Environmental and agronomical analysis of different compost-based peat-free substrates in potted rosemary

The main objective of this research was to test the hypothesis that the growing media coming from production processes with minimum environmental impact were also those guaranteeing the best performances to the plant. Our focus is also on the adoption of growing media in ornamental nurseries that are considered “sustainable”, particularly those that protect the environment. The research has been divided into four phases which chronologically followed one another: composts production; growing media preparation and characterization; environmental analysis; rosemary bio-agronomical evaluation. Six different biomasses, mixed with different percentage relations, were composted for 4 months, obtaining eight composts with which as much peat free growing media have been prepared (SC1 - SC8). LCA of growing media production in Southern Italy has been carried out to gain more knowledge about the environmental impact and resource use along the substrata chain. Chemical and physical analyses have been realized on the nine growing media. Furthermore, a bio-agronomical trial has been conducted comparing the eight peat-free growing media with the conventional peaty one (Speat), in order to evaluate the visual quality in rosemary containerised plants. The original hypothesis has turned out, in the experimental conditions in which we have worked, only partly valid. Among the three growing media with a low environmental impact productive cycle only the SC5 guarantees to the rosemary plants good productive performance, even if statistically different from those obtained with Speat. It is necessary to go on with the research even using different composting technologies.