Table 3. Effects of herbicide applications on the cumulative GHG emissions during the sampling times, the GWP of soil planted with alfalfa, and the effect of interaction on cumulative GHG emissions and GWP.

Year	Treatments	CH4 (g·ha−1)		CO2 (kg·ha−1)		N2O (g·ha-1)		Total GWP
2017	CK	−10.94 ± 0.52Aa		285.71 ±11.96Ac		4.28 ± 0.04Ba		286.71 ± 11.96Ac
	QE	−17.36 ± 0.76Ab		382.25 ± 4.29Aa		3.93 ± 0.16Ba		382.99 ± 4.31Aa
	BT	−16.37 ± 0.92Ab		349.38 ± 4.10Ab		4.13 ± 0.13Ba		350.20 ± 4.08Ab
	F	21.165		40.521		2.100		40.312
	P	<0.01		<0.001		0.204		<0.001
2018	CK	−12.27 ± 0.57Aa		285.55 ± 5.81Ab		5.81 ± 0.15Aa		286.97 ± 5.87Ab
	QE	−18.17 ± 0.59Ab		355.77 ± 2.40Ba		5.54 ± 0.06Aa		356.97 ± 2.41Ba
	BT	−18.79 ± 1.13Ab		340.57 ± 5.83Aa		5.73 ± 0.31Aa		341.81 ± 5.88Aa
	F	20.058		55.705		0.449		54.420
	P	<0.01		<0.001		0.658		<0.001
Variable		CH4		CO2		N2O		GWP
		F	P	F	P	F	P	F	P
Y		13.099	<0.01	160.459	<0.001	0.368	0.546	4.608	0.053
T		18.303	<0.001	33.574	<0.001	0.649	0.526	86.830	<0.001
S		5.562	<0.001	8.363	<0.001	0.465	0.832	–	–
Y × T		0.187	0.830	1.649	0.199	0.022	0.978	2.126	0.162
Y × S		0.800	0.529	8.782	<0.001	1.224	0.308	–	–
T × S		1.938	<0.05	0.986	0.471	0.169	0.999	–	–
Y × T × S		0.272	0.973	0.332	0.951	0.055	1.000	–	–

Note:

Y, year; T, treatment; S, sampling time; Y × T, interaction between year and treatment; Y × S, interaction between year and sampling time; T × S, interaction between year and sampling time; Y × T × S, interaction between year, treatment and sampling time. Different lowercase letters represent significant differences between the treatments at P < 0.05 in the same year, and different capital letters represent significant differences between the years at P < 0.05 in the same treatment. GWP, global warming potential.