Desert dust deposition enhances plant nutrition via direct foliar uptake in Mediterranean ecosystems

Atmospheric deposition of desert dust serves as a significant nutrient source, replenishing soil nutrient stocks and influencing the long-term productivity of infertile terrestrial ecosystems. However, the immediate impact on the vegetation after deposition remains unclear.

We present findings from a pioneering field experiment conducted in a natural Mediterranean ecosystem in Israel which regularly receives desert dust. In this study, we applied dust to three native plant species Salvia fruticosa, Teucrium capitatum and Cistus creticus over the course of three months (the dust period). Our results indicate that, while biomass and new growth organs remain unchanged compared to the control plants, dust application significantly increased the concentrations of Al, Mn, Fe, Ni, and Cu. In some cases, the increase was as high as 100% in the aboveground biomass across all three species, which are considered marginally bioavailable in the local soils due to their high alkalinity. We discovered that the nutrients were taken directly from the plant foliage and not via the roots and show that this unique process was facilitated by the acidic environment of the leaf surface which enables the partial dissolution of nutrients typically unavailable in alkaline soils.

These findings suggest that deposition of dust is an important source of mineral nutrients to plant and can enhance plant nutrition through foliar uptake mechanism, particularly in ecosystems with nutrient-poor soils. The acidic microenvironment on leaf surfaces plays a crucial role in solubilizing dust-borne nutrients, facilitating their uptake. This mechanism may be especially beneficial in regions experiencing frequent dust deposition, contributing to the resilience and productivity of plant communities in such environments.