Some crops are more sensitive than others to Mn deficiency. Sensitive crops include soybeans, small grains, peanuts, cucubits, onions, peas, radishes, and beans.
Mn in soils: The earth’s crust is about 0.11% Mn. Total Mn in soils generally ranges from about 20 to 3,000 ppm (0.002 to 0.30%), but only a fraction of this total is plant available. The most common form of Mn in soil solution is Mn2+, which is often complexed by organic compounds.