Effect of Compost Added with Compostable Plastic Packaging on Wheat Health and its Rhizosphere Microbiome

Aim: Packaging waste is steadily increasing in Europe. Thus, compostable plastics (CPs) may represent an environmentally friendly alternative to petroleum-based plastics for the development of innovative packaging solutions. However, the potential impact of CPs presence in compost on soil ecosystems and crop health, still needs to be assessed. The present investigation aims to evaluate and compare the effects produced by "standard" compost (C) obtained from urban organic waste (UOW) and UOW added with 3% compostable bioplastics (CV), on wheat health and its rhizosphere microbiome. Method: Field experiments were conducted at Agricultural Research Station, CERMIS, Italy. During 2021-2022, three treatments (C, CV, and B -no compost) with five replicates each, were tested. Soil chemical-physical properties were measured before and after composts distribution to evaluate changes in nutrient concentrations and presence of possible pollutants. At the flowering stage, ten plants and associated rhizospheric soils were collected in each plot. Morphological and productive wheat traits were measured. Rhizosphere bacterial communities were analysed by 16S rRNA metabarcoding. Results: No significant differences between treatments were detected by means of wheat traits. C and CV compost fertilization significantly changed the bacterial communities with respect to the untreated control. But no significant differences were found between the C and CV communities, which also showed similar composition. This demonstrates the equivalence of the two composts. Conclusions: Results showed that CPs addition do not negatively affect compost quality neither wheat nor microbiome health. Thus, CPs represent a sustainable alternative to conventional plastic that will be crucial in the green European transition.