Arbuscular mycorrhizal fungi (AMF) are key actors among soil microbial inhabitants, forming beneficial associations with most horticultural plants and crops (e.g., maize). For maize, the world most cultivated cereal, data on AMF species diversity in fields is sparse and even totally nonexistent in the southern part of Belgium where maize represents 8% of the cultivated area. In the present study, 14 maize fields in South Belgium under conventional, conversion, or organic management were analyzed for AMF diversity and species composition using 454 pyrosequencing. A large part (54%) of the 49 AMF species observed were unknown or have not been described in the literature. AMF diversity highly varied among fields, with the number of species ranging between 1 and 37 according to the field. A statistically significant effect of management was measured on AMF diversity, with the highest Hill index values (diversity and richness) under the organic management system compared with conventional management or conversion. Our results suggest a positive effects of organic management on AMF diversity in maize. They also highlight the rather high diversity or richness of AMF and the large portion of sequences not yet ascribed to species, thereby emphasizing a need to intensify AMF identification in cropping systems.

丛枝菌根真菌（AMF）是土壤微生物居民中的关键角色，与大多数园艺植物和农作物（例如玉米）形成了有益的联系。对于世界上耕种最多的谷物玉米而言，比利时南部的农田中AMF物种多样性的数据很少，甚至根本不存在，那里的玉米占耕地面积的8％。在本研究中，使用454焦磷酸测序分析了比利时南部14个常规，常规或有机管理的玉米田的AMF多样性和物种组成。观察到的49种AMF物种中有很大一部分（54％）未知或文献中没有描述。AMF的多样性在各个领域之间差异很大，根据该领域，物种数量在1至37之间。在有机管理系统下，与传统管理或转换相比，管理对AMF多样性具有统计学意义的显着影响，其希尔指数值（多样性和丰富度）最高。我们的结果表明有机管理对玉米AMF多样性具有积极作用。它们还强调了AMF的高度多样性或丰富性以及尚未归因于物种的大部分序列，从而强调了在耕作系统中加强AMF识别的需要。