Ebb-and-flow Subirrigation Strategies Increase Biomass and Nutrient Contents and Reduce Nitrate Levels in Lettuce

Abstract

<jats:p>Overhead irrigation is widely used to water lettuce during commercial production in China but exerts potential water wastage and pollution. Subirrigation is thought as a water-saving, high-efficiency fertigation strategy. However, few studies have compared the nutritional value and nitrate content of lettuce grown using subirrigation with plants cultivated with overhead irrigation. Therefore, this study explored the ability of ebb-and-flow subirrigation strategies to produce high yields of a leafy lettuce (cultivar Biscia Rossa) with high nutritional value and low nitrate content. Lettuce plants were cultivated in an ebb-and-flow subirrigation system with different irrigation frequencies (every 2 or 3 days) and immersion times (5, 10 or 15 minutes); overhead irrigation was used as control. Ebb-and-flow subirrigation significantly enhanced several lettuce growth parameters, significantly increased the level of vitamin C, and significantly decreased the nitrate content of lettuce leaves compared with overhead irrigation. The optimal subirrigation strategy for lettuce production was irrigation every 3 days with 15 minutes immersion; this ebb-and-flow subirrigation protocol could potentially be used to save water and resources, improve yield and nutrient contents and reduce nitrate content in commercial greenhouse lettuce production.</jats:p>

Evapotranspiration Model-based Scheduling Strategy for Baby Pakchoi Irrigation in Greenhouse

“…Plug trays filled with substrate is used for greenhouse baby leaf production with ebb-and-flow (E&F) irrigation systems (Danfeng et al, 2013). E&F irrigation is characterized as producing uniform plants, with a short production cycle, high water-and fertilizer-use efficiency, and adequate plant quality (Yang et al, 2018). In production practice, the quality of baby leaf is sensitive to substrate water content.…”

“…Few studies have reported the irrigation scheduling strategy for leafy greens by using subirrigation such as E&F irrigation. Irrigation frequency and flood time were identified as two key factors in the E&F irrigation strategy (Yang et al, 2018). In substrate type, flooding depth and time have also been studied to optimize E&F irrigation (Anlauf et al, 2012).…”