Responses of soil microbes and their interactions with plant community after nitrogen and phosphorus addition in a Tibetan alpine steppe

• Published in: Journal of soils and sediments Vol. 20; no. 4; pp. 2236 - 2247
• Main Authors: Dong, Junfu, Wang, Shuping, Niu, Haishan, Cui, Xiaoyong, Li, Linfeng, Pang, Zhe, Zhou, Shutong, Wang, Kui
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.04.2020; Springer Nature B.V
• Subjects: Actinomycetes; Arbuscular mycorrhizas; Bacteria; Biomass; Earth and Environmental Science; Environment; Environmental Physics; Environmental restoration; Fatty acids; Fungi; Genotype & phenotype; Grasslands; High altitude; Limiting factors; Microorganisms; Nitrogen; Phenotypes; Phospholipids; Phosphorus; Plant communities; Restoration; Sec 5 • Soil and Landscape Ecology • Research Article; Soil; Soil investigations; Soil microorganisms; Soil Science & Conservation; Soils; Steppes; Nitrogen fertilization and phosphorus fertilization; PLFA; Microbial community; Tibetan alpine steppe
• ISSN: 1439-0108; 1614-7480
• DOI: 10.1007/s11368-020-02586-3

Purpose Nitrogen (N) and phosphorus (P) additions are the widely used restoration management for degraded grasslands. However, soil microbial community responses to N and P additions are still not well understood, especially multiple levels or/and combined N and P additions in high-altitude grasslands. In this study, the single and interactive effects of N and P additions on the soil microbes were explored. Methods A field experiment with two factors (N 0, 7.5, and 15 g N m −2  year −1 ; P 0, 3.27, and 6.55 g P m −2  year −1 ) was conducted by a completely randomized block design in a Tibetan plateau steppe. Total and specific microbial biomass (bacteria, fungi, G+/G− bacteria, saprotrophs, actinomycetes, and arbuscular mycorrhizal fungi) were analyzed by using phospholipid fatty acids (PLFAs). Additionally, based on their fixed weight composites, we used a composite variable (phenotype) to represent the microbial community. Results The results showed that N addition decreased the microbe phenotype, total microbial biomass, and specific microbial biomass (total bacteria, G+, and G− bacteria). P application and its interaction with N application all increased the microbial phenotype, total microbial biomass, and specific microbial biomass (total bacteria, G+, G−, saprotrophs, and actinomycetes). Besides, the microbial phenotype was positively correlated with P application rates and not correlated with N application rates. Conclusion In conclusion, P was the key limiting factor for soil microbes, and its interaction with N is also important for some specific microbes. In addition, long-term responses of soil microbes after N and P amendments need further investigation in the Tibetan alpine steppe.