Abstract:

This study aimed to investigate the effects of reduced chemical fertilizer（10%，20%，30% reduction）application combined with microbial inoculants（Beilaiya agricultural microbial agent containing Bacillus velezensis，B. subtilis，and B. licheniformis，with an effective viable count of 10.0 × 10⁹ CFU · mL^-1）on soil physicochemical properties and fruit quality in the 10-year-old vineyard，meanwhile，high-throughput sequencing was used to analyze structural diversity of rhizosphere bacterial communities under different treatments. The results showed that reduced chemical fertilizer combined with microbial inoculants did not alter bacterial phyla composition or dominant bacterial communities in soil. Proteobacteria，the beneficial phylum，remained dominant. However，the reduced chemical fertilizer combined with microbial inoculants changed the relative abundance of bacterial communities. The relative abundance of Proteobacteria in soils with 20% and 30% fertilizer reduction was higher than that in the control. The highest relative abundance reached 35.90% under 20% fertilizer reduction combined with microbial inoculants. The relative abundance of soil Acidobacteria under 10%，20% and 30% fertilizer reduction combined with microbial inoculants was lower than the control（15.64%），reaching 7.67%，11.64% and 13.59%. Reduced chemical fertilizer combined with microbial inoculants decreased soil pH，available nitrogen，total potassium，total phosphorus and available phosphorus to varying degrees，while increasing soil total nitrogen content. Meanwhile，fruit coloration and comprehensive quality were significantly improved. Among all treatments，the 20% fertilizer reduction coupled with 300-fold dilution microbial inoculants achieved the maximum fruit color index of red grape（CIRG）value，soluble solids content and yield，which were 4.20，18.54 °Brix and 52.59 kg · hm^-2，respectively.

Key words: grape, orchard, chemical fertilizer reduction, microbial inoculant, community structure, berry quality