Fig. 8

Hyphal length density, nosZ gene copies, and their correlation in the long-term field experiment. A, B Hyphal length density (A) and nosZ-type gene copies (B) in long-term field soils of faba bean monoculture and maize/faba bean intercropping under different phosphate fertilizer application rates (n = 3). Asterisks, significant differences between monoculture and intercropping within each P application rate according to the two-tailed unpaired t test (*, P < 0.05; **, P < 0.01). C Correlation between hyphal length density and nosZ gene copies. Correlation analysis is based on the Spearman correlation coefficient. Gray shading denotes 95% confidence intervals