Influence of organic amendments on copper distribution among particle-size and density fractions in Champagne vineyard soils. Environmental Pollution 112

‘‘Capsule’’: Soil particle-size composition can be used to assess distribution of copper in soils. The intensive use for over 100 years of copper sulfate (Bordeaux mixture) to fight against mildew in vineyard soils has led to an important, widespread accumulation of Cu (100 to 1500 mg Cu kgÿ1 soil). In Champagne vineyards, organic amendments are used currently to increase soil fertility and to limit soil erosion. Organic amendments may have a direct eect on the retention of Cu in the soil. To assess the influence of the organic management on the fate of Cu in calcareous Champagne vineyard soils, we studied Cu distribution (1) in the soil profile and (2) among primary soil particles, in vineyard parcels with dierent amendments. Amendments were oak-bark, vine-shoots and urban compost. The results were compared with the amount and the distribution of Cu in an unamended calcareous soil. Physical soil fractionations were carried out to separate soil primary particles according to their size and density. Cu has a heterogeneous distribution among soil particle fractions. Two fractions were mainly responsible for Cu retention in soils: the organic debris larger than 50 mm or coarse particulate organic matter (POM) issued from the organic amendments, and the clay-sized fraction <2 mm. The POM contained up to 2000 mg Cu kgÿ1 fraction and the clay fraction con-tained up to 500 mg Cu kgÿ1 fraction. The clay-sized fraction was responsible for almost 40 % of the total amount of Cu in the four parcels. POM was predominantly responsible for the dierences in Cu contents between the unamended and the three amended parcels. Our results attested that methods of soil particle-size fractionation can be successfully used to assess the distribution o