Bacillus subtilis SL-13 biochar formulation promotes pepper plant growth and soil improvement.

The use of microbial fertilizers can help to avoid the harmful effects of traditional agricultural fertilizers and pesticides; however, there are many constraints on the practical application of such fertilizers. In this study, microbial biochar formulations (MBFs) were obtained by loading biochar, created from agricultural waste, with Bacillus subtilis SL-13. The effects of the MBF on pepper plant growth and soil fertility were studied in pot experiments. The MBF improved the soil texture and environment, and favored plant growth. Compared with Bacillus subtilis SL-13-only and biochar-only treatments, pepper plant growth and physiological indices increased significantly, and the physical-chemical properties and activities of several enzymes in the soil improved significantly in the MBF treatments. Therefore, the present study not only demonstrated that MBFs retain the beneficial effect of biochar in improving the soil properties but that they also improve the performance of Bacillus subtilis SL-13 in promoting plant growth.