稻鸭共作对不同栽培环境稻季CH_(4)和N_(2)O排放的影响

Effects of Rice-Duck Farming on CH_(4) and N_(2)O Emissions in Rice Season Under Different Cultivation Environments

稻田是大气温室气体甲烷(CH_(4))和氧化亚氮(N_(2)O)的重要排放源,稻田温室气体减排一直是农业生态研究的热点。本研究采用裂区设计,在露地和网室两种栽培环境条件下,以无鸭子放养的常规稻作和秸秆不还田处理为对照,在等养分条件下分析了秸秆全量还田与稻鸭共作模式对土壤氧化还原电位、CH_(4)排放量、产CH_(4)潜力及CH_(4)氧化潜力、N_(2)O排放量及N_(2)O排放高峰期土壤反硝化酶活性、全球增温潜势、水稻产量的影响。结果表明:麦秆还田增加土壤产CH_(4)潜力,提高CH_(4)排放量,降低土壤反硝化酶活性、土壤氧化还原电位和N_(2)O排放量,整体上导致全球增温潜势上升96.89%~123.02%;稻鸭共作模式由于鸭子的不间断活动提高了土壤氧化还原电位,降低了土壤产CH_(4)潜力,并显著降低了CH_(4)排放量,其全球增温潜势较无鸭常规稻作模式下降8.72%~14.18%;网室栽培较露地栽培显著提高土壤氧化还原电位,降低土壤产CH_(4)潜力和反硝化酶活性,减少稻田CH_(4)和N_(2)O排放量,从而降低全球增温潜势6.35%~13.14%。总体上,稻田CH_(4)氧化潜力是产CH_(4)潜力的9.46倍~12.20倍,稻鸭共作和秸秆还田均能增加水稻产量,网室栽培较露地栽培减少水稻产量1.19%~5.48%。稻鸭共作不仅减缓全球增温潜势,结合秸秆还田能增加水稻产量,具有广泛的推广应用价值。

Rice cultivation is an important source of CH_(4) and N_(2)O.Greenhouse gas emission reduction in rice field has always been a hot topic in agro-ecological research.In this study,under two conditions of open field cultivation and insect-proof net cultivation,the effects of rice-duck(RD)farming and wheat straw returning on greenhouse gas emission and related soil physiochemical properties of paddy field were investigated by a split-zone experiment.The treatments included conventional rice farming with inorganic nitrogen fertilization(CR+IN),RD farming with inorganic nitrogen fertilization(RD+IN),conventional rice farming with wheat straw returning(CR+WS)and RD farming with wheat straw returning(RD+WS),and the emissions of CH_(4) and N_(2)O,methanogenic potential and CH_(4) oxidation potential,soil denitrifying enzyme activity,and global warming potential of paddy fields were determined.The results showed that straw returning increased methanogenic potential and CH_(4) emission from paddy field,but decreased soil denitrifying enzyme activity,soil redox potential and N_(2)O emission.As a whole,the global warming potential of straw returning increased by 96.89%–123.02%.In RD farming,due to the uninterrupted activities of ducks,redox potential of paddy soil was increased,CH_(4) production potential and CH_(4) emission of paddy field was reduced,global warming potential decreased by 8.72%–14.18%compared with conventional rice without ducks.The insect-proof net cultivation significantly increased redox potential of paddy soil,decreased methanogenic potential and soil denitrifying enzyme activity of paddy field,reduced the emissions of CH_(4) and N_(2)O from paddy field and the global warming potential by 6.35%–13.14%.On the whole,CH_(4) oxidation potential of paddy soil was 9.46–12.20 times as high as methanogenic potential.RD farming and straw returning could increase rice yield.However,insect-proof net cultivation reduced rice yield by 1.19%–5.48%.In a word,RD farming could not only slow down the global warming potential,but also increase rice yield combined with straw returning,which had extensive application value.