Use of compost in urban greening to develop biodiverse herbaceous communities

摘要

Derelict urban soils are not suitable to grow ornamental traditional vegetation, but they can be effective in becoming areas of biodiversity and nature conservation. The compaction and very low quality of those soils, though do not enable a uniform covering and development of species and plant sizes, necessary to satisfy esthetical requests. Aim of our work was to evaluate the contribution of compost in improving the plant biodiversity and the self-sustainability in the cultivation of an herbaceous community sawn on derelict urban soil. The experimental study was carried out in eight, 2 m2 beds, filled with urban subsoil and sown with a mix of 29 autochthonous herbaceous species: annuals, biennials and perennials. The species selected for the trial are native in the surrounding countryside. We added compost, coming from selected municipal organic waste, in the first 15 cm of soil, then we sow the seed mixture on a thin layer (about 5-10 cm) of seeding substrate. The filling soil was poor in N (0.2 g kg-1) and Corg (4,3 g kg-1) and had alkaline pH (8.3), both this properties can affect negatively the growth of plants, the addition of compost could improve the content of N and Corg and decrease the value of pH. The vegetation was monitored every month since march, number of plants were counted inside a fixed quadrat. The plots with compost showed a more diverse vegetation in terms of species and a longer time of flowering.