Written by Jean Richie, who was known as the 'Mother of Folk'. She was born in 1922 in the mountains of Kentucky, one of 14 children, Her family were one of the two 'great ballad-singing families' of Kentucky celebrated among folk song scholars (the other was the Combs family of adjacent Knott County, whose repertoire formed the basis of the first scholarly work on the British ballads in America), and Cecil Sharp collected songs from Jean's older sisters Una and May.
IJean herself was recorded by Alan Lomax and became part of the late 40s folk scene, hanging out with Lomax, Leadbelly, Pete Seeger, Woody Guthrie et al and recording several albums of her own as well as contributing to Alan Lomax's Library of Congress project. This bit of film features Lomax introducing her and her with her dulcimer, intercut with a modern interview, and here is a great clip of her singing with Pete Seeger. She died in 2015.
In the Genesis story, after Adam and Eve had eaten the apple, they were found out by God, while he was walking in the garden in the cool of the day, so, presumably, in the song, we're about to get found out for not keeping the grasses green, feeding the sheep, keeping people free etc etc. BMC's version of the song is based on Coope Boyes and Simpson's version.
As for other versions of the song:
Despite being on Sub Pop records, this version isn't a grunge one, more's the pity.