Humus | A soil type described by Tom Stevenson (2011) as ‘organic material that contains bacteria and other micro-organisms that are capable of converting complex chemicals into simple plant foods. Humus makes soil fertile; without it, soil is nothing more than finely ground rock.’

Bibliography

Tom Stevenson (2011) The Sotheby’s Wine Encyclopedia 5th Edition by Tom Stevenson (Dorling Kindersley, 2011), p.17-19.