"Earth's Answer" is a direct response to William Blake's "Introduction," the poem that opens the Experience section of Songs of Innocence and of Experience. In "Introduction," a "Bard" (a kind of cosmic, time-traveling poet who appears throughout the collection) calls on the Earth to "Arise" and "renew" the world's "fallen light." Humankind has "lapsed," the Bard says, from its instinctive, joyful state.
In "Earth's Answer," the personified Earth responds to the Bard's call to "arise." All she can do, however, is wearily "rais[e] up her head," a phrase suggesting immense physical effort and a weakened state.
The Earth is shrouded by "darkness dread & drear," the pounding /d/ alliteration and growling /r/ consonance conveying just how beaten down she feels. Her "light" has "fled," leaving only a "Stony dread" in its wake (as opposed to, say, soil brimming with life). And her "locks," her hair, are "cover'd with grey despair." In other words, hair is "grey" with fright and worry.
The Earth should be a magnificent, beautiful, flourishing figure. Instead, the poem depicts her as dull and dried up, as though all the life and joy have been suck outed of her. In the next stanza, readers will found out who, exactly, has driven the Earth to this dismal state.