TABLE 2.

The abundance of microbial genes involved in nitrogen (N) cycling in the rhizosphere of tomato plants under furrow irrigation (FI) and subsurface drip irrigation (SDI).

Group	Target gene	Gene abundance (copies ng–1 genomic DNA)		P-value
		SDI	FI
Nitrification	Bacterial amoA	11,426.8(2944.1)	7,139.6(1582.1)	0.659
	Archaeal amoA	750.1 (185.0)	602.7 (109.6)	0.437
Denitrification	nosZ	461.4 (114.2)	395.2 (39.6)	0.672
N-fixation	nifH	262.8 (22.4)	238.7 (40.2)	0.638
Dissimilatory nitrate reduction to ammonium	nrfA	3,739.5(425.1)	3,787.5(422.0)	0.918

Numbers in parentheses represent standard error of the mean (n = 3).