Peat is an accumulation of partially decayed vegetation or organic matter.
Formation of Peat: When plant material; usually in wet areas; in inhibited from decaying fully because of acidic and anaerobic conditions, it results in formation of peat. Peat is mainly composed of wetland vegetation. Sphagnum is the main producer of peat; but many other plants may also be involved in peat formation. Most of the modern peats formed in high latitudes after the retreat of glaciers at the end of the last Ice Age. This
happened about 12,000 years ago. Peat accumulation is usually slow; at the rate of 1 millimeter per year.

Peat is an important source of domestic fuel in several countries; especially in Europe and America. Peat is also used in agriculture to improve soil fertility. This is also used as water purified in septic tanks.