Forms of Iron and Manganese in Some Soils of Arid Regions of Rajasthan

The distribution of different forms of iron and manganese in surface horizon and their relationship with soil characteristics have been examined. The contents of total and HCl soluble Fe and Mn in arid soils of Rajasthan were comparable with other soils but the reducible and active forms were relatively less. Reducible Mn appeared more dependent on clay and organic carbon content than on soil pH. The exchangeable and DTPA soluble Mn correlated negatively with pH and positively with percentage organic carbon. The DTPA extract able and exchangeable Fe contents were somewhat high in arid soils and even very light textured soils of dunes and sandy plains were seen well provided in this respect. Both these forms did not appear to be related with any of the soil properties studied. The multiple regression equations of different forms of Fe and Mn with the soil properties have been discussed.