The Earth Mother is a motif that appears in many mythologies. The Earth Mother is a fertile goddess embodying the fertile earth and typically the mother of other deities, and so, also are seen as patronesses of motherhood. This is generally thought of as being because the earth was seen as being the mother from whom all life sprang.
The Rigveda calls the Female power, Mahimata (R.V. 1.164.33), a term which literally means Mother Earth.