不同沼肥处理对小麦分蘖期土壤硝化作用强度及氨氧化细菌和古菌群落的影响

为了解沼肥对小麦分蘖期土壤硝化作用强度、氨氧化细菌和古菌群落的影响,设置沼肥低量(BL)、沼肥中量(BM)、沼肥高量(BH)、沼氮混合(BN)、化肥施用(NPK)及不施肥(CK)6种不同施肥处理,测定了不同处理下土壤硝化作用强度,采用16SrDNA PCR-DGGE和amoA PCR-DGGE分析了不同处理土壤氨氧化细菌(Ammonia-oxidizing bacteria,AOB)、氨氧化古菌(Ammonia-oxidizing archaea,AOA)多样性指数和群落变化。结果表明,施肥可显著提高土壤硝化作用强度(P0.05),土壤硝化作用强度以BH处理最高(54.83%),NPK处理次之(52.12%),BL处理最低(44.75%)。不同施肥处理下,小麦分蘖期土壤AOB多样性指数变化明显,其中BH和NPK处理显著高于其他处理;而AOA多样性指数变化幅度小,不同处理之间差异不显著。从选取代表性DGGE条带克隆测序结果和构建的AOB和AOA群落系统发育关系看,小麦分蘖期土壤AOB群落分类变化明显,形成了两个新的类群;amoA基因序列所反映的不同处理土壤AOA群落与已报道的土壤及淡水沉积物环境中的未培养奇古菌(Uncultured Thaumarchaeote)聚为一类,属于Cluster S,AOA群落分类尚未发生变化。

Effect of Biogas Manure on Soil Nitrification Intensity and Soil Ammonia-Oxidizing Bacteria and Ammonia-Oxidizing Archaea Communities at Wheat Tillering Stage

To understand the effects of biogas manure on soil nitrification intensity,soil ammonia-oxidizing bacteria(AOB) and ammonia-oxidizing archaea(AOA) communities at wheat tillering stage,six different fertilizing treatments,i.e. low amount of biogas manure(BL),2.7×10 kg·hm^-2; medium quantity of biogas manure(BM),4.5×10 kg·hm^-2; high quantity of biogas manure(BH),6.3×10 kg·hm^-2; biogas manure combined with chemical nitrogen fertilizer(BN),with biogas manure: 1.35×10 kg·hm^-2,and N(Urea): 126 kg·hm^-2; chemical fertilizer(NPK),with N(Urea): 252 kg·hm^-2,P₂O₅: 120 kg·hm^-2,and K₂O: 45 kg·hm^-2 and no fertilizer treatment(CK) were performed. Biogas fertilizer was collected from the livestock farm at Qiquan town in Chongzhou city. The soil samples at wheat tillering stage were collected,and the soil properties,soil nitrification intensity,16S rDNA PCR-DGGE for AOB communities,and amoA PCR-DGGE for AOA communities was analyzed,respectively; consequently,the representative DGGE bands were cloned and sequenced,and the phylogenic tree was constructed. The results showed that compare to CK,fertilization soil significantly improved the both soil nutrition content and nitrification intensity(P<0.05). The soil nitrification intensity varied as the following order: BH(54.83%)>NPK(52.12%)>BM(48.56%)>BN(47.78%)>BL(44.75%)>CK(38.93%). Based on the PCR-DGGE patterns,the AOB and AOA diversity index(H) was determined,and the results showed that the H value of AOB changed significantly(P<0.05). Of them,the H value of treatment BH was the highest(3.45),but the difference was not significant compared to treatment NPK; however,the H value of AOA within different treatments changed slightly. Sequencing and phylogeny analysis showed that AOB varies significantly at tillering stage,although band B15 belonged to genus Nitrosospira cluster 0,most of AOB formed two novel clusters; all preponderant amoA gene of AOA among the different treatment soils fell into the group of uncultured Thaumarchaeote from soils/fresh water sediments,which belonged to Soil/Sediment-associated cluster,and were very similar.