稻鸭共作对甲烷排放的影响

利用密闭箱技术，于2006和2007年研究了稻鸭复合系统CH₄的排放规律及影响因素.结果表明：与常规淹水稻田（CK）相比，由于鸭子的活动，养鸭稻田（RD）的田面水溶解氧浓度(DO)增加，CH₄的排放显著减少.2006年RD的平均CH₄排放通量为（6.84±1.49） mg·m^-2·h^-1，比CK的（10.17±1.25）mg·m^-2·h^-1降低32.7%，CH₄排放总量为（19.34±1.15） g·m^-2，比CK的（26.25±2.17） g·m^-2减少26.3%; 2007年RD的平均CH₄排放通量为(7.68±0.74) mg·m^-2·h^-1，比CK的（9.53±0.40）mg·m^-2·h^-1降低19.0%, CH₄排放总量为（18.41±1.05）g·m^-2，比CK的（22.81±0.75） g·m^-2减少19.3%.在水稻全生育期，各处理CH₄的排放通量分别在分蘖期和抽穗期出现2个排放高峰；CH₄排放通量的季节变化与土壤温度和土壤水溶性有机碳含量呈显著正相关，但与土壤总有机碳含量相关不显著.

Effects of rice-duck farming on paddy field's methane emission

By using closed-chamber technique, the characteristics of CH₄ emission from an integrated rice-duck ecosystem were studied in 2006 and 2007. The results showed that comparing with conventional flooded rice ecosystem (CK), integrated rice-duck system (RD) was distinguished in its high dissolved oxygen (DO) in field surface water and significantly lower CH₄ emission, due to the activities of duck. In 2006, the average CH₄ emission flux and the total CH₄ emission during the whole rice growth period of RD were 6.84±1.49mg·m^-2·h^-1 and 19.34±1.15 g·m^-2, being 32.7% and 26.3% lower than those of CK (10.17±1.25 mg·m^-2·h^-1 and 26.25±2.17 g·m^-2), respectively; while in 2007, the values of the two test items of RD were 7.68±0.74 mg·m^-2·h^-1 and 18.41±1.05 g·m^-2, being 19.0% and 19.3% lower than those of CK (9.53±0.40 mg·m^-2·h^-1 and 22.81±0.75 g·m^-2), respectively. The emission flux of CH₄ had two peaks, being appeared at tillering and heading stages, respectively. The seasonal fluctuations of CH₄ emission flux had significant positive correlations with soil temperature and soil dissolved organic carbon content (DOC), but no obvious correlation with soil total organic carbon.