EFFECTS OF STRAW RETURNING AND BIOCHAR ON SOIL BACTERIAL COMMUNITY DIVERSITY AND CO-OCCURRENCE NETWORK IN PADDY FIELD

Applying biochar to soil has been proposed as a strategy to enhance soil quality and crop productivity. Four treatments were undertaken, including no amendment of biochar and straw addition (CK), original straw return only (SR), biochar return only (BR), and straw return with biochar addition (SB). The results showed that compared with the CK treatment, SR, BR and SB significantly increased soil bacterial community diversity, and the contents of soil organic matter (SOM), soil total nitrogen (TN), soil total phosphorus (TP), soil available phosphorus (AP), soil available potassium (AK), soil total potassium (TK) and soil cation exchange capacity (CEC) could be significantly increased by applying straw returning and biochar. Based on NMDS analysis at the OTU level for the soil bacterial community compositions, SB clearly separated from CK, SR and BR. The results of RDA for bacteria showed that TP, TN, TK, SOM, CEC and AK were the main factors affecting the composition of bacterial communities, and simple plot of BR and CK had highly significant effects with TN. Compared with CK and SR co-occurrence networks, BR and SB form a more complex co-occurrence network structure.