Table 2: Effect of water management practices on daily and annually methane (kg CH4 ha-1) and nitrous oxide (g N2O ha-1) emission, grain yield, global warming potential (GWP) and yield-scaled global warming potential (GWPγ), above ground biomass at 50% heading, and rice grain yield.

Treatment

Methane

Nitrous Oxide

GWP (100-year time horizon)

GWPᵧ (Yield-scaled)

Above ground biomass at 50% Heading

Yield

Daily*

Seasonal

Daily*

Seasonal

CH4

N2O

Total

(kg CO2 eq Mg grain-1)

(kg ha-1)

(kg ha-1)

(kg CH4 ha-1)

(g N2O ha-1)

(kg CO2 eq ha-1)

2013

Delayed Flood (DF)

2.84 a

239 a

1.81 a

152 a

6692 a

40 a

6732 a

833 a

9912 a

8079 a

straighthead (SH)

2.48 a

209 a

1.68 a

141 a

5852 a

37 a

5889 a

796 a

9713 a

7398 ab

Intermittent Flood (IF)

1.49 a

125 b

1.74 a

146 a

3500 b

39 a

3539 b

499 b

8714 b

7097 b

2014

Delayed Flood (DF)

3.18 a

295 a

1.92 a

161 a

8260 a

43 a

8303 a

731 a

11917 a

11351 a

straighthead (SH)

3.09 a

287 a

2.11 a

177 a

8036 a

47 a

8083 a

729 a

10153 a

11083 a

Intermittent Flood (IF)

2.91 a

271 a

2.07 a

174 a

7588 a

46 a

7634 a

674 a

10433 a

11329 a

Means followed by the same letter within each column for individual year are not significantly different (P < 0.05, LSD). *Daily emissions were based on 84 and 93 days of the gas measurements in 2013, and 2014, respectively.