Nov 5, 2013 - but no difference was found among different N forms. Despite higher urease ... Introduction. Nitrogen (N) is an essential element and is one of the most .... NaNO3 for the Ni treatment, and NH4NO3 for the AN treat- ment. The two ... were a total of 42 soil samples (7 treatmentsÃ3 replicatesÃ2 sampling times) ...
Biol Fertil Soils DOI 10.1007/s00374-013-0889-0
ORIGINAL PAPER
Influence of nitrogen fertilization on soil ammonia oxidizer and denitrifier abundance, microbial biomass, and enzyme activities in an alpine meadow Xiao-Fang Tian & Hang-Wei Hu & Qiong Ding & Ming-Hua Song & Xing-Liang Xu & Yong Zheng & Liang-Dong Guo
Received: 14 August 2013 / Revised: 5 November 2013 / Accepted: 13 November 2013 # Springer-Verlag Berlin Heidelberg 2013
Abstract Terrestrial ecosystems are predicted to experience an increasing level of atmospheric nitrogen (N) deposition, which may cause significant shifts in plant community composition and concomitantly stimulate soil acidification. However, little is known concerning the effects of N deposition on belowground microbial communities in alpine grassland ecosystems such as on the Tibetan Plateau. This study examined the responses of soil N-transforming microbes (measured after DNA extraction and quantitative PCR), soil microbial biomass C (SMBC) and N (SMBN), and soil enzyme activities to different forms (NH4+-N, NO3−-N, and NH4NO3-N) and rates (1.5 and 7.5 g N m−2 year−1, denoted as low and high N, respectively) of N fertilization (addition) in two successive plant growing seasons. The N rate, not N form, influenced the abundance of ammonia-oxidizing archaea (AOA). High N addition significantly increased ammoniaoxidizing bacteria (AOB) abundance which differed across different N form treatments. Nitrogen addition had no significant impact on the abundance of soil denitrifiers. The SMBC and SMBN were significantly decreased by high N additions, but no difference was found among different N forms. Despite Electronic supplementary material The online version of this article (doi:10.1007/s00374-013-0889-0) contains supplementary material, which is available to authorized users. X.
