Figure 3

Partial least squares discrimination analysis (PLS-DA) showing the changes in bacterial community composition in different treatments in the 0–20 cm (a) and 20–40 cm (b) layers (using R V2.15.3). CK, CF, CS, and CB refer to different soil samples subjected to different treatments (i.e., non-fertilization, chemical fertilization, continuous straw returning, and continuous straw-derived biochar amendment, respectively).