Urban Soils - JASSUR project

Background

Urban agriculture can be characterized by the growing or breeding, within or in periphery of urban zones, of products edible or not, that can be transformed and commercialized. It uses resources, services and products found in the immediate environment. The soils of these urban gardens can be considered as specific agricultural soils, intensely worked and with potential high fertility. Indeed, they contain on average 4% of organic matters, as compared to the 1 to 3% of agricultural soils. These soils are heterogeneous because of their past usage that conditioned their nature but also because of the great variety of cultural practices. Few studies were conducted on the soil fauna.


Aims of the study
The aim of this work is to understand which mesological or anthropological factors influence earthworms in these special ecosystems. This work is specifically turned towards earthworms because of their role as engineers in soil ecosystems.


Progress made

A total of 101 gardens were sampled from the 7 metropolis Rennes, Nantes, Paris, Nancy, Toulouse and Marseille.

Results show large differences of abundance (from 0 to 1600 i/m²) related to historical factors of metallic contamination and other current factors of intense management.

Despite these differences, gardens reveal a very large diversity (from 10 to 27 taxa) on relatively small areas (territory from 70 to 100 km²).