Distribution of Fungicide-derived Copper in Soils, Litter and Vegetation of Different Aged Stands of Coffee (Coffea arabica L.) in Kenya
Ormand, K. L.
Lepp, N. W.
Dickinson, N. M.
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Samples of soils, litter and vegetation, collected from 24, 14 and 4 years old stands of coffee (Coffea arabica L.), which had been routinely treated with copper fungicides, were analysed for copper content. Total soil copper content was found to be a function of (a) stand age and (b) soil depth. Highest levels were encountered in the 0–20 cm zone of the 24 year old stand; soil collected beneath these bushes showed significant contamination to a depth of 80 cm. Soils from the younger stands showed proportionally less copper contamination. Copper levels in litter samples showed increases relative to stand age; litter from the oldest stand was heavily contaminated and leaf litter showed a higher copper content than that of the woody fraction. Tissues from coffee bushes could be divided into 2 groups on the basis of their copper content; those tissues which demonstrated a progressive age-dependent increase (bark, lateral stems and fine roots) and those tissues where copper levels did not reflect the cumulative exposure of the plant to this element (wood, different age classes of foliage).