PDF(Pubmed)
Abstract：
UNASSIGNED: Biological soil crusts (biocrusts) are known as biological hotspots on undisturbed, nutrient-poor bare soil surfaces and until now, are mostly observed in (semi-) arid regions but are currently poorly understood in agricultural systems. This is a crucial knowledge gap because managed sites of mesic regions can quickly cover large areas. Thus, we addressed the questions (i) if biocrusts from agricultural sites of mesic regions also increase nutrients and microbial biomass as their (semi-) arid counterparts, and (ii) how microbial community assemblage in those biocrusts is influenced by disturbances like different fertilization and tillage regimes.
UNASSIGNED: We compared phototrophic biomass, nutrient concentrations as well as the abundance, diversity and co-occurrence of Archaea, Bacteria, and Fungi in biocrusts and bare soils at a site with low agricultural soil quality.
UNASSIGNED: Biocrusts built up significant quantities of phototrophic and microbial biomass and stored more nutrients compared to bare soils independent of the fertilizer applied and the tillage management. Surprisingly, particularly low abundant Actinobacteria were highly connected in the networks of biocrusts. In contrast, Cyanobacteria were rarely connected, which indicates reduced importance within the microbial community of the biocrusts. However, in bare soil networks, Cyanobacteria were the most connected bacterial group and, hence, might play a role in early biocrust formation due to their ability to, e.g., fix nitrogen and thus induce hotspot-like properties. The microbial community composition differed and network complexity was reduced by conventional tillage. Mineral and organic fertilizers led to networks that are more complex with a higher percentage of positive correlations favoring microbe-microbe interactions. Our study demonstrates that biocrusts represent a microbial hotspot on soil surfaces under agricultural use, which may have important implications for sustainable management of such soils in the future.
UNASSIGNED: We compared phototrophic biomass, nutrient concentrations as well as the abundance, diversity and co-occurrence of Archaea, Bacteria, and Fungi in biocrusts and bare soils at a site with low agricultural soil quality.
UNASSIGNED: Biocrusts built up significant quantities of phototrophic and microbial biomass and stored more nutrients compared to bare soils independent of the fertilizer applied and the tillage management. Surprisingly, particularly low abundant Actinobacteria were highly connected in the networks of biocrusts. In contrast, Cyanobacteria were rarely connected, which indicates reduced importance within the microbial community of the biocrusts. However, in bare soil networks, Cyanobacteria were the most connected bacterial group and, hence, might play a role in early biocrust formation due to their ability to, e.g., fix nitrogen and thus induce hotspot-like properties. The microbial community composition differed and network complexity was reduced by conventional tillage. Mineral and organic fertilizers led to networks that are more complex with a higher percentage of positive correlations favoring microbe-microbe interactions. Our study demonstrates that biocrusts represent a microbial hotspot on soil surfaces under agricultural use, which may have important implications for sustainable management of such soils in the future.
摘要：
■生物土壤结皮（生物结皮）被称为未受干扰的生物热点，营养不良的裸露土壤表面，直到现在，主要在（半）干旱地区观察到，但目前在农业系统中知之甚少。这是一个至关重要的知识差距，因为中西区域的管理站点可以快速覆盖大面积。因此，我们解决了以下问题：（i）如果来自mesic地区农业地点的生物锈蚀也像它们的（半）干旱对应物一样增加养分和微生物生物量，（ii）这些生物锈病中的微生物群落组合如何受到不同施肥和耕作方式等干扰的影响。
■我们比较了光养生物量，营养浓度以及丰度，古细菌的多样性和共现，细菌,和真菌在农业土壤质量较低的地点的生物和裸露土壤中。
■与裸露的土壤相比，与施用的肥料和耕作管理无关，生物肥料积累了大量的光养和微生物生物量，并储存了更多的养分。令人惊讶的是,特别是低丰度的放线菌在生物锈菌网络中高度连接。相比之下,蓝细菌很少连接，这表明生物锈病微生物群落中的重要性降低。然而,在裸露的土壤网络中，蓝细菌是联系最紧密的细菌群，因此，由于它们的能力，例如，固定氮，从而诱导热点样特性。通过常规耕作，微生物群落组成不同，网络复杂性降低。矿物和有机肥料导致网络更加复杂，正相关百分比更高，有利于微生物-微生物相互作用。我们的研究表明，生物锈蚀代表了农业使用下土壤表面的微生物热点，这可能对未来此类土壤的可持续管理具有重要意义。
■我们比较了光养生物量，营养浓度以及丰度，古细菌的多样性和共现，细菌,和真菌在农业土壤质量较低的地点的生物和裸露土壤中。
■与裸露的土壤相比，与施用的肥料和耕作管理无关，生物肥料积累了大量的光养和微生物生物量，并储存了更多的养分。令人惊讶的是,特别是低丰度的放线菌在生物锈菌网络中高度连接。相比之下,蓝细菌很少连接，这表明生物锈病微生物群落中的重要性降低。然而,在裸露的土壤网络中，蓝细菌是联系最紧密的细菌群，因此，由于它们的能力，例如，固定氮，从而诱导热点样特性。通过常规耕作，微生物群落组成不同，网络复杂性降低。矿物和有机肥料导致网络更加复杂，正相关百分比更高，有利于微生物-微生物相互作用。我们的研究表明，生物锈蚀代表了农业使用下土壤表面的微生物热点，这可能对未来此类土壤的可持续管理具有重要意义。
