Table 4.

Changes in bacterial richness and biodiversity by nitrate

	Treatments			SEM	p-value	Contrast1
	0NR	1NR	2NR			PL	PQ
ACE	6,275	6,701	6,228	403.34	0.68	0.94	0.40
Chao1	5,862	6,320	5,740	400.87	0.59	0.84	0.33
Shannon	0.996	0.997	0.996	0.13	0.97	0.97	0.81
Simpson	9.97	10.01	9.98	0.001	0.77	0.79	0.52

SEM, standard error of the mean; ACE: abundance-based coverage estimation; 0NR: control; 1NR: 1% nitrate; 2NR: 2% nitrate.

¹P_L is liner tendency; P_Q is quadratic tendency.