Technical report on ZEOWINE composting process

Wine supply chain produces a considerable amount of organic wastes which remain as residues in the ecosystem. The environmental-friendly management of agricultural soils, usually involves the application of organic amendments. In addition, several recent researchers proposed the use of soil conditioners, such as zeolite, to improve the physical and chemical properties of agricultural soils. In this context, with the aim of improving the agronomic value of compost, and simultaneously achieving sustainable recycling of organic wastes, we developed a vine management system based on the composting of winery organic wastes and zeolite to obtain a fertilizer to be used for vineyard soils. The innovation of this composting process lies in the role of the natural zeolite on winery wastes valorization and recycling. In particular, we monitored the response of chemical and biochemical properties to different rates of zeolite on winery waste composting process. The winery waste material (pomace and stems), was composted in presence of natural clinoptilolite zeolite at the following rates: 1) zeolite 0% : wastes 100% (0%, control); 2) zeolite 10% : waste 90% (ZEOWINE 1:10); 3) zeolite 30% : waste 70% (ZEOWINE 1:2.5). The experimentation was set up in two areas in Tuscany (Central Italy): CMM-San Miniato and Col D'Orcia-Montalcino, characterized by a typically Mediterranean semiarid climate. The presence of zeolite at the two rates (10% and 30%) during the composting of winery wastes enabled an higher retention of nutrients, enzymatic activity and humification of organic matter with respect to control compost. In addition, it decreased the electrical conductivity and increased the germination index, thus improving the agronomic quality of the compost.