Copper distribution among physical and chemical fractions in a former vineyard soil

In a former vineyard soil, copper (Cu) concentration was detected in different soil chemical and physical fractions, with the aim: I) to identify soil fractions more important in Cu retention; II) to reveal if pain symptoms shown by herbaceous crops were attributable to phytoxicity of available Cu forms; III) to compare the effectiveness of different methodological approaches in detecting Cu concentration and distribution. A comparison of aqua regia and H2SO4 + HNO3 mixture as soil digestion procedures, in moist and dry soil samples, was performed. Both methods were valid in Cu determination, giving comparable results for this soil. Differently, a 21 % lower Cu concentration was found in moist samples with both methods. Two sequential procedures were used to chemically fractionate total Cu. The first one separated exchangeable, sorbed, organically bound, and precipitated forms. The second one separated water soluble, exchangeable, Fe and Mn and organic matter bound fractions. Despite t...