Yield prediction of wheat at different sowing dates and irrigation regimes using the AquaCrop model

Abstract

Water efficiency models are playing an increasingly important role in helping agricultural activities adapt to climate change. AquaCrop is one of the models that can accurately correlate water-plant-climate parameters. In this study, the effects of irrigation strategies (I1; rainfed, I2; irrigation at Germination (G)+Tillering (T)+Heading (H) stages, I3; irrigation at G+H stages, I4; irrigation at G+T stages) and sowing dates (SD1; normal sowing date, SD2; late sowing date) on winter wheat yield and soil water conditions were investigated in semi-arid climate conditions. Biomass, grain yield, soil water content and crop canopy cover values observed in field conditions and simulated by AquaCrop. According to results SD1 did not have a negative effect on grain yield and biomass however SD2 would significantly reduce grain yield and biomass amount. Considering the biomass and grain yields in terms of irrigation, the highest yield was obtained in the irrigation water applied during the I2SD1 treatment. The yield reduction was 39% in rainfed treatments, 22% when irrigated in G+T periods, and 5% when irrigated in G+H stages. The model predicted 2-year grain yield and biomass values more accurately in SD1 than in SD2. The model predicted yield, biomass, soil moisture content and canopy cover values with an acceptable accuracy.