Compost is an organic manure. Organic manure is a type of fertilizer made from natural sources, such as animal or plant materials. Compost is made by decomposing organic waste such as food scraps, leaves, grass clippings, and manure. It is rich in nutrients that plants need to grow, such as nitrogen, phosphorus, and potassium. Compost is often used to improve soil fertility and structure, as well as to retain moisture in the soil.