Tree age progressively shapes grapevine rhizosphere microbial activity and nitrogen nutrition in a temperate vitiforestry system

Background and Aims Agroforestry, i.e., the planting of trees within agricultural systems, has been shown to enhance soil fertility, biodiversity, and the functioning of ecosystems. In temperate vineyards, vitiforestry represents a new type of agroforestry combining perennial grapevines and trees, either within or around vine rows. However, the effects of trees planted within vine rows on belowground microbial processes and grapevine growth remain underexplored. Methods In this study, we investigate soil physicochemical properties, microbial enzymatic activities associated with carbon (C), nitrogen (N), and phosphorus (P) acquisition, and nutrient acquisition strategies in bulk soil and grapevine rhizosphere compartments in a vineyard where trees were planted within vine rows either five years ago (5YO) or ten years ago (10YO). Results The results indicated that soil organic C and total N contents were higher near 10YO trees compared with soils from control rows (i.e., far from trees). Enzymatic activities increased in the rhizosphere of grapevines planted near trees compared with those planted farther away, and this effect was more pronounced near 10YO trees. Vector analysis revealed a shift toward greater relative investment in P-acquiring enzymes near older trees. The presence of trees also had a positive influence on vine nitrogen status without affecting berry yield per vine. Conclusion Overall, trees enhanced grapevine rhizosphere enzymatic activities, promoted nitrogen acquisition, and improved soil quality, offering a practical pathway toward more resilient and sustainable viticultural systems.