Man-made landscaping materials form uppermost soil layers in urban green parks and lawns. To optimize effects of landscaping materials on biodiversity, plant growth and human health, it is necessary to understand microbial community dynamics and physicochemical characteristics of the landscaping materials during storage. In the current three-year study, the consequences of long-term storage on biotic and abiotic characteristics of eight commercial landscaping materials were evaluated. We hypothesized that long-term storage results in changes in microbial utilization of various energy sources and the diversity and relative abundance of bacteria with pathogenic or immunomodulatory characteristics. Three-year storage led to remarkable changes in bacterial community composition. Diversity and richness of taxa associated with immune modulation, particularly phylum Proteobacteria and class Gammaproteobacteria, decreased over time. Bacteroidetes decreased while Actinobacteria increased in relative abundance. Functional orthologs associated with biosynthesis of antibiotics and degradation of complex carbon sources increased during storage. Relative abundance of genera containing potential pathogens were mostly constant or decreased with time. Major changes can be explained by tightening competition over lessening resources. Bacterial communities in landscaping materials adjust to absent inflow of carbon and nutrients during storage. The increased signalling of functional orthologs related to degradation of complex carbon sources hints that bacteria dependent on labile carbon and readily available nutrients were outcompeted. This suggests storage reduces plant seedling growth. Long-term storage seems to decrease immunomodulatory potential of landscaping materials, but storage did not enrich pathogens or functional orthologs associated with pathogenicity. We recommend short storage and shelf life of organic landscaping materials.

人造美化材料在城市绿色公园和草坪中形成最上层的土壤层。为了优化园林绿化材料对生物多样性，植物生长和人类健康的影响，有必要了解园林绿化材料在存储过程中的微生物群落动态和理化特性。在当前的三年研究中，评估了长期保存对八种商业园林材料的生物和非生物特征的影响。我们假设长期存储会导致各种能源的微生物利用以及具有致病性或免疫调节特性的细菌的多样性和相对丰度发生变化。三年存储导致细菌群落组成发生显着变化。与免疫调节有关的分类单元的多样性和丰富性，随着时间的流逝，特别是门的Proteobacteria和Gammaproteobacteria。拟杆菌的数量相对减少，而放线菌的数量增加。在储存过程中，与抗生素的生物合成和复杂碳源的降解有关的功能直向同源物增加。含有潜在病原体的属的相对丰度大多是恒定的，或者随着时间的推移而下降。可以通过在减少资源方面加强竞争来解释重大变化。环境美化材料中的细菌群落会根据储存过程中碳和养分的缺乏而进行调整。与复杂碳源的降解有关的功能直向同源物信号的增加暗示了依赖于不稳定碳和容易获得的养分的细菌的竞争已不复存在。这表明储存减少了植物幼苗的生长。长期储存似乎降低了美化材料的免疫调节潜能，但储存并没有丰富病原体或与致病性相关的功能直系同源物。我们建议有机美化材料的储存期短和保质期。