Effects of fertilization and management practices on soil chemistry, physical properties, and microflora in vineyards

To promote environmentally sustainable agriculture, we investigated the long-term impacts of organic amendments and the subsequent cessation of fertilizer treatments on soil properties and microbial communities in a vineyard. Organic amendments were applied annually for 28 years, followed by 14 years of unfertilized management. To evaluate tempo­ral trends during this latter period, we monitored the total carbon and nitrogen levels over the past 5 years, which showed little variation. Among the treatments, bark com­post-treated plots maintained the highest carbon content, followed by cattle manure compost-treated ones. The bark compost treatment was also associated with elevated pH and electrical conductivity, suggesting that the organic amend­ments exerted effects long after the treatments themselves stopped. At the end of the 14 years of unfertilized manage­ment, in 2024, we examined the relationship between soil properties and microbial communities by analyzing bacterial and fungal compositions. The bacterial community in the bark compost-treated plots was distinct from those in the other treatments. In contrast, fungal communities exhibited lower variability within the vineyard and formed clusters dis­tinct from those in the control apple orchard. These findings suggest that fungal community composition in soil is more strongly influenced by the cultivated plant species than by historical treatment of organic amendments. This study demonstrates how long-term organic amendments influence soil physicochemical properties and highlights the enduring effects of previous soil management practices on microbial communities and soil conditions.