"Dynamite" joke

A kid comes home from college. His father is a farmer, and
he's shoveling all the manure out of the outhouse onto the
hay crop to fertilize it. The kid says, "Hey, Pop - I
learned in college that there is an easier way to do
everything."
They go into town and get some dynamite. They're gonna rig
it up under the outhouse and blow the manure into the hay
field. They get it all rigged up, but they don't see
Grandma coming to use the outhouse. Ba-Booom!
The manure goes flying, and so does Grandma. Ploop! She
lands in the hay field. They go running up to her.
"Grandma, Grandma! My God, are you alright? Are you
alright?"
She says, "Yeah, I'm fine. Phew! I'm certainly glad I
didn't let that one go in the kitchen!"