BIOCOMPOST: A CHAIN PROJECT TO PRODUCE AMENDMENTS WITH ENHANCED AGRONOMIC AND SUPPRESSIVE PROPERTIES FROM OLIVE MILL WASTES.

Olive mill wastes (OMW) are of great concern worldwide due to their phytotoxic and antimicrobial effects. Over 3 million tons of olive husks and about one million tons of olive wastewater per year are generated in Italy, with higher amounts produced in the Central-South regions. The composting process proved to be a reliable method for bioremediation and valorization of OMW since it reduces the harmful effect on soil and plant due to spreading of crude untreated wastes. Moreover, OMW composts can actively contribute to the biological control of plant pathogens and to improve soil physico-chemical properties and plant growth. In this context the BioCompost project (IT-Molise Region, POR-FESR 2007-2013), involving the join participation of scientific institutions, private industries and farms, meets the need of olive oil producer to sustainably and economically dispose OMW and of farm/nursery to reduce fertilizers, pesticides and growth substrates inputs. Our investigations showed that composted and improved amendments, derived from olive mill wastes could effectively be used in ecocompatible crop production systems for both positive agronomic properties and high suppressive activity against fungal pathogens on different crops. The suppressive effect of composted OMW are mainly due to the antagonist microflora selected during the composting process. Finally, suppressive activity of OMW composts as well as their beneficial effect on soil and plant can be further improved by enrichment with selected microorganisms. The structure of the BioCompost project as well as some key results obtained and future perspectives of our research are reported and discussed.