Nitrate is also one of the ingredients in gun powder because
of it's combustible nature and it's rapid expansion as an explosive.
This was known during The Civil War. When the Union blockade of Southern ports caused a shortage of gunpowder Southern women were enjoined to donate their ''soiled water'' to The Cause so nitrate could be distilled from it. Might explain why my North Carolinian sister-in-law can be a bit feisty at times.
Comment 50 also has interesting information on how they have used human waste to manage their organic garden successfully. I had an interesting observation when deer were eating the hostas by my cabin in the country. My husband started peeing around the border of the plot where the hostas were growing. They deer soon stopped coming. He would spread the pee in a line along the edge. He grew up in farm country.