Maize production, N fertilizer consumption and total GHG emission between the regional N rate and farmers' practice in 12 agro-ecological subregions.

aDifferent mean the different of maize production, N fertilizer consumption, and total GHG emission between regional N rate and farmer's practice.bNational values are computed from the regional values weighted by area. The regional weights are as follows:NE1, 4.5%; NE2, 14.9%; NE3, 4.7%; NE4, 6.4%; NCP1, 25.6%; NCP2, 6.0%; NW1, 10.4%; NW2, 7.3%; NW3, 2.6%; SW1, 3.5%; SW2, 7.9%; SW3, 6.2.