| In March 2023, a field experiment was conducted in a jujube orchard in the Aksu region to investigate the effects of biochar on the physicochemical properties, enzyme activities, and bacterial diversity of saline\|alkali soils. Biochar application levels were set at 0 (CK), 5 (J1), 10 (J2), 20 (J3), and 30 (J4) t·hm-2. The results indicated that, compared to CK, the soil bulk density in the J1~J4 treatments decreased by 2.10% to 22.38%, soil pH increased by 0.36% to 1.32%, cation exchange capacity (CEC) increased by 6.83% to 18.39%, and organic matter content increased by 16.46% to 38.12%. Compared to CK, the activities of soil catalase, urease, and alkaline phosphatase in the J1~J4 treatments increased by 6.67% to 28.00%, 2.94% to 45.52%, and 2.83% to 30.29% respectively, while sucrase activity varied from -0.42% to 27.24%. The activities of these four enzymes showed a trend of initially increasing and then decreasing with the increasing amount of biochar application. Compared to CK, the Chao1 index and Shannon index in the J1~J4 treatments increased by 7.2% to 13.5% and 0.15% to 0.96% respectively, while the relative abundance of the top 10 bacterial phyla decreased by 4.87% to 9.68%. Correlation analysis revealed relationships between soil enzyme activities and soil physicochemical properties and microbial characteristics. Enzyme activities were significantly positively correlated with CEC, and sucrase activity was extremely significantly positively correlated with organic matter content. The Chao1 index (bacterial alpha diversity index) was significantly positively correlated with catalase activity, while the NMDS1 index (bacterial beta diversity index) was extremely significantly positively correlated with alkaline phosphatase activity. In summary, an application rate of 10 t·hm-2 of biochar is the optimal scheme for improving the physicochemical properties, enzyme activities, and bacterial diversity of soils in the jujube orchards of the Aksu region in Xinjiang. |