Rice cultivation by direct drilling and delayed flooding reduces methane emissions

摘要

During a project at Vercelli, N. Italy, involving intensive CH_4 flux measurement in a traditionally managed rice field, we also measured the N_2O flux prior to flooding, and both the CH_4 and N_2O emissions in other fields managed by direct drilling and delayed flooding. Total seasonal emissions of CH_4 were reduced to about 25% compared those under traditional management. Part of this gain was offset by prolonged N_2O emissions during the extended period before flooding. However, we estimate the net gain in terms of reduced global warming commitment to be equivalent to 1-2 t of sequestered CO_2-C ha~(-1)y~(-1). Other investigations at Vercelli have demonstrated that there are no associated yield or crop quality penalties. Thus the practice appears to offer a desirable "win-win" combination of agricultural and environmental benefits.