Table 2. Above-ground biomass yields and plant C/N contents of switchgrass affected by N fertilization levels as well as their association with community structure of bacteria/archaea and fungi by marginal test of DistLM.

Different letters within each column indicate significant effects by N fertilization levels at α = 0.05. The *, **, and *** indicate significant DistLM relationship at α = 0.05, 0.01, and 0.001, respectively.

	Yield (Mg Ha-1)	C (%)	N (%)	C/N
N level (kg N ha-1)
0	29.6 b	50.43 a	0.28 a	189.46 a
100	42.4 ab	49.70 b	0.83 b	74.73 b
200	80.1 a	49.47 b	0.98 b	60.62 b
Proportion of explained variation
Bacteria/archaea	2.6%***	1.2%*	1.0%	0.6%
Fungi	1.2%**	1.0%	1.0%	0.8%