Foliar Spraying with Kaolin, Salicylic Acid And Urea on Squash Plants Under Different Water Stress Levels

Abstract

This research was carried out in Erah Research Station / Sewida  Agricultural Research Center / General Commission for Scientific Agricultural Research / Syria in the summer of 2022. The aim of this research was to evaluate the effect of foliar spraying with kaolin, salicylic acid and urea on some growth and productivity indicators of summer squash plants grown under water stress. Three irrigation levels were applied (100, 70, and 40% of field capacity), and three compounds were used for foliar spraying: kaolin (2%), salicylic acid (0.013%), urea (0.5%), and water (control treatment). The results showed a decrease in all indicators studied (plant length, leaf area, number of fruits per plant, total yield, early yield, marketable yield, sex ratio, and number days of first female flowering) under the influence of water stress, whereas foliar spraying with kaolin, salicylic acid, and urea led to an improvement in the values of the previous indicators, and it was clear that there were no significant differences between the spraying treatments and the control (treated with water) at 100% field capacity for most indicators. Additionally, spraying with each of kaolin and urea gave significant differences compared to the control at the 70% stress level, as the value of the indicators of leaf area and total plant production increased from 173 cm2 and 1.098 kg/plant in the control treatment, to 216.5 cm2 and 1.309 kg/plant in the kaolin treatment, and 219.2 cm2 and 1.328 kg/plant in urea treatment .At 40% of field capacity, all treatments significantly excelled the control for most of the indicators studied, where the value of number of fruits per plant index was 8.75, 10.46, 11.09, and 11.50 fruits/plants in the control, kaolin, salicylic acid and urea treatment respectively.