Table 3.

Effect of biochar application and N fertilizer reduction on the accumulation of NH₃ volatilization, emission factor and yield-scale NH₃ volatilization at different fertilization periods and the whole reproductive period of rice.

Treatment	NH3 volatilizations (g/pot)				Emission factor	Yield-scale NH3 volatilization
	BF	SF1	SF2	Accumulation	%	g/kg
Control	0.02 ± 0.00 d	0.01 ± 0.00 d	0.03 ± 0.01 f	0.06 ± 0.01 d	–	1.31 ± 0.09 d
N160	0.06 ± 0.01 c	0.18 ± 0.08 ab	0.14 ± 0.01 b	0.38 ± 0.09 b	28.7 ± 7.6 a	5.25 ± 1.22 b
N160 + BC	0.06 ± 0.02 c	0.11 ± 0.01 c	0.09 ± 0.01 c	0.26 ± 0.01 c	18.0 ± 1.0 b	3.69 ± 0.24 c
N200	0.07 ± 0.02 c	0.13 ± 0.04 bc	0.06 ± 0.02 de	0.27 ± 0.03 c	15.0 ± 2.1 bc	2.98 ± 0.81 c
N200 + BC	0.06 ± 0.02 c	0.09 ± 0.03 c	0.05 ± 0.01 ef	0.20 ± 0.04 c	10.5 ± 3.0 c	1.41 ± 0.30 d
N240	0.15 ± 0.02 b	0.18 ± 0.03 ab	0.20 ± 0.02 a	0.53 ± 0.02 a	28.1 ± 1.0 a	6.47 ± 0.81 a
N240 + BC	0.18 ± 0.00 a	0.23 ± 0.02 a	0.07 ± 0.2 cd	0.49 ± 0.02 a	25.3 ± 1.2 a	3.47 ± 0.08 c

BF, basal fertilizer; SF1, first supplementary; SF2, second supplementary fertilization of urea-N in rice season. Data are means ± SD (n = 3); different lowercase letters in the same column indicate significant differences between treatments (p < 0.05).