Response of microbial functional groups involved in soil N cycle to N, P and NP fertilization in Tibetan alpine meadows

摘要: The nitrogen (N) cycle is an important part of earth's biogeochemical cycles and N a critical element for all life. Whereas the response to - more rarely phosphorus, P fertilization some microbial groups involved in soil cycling has been studied, comprehensive view how major dynamics respond combined lacking, which restricts our understanding ecosystem responses fertilization. Here we investigated effects different N, NP fertilizer levels (4 without P; 4 N; with constant addition) on abundances 9 dynamics. Real time PCR was used target free N2 fixers, nitrifiers (bacterial archaea ammonia oxidizers, AOB AOA, respectively; nitrite oxidizers Nitrobacter Nitrospira), nitrate reducers, nirK- nirS-nitrite nitrous oxide reducers. Soil physical-chemical characteristics potential nitrification, PNR, were also measured. increased but did not affect other groups. decreased reducers AOA nirK-nitrite Using correlation network analysis, demonstrate strong coupling generally observed these grasslands between Nitrospira, narG-nitrate nirK-denitrifiers (most them responding N/P availability, being known be favored by low oxygen availability); (known high levels) that controlled changes PNR. (de)coupling may have consequences losses from fertilized Tibetan alpine meadows.