不同农业措施对稻田甲烷排放通量的影响

经过三年的田间试验发现,稻田甲烷排放通量随着农业措施的不同而大幅度地变化。在1990年至1992年的三个晚稻生长季节里,试验地块的甲烷排放通量分别为10.83、25.18及19.85mg/m~2·h。半旱式栽培使甲烷排放量减少了约1/3;施用硫酸铵、烤田、间歇灌溉亦可显著地降低甲烷排放通量。高有机肥与长期淹水是造成稻田甲烷排放量大的主要原因。控制稻田甲烷排放的关键在于调节灌溉水。只要采用合适的灌溉制度。有机肥用量的增加不一定引起甲烷排放量的增大。

Effect of Various Agricultural Measures on Methane Emis- sion Fluxes from Rice Paddies.

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, CH4 emission fluxes from the experimental fields were 10. 83, 25.18 and 19. 85 mg/m2. h, respectively. Semi-dry cultivation reduced the CHt emission fluxes by about one third, sunning field, applying ammonium sulfate and intermittently flooded irrigation might also make the CH4 emission fluxes decreased significantly. The principal reasons for high CH4 emission fluxes are heavy application of organic fertilizer and long-term flooding. The key of controlling CH4 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 CH4 emissions.