In the 'solitary reaper', why did the poet bear the music in his heart?

The melody of the song was so sweet that it struck the heart of the poet . He was so impressed that he carried the melody of the song with him long after the song had been ended by the reaper girl. Actually, the poet being a lover of nature was profoundly impressed by this natural scene. He remembered for its natural melodious effect. Therefore he carried the music in his heart only to make it immortal in his poem.