水氮组合模式对双季稻甲烷和氧化亚氮排放的影响

为给双季稻水肥高效利用调控技术提供理论基础,设置间歇灌溉和淹水灌溉两种灌溉方式,高氮、中氮、低氮和不施氮这4种施肥方式,开展大田小区试验,探讨了水氮组合模式对双季稻CH4和N2O排放的影响.结果表明,间歇灌溉显著降低了CH4积累排放量,与淹水灌溉相比,早晚稻分别降低13.18~87.90 kg·hm-2和74.48~131.07 kg·hm-2,分别减排了24.4%~67.4%和42.5%~66.5%;但促进了N2O排放,早晚稻的增排量分别为0.03~0.24 kg·hm-2和0.35~1.53 kg·hm-2,分别比淹水灌溉增加6.2%~18.3%和40.2%~80.9%.总体上,间歇灌溉降低了稻田温室气体的增温潜势,其中早稻降低了18.8%~58.6%,晚稻降低34.4%~60.1%,两季综合降低2 388~4 151 kg·hm-2(以CO2eq计),下降41%~54%.通过相关分析发现,土壤CH4排放和土壤溶液Eh显著负相关,和溶液CH4浓度显著正相关.与淹水灌溉相比间歇灌溉模式有利于减排CH4,虽增排了N2O,但增温潜势显著减少.综合来看,间歇灌溉配施中氮更有利于双季稻种植.

Effects of Water and Nitrogenous Fertilizer Coupling on CH4 and N2O Emission from Double-Season Rice Paddy Field

To provide support for the efficient use of water and fertilizer technology to double-season rice cultivation, water and fertilizer coupling mode was applied in this research, including two irrigation methods and four N levels. The irrigation methods were flood irrigation and intermittent irrigation, while four N levels were high-N, middle-N, low-N and none-N. Field experiment was conducted to study the effect of water and fertilizer coupling mode on CH₄ and N₂O emission. The results showed that the accumulated CH₄ emissions were significantly reduced by intermittent irrigation, in comparison with flood irrigation, the reduction in early rice season were from 13.18 kg ·hm^-2 to 87.90 kg ·hm^-2, and were from 74.48 kg ·hm^-2 to 131.07 kg ·hm^-2 in late rice season, with a rate of 24.4%-67.4% and 42.5%-65.5% respectively; whereas the accumulated N₂O emissions were increased, the increment were from 0.03kg ·hm^-2 to 0.24 kg ·hm^-2 in early rice season and from 0.35kg ·hm^-2 to 1.53 kg ·hm^-2 in late rice season when compared flood irrigation, increased by 6.2% -18.3% and 40.2% -80.9% respectively. On the whole, intermittent irrigation reduces the warming potential of greenhouse gases (GWP), which were decreased by 18.8% to 58.6% in early rice season and by 34.4% to 60.1% in late rice season, and the reduction of total GWP were from 2388 to 4151 kg ·hm^-2 (CO₂ eq), with a rate of 41%-54%. Through correlation analysis it found that CH₄ emissions from soil were significantly related with soil solution Eh and solution CH₄ concentration. In comparison with the flood irrigation, the application of intermittent irrigation in double-season rice cultivation was conducive to CH₄ reduction, though the increase came in N₂O, but the GWPs were significantly reduced. Comprehensively, intermittent irrigation matching with middle-N is more benefit to double-season rice cultivation.