Xia Zongwei, Yang Jingyi, Sang Changpeng, Wang Xu, Sun Lifei, Jiang Ping, Wang Chao, Bai Edith
CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
Microorganisms. 2020 Nov 20;8(11):1828. doi: 10.3390/microorganisms8111828.
Increased soil nitrogen (N) from atmospheric N deposition could change microbial communities and functions. However, the underlying mechanisms and whether soil phosphorus (P) status are responsible for these changes still have not been well explained. Here, we investigated the effects of N and P additions on soil bacterial and fungal communities and predicted their functional compositions in a temperate forest. We found that N addition significantly decreased soil bacterial diversity in the organic (O) horizon, but tended to increase bacterial diversity in the mineral (A) horizon soil. P addition alone did not significantly change soil bacterial diversity but mitigated the negative effect of N addition on bacterial diversity in the O horizon. Neither N addition nor P addition significantly influenced soil fungal diversity. Changes in soil microbial community composition under N and P additions were mainly due to the shifts in soil pH and NO contents. N addition can affect bacterial functional potentials, such as ureolysis, N fixation, respiration, decomposition of organic matter processes, and fungal guilds, such as pathogen, saprotroph, and mycorrhizal fungi, by which more C probably was lost in O horizon soil under increased N deposition. However, P addition can alleviate or switch the effects of increased N deposition on the microbial functional potentials in O horizon soil and may even be a benefit for more C sequestration in A horizon soil. Our results highlight the different responses of microorganisms to N and P additions between O and A horizons and provides an important insight for predicting the changes in forest C storage status under increasing N deposition in the future.
大气氮沉降导致土壤氮（N）增加，这可能会改变微生物群落及其功能。然而，其潜在机制以及土壤磷（P）状况是否是这些变化的原因仍未得到很好的解释。在此，我们研究了添加氮和磷对温带森林土壤细菌和真菌群落的影响，并预测了它们的功能组成。我们发现，添加氮显著降低了有机（O）层土壤中的细菌多样性，但倾向于增加矿质（A）层土壤中的细菌多样性。单独添加磷并没有显著改变土壤细菌多样性，但减轻了添加氮对O层细菌多样性的负面影响。添加氮和磷均未显著影响土壤真菌多样性。添加氮和磷后土壤微生物群落组成的变化主要归因于土壤pH值和NO含量的变化。添加氮会影响细菌的功能潜力，如尿素分解、固氮、呼吸作用、有机质分解过程，以及真菌类群，如病原菌、腐生菌和菌根真菌，在氮沉降增加的情况下，O层土壤中可能会损失更多的碳。然而，添加磷可以减轻或改变氮沉降增加对O层土壤微生物功能潜力的影响，甚至可能有利于A层土壤中更多的碳固存。我们的研究结果突出了O层和A层微生物对添加氮和磷的不同响应，并为预测未来氮沉降增加下森林碳储存状况的变化提供了重要见解。
