Earthworms as useful bioindicators of agroecosystem sustainability in orchards and vineyards with different inputs

Earthworm communities were studied in 72 different agroecosystems including vineyards and three types of orchards: apple, peach and kiwi. Orchards had different agricultural inputs, in particular copper (namely, copper sulphate applied as fungicide), and soil cultivation. Heavy metals were analyzed together with other soil parameters (nutrients, bacteria and fungi). No differences were detected regarding microorganisms in orchards subjected to different agricultural practices. Copper concentration was higher in vineyards. Total earthworm abundance and biomass were severely reduced both by copper input and soil tillage. Individual species gave different responses to agricultural practices. Aporrectodea caliginosa was negatively affected by both copper concentration and soil cultivation, while Allolobophora chlorotica was negatively affected only by copper input. Lumbricus rubellus and Lumbricus castaneus were nearly absent in tilled orchards but apparently they were not much affected by copper input. Octodrilus lissaensis and Octodrilus pseudocomplanatus did not seem to be reduced by copper input and soil tillage. Species number and biomass were reduced both by tillage and copper input. Negative effects of tillage and fungicide residues (Cu, Zn) are clear enough factors to promote more extensive use of earthworms as reliable bioindicators in the rural landscape.