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华北平原是我国北方最重要的粮食主产区之一,过去30年间其粮食产量稳定提高的同时,肥料等生产资料的投入也大幅增加。丛枝菌根(Arbuscular mycorrhiza,AM)真菌作为一类重要的土壤功能性微生物,研究施肥措施对其群落、功能的影响,在挖掘农田有益微生物的潜在作用方面具有重要意义。本研究采用分子生物学方法测定了华北平原典型集约化农田体系中不同养分用量和投入模式对土壤AM真菌群落的影响。试验样地于2007年开始对冬小麦-夏玉米轮作体系进行施肥处理:有机肥(牛粪9 000kg/hm~2)、高量化肥(296.4kg N/hm~2、177.3kg P/hm~2、287.8kg K/hm~2,较当地常规化肥施用量上调25%)、低量化肥(74.1kg N/hm~2、44.3kg P/hm~2、71.9kg K/hm~2,较当地常规化肥施用量下调75%)和不施肥对照,每个处理3次重复,于2011年10月玉米收获季进行土壤取样。试验获得的31个OTUs主要属于Glomerales目(球囊霉目)(Glomus Group A/B)及Diversisporales目(多孢囊霉目),其中部分AM真菌类群如Glo12、Aca3、Scutellospora aurigloba(Scut.aurigloba全球盾巨孢囊霉)以及Div2仅在有机肥处理中被检测到。与其他处理相比,有机肥处理的116bp片段(Glo9/12/13/14;Fun1/2;Rhi1)相对丰度显著升高,而140bp片段(Uncultured Glomus)(球囊霉属)则主要受到化肥处理的促进。对于Diversisporales目AM真菌所对应的片段(141、142、169bp),施肥明显对其有促进作用。4年的肥料施用对土壤AM真菌物种多样性无显著影响,施肥处理0–20、20–40、40–60cm深度土壤AM真菌群落的多样性水平分别为1.14–1.78、1.61–1.84、1.23–2.07,丰富度分别为3.7–7.5、8.0–8.3、5.0–7.3。表明深层土壤是AM真菌重要的库,多样性水平并不低,对于维持土壤微生物多样性水平具有重要作用。本研究发现,p H值是影响表层土壤AM真菌群落分布的主要原因,土壤全氮、全碳、速效磷等肥力因子也是影响表层土壤AM真菌群落分布的重要因子,而深层土壤AM真菌的群落组成与固有的盐分特征(土壤电导率EC)有着较好的相关性。
The North China Plain is one of the most important grain-producing areas in northern China. While its grain output has steadily risen over the past 30 years, inputs for fertilizer and other means of production have also risen sharply. Arbuscular mycorrhizal (AM) fungi, as an important class of soil functional microorganisms, is of great importance to study the impact of fertilization on their community and function and to explore the potential role of beneficial microbes in farmland. In this study, molecular biology methods were used to determine the effects of different nutrient contents and input modes on AM fungal community in a typical intensive farmland system in the North China Plain. The experimental plots started to apply winter wheat-summer maize rotation system in 2007: organic fertilizer (cow manure 9 000 kg / hm 2), high amount of fertilizer (296.4 kg N / hm 2,177.3 kg P / hm 2 , 287.8kg K / hm ~ 2, 25% higher than that of routine chemical fertilizers in the local area), low-level fertilizer (74.1kg N / hm ~ 2,44.3kg P / hm ~ 2,71.9kg K / Conventional fertilizer application rates were reduced by 75%) and no fertilization control, with 3 replications per treatment and soil sampling at the October 2011 maize harvest season. The 31 OTUs obtained from the experiment mainly belonged to Glomerales species (Glomus Group A / B) and Diversisporales species (Aeromonas spp.). Some of the AM fungi such as Glo12, Aca3, Scutellospora aurigloba (Scut. Aurigloba Globoderma spp.) And Div2 were only detected in organic manure treatments. Compared with other treatments, the relative abundance of 116bp fragment (Glo9 / 12/13/14; Fun1 / 2; Rhi1) treated with organic manure significantly increased, whereas the 140 bp fragment (Globals) Fertilizer treatment promotion. Fragments (141, 142, 169 bp) corresponding to the AM fungi of Diversisporales showed that the fertilization was obviously promoted. Four years of fertilizer application had no significant effect on the species diversity of AM fungi. The diversity of AM fungi community in the depth of 0-20, 20-40 and 40-60 cm were 1.14-1.78, 1.61-1.84 and 1.23- 2.07, respectively, richness of 3.7-7.5,8.0-8.3,5.0-7.3. The results showed that the deep soil is an important reservoir of AM fungi and its diversity is not low, which plays an important role in maintaining soil microbial diversity. In this study, it was found that the p H value was the main factor affecting the distribution of AM fungi community in the topsoil. Fertility factors such as total N, total carbon and available P were the important factors affecting the distribution of AM fungi in the topsoil, There is a good correlation between composition and intrinsic salinity characteristics (soil conductivity EC).