seventh month, and then the values decreased at the end of the season for wheat and barley crops.