Mixed vineyard prunings and sheep manure compost: Creating changes in vineyard soil dominant microbiota to impact fruit quality

Abstract

Vineyard prunings are an excellent composting substrate when suitably treated. However, the potential link between vineyard prunings composting and promoting changes in soil microbial communities in vineyards and the impact on fruit quality remains unclear. This study aimed to assess the effects of various combinations of vineyard prunings and sheep manure compost on vineyard soil properties, microbial composition, and fruit quality. The results indicated that compost improved soil physicochemical properties. Changes in soil properties influenced microbial characteristics and functions, compost with a higher proportion of sheep manure altered the dominant bacterial phylum in the soil with Actinobacteria becoming predominant in 30 % vineyard prunings +70 % sheep manure composting (GM3) and 100 % sheep manure composting (SM), representing 30.7 % and 33.2 % of total abundance. The dominant bacterial genus in GM3 treatment was SBR1031, which increased its relative abundance by 6.9 %. These dominant microbiota were positively correlated with soil nutrients and enzyme activities, which promoted the release of available potassium (AK) and available phosphorus (AP). Microbial function prediction indicated that GM3 treatment upregulates metabolic pathways, including the citric acid cycle and amino acid metabolism. Moreover, soil characteristics demonstrated positive correlations with reducing sugars, soluble solids, and total tannins. Compost application, especially GM3, had a positive impact on fruit quality, outperforming pure sheep manure compost. The results highlight that compost from a combination of vineyard prunings and sheep manure fosters vineyard soil properties and microbial functions, thereby exerting a positive impact on Pinot Noir fruit.