Compost based ecological growing media according EU eco-label requirements

Abstract

Green compost is seen as one of the best solutions for peat replacement in growing media and for increasing their sustainability. However, the poor quality of many composts has restricted their use as substrate components. The EU Ecolabel may be awarded to products and services that have a reduced environmental impact throughout their life cycle. It is voluntary and ensures certain aspects of the origin and quality. The primary aim of this work was to obtain a gorse compost-based substrate fulfilling the requirements for award of the eco-label.Forest biomass consisting mainly of gorse was composted in dynamic piles with or without irrigation (I) at the beginning and with or without addition of 5% v/v poultry manure (PM). There were thus four different composting treatments that were designated PM0I, PM5I, PM5 and PM0. Temperature, moisture, pH and the C/N ratio of the composting biomass were monitored over a period of nearly 10 months. The resulting composts were characterized in physical, chemical and biological terms, and evaluated for compliance with the requirements of the European Union eco-label for growing media. All composts were found to be mature, stable and pathogen-free. All of them were suitable for use as growing media, exhibiting a high aeration and drainage capacity, little water retention and adequate level of available nutrients. In general they also met the requirements of the EU eco-label, although not all were weed seed-free, which was possibly the sole unfulfilled EU eco-label requirement.