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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 to ensuring the yield of rice (Oryza sative L.) and it also affects greenhouse gas emissions from paddy fields. The effects of nitrogen application rate on CH4, N2O emission and rice yield in paddy fields in Jianghan Plain were studied in order to screen suitable low carbon and high yield nitrogen fertilizer management measures. Four nitrogen application rates (T0: control, 0 kg N / hm2; T1: 90 kg N / hm2; T2: 150 kg N / hm2; : 210 kg N / hm ~ 2). The static dark-gas chromatography was used to monitor the CH4 and N2O fluxes in rice paddy continuously. The output of rice and the seasonal emission of CH4 and N2O were measured. The integrated greenhouse effect and emission intensity were analyzed. The results showed that the seasonal variation of CH4 and N_2O fluxes under different nitrogen treatments showed a significant seasonal variation. The cumulative CH4 emissions during the T2 treatment were 302.5 kg / hm2, significantly higher than those of T0, T1 and T3, and increased with the increase of T0 CH4 emissions were 106.7%, and cumulative emissions of CH4 in the T3 treatment paddy fields were 160.5 kg / hm2, which was lower than that of T2 and T1 treatment. The cumulative N 2 O emissions of different nitrogen treatments were between 0.465-0.631 kg / hm 2 in the growing season, and the cumulative emissions of N 2 O at T3, T2 and T1 treatments were significantly higher than that of T0 treatments, but there was no significant difference between T3, T2 and T1 treatments. The rice yield increased with the increase of nitrogen level. The intensity of greenhouse gas emission on the 100-year scale was the lowest in T3 and 0.79 in T3, and the difference was significant (P <0.05). Therefore, 210 kg N / hm2 can be recommended as suitable nitrogen input for low-carbon and high-yielding rice in Jianghan Plain.