Fig. 3
From: Competitive interaction with keystone taxa induced negative priming under biochar amendments
The bacterial co-occurrence networks under the non-amended (CK and CF) and biochar-amended (LB, MB, and HB) treatments based on correlation analysis in the field experiment and stable isotope probing (SIP) microcosms. A connection stands for a strong (Spearman’s P > 0.8) and significant (P value < 0.01) correlation for the non-amended and biochar-amended treatments. The non-amended (a, c) and biochar-amended (b, d) networks in the field experiment are colored by the bacterial phyla/classes and modules, respectively. The bacterial modules I–VI in the non-amended and biochar-amended networks were the six clusters of closely interconnected nodes. The bacterial keystone taxa (module hubs) and their connected edges in the networks are in bold. The size of each node is proportional to the number of connections (degree), and the thickness of each connection between two nodes (edge) is proportional to the value of Spearman’s correlation coefficients. The blue edges indicate positive interactions between two bacterial nodes, while red edges indicate negative interactions. The non-amended (e) and biochar-amended networks (f) in the SIP microcosms are colored by bacterial phyla/classes. The gray nodes and edges are not detected