Many of the problems related to the management of plants in urban areas derive from the quality of soil.The use of compost as amendment could be a possible help,but general quality factors have to be satisfied,such as:absence of alien materials and pollutants,high stability and low salt content.Many studies have been conducted to improve the quality of compost,while many efforts have been carried out by the municipalities to achieve a better selection of the organic solid waste."Quality compost",defined as source-separated municipal solid waste compost,has been employed in the management of urban green areas as soil amendment and mulching,especially for tree planting.This practice reduced the transplanting failures of trees,thus reducing the planting costs.In this connection a possible more effective employ to improve the sustainability is to use this kind of quality compost as amendment on urban derelict soils.Soils of roadsides,roundabouts,filling soils,are generally highly compacted subsoils,poor in organic matter and structure,and they are unsuitable to grow any ornamental vegetation.These soils could benefit by the treatment with compost,improve their structure and water holding capacity and be able to grow some omamental vegetation.The aim of this study was to see whether the use of source-separated municipal solid waste compost on a roadside low quality urban soil could create better conditions for the sustainable management of a naturalistic sown herbaceous vegetation,without watering and fertilizing.In order to that a roundabout area was tilled to a depth of 10 cm,then half of the surface was treated with mature compost (300q/ha),the other half was not.A mixture of 25 herbaceous annuals was sown (e.g.Centaurea cyanus,Dimorphoteca aurantica,Papaver rhoeas,Trifolium incamatum) in the all area.Soil samples were analysed (texture,pH,bulk density,porosity and pore size distribution,organic Carbon and Nitrogen content) at different times and the vegetation was monitored in its growth and development.Soil added with compost showed an increase in organic Carbon content.Total porosity increased with time in the compost treated soil,due to a higher quantity of pores greater than 30 μm,i.e.transmission pores that play a role in water movement.As a consequence,the compaction process that usually follows the tillage was observed in the untreated soil,whilst the bulk density decreased in the compost treated area.Also soil aggregate stability improved in the compost treated soil.The plant emergence started in January and the flowering in March.No phytotoxic symptoms were observed in the plants growing on the compost-amended soil.