Root foraging for calcium and magnesium in common meadow plant species

Abstract Background and Aims Plants forage for nutrients by root proliferation in nutrient-rich patches. While foraging for nitrogen (N) and phosphorus (P) has been repeatedly confirmed, foraging for other essential nutrients, calcium and magnesium, has hardly been examined. Compared to N and P, these elements form much more stable patches in the soil, which makes foraging for them highly reasonable. In this study we aimed at investigating plant´s ability to forage for these essential cations and its relation to foraging for other nutrients and plant characteristics. Methods We examined preferential root placement into calcium (Ca) and magnesium (Mg) rich patches, created by dolomite limestone, in a pot experiment with 16 common meadow species. Further we compared Ca + Mg foraging with foraging for N, P and potassium mixture (NPK). Results Eight of the 16 (50%) species showed significant root proliferation in dolomite-rich patches. It was less common than foraging for NPK recorded in 79% of species (11 out of 14 for that we have the data). Assuming that foraging for NPK shows the potential of species to change their root systems by proliferation, not all species use this potential to respond to the Ca + Mg gradient. Intensity of Ca + Mg foraging did not show any relationship to species preferences to soil pH, or forb-grass difference, but it was stronger in species with low Ca and Mg tissue concentrations. Conclusion Our experiment demonstrated, for the first time, active root proliferation in response to calcium- and magnesium-rich patches in heterogeneous substrate.