Figures & data
Table 1 Management and environmental conditions in the Ibaraki-Nanbu area for the baseline and alternative scenarios used for the sensitivity test
Figure 1 Methane (CH4) emission and paddy area in 1990. The ratio of methane emission and paddy area classified by (a) the 11 regions, (b) soil group and (c) drainage and groundwater level, respectively. Abreviations of soil groups are as follows: L: Lithosols; RS: Regosols; A: Andosols; AW: Wet Andsols; AG: Gleyed Andosols; B: Brown Forest soils; GrU: Gray Upland soils; GU: Gley Upland soils; R: Red soils; Y: Yellow soils; DR: Dark Red soils; BL: Brown Lowland soils; GrL: Gray Lowland soils; G: Gley soils; M: Muck soils; and P: Peat soils.
Figure 2 Average methane (CH4) flux from different soil groups and drainage indices. Labels indicate the drainage index and soil group name in the Japanese system. L, Lithosols; RS, Regosols; A, Andosols; AW, Wet Andsols; AG, Gleyed Andosols; B, Brown Forest soils; GrU, Gray Upland soils; GU, Gley Upland soils; R, Red soils; Y, Yellow soils; DR, Dark Red soils; BL, Brown Lowland soils; GrL, Gray Lowland soils; G, Gley soils; M, Muck soils; P, Peat soils.
Figure 3 (a) Sensitivity of methane (CH4) flux to soil properties under continuous flooding (CF) and conventional (CV) water regime; (b) baseline CH4 flux under different drainage rates and CF. SOC, soil organic carbon; BD, soil bulk density; FWC, field water capacity.
Figure 4 Uncertainties in methane (CH4) flux from gray lowland soil (GrL) due to the soil heterogeneity in the Ibaraki-Nanbu area, quantified by the most sensitive factor (MSF) method. C, carbon.
Table 2 Methane (Ch4) emission levels from rice Oryza sativa L.) paddy under different drainage index in Ibaraki-Nanbu, as predicted by the DeNitrification-DeComposition(DNDC)-Rice model
Table 3 Comparison between the result of GIO (Citation2011) and this study