江汉平原施氮水平对稻田CH_4和N_2O排放及水稻产量的影响

Effect of Different Nitrogen Fertilizer Level on CH_4 and N_2O Emission from Single Cropping Rice Field in Jianghan Plain

氮素是保证水稻(Oryza sative L.)产量的关键,同时也会影响稻田温室气体的排放。研究施氮水平对江汉平原地区稻田甲烷(CH4)、氧化亚氮(N_2O)排放和水稻产量的影响,旨在筛选出适合当地的低碳高产氮肥管理措施。以单季稻"丰两优香1号"为研究对象,设置4个施氮水平(T0:对照,0 kg N/hm2;T1:90 kg N/hm2;T2:150 kg N/hm2;T3:210 kg N/hm^2),采用静态暗箱-气相色谱法对稻田CH4和N_2O排放通量进行连续监测,测定水稻产量及CH4和N_2O季节排放特征,分析综合温室效应和排放强度。结果表明,不同施氮处理下CH4和N_2O排放通量具有较为明显的季节变化规律,T2处理的CH4季节累积排放量为302.5 kg/hm2,显著大于T0、T1和T3处理,与T0相比增加CH4排放106.7%,T3处理稻田CH4季节累积排放量为160.5 kg/hm2,比T2、T1水平处理低。不同施氮处理生长季N_2O累积排放量在0.465~0.631 kg/hm2之间,T3、T2、T1处理N_2O累积排放量显著大于T0处理,但T3、T2、T1处理间差异不显著。水稻产量随着氮素水平增加而增加,100年尺度上的温室气体排放强度以T3处理最小为0.39,T2处理最大为0.79,二者差异显著(P<0.05)。因此,210 kg N/hm2可推荐为江汉平原地区水稻低碳高产的适宜氮素投入量。

Nitrogen is the key issue for securing rice（ Oryza sative L.） output,and at the same time will affect greenhouse gases（ GHGs） emission. This paper studied the effect of different nitrogen fertilizer applications on GHGs emission and rice yield at single cropping rice field in Jianghan Plain,so as to select a nitrogen fertilizer management suitable for low GHGs emmision and high rice yield at the locality. Taking single crop rice ‘Fengliangyouxiang1＇as material,4 nitrogen fertilizer application treatments（ T0： CK,T1： 90 kg N / hm^2,T2： 150 kg N/hm2,T3： 210 kg N / hm2） were designed and static chamber-GC（ gas chromatography） method was adopted to continousely supervise CH4 and N_2O emission in paddy fields. At the same time,rice yield was tested,seasonal CH_4 and N_2O emission characteristics and comprehensive greenhouse effect（ CO_2-e） and greenhouse emision intensity were analyzed comprehensively. The results indicated that CH_4 and N_2O emission quantity had an obvious seasonal variation lawunder different nitrogen application treatments. Under T_2 treatment,the seasonal cumulative CH4 emission quantities were maximum（ 302.5 kg / hm2）,increased 106.7% compared with T_0,which was significantly greater than those of treatments T0, T1, and T3. Under T3 treatment, the seasonal cumulative CH_4 emission quantities were160.5 kg / hm^2,which were lower than that of T2 and T1 treatments. Under different nitrogen treatments,the growing season cumulative N_2O emission quantities were between 0. 465 ~ 0. 63 kg / hm2. Under T3,T2 and T1 treatments,cumulative N_2O emission quantities were significantly greater than T0 treatment,but there were not much differences between treatments T3,T2 and T1. Rice yield increased along with the increase of nitrogen application leves.Additionally,GHGI of T3 was minimum（ 0.39） and that of T2 was maximum（ 0.79）. The differences between these2 were significant（ P〈0.05）. Therefore,210 kg N / hm2 could be recommended as suitable nitrgen input for low GHG emission and high rice yield system in Jianghan Plain.