Effects on growth and biomass production of patè olive cake for agronomic application

The cultivation of olive trees (Olea europaea L.) is very important worldwide and especially for the Mediterranean area. This crop is mainly used for the production of oil, but also of olives and precious wood. The chemical-physical characteristics of the by-products derived from the transformation of olives depend on the synergy between the soil and climatic conditions of the cultivation area, the variety, the state of ripeness of the olives and, above all, the processing system adopted. These wastes, in fact, due to their acidity, the presence of phenolic compounds, suspended substances and the high organic load, can be characterized by a high polluting and phytotoxic degree. These characteristics, combined with the seasonality of olive production, concentrated from October to March, and therefore the high concentration of potential pollutants in a short period of the year, are unable to guarantee cost-effectiveness of management in the transformation and disposal phase. The need arises for the recovery and recycling of oil waste for the production of compounds of commercial value to be reused in agriculture as an excellent combination between the enhancement of the by-product and waste management. This requires both the use of eco-sustainable separation and extraction technologies for the selective recovery of biological macromolecules of high added value, and the implementation of the agricultural use of the fractions with greater bio-stimulating potential. In this context is the study conducted within the ABASA project (Agricultural By-products into valuable Assets for Sustainable Agriculture), funded by Lazio Innova-Regione Lazio, CUP: B81G18000770002 "Green technologies for sustainable agriculture: protection from phytopathogens and fertilizers of agri-food crops using biomolecules obtained from oil waste". Object of this work is the evaluation of the effect on plant growth and biomass production of a new olive mill by-products named “Patè Olive Cake” (POC) generated by a multi-phase decanter (DMF) technology that combine an extraction technology without the addition of water. POC is an olive mill by-product consisting of olive pulp, olive skin and vegetative water. The aim of this research was to adopt protocols for the evaluation of different POC fractions through laboratory bioassays to highlight their nutritional, bio-stimulating, toxic and genotoxic properties. In the present work the first results obtained are reported and discussed. Tests in pots are being carried out in order to investigate the effects of different fractions on growth and biomass production tested on ryegrass (Lolium perenne L.) and on the chemical and microbiological characteristics on two different soils used for the experimental test.