What do the "pastures new" mentioned in the final lines of the poem, Lycidas, represent?

The "pastures new" at the end of the poem symbolize new genres of poetry. The third-person speaker announces that the shepherd who has been singing will seek new pastures tomorrow, suggesting that the poet will forge a name for himself beyond the pastoral genre. As Milton has spent nearly all of "Lycidas" aligning himself with Virgil, these lines imply that he will follow Virgil's poetic trajectory by moving to the genre of epic. Milton's now-canonical epic Paradise Lost was published in 1667.