Department of Soils, Punjab Agricultural University, Ludhiana, Punjab
*Present address: Department of Soil Science and Agricultural Chemistry, Rajendra Agricultural University, Pusa, Samastipur, Bihar
Sodic soils differing in pH, EC, organic C, texture and ESP were treated with different levels of gypsum under submerged conditions. An asymptotic variation in the amounts of different fractions of Mn was observed depending on the level of gypsum applied and the period of submergence of the soils. The water soluble, exchangiable and DTP A extract able forms of Mn increased with increasing periods of submergence at all levels of gypsum application. The HNO3 and HCl extractable forms of Mn, on the contrary, did not display any consistent trend of variation. The aqueous pH of the soil suspension and fluctuations of partial pressure of CO2 and redox-reactions exert a profound influence on solubility of Mn in soils.
Gypsum, submergence, DTPA, redox-reactions
