Silver white, very brittle heavy metal or element (Mn). In nature it often occurs in many minerals in combination with iron. These are brownite, manganese dioxide, hausmannite and manganite as well as iron ores. Manganese is important for the vine as a nutrient in small quantities. It is involved in carbohydrate and protein metabolism, as well as in the formation of cell membranes and also supports photosynthesis. Close interrelationships between manganese and iron are suspected in the metabolism of plants. On alkaline soils with a high pH value, a lack of plant-available manganese is most frequently to be expected. Likewise, high levels of calcium also inhibit absorption and transport in the plant.
Particularly calcareous, black or humous sandy soils tend to lack manganese, which leads to a reduction in green and yellow leaf pigments. This manifests itself by small pale to yellow-green, dot-shaped chlorosis. Sufficient manganese is especially present in clayey soils. On moist soils or with longer irrigation, the available contents are usually higher. In dry years manganese deficiency is therefore more frequent than in moist years. Enrichment is achieved, for example, with the manganese-containing fertilizers blast-furnace lime and Thomas flour. An excess of manganese occurs above all in acidic soils with low pH values and has a negative effect on growth and yield.