An international team of ecologists has discovered that plants can absorb minerals directly from atmospheric dust, bypassing their root systems. Leaves secrete organic acids that dissolve solid dust particles, allowing elements such as iron, phosphorus, and copper to penetrate into the plant. Mathematical modeling showed that this aerial pathway can provide up to 17% of the nutrient needs in tropical and arid ecosystems.

Traditional Views and New Findings

Classical botany has long considered soil as the main source of mineral nutrition for terrestrial plants. While atmospheric dust is recognized as a fertilizer for oceans, its role on land was thought to be minor, contributing only to the slow enrichment of soil over millennia. Direct absorption of nutrients through leaves in the wild remained poorly studied due to the difficulty of distinguishing fresh dust from old soil reserves.

Experimental Research

During a three-month field experiment in the Judean Mountains (Israel), protective barriers were set up around three species of local shrubs, and artificial dust storms were simulated. Volcanic dust from Mount Etna, with its unique ratio of rare earth elements, was used as a fertilizer, serving as a chemical marker. One group of plants had dust applied to their leaves, while another received it at the roots. After three months, the dust was washed off, plant tissues were digested in acid, and metal concentrations were measured using mass spectrometry.

Results and Modeling

Field tests confirmed direct foliar uptake: shrubs that received dust on their canopies showed a fourfold increase in iron concentration in shoots, a 3.3-fold increase in nickel, and a 1.5–2-fold increase in manganese and copper. Plants with root fertilization showed almost no change. Analysis of the washings revealed that leaves were coated with malic and citric acids (pH around 6), which help dissolve solid minerals. In the local alkaline soil (pH 7.85), these elements form insoluble precipitates and become unavailable to roots. The chemical profile of rare earth markers in the shoots matched that of Sicilian volcanic dust, confirming an atmospheric source of metals.

Based on field data, an uptake coefficient was calculated—the fraction of minerals a leaf can absorb from a single dust particle. This figure was then scaled globally using geospatial modeling, combining satellite data on dust transport, chemical composition, and global maps of soil depletion. A computer algorithm determined the contribution of aerial nutrition to forests worldwide.

Significance for Ecosystems

The global model revealed the critical importance of this mechanism for ecosystems with poor soils. In the tropical forests of eastern Amazonia, where soils are depleted by heavy rainfall, trees receive up to 12% of their annual phosphorus supply from atmospheric dust carried by winds from the Sahara. In the western United States, leaves absorb up to 17% of their required iron from the air. In the Mediterranean, during intense dust storms, aerial fertilization can exceed root nutrition by several times.

Perspectives and Impact on Climate Models

Foliar absorption allows plants to obtain scarce elements before they become unavailable in the soil. As deserts expand and wind patterns shift due to climate change, the role of atmospheric dust in sustaining ecosystems is expected to grow. Modern climate models are recommended to account for tree canopies not only as carbon dioxide sinks but also as active filters that capture mineral nutrients from the atmosphere.