In calcareous soils, after application of MnSO₄ for dozens of days, about 70% of applied Mn transformed into easily reducible Mn, yet, little applied Mn transformed into chelated or phosphate-soluble Mn. While the rates of Mn application increased, the amount of exchangeable Mn decreased significantly. This phenomenon, perhaps, could be attributed to the strong absorption of newly-formed Mn-oxides to soil Mn of eachangeable form. It was observed that the exchangeable and chelated Mn were very unstable in plant-grown mils, in fact, the violent uptake of plants. The easily reducible Mn, however, did not change very mach in a period of time, so it was easy to define the status of this form in a soil, what is more, this form was the only one that related with Mn uptake of plants. The conclusion is that in calcareous soils both chelated and exchangeable Mn are of little importance in the nutrient status of a soil and easily reducible Mn exceedingly affects soil Mn supply for plant requirement.