Final answer:
The nature imagery referenced in these lines is dirt and grass to show that the speaker's body will become part of nature.
Step-by-step explanation:
The nature imagery referenced in these lines is dirt and grass to show that the speaker's body will become part of nature. The lines suggest that the speaker's physical self will decompose and be absorbed by the earth, to be reborn as new life in the form of grass.
Learn more about Whitman's nature imagery