【摘要】 本研究设置不施用氮肥且不施用儿茶素（对照,CK1）、施用0.17 g/kg氮肥但不施用儿茶素（对照,CK2）、施用0.17 g/kg氮肥和0.075 g/kg儿茶素（T1）、施用0.17 g/kg氮肥和0.150 g/kg儿茶素（T2）模拟田间氮肥施用量,探究儿茶素对N₂O排放量、氮形态转化、土壤微生物群落及反硝化功能基因的影响。另设置不添加儿茶素（对照,CK3）、儿茶素添加量0.075 g/kg（T3）、儿茶素添加量0.150 g/kg（T4）、儿茶素添加量0.300 g/kg（T5）探究儿茶素对土壤反硝化潜势和呼吸速率的影响。研究结果表明,培养1 d后和4 d后,各处理N₂O排放通量均表现为CK2>T1处理>T2处理。CK2土壤N₂O累积排放量显著高于T1处理和T2处理（P<0.05）,CK1土壤N₂O累积排放量显著低于T1处理和T2处理（P<0.05）。儿茶素对土壤铵态氮（NH₄⁺-N）含量无显著影响,培养1～3 d,T2处理硝态氮（NO₃^-N）含量增幅大于CK2,亚硝态氮（NO₂^--N）含量降幅大于CK2,表明儿茶素可抑制NO₃^--N还原并促进NO₂^--N转化。随着儿茶素添加量增加,土壤反硝化潜势显著降低（P<0.05）。培养15 d后,T2处理亚硝酸还原酶编码基因nirK、nirS拷贝数显著低于CK2,氧化亚氮还原酶编码基因nosZ拷贝数显著高于CK2,且（nirK拷贝数+nirS拷贝数）/nosZ拷贝数显著降低（P<0.05）,表明儿茶素可通过抑制N₂O生成、促进N₂O还原双路径调控反硝化过程。T4处理土壤本底呼吸速率显著低于CK3和T3处理（P<0.05）,T3处理、T4处理基质诱导呼吸速率均显著低于CK3,且T4处理基质诱导呼吸速率显著低于T3处理（P<0.05）,表明儿茶素可抑制土壤微生物代谢活性,进而削弱反硝化过程。本研究为农业生态系统N₂O减排及土壤氮素高效管理提供理论依据。更多还原

【Abstract】 In this study,four treatments were set up to simulate field nitrogen application rates:no nitrogen fertilizer and no catechin（control,CK1）,0.17 g/kg nitrogen fertilizer without catechin（control,CK2）,0.17 g/kg nitrogen fertilizer combined with 0.075 g/kg catechin（T1）,and 0.17 g/kg nitrogen fertilizer combined with 0.150 g/kg catechin（T2）.The effects of catechin on N₂O emission flux,nitrogen form transformation,soil microbial community and denitrification functional genes were investigated.In addition,another four treatments were designed to explore the effects of catechin on soil denitrification potential and respiration rate:no catechin（control,CK3）,0.075 g/kg catechin addition（T3）,0.150 g/kg catechin addition（T4）,and 0.300 g/kg catechin addition（T5）.The results showed that after 1 d and 4 d of incubation,the N₂O emission flux in all treatments followed the order of CK2>T1>T2.The cumulative N₂O emission from soil in CK2 was significantly higher than that in T1 and T2 treatments（P<0.05）,while the cumulative N₂O emission in CK1 was significantly lower than that in T1 and T2 treatments（P<0.05）.Catechin had no significant effect on soil ammonium nitrogen（NH₄⁺-N） content.During 1-3 d of incubation,the increase range of nitrate nitrogen（NO₃^--N） content in T2 treatment was higher than that in CK2,and the decrease range of nitrite nitrogen（NO₂^--N）content was higher than that in CK2,indicating that catechin could inhibit NO₃^--N reduction and promote NO₂^--N transformation.With the increase of catechin addition amount,the soil denitrification potential decreased significantly（P<0.05）.After 15 d of incubation,the copy numbers of nitrite reductase encoding genes nirK and nirS in T2 treatment were significantly lower than those in CK2,while the copy number of nitrous oxide reductase encoding gene nosZ was significantly higher than that in CK2,and the ratio of the sum of nirK and nirS copy numbers to nosZ copy number decreased significantly（P<0.05）.These results indicated that catechin could regulate the denitrification process through dual pathways of inhibiting N₂O production and promoting N₂O reduction.The soil basal respiration rate in T4 treatment was significantly lower than that in CK3 and T3 treatments（P<0.05）.The substrate-induced respiration rates in T3 and T4 treatments were significantly lower than that in CK3,and the substrate-induced respiration rate in T4 treatment was significantly lower than that in T3 treatment（P<0.05）,suggesting that catechin could inhibit the metabolic activity of soil microorganisms,thereby weakening the denitrification process.This study provides a theoretical basis for N₂O emission reduction and efficient soil nitrogen management in agricultural ecosystems.更多还原