Personification is a literary device that adds human traits an qualities to inanimate objects, situations, and even animals.
The text in the passage that uses that literary device is Sometimes whoever seeks abroad may find Thee sitting careless on a granary floor, Thy hair soft-lifted by the winnowing wind.
Here the poet is giving to Autumn human qualities similar to the ones in a lady, talking about her hair and how it flows with the winds of fall, when in fact he is talking about elements in nature during that season.