Grape Pruning Material Improves Root Development and Soil Microecology in ‘Shine Muscat’ Grape Soils

The addition of pulverized grape pruning wood to grape soils has a positive effect on fruit quality. However, its effects on the soil microecology of the root zone and the growth of the grape plants are not fully understood. To address this, ‘Shine Muscat’ grapes were cultivated in media consisting of garden soil and crushed grape pruning material at different mass ratios [100:1 (T1), 50:1 (T2), 30:1 (T3), 20:1 (T4), and 10:1 (T5)] and in garden soil without the pruning material, as a control. The changes in the plant fresh weight, leaf area, soil and plant analyzer development (SPAD) value, root development, soil organic carbon, microbial biomass carbon, and soil enzyme activity were determined over time. High-throughput sequencing technology was used to determine the soil bacterial community structures. The pruning supplementation increased the grape plants fresh weight, leaf area, and SPAD values. The T2 and T3 treatments increased the grape root length, surface area, and the projected area and number of the root tips; the soil organic carbon content, microbial biomass carbon content, soil invertase activity, amylase activity, and β-glucosidase activity were also significantly increased. The addition of the grape pruning material was found to increase the bacterial diversity and richness 60 and 150 days after treatment. At the phylum level, Proteobacteria, Acidobacteria, and Actinobacteria were the dominant groups, and the grape pruning material increased the relative abundance of the Acidobacteria and Actinobacteria after 60 and 150 days. The relative abundance of the Actinobacteria in the T2 treatment was 1.7, 1.3, 1.5, and 1.3 times that of the control, after 60, 90, 120, and 150 days, respectively. The T2 treatment was identified as the optimal treatment for grapes in the field because it improved the soil microecology and promoted root and tree development the most compared with the other treatments tested.