| To investigate the effects of biochar, clover and earthworm cultivation on bacterial community diversity, functional prediction and nutrients in watermelon rhizosphere soil, a field plot experiment was conducted. Eight treatments including control (CK), biochar (B), clover (T), earthworm cultivation (V), biochar + earthworm cultivation (BV), clover + earthworm cultivation (TV), clover + biochar (BT) and clover + biochar + earthworm cultivation (BTV) were set up. The results showed that different treatments had significant effects on soil nutrients in watermelon rhizosphere. Compared with CK, BV treatment had the highest soil available K (383.41 mg·kg-1), significantly increased by 102.23%. The soil total nitrogen under TV treatment was the highest, which was 0.79 g·kg-1, significantly increased by 75.56%. The content of soil available P in BTV treatment was the highest, which was 427.51 mg·kg-1, significantly increased by 23.88%. The Shannon index of BTV treatment was significantly higher than that of other treatments. Simpson index of TV treatment was 56.52% higher than that of T treatment. ACE and Chao 1 indexes of B treatment were 10.95% and 12.59% higher than those of BTV treatment, respectively. Different soil treatments affected the relative abundance of bacterial community composition, of which Proteobacteria, Actinobacteria, Chlorobacteria and Firmicutes were the dominant phyla. Compared with CK, the relative abundance of Proteobacteria and Actinobacteria increased by 47.85% and 30.47%, respectively, while the relative abundance of Acidobacteria decreased by 48.36%. Functional prediction analysis of PICRUST2 showed that BTV enhanced the activities of metabolism, amino acid metabolism and global overview pathway in rhizosphere bacterial community, and the active microorganisms might play an important role in the “biochar\|clover\|earthworm farming\|watermelon” complex habitat. This study showed that different soil treatments improved soil bacterial community diversity and soil nutrients, and biochar and clover combined with earthworm cultivation had the best comprehensive effect. |