The available nutrients (Ca, K, Mg, P) were measured using Mehlich 3 extraction [29]. Soil 0.01 mol L1 CaCl2-extractable concentrations of Cd, Zn and Pb were determined according to Houba et al. [30]. Soil pH (pH-CaCl2) was measured in the 0.01 mol L1 CaCl2 extract.