Jiang Chang-sheng, Wang Yue-si, Zheng Xun-hua, Zhu Bo, Huang Yao
Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China.
Huan Jing Ke Xue. 2006 Feb;27(2):207-13.
Using the static opaque chamber method, a field experiment was conducted in situ for two years to study the effects of three cultivation systems on CH4 and N2O emissions from permanently flooded rice fields in a hilly area in Southwest China. The results show that the average CH4 fluxes from a permanently flooded rice field with a single middle rice crop and flooded with no winter crop (PF) were (21.44 +/- 1.77) mg x (m2 x h)(-1) and (3.77 +/- 0.99) mg x (m2 x h)(-1) during rice-growing and non-rice growing periods, respectively, where both values were much lower than many previous reports from similar regions in Southwest China. The annual CH4 emission was mainly occurred in the rice growing period, being only 23.2% of the total annual CH4 flux emitted from the non-rice growing period, though the latter occupied two thirds of a year. The annual average flux of nitrous oxide was (0.051 +/- 0.008) mg x (m2 x h)(-1) and the N2O emission also intensive in the rice growing period. However, being only 8.1% of total annual N2O flux emitted from the non-rice growing period. After implementing the rice-wheat rotation (RW) and rice oil-seed rape rotation (RR), the CH4 emissions were reduced substantially, only 43.8% and 40.6% of those of PF, respectively. However, the N2O emissions were increased after conducting RW and RR systems, which were 3.7 and 4.5 times larger than those of PF. The global warming potentials (GWPs) of the CH4 and N2O emissions under the three tillage-cropping systems were assessed in an integrated way. The results show that the integrated GWPs of the CH4 and N2O emissions are in the following sequence: PF>>RR approximately equal to RR. Within 20, 100 and 500 years spans, the GWPs of the CH4 and N2O emissions of PF were 2.6, 2.1 and 1.7 times larger than those of RW (or RR), respectively. After introducing rice-wheat or rice oil-seed rape rotation systems into the permanently flooded rice fields, the integrated GWPs of the CH4 and N2O emissions were decreased largely.
采用静态不透光箱法，在中国西南山区进行了为期两年的田间原位试验，以研究三种种植制度对常年淹水水稻田CH4和N2O排放的影响。结果表明，单季中稻且冬季不淹水的常年淹水水稻田（PF）在水稻生长季和非水稻生长季的CH4平均通量分别为(21.44±1.77)mg·(m2·h)-1和(3.77±0.99)mg·(m2·h)-1，这两个值均远低于中国西南类似地区先前的许多报道。CH4年排放量主要发生在水稻生长季，仅占非水稻生长季CH4年总通量的23.2%，尽管非水稻生长季占一年的三分之二。氧化亚氮的年平均通量为(0.051±0.008)mg·(m2·h)-1，N2O排放也集中在水稻生长季。然而，仅占非水稻生长季N2O年总通量的8.1%。实施稻麦轮作（RW）和稻油轮作（RR）后，CH4排放量大幅降低，分别仅为PF的43.8%和40.6%。然而，实施RW和RR制度后N2O排放量增加，分别是PF的3.7倍和4.5倍。综合评估了三种耕作种植制度下CH4和N2O排放的全球变暖潜势（GWP）。结果表明，CH4和N2O排放的综合GWP顺序为：PF>>RR≈RW。在20年、100年和500年的时间跨度内，PF的CH4和N2O排放的GWP分别是RW（或RR）的2.6倍、2.1倍和1.7倍。在常年淹水水稻田中引入稻麦或稻油轮作制度后，CH4和N2O排放的综合GWP大幅降低。
