Xu Qicheng, Ling Ning, Chen Huan, Duan Yinghua, Wang Shuang, Shen Qirong, Vandenkoornhuyse Philippe
Jiangsu Provincial Key Lab for Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural University, Nanjing, Jiangsu, China.
Université de Rennes 1, CNRS, UMR 6553 EcoBio, Campus Beaulieu, Rennes, France.
mSystems. 2020 Jul 14;5(4):e00337-20. doi: 10.1128/mSystems.00337-20.
Fertilization regimes are known to drive succession of the soil microbial community, whereas the assembly rules involved remain elusive. Moreover, the ecological roles of microbial "generalists" and "specialists" in soils with contrasting fertilization regimes have not been characterized. We explored how long-term fertilization regimes (i.e., treatments conducted for at least 30 years) impact the soil bacteria by modifying species richness, diversity, bacterial assembly, and niche breadth. Compared with long-term organic fertilizer input, the soils having undergone chemical-only fertilization contained smaller amounts of carbon resources and had a more acidic environment. This strong environmental constraint lowered the soil bacterial reservoir and resulted in a detectable ecoevolutionary transformation, with both a higher proportion of specialists and a stronger signature of deterministic processes. Overall, this study provided a new comprehensive understanding of the assembly rules of bacterial generalists and specialists under long-term fertilization regimes. This study also highlighted that chemical-only fertilization, a ubiquitous agricultural practice of current conventional agriculture, induced a strong and similar environmental force that transformed the soil microbiota from 28°N to 46°N included in this study. Chemical-only fertilization is ubiquitous in contemporary conventional agriculture despite the fact that sustainability of this agricultural practice is increasingly being questioned because of the current observed soil degradation. We explored how long-term chemical-only versus organic-only fertilizations impacted the soil microbiota reservoir in terms of both diversity and induced assembly processes. The results showed that long-term chemical-only fertilization resulted in deep selection pressure on the soil microbial community reservoir, with both a higher proportion of specialists and a stronger signature of deterministic processes. The soil microbiota has clearly changed as a consequence of the fertilization regime. The diagnoses of the functional consequences of these ecoevolutionary changes in relation to agricultural practices are key to imagining agriculture in the time ahead and especially regarding future efforts for the conservation, restoration, and management of the soil microbiota reservoir which is key to the fertility of the ecosystem.
已知施肥制度会推动土壤微生物群落的演替，但其涉及的组装规则仍不明确。此外，在施肥制度不同的土壤中，微生物“通才”和“专才”的生态作用尚未得到描述。我们探讨了长期施肥制度（即至少持续30年的处理）如何通过改变物种丰富度、多样性、细菌组装和生态位宽度来影响土壤细菌。与长期施用有机肥相比，仅施用化肥的土壤碳资源含量较少，且环境更酸性。这种强烈的环境限制降低了土壤细菌库，并导致了可检测到的生态进化转变，专才的比例更高，确定性过程的特征更强。总体而言，本研究为长期施肥制度下细菌通才和专才的组装规则提供了新的全面理解。本研究还强调，仅施用化肥这一当前传统农业中普遍存在的农业实践，会引发强大且相似的环境力量，使本研究涵盖的北纬28°至46°的土壤微生物群发生转变。尽管由于目前观察到的土壤退化，这种农业实践的可持续性越来越受到质疑，但仅施用化肥在当代传统农业中仍然普遍存在。我们探讨了长期仅施用化肥与仅施用有机肥如何在多样性和诱导组装过程方面影响土壤微生物库。结果表明，长期仅施用化肥对土壤微生物群落库产生了深度选择压力，专才的比例更高，确定性过程的特征更强。施肥制度导致土壤微生物群发生了明显变化。诊断这些与农业实践相关的生态进化变化的功能后果，对于设想未来的农业，尤其是对于土壤微生物库的保护、恢复和管理的未来努力至关重要，而土壤微生物库是生态系统肥力的关键。
