Ecological and agronomical perspectives of vermicompost utilization in Mediterranean agro-ecosystems.

Fields experiments were conducted to treat an agronomic soil using three types of fertilizers: organic (vermicompost), mineral, and a mixture of organic and mineral (vermicompost + NPK), added to soil with two N application doses (100 and 200 kg/ha). Vermicompost was obtained through aerobic stabilization of biological sludge, performed by earthworms (Eisenia fetida). The soil was cropped with maize (Zea mays) and sunflower (Helianthus annuus). Plant productivity and effects of treatments on soil chemical and biochemical properties were evaluated. Results showed an increase of plant productivity (expressed as kg of seeds produced per plot) in the treatment with vermicompost and mineral fertilizer, for both plant species and application rates. Mineral fertilization reduced soil microbial activity and increased the release of carbon and nitrogen soluble compounds suggesting a degradation of native soil organic matter and impacting on environmental quality. _____________________________________________________________________________________________________________