Influence of Land Use Practices on Soil Extractable Iron and Manganese

Land use changes may influence the availability of iron (Fe) and manganese (Mn) in soil.Therefore, the present study was undertaken to assess the influence of land use changes on the extractability of Fe and Mn by different chemical reagents.Four land use practices such as rice-rice, rice-fallow, rice-green gram and uncultivated fallow were chosen for the study.Soil samples were collected from these land use practices and the Fe and Mn contents were extracted with different extractants (DTPA, AB-DTPA, Mehlich-3 and HCl).The land use practices highly influenced the extractability of soil Fe and Mn.Mehlich-3 extracted higher amount of Fe and Mn compared to other extractants across the land use practices.The HCl and Mehlich-3 extractants extracted on average 1.9 and 3.8 and 1.9 and 2.5 times more Fe and Mn than those extracted with DTPA extractant, respectively.Across the land use practices, AB-DTPA and DTPA extractants extracted similar magnitude of Fe and Mn.Among the four land use practices, the rice-green gram system always had the highest amount of extractable Fe and Mn compared to others.Significant positive correlations were observed among the extractants which is a testament to the fact that these extractants could extract Fe and Mn from similar pools.Pearson correlations showed significant positive correlations between organic carbon and extractable Fe and Mn.The inclusion of soil properties in the regression equation resulted improved predictability of extractable soil Fe and Mn.