Compost is type of organic fertilizer. (Source: © ronstik / stock.adobe.com)

A substance of organic origin that adds nutrients to the soil, e.g. made from manure or agricultural waste. By adding manure to crops it adds nitrogen, potassium, phosphorus, sulphur, magnesium and calcium. Organic fertilizers are produced naturally or they can be waste residues from biogas production by anaerobic digestion.