有机-无机氮肥施用对滨海盐土稻田CH_4和N_2O排放及综合温室效应的影响

Effects of Organic and Inorganic Nitrogen Fertilizer on CH_4, N_2O Emissions and the Global Warming Potentials in Coastal Saline Rice Paddy Field

不同类型氮肥对稻田温室气体排放的影响已有较多研究,然而有关不同类型氮肥对滨海盐土稻田温室气体排放的影响却鲜有报道。为了评估不同类型氮肥对稻田生态系统综合温室效应(GWP)和温室气体强度(GHGI)的影响,在充分考虑农业化学品投入(Ei)和农事操作(Eo)所引起的碳排放基础上,设置4个田间处理试验,分别为不施氮肥(N0)、施用无机氮肥(Nu)、施用有机氮肥(Nw)、施用有机-无机混合氮肥(Nm),于2016年6月—2016年10月采用静态暗箱-气相色谱法对滨海盐土稻田温室气体排放通量进行观测与比较研究,结果可为寻求适宜的施肥方案以减缓滨海盐土稻田生态系统温室气体排放提供科学依据。结果表明:与N0处理相比,Nu、Nm和Nw处理稻田CH4累积排放通量分别显著提高了42.1%(P<0.05)、63.1%(P<0.05)和67.2%(P<0.05);N2O累积排放通量分别提高了83.5%(P<0.05)、78.0%(P<0.05)和37.8%(P=0.095)。与N0处理相比,Nu、Nm和Nw处理稻田GWP分别显著提高了51.3%(P<0.05)、66.9%(P<0.05)和70.3%(P<0.05);水稻产量分别显著提高了44.0%(P<0.05)、77.5%(P<0.05)和38.4%(P<0.05),其中,Nm处理的水稻产量显著高于Nu和Nw处理(P<0.05)。Nm处理稻田GHGI较Nu和Nw处理分别降低了12.3%(P=0.32)和23.7%(P<0.05)。综合对比3种不同类型氮肥处理的GWP和GHGI,推荐使用Nm施肥方案,以提高滨海盐土区稻田的水稻产量,并降低其GHGI。

The effects of different N fertilizer types on greenhouse gas(GHG)emissions in rice field have been studied by many researchers,however,the effects of different N fertilizer types on GHG emissions in coastal saline rice filed remains poorly understood.In an effort to evaluate the effects of different types of N fertilizers on global warming potential(GWP)and greenhouse gas intensity(GHGI),a field experiment with four treatments,namely,without N(N0),inorganic N fertilizer(Nu),organic N fertilizer(Nw)and organic-inorganic mixed N fertilizer(Nm)was designed by using the static opaque chamber and gas chromatography method and fully taking the carbon emissions from agrochemical inputs(Ei)and farm operation(Eo)into consideration,in a coastal saline paddy from June,2016 to October,2016.The results can provide scientific basis for seeking appropriate fertilization scheme to slow down GHG emissions,in the coastal saline rice field.Results showed that compared to N0 treatment,the cumulative CH4 emissions were significantly increased by 42.1%(P<0.05),63.1%(P<0.05)and 67.2%(P<0.05),respectively in Nu,Nm and Nw treatments,and the cumulative N2O emissions were significantly increased by 83.5%(P<0.05),78.0%(P<0.05)and 37.8%(P=0.095),respectively in Nu,Nm and Nw treatments.Compared to N0 treatment,GWP was significantly increased by 51.3%(P<0.05),66.9%(P<0.05)and 70.3%(P<0.05),respectively,in Nu,Nm and Nw treatments.Grain yield were significantly increased by 44.0%(P<0.05),77.5%(P<0.05)and 38.4%(P<0.05)in Nu,Nm and Nw treatments relatively to N0 treatment,meanwhile,compared to Nu and Nw treatments,grain yield was also significantly increased in Nm treatment(P<0.05).The GHGI in Nm treatment was decreased by 12.3%(P=0.32)and 23.7%(P<0.05)in relation to Nu and Nw treatments,respectively.Therefore,the Nm fertilization scheme is recommended for increasing grain yield and decreasing GHGI simultaneously during the rice production in coastal saline rice filed,by doing comprehensive compare between GWP and GHGI from three different N fertilizer types.