N₂O Emissions from an Apple Orchard in the Coastal Area of Bohai Bay, China

Table 2

Average concentrations (mean ± SE) of soil DOC (mg C kg⁻¹) and IN (mg N kg⁻¹) during the experimental period.

Items	N treatment	Site A	Site B	Weighted average
DOC	SN	153.9±13.0	145.4±12.3	151.4±12.8
	CK	140.9±16.7	121.0±17.2	135.0±16.8
NO3^−–N	SN	73.7±14.1	29.7±9.0	60.5±12.6
	CK	42.4±12.4	24.1±9.2	36.9±12.9
NH4^+–N	SN	113.6±22.8	10.7±4.2	82.8±17.2
	CK	42.0±14.4	13.8±7.5	33.5±12.3

SN means the synthetic N fertilizer treatment. CK means the treatment without synthetic N fertilizer. Site A means the fertilization area in an apple tree canopy projection area. Site B means the nonfertilization area in an apple tree canopy projection area. The weighted averages were calculated from the emissions from site A and site B according to their area ratio.