Evaluation N2O Emissions from Intensive Manure Managements in a Dairy Area

Abstract

To investigate N 2 O emissions from intensive manure managements, eight farmer's fields covering paddy rice and uplands cropping systems in a livestock watershed of central Japan has been selected. The manure was popular applied with PIAF (Ploughing Immediately after Fertilization), FKSSL (Fertilizer Keeping on the Surface Soil for a Longer Time) and only applied in winter fallow season for paddy rice under the application rate of 200-800 kg N ha -1 yr -1 . Field gas samples were conducted by static chamber method. The result showed that N 2 O flux varied from 0 to 1607 µg N m -2 h -1 in upland crop systems and from 0 to 924 µg N m -2 h -1 in paddy fields. And the annual emission ranged from 1.91-9.26 kg N ha -1 yr -1 accounting for 0.48 ± 0.41% of input N in uplands and 1.28-1.91 kg N ha -1 yr -1 accounting for 0.43 ± 0.27% of input N in paddy rice, respectively. In rice/fallow system, more N 2 O emitted and the emission factor was 0.59 ± 0.07% due to the manure applied in fallow winter season. The N 2 O emission from FKSSL was 0.85 ± 0.79% of input N, and 3.4 times higher than PIAF. Slurry application contributed N 2 O emission 0.71 ± 0.37% of input N with 2 times higher than that of dry compost manure plots.