Department of Soils, Punjab Agricultural University, Ludhiana, Punjab, 141 004.
In the soils from four major agro-climatic regions of Punjab, viz. undulating, central, western and flood-plain regions, total and DTPA-extractable Mn in these soils ranged from 200 to 550 and 2.6 to 9.9 mg kg−1 soil with average values of 373 and 5.1 mg kg−1 soil, respectively. A sequential fractionation showed that Mn-exchangeable, weakly adsorbed, moderately adsorbed, strongly adsorbed, associated with; organic matter, occluded and bound by carbonates/acid soluble minerals were in very low proportion while most of the total Mn (35.3 to 84.9%) was in the residual fraction. The chemical pools of Mn were positively correlated with major soil properties.
Mn fractions, freeoxides of Fe and Mn, clay, organic carbon
