Ding Leilei, Wang Puchang
Guizhou Institution of Prataculture, Guizhou Academy of Agricultural Sciences, Guiyang 550006, Guizhou, China.
Guizhou Institution of Prataculture, Guizhou Academy of Agricultural Sciences, Guiyang 550006, Guizhou, China.
Sci Total Environ. 2021 Mar 20;761:143663. doi: 10.1016/j.scitotenv.2020.143663. Epub 2020 Nov 21.
Microbes simultaneously drive multiple functions (multifunctionality) that support human well-being. However, the structure and function of microbial communities and their impact on soil multifunctionality following grassland afforestation remains unknown, thus hindering our ability to formulate conservation policies. We compared soil bacterial and fungal communities, soil abiotic properties, and soil nitrogen (N) function and multifunctionality in the afforested sites that were previously grassland, on a subtropical plateau in China. We also explored the degree to which the niche complementarity effect and the selection effect of microbes are linked to soil N function and multifunctionality. We found that afforestation of grassland significantly decreased pH, available N concentration and density, and soil multifunctionality. However, afforestation significantly increased C (carbon) limitation and shifted soil microbes from being limited by N to, instead, being co-limited by N and P (phosphorus). The significant decrease in available N was primarily driven by soil microbes. In shaping soil N availability, the effect of bacterial diversities was stronger than that of fungal diversities, and the effect of fungal functional diversities was stronger than that of bacterial functional diversities. The effect of functional diversities was greater than that of all the significant changes in the functions and, also, the significant changes in the N-related functions. These results further emphasized that functional niche complementarity dominated soil N availability. In addition, bacterial taxonomic diversities showed positive effects of niche complementarity on soil multifunctionality; ultimately, the losses in bacterial taxonomic diversities derived from the increases in C limitation and the shifts in NP limitation combined to impaired soil multifunctionality. Our results suggested that the optimization of soil microbial functional diversities might increase soil N availability, and that minimizing losses of soil microbial taxonomic diversities by optimizing soil abiotic environments might improve soil multifunctionality.
微生物同时驱动多种支持人类福祉的功能（多功能性）。然而，草地造林后微生物群落的结构和功能及其对土壤多功能性的影响仍然未知，这阻碍了我们制定保护政策的能力。我们比较了中国亚热带高原上先前为草地的造林地的土壤细菌和真菌群落、土壤非生物特性以及土壤氮（N）功能和多功能性。我们还探讨了微生物的生态位互补效应和选择效应与土壤N功能和多功能性的关联程度。我们发现，草地造林显著降低了土壤pH值、有效氮浓度和密度以及土壤多功能性。然而，造林显著增加了碳（C）限制，并使土壤微生物从受氮限制转变为受氮和磷（P）共同限制。有效氮的显著下降主要是由土壤微生物驱动的。在塑造土壤氮有效性方面，细菌多样性的影响强于真菌多样性，真菌功能多样性的影响强于细菌功能多样性。功能多样性的影响大于所有功能的显著变化以及与氮相关功能的显著变化。这些结果进一步强调了功能生态位互补主导了土壤氮有效性。此外，细菌分类多样性对土壤多功能性显示出生态位互补的积极影响；最终，碳限制增加和氮磷限制变化导致的细菌分类多样性丧失共同损害了土壤多功能性。我们的结果表明，优化土壤微生物功能多样性可能会提高土壤氮有效性，通过优化土壤非生物环境来尽量减少土壤微生物分类多样性的损失可能会改善土壤多功能性。
