有机-无机肥配施对黄土高原半干旱区农田土壤N2O排放的影响

为探明不同施肥方式对旱作麦田土壤N₂O排放的影响，以不施肥(CK)为对照，设置单施有机肥(M)、单施无机肥(N)、有机-无机肥配施(MN)3种施肥方式，采用静态箱-气相色谱法对春小麦地土壤N₂O排放通量进行测定，并对其影响因子(NO^-₃-N、NH⁺₄-N、土壤温度、土壤含水量)和春小麦产量进行同期测定。结果表明：春小麦地在整个生育期内表现为N₂O排放源，各处理均在施肥后出现N₂O排放峰。不同处理土壤N₂O累积排放量表现为N>MN>M>CK,N₂O净损失量(以氮计算)为1.175 8～1.428 kg·hm^-2,占当季施氮量的1.12%～1.36%,有机-无机肥配施降低了氮肥中氮素以气态形式的损失量。MN、N、M处理春小麦产量分别较CK处理增加了45.1%、31.0%、18.8%,各处理土壤NO^-_3<...

Effects of combined organic\|inorganic fertilizer application on soil N2O emissions from farmland in the semi\|arid area of the Loess Plateau

To explore the effects of different fertilization methods on N₂O emission from dryland wheat field soil, three fertilization methods of single application of organic fertilizer (M), single application of inorganic fertilizer (N) and combined application of organic and inorganic fertilizer (MN) were arranged with no fertilization (CK) as the control. The soil N₂O emission flux in spring wheat field was determined by static box\|gas chromatography, and the related factors affecting soil N₂O emission (NO^-₃-N, NH⁺₄-N, soil temperature, soil water content) and spring wheat yield were determined simultaneously. The results showed that the spring wheat field was the N₂O emission source in the whole growth period, and the N₂O emission peak appeared in each treatment after fertilization. The order of cumulative N₂O emissions from soil under different treatments was N>MN>M>CK, the net loss of N₂O (calculated as N) was 1.1758~1.428 kg·hm^-2, accounting for 1.12%~1.36% of the nitrogen application amount in the current season. The combined application of organic and inorganic fertilizers reduced the loss of nitrogen in nitrogen fertilizers in the form of gas. Compared with the CK treatment, the spring wheat yields of the MN, N and M treatments increased by 45.1%, 31%, and 18.8%, respectively. The soil NO^-₃-N and NH⁺₄-N of each treatment increased significantly due to the influence of fertilization and topdressing, and showed a steady downward trend with the advancement of spring wheat growth period. The contents of soil NO^-₃-N and NH⁺₄-N among different treatments were the highest in N treatment. Correlation analysis showed that soil temperature, moisture and NH⁺₄-N were the most significant factors affecting N₂O emission under CK treatment.After fertilization, soil NO^-₃-N and NH⁺₄-N were the dominant factors affecting soil N₂O emissions, and correlation analysis showed that both were extremely significant positive correlations. In summary, fertilization had a greater impact on soil N₂O emissions from dry\|fed spring wheat fields, and the response of soil N₂O fluxes to temperature and water decreased after fertilization. On the other hand, compared with N and M treatments, MN treatment greatly improved crop yield without significantly increasing soil N₂O emissions. Therefore, comprehensively considering N₂O emissions and crop yield, MN treatment was the best fertilization method in semi\|arid areas of the Loess Plateau.