Abstract

This study assessed both the soil and litter copper (Cu) levels and their relationships with soil microbial activity, in fruit-tree production areas of central Chile where Cu-based pesticides are intensively sprayed. Samples of soil (0-20 cm depth) and litter from a number of selected orchards (kiwi, table grape, plum, and cherry) were collected and analysed for their Cu content and C-induced soil microbial activity. Results showed that the mean total soil Cu level was 225 mg/kg and soluble soil Cu was less than 0.01% of total soil Cu, as expected from pH values of study soils (range of 6.33 to 7.93). However, leaf litter Cu content was 3-7 times higher than in soil (mean of 681 mg/kg). Despite the soil and leaf litter Cu concentrations, no effect was observed on the C-induced soil microbial activity. We conclude that leaf litter exerts a protective role, preventing the entry of Cu into the soil and thus soil microbial toxicity.