Distribution of Copper Fractions in the Salt-affected Soils of Muktsar District of Punjab

摘要

Distribution of chemical fractions of copper (Cu) in relation to variation in soil properties was studied in the salt-affected soils of Muktsar district of Punjab. Sequential fractionation showed that most of the copper (70.74%) resided in the inert residual fraction (RES). Water soluble plus exchangeable fraction (WSEX-Cu), specifically adsorbed (SpAd-Cu), organically bound (OM-Cu), Mn oxide bound (MnOX-Cu), amorphous oxide bound (AFeOX-Cu) and crystalline oxide bound (CFeOX-Cu) copper fractions constituted 0.38, 0.75, 3.66, 0.42, 3.76 and 17.57% of total Cu, respectively. The plant-available (DTPA-extractable) Cu ranged from 0.16 to 2.94 mg kg~(-1); the highest (0.78 mg kg~(-1)) and lowest (0.48 mg kg~(-1)) mean DTPA-Cu content were obtained in saline and sodic soils, respectively. DTPA extractable Cu showed significant positive correlation with electrical conductivity (r = 0.69~*). The MnOX-Cu fraction was significantly and positively correlated with SpAd-Cu (r = 0.27~*). Among the different oxides, copper associated with amorphous iron oxide showed positive correlation with DTPA-Cu, thus showing its influence on Cu phytoavailability.