生物硝化抑制剂对黔西南黄壤硝化作用及N2O排放的影响

为探索生物硝化抑制剂对贵州黔西南地区黄壤硝化作用及氧化亚氮(N2O)排放的影响,通过三周的室内培养试验,研究两种生物硝化抑制剂对羟基苯丙酸甲酯(MHPP)和丁香酸(SA)对黄壤中的无机态氮素含量、氨氧微生物功能基因以及N2O排放量的影响。结果表明,与对照CK相比,MHPP和SA在黄壤上均能明显抑制硝化作用,对土壤硝化速率的抑制率分别为6%~43%和5%~51%。MHPP和SA均抑制了黄壤氨氧化古菌AOA(12%~22%,27%~41%)与氨氧化细菌AOB(6%~19%,26%~46%)amoA基因的丰度。整个培养期内,黄壤的硝态氮含量与AOB的amoA基因丰度显著正相关,而与AOA的amoA基因丰度无显著相关,表明AOB对黄壤硝化作用起了主导作用。在N2O排放方面,MHPP和SA分别显著抑制了黄壤51%和21%的N2O排放积累量,MHPP的减排效果优于SA。MHPP降低了黄壤N2O排放的峰值,而SA主要延缓了黄壤N2O产生高峰的出现。总之,生物硝化抑制剂MHPP和SA在贵州黔西南黄壤上具有氮肥减施增效的潜力,这为今后烤烟新型绿色专用肥的开发提供了理论依据。

Effects of Biological Nitrification Inhibitors on Nitrification and N2O Emissions of Yellow Soil in Southwestern Guizhou

In order to investigate the effects of biological nitrification inhibitors on nitrification and nitrous oxide (N2O) emissions on yellow soil in southwestern Guizhou, a three-week soil incubation experiment was conducted to explore the variability of soil inorganic nitrogen content, amoA gene expressions of ammonia-oxidizing microorganisms and N2O production. The results showed that compared with the control (CK), the two BNIs, methyl 3-(4-hydroxyphenyl) propionate (MHPP) and syringic acid (SA), both significantly impeded the nitrification process. The inhibition of nitrification rates by MHPP and SA were 6%~43% and 5%~51%, respectively. Moreover, MHPP and SA both reduced the abundance of ammonia-oxidizing archaea (AOA) by 12%~22% and 27%~41%, and the abundance of ammonia-oxidizing bacteria(AOB) by 6%~19% and 26%~46%. Meanwhile, the nitrate nitrogen content in yellow soil was significantly positively correlated with AOB abundance during the whole incubation, but had no significant correlation with AOA abundance, indicating that AOB played a dominant role in the nitrification process of the yellow soil. In terms of N2O emission, MHPP and SA showed strong inhibitory effects of 51% and 21% on the total N2O cumulative production, respectively, and the reduction of MHPP was better than SA. MHPP decreased the N2O peak while SA mainly delayed the emergence of the peak of N2O production rate in yellow soil. This study indicates the biological nitrification inhibitors MHPP and SA have the potential to reduce nitrogen fertilizer consumption and increase nitrogen use efficiency of the yellow soil in southwestern Guizhou, which provides a theoretical basis for the development of new green fertilizers for flue-cured tobacco in the future.