Determination of Chemical Forms of Manganese and Their Relations with Soybean Responses in Some Calcareous Soils of Fars Province

In order to investigate mineral manganese forms and their relations with plant responses, 22 soil samples from Fars province (0-20 cm) were in a greenhouse experiment filled in 3 liter pots, and soybean (Glycine max (L.) merr.,CV.Williams) was grown for 7 weeks. Chemical forms of manganese were determined in soils by warden and Reisenauer sequential extraction method (readily soluble, weakly adsorbed, carbonate bound and oxide bound extracted with Ca(No3)2, Ca DTPA +Na2B4O7, HNO3 and NH2OH. HCl, respectively) after harvesting the plants. Results showed that the amount of Mn in different forms was in the following order: Carbonatic Mn >Mn Oxides >Weakly adsorbed Mn > Soluble Mn. Regression equations between soil properties and Mn forms showed a significant correlation between calcium carbonate equivalent and carbonate bound Mn. Significant correlation between Carbonate bound Mn and concentration of Mn in the aerial part of soybean showed that this fraction plays an important role in plant nutrition.