Document Type
Article
Publication Date
Spring 4-12-2013
Abstract
Elevated nitrogen (N) deposition in humid tropical regions may exacerbate phosphorus (P) deficiency in forests on highly weathered soils. However, it is not clear how P availability affects soil microbes and soil carbon (C), or how P processes interact with N deposition in tropical forests. We examined the effects of N and P additions on soil microbes and soil C pools in a N-saturated old-growth tropical forest in southern China to test the hypotheses that (1) N and P addition will have opposing effects on soil microbial biomass and activity, (2) N and P addition will alter the composition of the microbial community, (3) the addition of N and P will have interactive effects on soil microbes and (4) addition-mediated changes in microbial communities would feed back on soil C pools. Phospholipid fatty acid (PLFA) analysis was used to quantify the soil microbial community following four treatments: Control, N addition (15 g N m-2 yr-1), P addition (15 g P m-2 yr-1), and N&P addition (15 g N m-2 yr-1 plus 15 g P m-2 yr-1). These were applied from 2007 to 2011. Whereas additions of P increased soil microbial biomass, additions of N reduced soil microbial biomass. These effects, however, were transient, disappearing over longer periods. Moreover, N additions significantly increased relative abundance of fungal PLFAs and P additions significantly increased relative abundance of arbuscular mycorrhizal (AM) fungi PLFAs. Nitrogen addition had a negative effect on light fraction C, but no effect on heavy fraction C and total soil C. In contrast, P addition significantly decreased both light fraction C and total soil C. However, there were no interactions between N addition and P addition on soil microbes. Our results suggest that these nutrients are not co-limiting, and that P rather than N is limiting in this tropical forest.
Recommended Citation
Liu L, Zhang T, Gilliam FS, Gundersen P, Zhang W, et al. (2013) Interactive Effects of Nitrogen and Phosphorus on Soil Microbial Communities in a Tropical Forest. PLoS ONE 8(4): e61188. doi:10.1371/journal.pone.0061188
Included in
Biology Commons, Forest Biology Commons, Systems Biology Commons
Comments
The copy of record is available from the publisher at http://dx.doi.org/10.1371/journal.pone.0061188. Copyright: 2013 Liu et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.