The change of functional genes under different nitrogen addition based on Geochip 5.0. soil metagenome

Anthropogenic nitrogen (N) deposition affects soil organic carbon (SOC) decomposition, thus affecting the global terrestrial carbon (C) cycle. Our analysis of microbial mmunities in soils subjected to 5-years of different levels of N addition (0, 3, 6, and 9 g N m–2 y–1) in an artificial Pinus tabulaeformis forest on the Loess Plateau of China showed that the N addition significantly shifted C-cycling functional gene structure. Under low N (3 or 6 g N m–2 y–1) addition, overall C-cycling functional gene abundance and diversity were increased, and especially, the labile C degradation gene abundance was significantly increased, but there was no significant effect on recalcitrant C (vanillin/lignin, lignin) degradation gene abundance. Under high N (9 g N m–2 y–1) addition, overall C-cycling functional gene abundance and diversity were significantly decreased, and both labile and recalcitrant C degradation gene abundance were significantly decreased.