Abstract:In order to study the effects of reducing chemical fertilizer combined with application of different organic fertilizers on soil bacterial community structure during the rice season, Illumina high-throughput sequencing technology was used to compare soil environmental factors and soil bacterial community structures in different soil layers under three fertilization modes, namely chemical fertilizer, reducing chemical fertilizer combined with rapeseed cake and earthworm manure. Compared with chemical fertilizer treatment, the treatments with combined application of organic fertilizers significantly increased soil organic matter(SOM) and EC in each soil layer, and the treatments with combined rapeseed cake increased SOM and EC significantly. Soil N, P and K nutrients were significantly increased in each soil layer, which were highest in the treatment with combined application of wormcast. The treatments with combined application of organic fertilizers increased soil bacterial Sobs index and Shannon index. Proteobacteria, Acidobacteria and Chloroflexi were the first three abundant in soils under different treatments at phyla level, reached 36.24%, 18.30% and 13.87%, respectively. Reducing chemical fertilizer combined with application of organic fertilizers had a greater effect on the phyta whose relative abundance was less than 1%. Soil bacterial community structure was greatly affected by soil pH and TP in the 0-5 cm soil layer, mainly affected by EC, pH and TP in the 5-10 cm soil layer, and greatly affected by soil TN and pH in the 10-15 cm soil layer. In conclusion, reducing chemical fertilizer combined with application of organic fertilizer can affect soil bacterial community structure, especially rare bacteria, by changing soil physical and chemical properties.