Increasing organic fertilizer application can improve the sustainability of soil productivity, but the effects of increased organic fertilizer application with reduced chemical fertilizer application over different time periods on chemical properties and bacterial community of grape rhizosphere soil in an arid region are not clear. In this study, three years of fixed-point field tests were used to compare the effects of various fertilization treatments on the soil properties and bacterial community in the grape rhizosphere. The results showed that (1) T1 and T2 significantly increased SOM, AN, AP and AK contents in grape rhizosphere soil. TN, TP and TK contents in grape leaves of T2 were the highest of those in five fertilization treatments. (2) The abundances of Proteobacteria and Bacteroidetes phyla and especially of Arthrobacter, Pseudomonas, Nitrosopira and Bacillus genera were higher in T2 than in the other samples. (3) SOM, AP and AN contents in soil were the main factors affecting soil bacterial community and mineral element contents in grape leaves and roots according to an RDA analysis. In summary, the application of organic fertilizer with reduced chemical fertilizer for two years had the greatest impact on the soil properties and bacterial community of the grape rhizosphere soil. Soil microbes play an important role in maintaining soil productivity through biochemical processes such as litter decomposition and nutrient recycling 1. The soil microbial community is an important factor influencing plant health because plant disease resistance mainly relies on the rhizosphere microbial community 2. Microbes are regarded as early warning indicators of soil quality because of their rapid response and sensitivity to environmental changes 3. Soil properties are greatly influenced by agronomic practices such as tillage, irrigation, and fertilization 4. Fertilization is widely used worldwide to improve soil fertility. Excessive fertilizer application aggravates the decline of soil organic matter and fertility and accelerates soil acidification 5. Soil properties affect the community structure of soil microbes 6. Fertilization influences soil microbial diversity through direct effects on the soil nutrient content 7. Soil microbial communities are sensitive to fertilization and their responses to manure and/or mineral fertilizers in soils have been well studied over the past several years 8,9. The long-term application of nitrogen fertilizer or nitrogen fertilizer in combination with other mineral fertilizers affects the nitrogen cycle and related bacterial populations 10. Repeated overuse of chemical fertilizer can have a negative effect on soil quality and soil microbial community structure. The long-term application of chemical fertilizers can significantly reduce soil pH which is closely associated with decreased bacterial diversity and significant changes in bacterial community composition, livestock manures can prevent soil acidification and its effects on soil bacteria 11. Geisseler and Scow found that with...

The use of water-soluble chemical fertilizers for years under drip irrigation conditions results in soil compaction, fertility decline, and fruit quality decrease in arid areas. Currently, little research has been reported regarding the effects of increasing organic fertilizer and reducing drip chemical fertilizer on the growth of grape plants under different conditions in arid areas. In this study, five different treatments were conducted. Compared with no fertilizer for 3 consecutive years (CK) and single fertilizer for 3 consecutive years (T0), organic fertilizer plus 1 year of reducing drip chemical fertilizer (T1), organic fertilizer plus 2 years of reducing drip chemical fertilizer (T2), and organic fertilizer plus 3 years of reducing drip chemical fertilizer (T3) improved the soil pH, electrical conductivity (EC) values, and soil organic matter content to different degrees during early growth stages (15 days after anthesis) and mature stages (75 days after anthesis). The available N, P, and K contents in the T1 and T2 treatments increased significantly. With the T2 treatment, the longitudinal and transverse diameters of the ‘Summer Black’ grapes were the largest during the two fruit expansion periods. The anthocyanin content of grape peel with the T2 treatment was 22.0% higher than that with the T0 treatment. The soluble solids, sugar–acid ratio, various sugar contents, vitamin C, and total phenol of the fruit increased significantly with the T2 treatment, indicating that the T2 treatment was best for promoting grape growth and fruit quality and that the T3 treatment was the second best.