中文摘要：

【目的】氨氧化是氮转化过程的限速步骤,其由氨氧化微生物所驱动。本研究旨在探明37年玉米–大豆轮作施肥条件下影响棕壤氨氧化微生物丰度的主要影响因子及变化规律。【方法】以沈阳农业大学棕壤肥料长期定位试验耕层土壤（0—20 cm）为材料,选取其中9个施肥处理进行取样分析：不施肥（CK）、低量氮肥（N_1）、高量氮肥（N_2）、氮磷肥（N_1P）、氮磷钾肥（N1PK）、高量有机肥（M_2）、高量有机肥＋低量氮肥（M_2N_1）、高量有机肥＋氮磷肥（M_2N_1P）、高量有机肥＋氮磷钾肥（M_2N_1PK）。采用实时荧光定量PCR技术测定其氨氧化微生物丰度,通过对土壤基本化学性质和氨氧化微生物丰度的冗余分析找出影响氨氧化微生物丰度的主要因素。【结果】施用有机肥处理的土壤p H、有机质、全氮、碱解氮、速效钾、速效磷、铵态氮、硝态氮含量明显高于不施肥和单施化肥处理。各施肥处理土壤有机质、全氮、碱解氮、速效钾、速效磷的含量总体呈现有机肥处理〉化肥处理〉CK;与不施肥处理（CK）相比,单施化肥处理显著降低了土壤p H值,施用有机肥处理显著提高了土壤pH值,其中N_2处理的土壤pH最低,M_2处理的土壤pH最高。不同施肥处理氨氧化细菌（AOB）的丰度为0.94×10~6~5.77×10~6 copies/g干土,氨氧化古菌（AOA）的丰度为3.56×10~6~1.22×10~7 copies/g干土;施用有机肥处理AOB和AOA丰度显著高于不施肥和单施化肥处理,其中M2处理的AOB和AOA丰度最高,单施氮肥处理的AOB和AOA丰度最低。冗余分析（RDA）表明,影响棕壤AOB和AOA丰度的主要环境因子有土壤pH、有机质、全氮、碱解氮、速效磷、速效钾,且与AOB和AOA丰度呈正相关关系。【结论】长期轮作施肥显著改变了棕壤的化学性质,从而对氨氧化微生物的丰度产生了显著影响。长期施用有机肥显著提高了土壤养分含量及AO

英文摘要：

[ Objectives ] Ammoxidation, driven by the ammonia-oxidizing microorganisms, is a rate-limiting step of nitrogen transformation processes. The aim of this study was to explore the main factors which influenced abundance of ammonia-oxidizing microorganisms under a corn-soybean rotation system and a long-term fertilization for 37 years in a brown soil. [ Methods ] Soil samples （0-20 cm） were collected from the nine treatments of the long-term fertilization trial： no fertilization （CK）, low chemical N input （N1）, high chemical N input （N2）, chemical N and P input （NIP）, chemical N, P and K input （N1PK）, pig manure （M2）, pig manure and chemical N （M2N1）, pig manure, chemical N and P （M2NtP） and pig manure, chemical N, P and K （M2N1PK）. The abundance values of ammonia-oxidizing microorganisms were analyzed using qPCR methods. Main factors influencing the abundance of ammonia-oxidizing microorganisms were found out by the redundancy analysis （RDA） of soil chemical properties and the abundance of ammonia-oxidizing microorganisms. [ Results ] The pH, the soil contents of organic matter, total N, alkali-hydrolysable N, available K, available P, ammonium and nitrate in the organic fertilizer treatments were significantly higher than those in the CK and chemical fertilizer treatments. The soil organic matter, alkali-hydrolysable N, available K, available P and total N was in order of manure treatments 〉 chemical fertilizer treatments 〉 CK. Compared with the CK, the pure chemical fertilization decreased soil pH, while the manure application increased soil pH. The pH values of soil were the lowest in one with the N2 treatment and the highest in the Ms treatment. The abundances of ammonia oxidizing bacteria （AOB） were 0.94 × 106 - 5.77× 107 copies/g dry soil, and the abundances of ammonia oxidizing archaea （AOA） were 3.56 × 106 - 1.22 × 107 copies/g dry soil in different fertilization treated soils, respectively. The abundances of AOB and AOA in manure treatment soi