This study assessed the capacity of leaf litters to adsorb copper ions applied as a copper-based pesticide. Leaf litters of two fruit tree species with different lignin/N ratios were examined to determine their protective role against the incorporation of Cu into soil. A leaf litter Cu-adsorption capacity assay and a degradation assay were performed using table grape (lignin/N = 2.35) and kiwi (lignin/N = 10.85) leaf litters. Table grape leaf litter had a significantly (p = 0.001) higher Cu-adsorption capacity (15,800 mg kg-1) than kiwi leaf litter (14,283 mg kg-1). Following leaf litter degradation, significant differences (p = 0.011) were observed in the release of Cu from Cu-enriched leaf litter into soil, showing that kiwi litter has a greater protective effect against the incorporation of Cu into soil, regardless of the amount of Cu applied. This protective role is reflected in a significantly higher (p = 0.015) Cu concentration in table grape soil (41.71 ± 2.14 mg kg-1) than in kiwi soil (35.87 ± 0.69 mg kg-1). Therefore, leaf litter with higher lignin/N ratio has greater protective role against copper incorporation into soil.
Keywords: Degradation; Lignin; Metals; Microbial activity; Orchards; Pesticides.
© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.