长期不同施肥类型对稻田甲烷和氧化亚氮排放速率的影响

以湖南双季稻田长期不同施肥类型为研究对象,利用静态箱法测定了晚稻期间4种不同施肥方式下(无肥区、化肥区、秸秆区和习惯性施肥区)CH4和N2O的排放速率,并计算了其综合温室效应。结果表明,晚稻生育期内CH4的排放速率呈先升高后降低的变化趋势,习惯性施肥区和无肥区插秧15d达到最高峰,化肥区和秸秆还田区则推迟5 d到来;晒田期间稻田表现为甲烷的汇。无肥区和秸秆还田区N2O在整个测定期只有一个排放高峰,化肥区和习惯性施肥区N2O排放有两个峰值,分别在插秧后15和35d。秸秆区和习惯性施肥区CH4温室效应较大,化肥区和习惯性施肥区N2O温室效应较大,其中综合温室效应以秸秆区最大,习惯性施肥区和化肥区次之,无肥区最低。

Effects of Different Long-Term Fertilization on Emission of CH4 and N2O from Paddy Soil

Emission of CH4 and N2O is likely an important contribution to greenhouse gases in China.Agricultural management such as fertilizer or manure application has a substantial influence on CH4 and N2O in paddy soil,especially,for long-term different fertilization.A field experiment with long-term different fertilization was conducted at Ningxiang Experimental Station from 1986 to now.The treatments included non-fertilization(NF),straw return(SR),inorganic fertilization(IF) and chronic fertilization(CF).We investigated effects of long-term different fertilization on emission of CH4 and N2O in paddy soil,and calculated the overall potential for greenhouse gases.The results showed that the emission velocity of CH4 increased from transplant rice seedlings to 15 days after transplant rice seedlings for NF and CF and that to 20 days after transplant rice seedlings for SR and IF,then declined in an order as: SR > CF>IF>NF.Drained condition absorbed CH4.The emission velocity of N2O increased only had one peak in 15 and 20 days after transplant rice seedlings for NF and SR,respectively,while for IF and CF in 15 and 35 days after transplant rice seedlings in an order as: IF > CF> SR >NF.The overall potential for greenhouse effect caused by the emitted greenhouse gases,calculated according to their potential in absorbing thermal radiation,was the highest under SR and the lowest under the NF,respectively.