Effects of irrigation methods on transpiration and water use efficiency of tomato

Abstract

Objective: To explore the effect of high-frequency drip irrigation on the physiological water savings of facility tomatoes. Methods: A pot experiment was conducted to study the effects and mechanisms of conventional flood irrigation (CFI) and high-frequency drip irrigation (HDI) on the transpiration and water use efficiency of tomatoes. Results: a. During the whole growth period, the irrigation times of high-frequency drip irrigation were 44 times, which was 3.4 times of traditional flood irrigation, and the irrigation amount was only 71.0% of flood irrigation. However, there was no significant difference in fruit, stem, or leaf dry weight between the two treatments (<em>p</em> > 0.05). b. The average transpiration of tomatoes under high-frequency drip irrigation was 28.95 L/plant, which was significantly lower than that under traditional flood irrigation by 24.6%. c. Compared with conventional flood irrigation, high-frequency drip irrigation treatment significantly increased irrigation water use efficiency (biomass/irrigation volume) and water physiological use efficiency (biomass/transpiration volume) by 21.2% and 14.2%, respectively (<em>p</em> < 0.05). d. Compared with conventional flood irrigation, high-frequency drip irrigation significantly decreased tomato leaf area, stomatal conductance, and transpiration rate by 32.6%, 69.8%, and 54.3%, respectively, and significantly increased leaf δ<sup>13</sup>C value (<em>p</em> < 0.05). Conclusion: High-frequency drip irrigation can not only reduce the amount of irrigation, and improve the utilization efficiency of irrigation water, but also put the plant in a certain state of water deficit, reduce leaf area, stomatal conductance, and transpiration rate, and then significantly reduce transpiration water consumption, improve the physiological water use efficiency of tomatoes, and realize physiological water savings.