Objective The aims to provided basis for the application of Paenibacillus terrae NK3-4 and organic fertilizer on rice from the perspective of soil microbial feedback,

Method Five treatments were set up, namely, conventional fertilization (F), NK3-4 combined with conventional fertilization (F + NK3-4), NK3-4 combined with 70% conventional fertilization rate (70%F + NK3-4), and two application levels of organic fertilizer (OF1: 2,250 kg hm^-2 and OF2: 4,500 kg hm^-2). The rice field plot experiment was carried out, rhizosphere soil was collected at tillering stage of rice, rhizosphere microbial community was analyzed, and rice yield was determined.

Result There was no significant differences in yield components and yield between treatment F and other treatments, except that 1000-grain weight of F treatment was more than that of OF2. While spike number of OF2 was 21.10% more that of 70%F + NK3-4, and the 1000-grain weight was 8.96% lower. The number of grains per panicle of OF1 was 19.22% lower than that of 70%F + NK3-4. The number of grains per unit area of 70%F + NK3-4 was 18.02% higher than that of F + NK3-4. No significant difference was found in yield among70%F + NK3-4, OF2, F and F + NK3-4, but the yield of 70%F + NK3-4, OF2 and F were 12.44%, 12.14% and 11.94% higher than that of OF1, respectively. Rhizosphere microbial community in F treatment showed a trend of lower and lower similarity from Phylum to Order taxonomic hierarchiers with other treatments, then showed furthest clustering relationship with other treatments at Phylum and its below taxonomic hierarchiers. 70%F + NK3-4 enriched Pseudomaondaota to the greatest extent and the greatest number, while F + NK3-4 enriched viruses to the greatest extent, and enriched a species of Eurygoarchaea to the greatest number. OF1 enriched Euryarchaea to the greatest extent, while OF2 enriched Bacteroidetes and Firmicutes strongly. OF2, F + NK3-4 and 70%F + NK3-4 increased the abundance of Chloroflechina, both OF2 and 70%F + NK3-4 increased the abundance of Chloroflechina unclassified genera, and 70%F + NK3-4 increased the abundance of Bradyrhizobium spp.

Conclusion  NK3-4 and organic fertilizer differentially affected rice yield components, yield and rhizosphere microbial community structure, especially the 70%F + NK3-4 and OF2 treatment domesticated the rice rhizosphere microbial community with increasing the abundance of beneficial microorganism. The results provided a basis for the application of bio-organic fertilizer prepared by NK3-4 and organic materials.