Abstract:
The field experiments conducted over the past three years indicate that the methane emission fluxes from the rice paddies vary drasticaly with various agricultural measures. During the three late rice growing seasons from 1990 to 1992, CH
4 emission fluxes from the experimental fields were 10. 83, 25.18 and 19. 85 mg/m
2·h, respectively. Semi-dry cultivation reduced the CH
4 emission fluxes by about one third, sunning field, applying ammonium sulfate and intermittently flooded irrigation might also make the CH
4 emission fluxes decreased significantly. The principal reasons for high CH
4 emission fluxes are heavy application of organic fertilizer and long-term flooding. The key of controlling CH
4 emission lies in regulating irrigation water. As long as a proper irrigation scheme is adopted, an increase of organic fertilizer may not be followed by an increase of CH
4 emissions.