Marl is a soil type described by Tom Stevenson (2011, p19) as‘ a cold, calcareous clay-like soil (usually 50 per cent clay content) that delays ripening and adds acidity to wine.’ Marl is friable and consists of clay and calcium carbonate. Marl can be used as a fertilizer for soils deficient in lime.

Bibliography

Tom Stevenson, The Sotheby’s Wine Encyclopedia 5th Edition (Dorling Kindersley, 2011.