Key Laboratory of Low-carbon Green Agriculture in Northwestern China, Ministry of Agriculture and Rural Affairs of China, College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, China; State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling, Shaanxi 712100, China.
Key Laboratory of Low-carbon Green Agriculture in Northwestern China, Ministry of Agriculture and Rural Affairs of China, College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, China; State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling, Shaanxi 712100, China.
Sci Total Environ. 2023 Jun 20;878:162972. doi: 10.1016/j.scitotenv.2023.162972. Epub 2023 Mar 21.
Soil microbes play key roles that support forest ecosystem functioning, while their community characteristics are strongly determined by tree species identity. However, the majority studies primarily focus on soil microorganisms in the topsoil, resulting in limited understanding of the linkages between tree species identity and the microbial communities that inhabit deep soils. Here we investigated the diversity, structure, function, and co-occurrence networks of soil bacterial and fungal communities, as well as related soil physicochemical properties, to a depth of two meters in dryland forests dominated by either Pinus tabuliformis, a native coniferous species, Robinia pseudoacacia, an exotic broadleaf and nitrogen-fixing species, or both. Tree species identity had stronger effects on soil multifunctionality and microbial community structure in the deep layers (80-200 cm) than in the top layers (0-60 cm). In addition, fungal communities were more responsive to tree species identity, whereas bacteria were more sensitive to soil depth. Tree species identity strongly influenced microbial network stability and complexity, with higher quantities in R. pseudoacacia than the other plantations, by affecting microbial composition and their associations. The increased in microbial network complexity and the relative abundance of keystone taxa enhance the soil multifunctionality of microbial productivity, sugar and chitin degradation, and nutrient availability and cycling. Meanwhile, the relative abundance of keystone taxa was more representative of soil multifunctionality than microbial diversity. Our study highlights that tree species identity significantly influences soil microbial community characteristics and multifunctionality, especially in deep soils, which will help us understand soil nutrients processed in plantation forest ecosystem and provide a reference for tree species selection in ecological restoration.
土壤微生物在支持森林生态系统功能方面发挥着关键作用，而它们的群落特征则强烈取决于树种的身份。然而，大多数研究主要集中在表土中的土壤微生物，导致对树种身份与栖息在深层土壤中的微生物群落之间的联系的理解有限。在这里，我们调查了干旱林土壤中细菌和真菌群落的多样性、结构、功能和共生网络，以及相关的土壤理化性质，深度可达两米，这些森林主要由乡土针叶树种白皮松、外来阔叶树种刺槐或两者共同组成。树种身份对深层（80-200cm）土壤多功能性和微生物群落结构的影响大于表层（0-60cm）。此外，真菌群落对树种身份的响应更为敏感，而细菌对土壤深度的响应更为敏感。树种身份强烈影响微生物网络的稳定性和复杂性，刺槐林的微生物网络稳定性和复杂性高于其他林分，这是通过影响微生物组成及其相互作用来实现的。微生物网络复杂性的增加和关键类群的相对丰度提高了微生物生产力、糖和几丁质降解以及养分有效性和循环的土壤多功能性。同时，关键类群的相对丰度比微生物多样性更能代表土壤多功能性。我们的研究强调了树种身份显著影响土壤微生物群落特征和多功能性，特别是在深层土壤中，这将有助于我们了解人工林生态系统中土壤养分的处理过程，并为生态恢复中的树种选择提供参考。
