Trifolium repens and biochar addition affecting soil nutrients and bacteria community

Biochar has wide application prospects as a good soil conditioner, leguminous plants can fix nitrogen and improve soil available nutrients. However, it is not clear how adding biochar when planting leguminous plants affects soil bacterial community and soil available nutrients. This study investigates the effects of biochar addition on the content of ammonia nitrogen, Olsen-P, and available potassium in northeastern farmland soils under the plantation of Trifolium repens and then compared with the application of organic fertilizer. A 90-day incubation experiment was conducted to compare the changes in the structure and relative abundance of soil microflora under varied biochar additions. It was found that the addition of biochar could affect the structure of the microflora and the available nutrients in the soil. When compared with soil planted with T. repens without the addition of biochar, with the application of 3% biochar increased the content of ammonia nitrogen, Olsen-P, and available potassium in the soil by 31.71%, 21.40%, and 11.51%, respectively. High throughput sequencing revealed that the relative abundance of functional bacteria such as azotobacter, rhizobacteria, and phosphorus solubilizing bacteria in the soil increased with the addition of biochar. Furthermore, the effect was more obvious with the addition of organic fertilizers. The addition of biochar improved the microbial community structure and increased the relative abundance of functional bacteria and the content of available nutrients in the soil. This is expected to reduce the application of chemical fertilizers, thereby protecting the environment and conserving natural resources.