Over two years study: Peanut biochar promoted potassium availability by mediating the relationship between bacterial community and soil properties

Abstract

In acidic soil, potassium (K) deficiency is a main limiting factor that restricts the growth of fruit trees. Biochar has been used as a soil amendment to increase pH and nutrients. However, studies on the effect of biochar on the bacterial community and soil properties in potted experiments are limited. Therefore, we used peanut shell biochar to investigate the effect of biochar on the structure and function of bacterial communities by high-throughput sequencing, soil enzymes (urease, dehydrogenase, and extracellular enzymes), and gene function prediction in response to K deficiency in acidic soil. The results indicated that soil pH, enzyme activity, and available nutrients were improved by biochar. In particular, biochar still had a beneficial effect on improving soil and plant K levels after thirty months of application. In addition, biochar promoted the growth of K-dissolving bacteria and relative abundance of bacteria (p_actinomycetes, p_chloroflexi, p_proteobacteria, p_acidobacteriota, and p_firmicutes). Based on the above results, we assumed that biochar application can effectively improve soil K levels and bacterial functions. Such as: K-dissolving, soil organic matter decomposition and the conversion of nutrients. Our findings encourage and support the use of biochar as an amendment in acidic soil.