Field experiments conducted recently in provinces of North China showed that in calcareous soil of loess parent material and fluvisol in the region of the Yellow and Huai rivers,Mn deficiency was becoming a problem in crop production.It seems that further study on Mn in calcareous soils and crops,effect of Mn-application and applicability of soil testing procedures for prediction of requirement of Mn by plant in the soil are of not only theoretical significance in micronutrient researches,but also of practical importance for improving yields.In order to achieve the objectives mentioned above,this study involves the following three harts:Ⅰ.Mn absorbtion of plants from applied Mn and crop response In pot experiments,MnSO₄ was applied at 5 rates to three calcareous soils which were collected from different provinces of North China.