NELIGH, Neb. — From the edge of a rye field teeming with grasshoppers, Willie Nelson and Neil Young sang on Saturday in opposition to the proposed Keystone XL project, warning through lyrics that a “company wants to build a tar sand pipeline where it don’t belong.”

The site of the concert — a patch of farmland where 26 acres of corn were harvested early to create a makeshift parking lot — was as unlikely as the coalition of Nebraskans who have united against Keystone XL and made this state the legal and emotional center of the pipeline opposition.

“I’ve told them, ‘You’ll have to haul me out from in front of that bulldozer, because I’m going to protect this farm,’ ” said Art Tanderup, who with his wife, Helen, hosted the concert. Their land in the rolling hills of northeast Nebraska would be directly along the pipeline route.