Effects of Irrigation with Desalinated Water on Lettuce Grown under Greenhouse in South Korea

Abstract

This study assessed the effects of irrigation with desalinated water on the growth of lettuce (Lactuca sativa L.). Two experiments, the first using saline and the second desalinated irrigation water, respectively, were designed to grow lettuce in plots (22 m × 0.4 m × 0.4 m) under controlled greenhouse conditions. Three levels of saline irrigation water and tap water (control) were used for the first experiment. In the second experiment, the three saline levels underwent a desalination process. Each experiment was carried out twice, in succession, with two replications. The results from the first experiment showed that the use of saline irrigation water caused an increase in the salinity level of soil and, consequently, adversely affected lettuce growth and yields. The results from the second experiment showed that the use of desalinated irrigation water does not negatively affect soil salinity and lettuce growth and yield. However, the need for additional application of the elements such as Ca2+ and Mg2+ was also identified since continued use of desalinated water irrigation correlated with a decrease in the sodium adsorption ratio (SAR), leading to increased risk of soil sodicity. This is due to the elimination of nutrients during the desalination process.