Cobalt (Co) - Micronutrients
The Co concentration in the dry matter of plants grown in soil normally lies around 0.02 to 0.5 ppm. In soils the content varies from 1 to 40 ppm. Cobalt is not readily mobile in the plant.
Co is essential for symbiotic N2-fixation. Increasing the supply of Co increases rhizobial growth, N2-fixation and the formation of leghaemoglobin in nodules. Co is essential component of vitamin cyanocobalamin.