Soil moisture depletion rates on sunflower yield

ntroduction: Optimizing the irrigation water resource is essential due to its scarcity, so it is therefore important to consider efficient crops such as sunflower. Objective: To estimate the sunflower grain yield at different levels of available soil moisture depletion to estimate water use efficiency (WUE) of the crop under different water conditions. Methodology: Seven treatments resulting from four soil moisture levels (40, 60, 60, 80 and 100 % of available soil moisture [ASM] and two periods of sunflower growth (from emergence to the beginning of flowering [first stage] and from flowering to physiological maturity [second stage]). Results: The highest grain yield (5.5 t·ha-1) and WUE of (0.922 kg·m-3) were recorded in the 60-60 % ASM treatment in the first and second stages of sunflower development, and by consuming 62.8 cm of water. Limitations of the study: The results should not be extrapolated to conditions outside the study levels. Originality: To generate research methodologies to quantify, in a more realistic way, the relationship of yields with crop water requirements. Conclusions: The highest WUE in sunflower (0.922 kg·m-3) was recorded when it consumed 31.4 and 28.12 cm of water, with 58.8 and 60.5 % of ASM in the first and second stages, respectively, which was similar to the 60-60 % treatment.