Many rock-derived elements, such as K, Ca, Mg, and Fe are essential nutrients for higher plants. With associated microorganisms near their roots, plants aid to dissolve minerals, thereby form soil, and cycle elements many times through the vegetation before the elements are discharged into rivers. Stable isotope fractionation of these elements occurs during transfer through the root’s cell membrane and during translocation within the plant. We detect this minute shifts in isotope ratios with precise mass spectrometry to fingerprint the cycles in this giant biogeochemical reactor.