双氰胺和3,4-二甲基吡唑磷酸盐对蔬菜种植土壤氨氧化细菌和古菌的影响

Impact of Dicyandiamide (DCD) and 3,4-Dimethylpyrazole Phosphate (DMPP) on Ammonia-oxidizing Bacteria and Archaea in a Vegetable Planting Soil

硝化抑制剂双氰胺(DCD)和3,4-二甲基吡唑磷酸盐(DMPP)在抑制农业土壤硝化作用和提高氮肥利用率等方面效果显著,为了探讨它们对蔬菜种植土壤氨氧化细菌(AOB)和古菌(AOA)的作用机制,选取40 a以上蔬菜种植土壤,在施加尿素(CK)基础上,分别添加DCD和DMPP进行室内培养,系统监测了土壤中NH4^+-N、NO3^--N和硝化势的变化,同时运用荧光定量PCR和高通量测序等技术揭示了AOB和AOA种群丰度和多样性的演替规律.结果表明,相比CK处理,DCD处理和DMPP处理的NH4^+-N含量升高了213%和675%;NO3^--N含量降低了13.3%和37.2%;硝化势降低了20.4%和82.4%;同时,AOB丰度降低了51.2%和56.5%;AOA丰度降低了6.0%和27.0%.不同抑制剂处理间AOB和AOA的α多样性指数没有显著差异;nork-environmental-samples、unclassified-Nitrosomonadaceae、unclassified-Bactertia和Nitrosospira是AOB序列属水平的主要优势类群;norank-Crenarchaeota、norank-enviromental-samples和Nitrososphaera是AOA序列属水平的主要优势类群,施用DCD和DMPP显著改变了AOB和AOA的群落组成.综上所述,尿素与DCD和DMPP配施显著抑制NH4+-N的转化,降低AOB和AOA的种群丰度并改变其群落组成.相比DCD,DMPP对硝化作用的抑制和对AOB和AOA群落的影响更强.

Nitrification inhibitors(NIs)dicyandiamide(DCD)and 3,4-dimethylpyrazole phosphate(DMPP)showed significant effects in the inhibition of nitrification and the improvement of the utilization efficiency of nitrogen fertilizer in agricultural soils.However,the effects of different NIs on ammonia-oxidizing bacteria(AOB)and archaea(AOA)is still unclear.To verify the inhibitory effect of DCD and DMPP on AOB and AOA,a pot experiment was performed,including Urea,Urea+DCD,and Urea+DMPP treatments.The dynamics of NH4^+-N and NO3^--N and nitrification potential among different treatments were measured.In addition,real-time PCR and high-throughput sequencing approaches were applied to investigate the changes in the AOB and AOA population abundance and composition.The results revealed that the concentrations of NH4^+-N in Urea+DCD and Urea+DMPP treatments were 213%and 675%higher than that in the CK treatment,respectively.However,the concentrations of NO3^--N and the nitrification potentials were 13.3%and 37.2%,and 20.4%and 82.4%lower than that in CK treatment,respectively;Furthermore,the copy numbers of the bacterial and archaeal amo A gene were 51.2%and 56.5%,and 6.0%and 27.0%lower than that in the CK treatment,respectively.However,the diversity indexes of AOB and AOA communities,including evenness and richness,exhibited no significant differences after addition of DCD and DMPP.The nork-environmental-samples,unclassified-Nitrosomonadaceae,unclassified-Bacteria,and Nitrosospira,were the predominant genera of the AOB community.The no rank-Crenarchaeota,no rankenvironmental-samples and Nitrososphaera were the predominant groups in the AOA community.Summarily,application of DCD and DMPP significantly delayed the transformation of NH4^+-N,decreased the formation of NO3^--N,inhibited the abundance and changed the composition of AOB and AOA communities.DMPP had a stronger inhibitory effect on nitrification,and on AOB and AOA than DCD.Therefore,compared with DCD,DMPP had a better application prospect regarding the improvement of the nitrogen utilization efficiency in vegetable soil.