The spirits that work in the Earth are called gnomes.
Image by Marie Laure Viriot
"These root-spirits, are, so to say, a quite special earth-folk, invisible at first to outer view, but in their effects so much the more visible; for no root could develop if it were not for what is mediated between the root and the earth-realm by these remarkable root-spirits, which bring the mineral element of the earth into flux in order to conduct it to the roots of the plants."
Rudolf Steiner, The Plant-World and the Elemental Nature-Spirits, Lecture VII