Effects of Crop Residue Management on N2O Emission from a Cultivated Andosol in Central Japan.

Incorporation of crop residue to the soil is expected to increase both soil fertility and soil carbon content. But we need to check the possibility of the extra emission of N2O under such an agricultural field　management. In this study we measured GHG fluxes through years at an Andosol vegetable field located in central Japan.

Three years' monitoring showed clear increase of accumulated N2O emission in plant residue applied site. In detail, the amount of increased N2O differed with quality and quantity of the residue which applied to soil. The most significant increase were observed after application of sorghum which were in earing period. Calculated emission factors　varied in the range of 0.13% to 1.3% between type of applied residue. Besides that, the meteorological event such as heavy rain caused by the typhoon was also an important factor which affected the amount of increased N2O.