Crop Coefficient Estimation and Effect of Abscisic Acid on Red Cabbage Plants (Brassica oleracea var. Capitata) under Water-Stress Conditions

Understanding the anticipated impact of climate change on agriculture, as well as water conservation, is critical to achieving food security. Therefore, during this critical time and due to reduced water resources and increased food demand, it is important to study the impact of water-stress conditions on crops. Two successive seasons were carried out through the 2021 and 2022 seasons to estimate the crop coefficient (K-c) and study the effect of abscisic acid on red cabbage plants (Brassica oleracea var. capitata) under water-stress conditions at a private farm in the Bilbeis region, Sharqia Governorate, Egypt. The aim was to estimate the crop coefficient (K-c) and effect of different concentrations of abscisic acid (ABA) (0, 25, 50, and 75 ppm) under various irrigation levels (100, 80, and 60% of field capacity "FC") on the growth process and yield parameters of red cabbage plants. The results revealed that the average estimated crop coefficient (K-c) for red cabbage crops under standard conditions, 100% of FC, was 0.75, 1.07, 1.2 and 0.88 and 0.77, 1.2, 1.25 and 0.82 for Initial, Development, Mid, and End stages during the 2021 and 2022 growing seasons, respectively. Data collected during both seasons clearly showed that all treatments significantly increased both the plant's growth process and yield parameters when compared to the control. However, abscisic acid (ABA, 75 ppm) application with irrigation requirements (80% of FC) was statistically the most effective treatment in this study. Hence, this means a water savings of 20% can be achieved without significantly compromising the yield.