Organic and conventional agricultural systems present differences in soil microbial biomass, activity and community composition. However, data concerning the network of correlations among the microbial members in agricultural soils are too limited. In this paper, we examined structural characteristics of the network of these correlations developed in two soils of different legacy (an organic maize (O) and a conventional barley cultivation (C)) cultivated with lettuce (Lactuca sativa L.) plants in a pot experiment. Further, in each soil, inoculation with Plant Growth Promoting Rhizobacteria (PGPR) took place once: Bacillus subtilis (Ba; gram-positive), Pseudomonas fluorescens (Ps; gram-negative), both inoculants (Ps + Ba) and a control without inoculants. We considered inoculation as perturbations for the rhizosphere soil microbes and we estimated the robustness of the soil microbial networks denoting their ability to retain connectivity. Networks from all treatments exhibited positive values of modularity, small-worldness index (SW) >1 and clustering coefficient > 0.4, indicating modular structure, small world properties and the predominance of direct connections. The network in C control exhibited higher values of density and centrality and lower values of fragmentation and SW compared to O control. In organic system, the highest fragmentation (0.55 and 0.62) and SW values (4.98 and 5.48) were in control and co-inoculated soils respectively while in conventional system the highest values were in soils with Ba or Ps inoculants; fragmentation 0.52 (Ba) and 0.48 (Ps), SW 3.54 (Ba) and 4.14 (Ps). The robustness of the soil microbial communities depended on soil legacy (prior management system) as well as whether each inoculant applied individually or jointly, while the type of inoculant was insignificant.

有机和常规农业系统在土壤微生物生物量，活性和群落组成方面存在差异。但是，有关农业土壤中微生物成员之间的相关网络的数据太有限了。在本文中，我们研究了在锅中用莴苣（Lactuca sativa L.）植物种植的两种不同遗产（有机玉米（O）和常规大麦栽培（C））中开发的这些相关性网络的结构特征。实验。此外，在每种土壤中，接种了一次植物促生根瘤菌（PGPR）：枯草芽孢杆菌（Ba；革兰氏阳性），荧光假单胞菌（Pseudomonas fluorescens）（Ps；革兰氏阴性），同时接种（Ps + Ba）和不含接种物的对照。我们认为接种是对根际土壤微生物的扰动，我们估计了土壤微生物网络的健壮性，表明它们保持连通性的能力。来自所有处理的网络均显示出模块化的正值，小世界指数（SW）大于1，聚类系数> 0.4，表明模块化结构，小世界特性和直接连接的优势。与O对照相比，C对照中的网络显示出较高的密度和中心度值，而碎片和SW值较低。在有机体系中，最高的碎片度（0.55和0.62）和SW值（4.98和5）。48）分别为对照和共接种土壤，而在常规系统中，最高值为含Ba或Ps接种剂的土壤；碎片0.52（Ba）和0.48（Ps），SW 3.54（Ba）和4.14（Ps）。土壤微生物群落的健壮性取决于土壤遗产（先前的管理体系）以及每种接种剂是单独施用还是联合施用，而接种剂的种类则微不足道。