Evaluation of Extractants for Available Copper in Alfisols and Entisols

A pot culture experiment was conducted with maize (Col) using twenty surface soil samples from the maize-growing areas of Amaravathi river command area constituting Entisols and Alfisols. The available copper was extracted using eight extractants. Among the eight, 0.005 M DTPA was inferred to be the best extractant as it recorded the highest correlation with Bray's per cent yield (r = 0.707**), copper content (r=0.698**) and uptake by maize at 7 weeks (r=0.651**). The performance of Mehlich 2, Bray 1, NH₄HCO₃-DTPA and NH₄OAc (pH 4.8) was very poor.