Table 2.

Effects of nitrate on the relative abundance of bacterial phyla (% of total sequences) using NGS technology

	Treatments			SEM	p-value	Contrast1
	0NR	1NR	2NR			PL	PQ
Bacteroidetes	57.36	56.81	53.35	2.25	0.44	0.25	0.62
Firmicutes	33.12	29.82	34.24	2.97	0.58	0.80	0.33
Proteobacteria	3.30	5.20	6.34	1.01	0.18	0.08	0.77
Unclassified	2.43b	3.11a	2.28b	0.13	0.01	0.45	<0.01
Tenericutes	0.81b	1.32a	0.70b	0.12	0.03	0.56	0.01
Fibrobacteres	0.71	1.06	0.83	0.20	0.49	0.70	0.27
TM7	0.43	0.64	0.56	0.07	0.22	0.25	0.18
Spirochaetes	0.36b	0.69a	0.43b	0.07	0.03	0.48	0.01
SR1	0.44	0.45	0.53	0.18	0.93	0.74	0.87
Verrucomicrobia	0.35a	0.20b	0.14b	0.04	0.02	0.01	0.39
Synergistetes	0.14	0.15	0.20	0.03	0.43	0.24	0.63
Cyanobacteria	0.18b	0.22a	0.09b	0.02	0.01	0.02	0.01
Actinobacteria	0.16	0.09	0.18	0.02	0.08	0.57	0.03
Elusimicrobia	0.12	0.07	0.05	0.02	0.09	0.04	0.60
Lentisphaerae	0.06	0.12	0.05	0.02	0.09	0.68	0.04
WPS	0.02	0.02	0.02	<0.01	0.33	0.21	0.45

NGS, next-generation DNA sequencing; 0NR, control; 1NR, 1% nitrate; 2NR, 2% nitrate; SEM, standard error of the mean.

¹P_L is liner tendency; P_Q is quadratic tendency.

Different superscripts in the same row represent significant differences (p<0.05).