Mollic gleysol is a wet soil where water has leached the minerals serving as a source of calcium into deeper layers from the upper layer. The characteristic greenish or rusty patches are generated by bacterial activity in oxygen-poor conditions resulting from excess moisture. There may be a thin layer of peat on the soil’s surface.
Although these soils are rich in nutrients, plants cannot always easily access them. When drained, however, mollic gleysols with a thicker humus layer make good farmlands and pastures.
Mollic gleysols support mainly birch, black alder, and mixed spruce forests. The understorey is rich in plant species, with bird cherry and mountain currant as well as ferns, sedges, and meadowsweet being more typical species.
Mollic gleysols are among the most common types of soil in Estonia, making up approximately 13% of the country’s soil cover. They are found mostly in North, West, and Central Estonia.