DIFFERENTIAL EFFECTS OF PLANTATION FORESTRY AND AGRICULTURE ON EARTHWORM ABUNDANCE AND THE HEAVY METALS IN SUBURBAN SOILS IN SHANGHAI, EASTERN CHINA

摘要

In suburban areas of countries where a rapid urbanization is being experienced, both agricultural and forest ecosystems play essential roles in mitigating environmental load while being directly and indirectly affected at the same time. Relative to farmlands, usually, forest ecosystems have stronger ability of absorbing and immobilizing pollutants (e.g. heavy metals) in biomass and soils for restoring polluted soils and protecting water resources along a river. We examine this claim in one crop field and two plantation stands, which were established in the original farmland nine years ago, in the suburban area of Shanghai, eastern China. The results showed that compared with the agricultural soils, higher abundance and density of earthworms were found in the plantation soils in the suburban area of Shanghai, eastern China. The concentrations of Cu, As, Cd, Cr and Pb were lower in the soils of the plantations than in the farmland, in particular, the difference in Cd concentration was significant in the two kinds of soils. The concentrations of heavy metals in earthworm derived from the plantations were lower than those from the farmland. These results have significant implications for mitigating soil pollution, restoring polluted soils and increasing soil biodiversity by means of establishing plantations in suburban areas.