Deficit Irrigation and Soil Amendment as Drought Adaptation Strategies: Water Use Efficiency in Pot Experiments With Wheat

ABSTRACT Amidst climate change and recurring droughts, increasing irrigation water amount and frequency alone is not a definitive solution to address water scarcity in agricultural crop production, particularly in soils with poor water retention capacity. This study evaluated the effects of two drought adaptation strategies (deficit irrigation and soil amendment) based on data from a pot experiment. The results indicated that the combined use of a soil amendment product with deficit irrigation enhanced the water use efficiency (WUE). Deficit irrigation starting in the midstage combined with the soil amendment product achieved higher water use efficiency (0.24 and 0.32 g/L for spring and winter wheat, respectively). This is considered to be an optimum WUE, as it was attained with a reduced actual evapotranspiration of 3.78 L for spring wheat. In contrast, with full irrigation, a higher WUE of 0.40 g/L was achieved but with approximately double the actual evapotranspiration of 6.10 L. Additionally, the drought coping of wheat was manifested by the stage‐wise adjustment of its crop coefficient. In general, the influence of deficit irrigation on the crop coefficient adjustment was more pronounced than the effect of soil amendment was.