Combining selenium biofortification with vermicompost growing media in lamb’s lettuce (Valerianella locusta l. laterr)

Abstract

Leafy vegetables are a daily part of the human diet all over the world. At the same time, a worldwide problem of Se malnutrition is present in human populations, mostly due to low soil Se contents. As plants represent the main source of this element in the human diet, with Se being an essential trace element for humans and animals, plant foods containing Se can be used as an efficient means of increasing the Se in the human diet, as well as in animal feed (biofortification). At the same time, the production of growing media relies on limited peat reserves. The use of earthworms facilitates the production of composted organic masses mostly consisting of organic waste, called vermicompost. The aim of this study was to investigate the influence of three different growing media (commercial peat media, vermicompost, and a 1:1 mixture) on Se biofortification’s efficacy and yield in lamb’s lettuce. The Se biofortification was performed with sodium selenate (Na2 SeO4 ). It was shown that biofortification increased the Se contents such that a mass of only 48.9 g of fresh leaves contained enough Se for the recommended daily intake in human nutrition (55 µg Se/day), which represents a significant potential for solving Se malnutrition. Furthermore, the use of a 1:1 vermicompost–commercial substrate mixture showed a similar performance to the peat growing medium, contributing to the preservation of peat reserves.