Species Composition Influences Zinc and Selenium Uptake in Multispecies Grasslands

Abstract

The aim of this study was to assess and analyse the effect of species richness on zinc (Zn) and selenium (Se) uptake and concentrations in grasslands while investigating the potential role of grass species in facilitating their uptake in mixtures. We conducted a grassland experiment at both pot and field scales. In the greenhouse pot experiment, three grasses, four legumes and five forb species were grown as monocultures and mixtures along a species richness gradient. In the field experiment, we compared a monoculture of Lolium perenne sward with two multispecies mixtures (comprising grasses, legumes and forbs). At harvest, Zn and Se uptake values were determined for all the monocultures and mixtures in both experiments. Zinc and Se uptake increased with increasing species richness (p < 0.05). Higher Zn and Se uptake in the multispecies mixtures was primarily due to high aboveground biomass production and/or high shoot Zn and Se concentrations of some of the component species in the mixtures. However, there was insufficient evidence supporting the facilitation of Zn and Se uptake by grass species. To optimise Zn and Se uptake by multispecies mixtures, it is suggested that the choice of forage species should be based on biomass production potential as well as Zn and Se concentrations of the component species in the mixture.