Night soil was used for centuries in this country as a fertiliser

http://en.wikipedia.org/wiki/Night_soil#United_Kingdom

http://en.wikipedia.org/wiki/Gong_farmer

Near where I am (south of Manchester) it was all farms and market gardens until not that long ago (there are still one or two), during the 19th century human waste was transported from the city along the canals at night and then unloaded over the gardens and farms as manure.