Mulching with Municipal Solid Waste (MSW) Compost Has Beneficial Side Effects on Vineyard Soil Compared to Mulching with Synthetic Films

Municipal solid waste (MSW) compost represents a sustainable alternative to plastic film for mulching in viticulture. This study investigated the effects of MSW compost on vineyard soil properties, specifically focusing on side effects such as soil temperature and microbial decomposition activity, independently from its role in weed control. The experiment was conducted in a vineyard located in the Mediterranean region (Southern Italy), with six different mulching treatments: black polyethylene (PE) film, black and white biodegradable film, three different amounts of MSW compost (8, 15, and 22 kg plant−1), and a control without mulching. Weed growth was monitored to determine the optimal compost application amount. The 15 kg plant−1 treatment was selected for further analyses, as it did not significantly impact weed growth compared to the control. Results indicated that MSW compost mulching maintained lower soil temperatures compared to other treatments (up to 5 °C in the warmest hours) and reduced the amplitude of the thermal wave up to 50% compared to the non-mulched soil and even more compared to black film mulched soil, particularly during the warmest periods. This suggests that MSW compost can mitigate heat stress on plant roots, potentially enhancing plant resilience and preserving crop production also in stressful growing conditions. Microbial decomposition activity, assessed using the tea bag index, was higher in the MSW compost treatment during spring compared to the control, indicating temperature as a key driver for organic matter decomposition, but this effect disappeared during summer. These findings highlight the potential of MSW compost to support sustainable viticulture by reducing reliance on synthetic mulching materials and promoting environmental sustainability through the recycling of organic municipal waste.