In the terminology of North American agriculture, muck is a soil made up primarily of humus from drained swampland. It is known as black soil in The Fens of eastern England, where it was originally mainly fen and bog. It is used there, as in the United States, for growing specialty crops such as onions, carrots, celery, and potatoes. Holland Marsh, north of Toronto, Ontario, is the site of the Muck Crops Research Station, a part of the University of Guelph.