Belowground responses of Picea asperata seedlings to warming and nitrogen fertilization in the eastern Tibetan Plateau

• Published in: Ecological research Vol. 26; no. 3; pp. 637 - 648
• Main Authors: Liu, Qing, Yin, Huajun, Chen, Jinsong, Zhao, Chunzhang, Cheng, Xinying, Wei, Yunyan, Lin, Bo
• Format: Journal Article
• Language: English
• Published: Japan Springer Japan 01.05.2011; Blackwell Publishing Ltd
• Subjects: Air temperature; Behavioral Sciences; Biomass; Biomedical and Life Sciences; Climate change; Coniferous forests; Ecology; Evolutionary Biology; Forest ecosystems; Forest soils; Forestry; Global climate; Life Sciences; Nitrification; Nitrogen; Organic carbon; Original Article; Picea; Picea asperata; Plant Sciences; Rhizosphere; Rhizosphere microbial process; Rhizosphere soil process; Root; Seedlings; Soil temperature; Soils; Temperature effects; Terrestrial ecosystems; Trees; Zoology; Tibetan Plateau; China, People's Rep., Xizang, Tibetan Plateau; Root; Rhizosphere microbial process; Rhizosphere soil process
• ISSN: 0912-3814; 1440-1703
• DOI: 10.1007/s11284-011-0824-5

The impacts of global climatic change on belowground ecological processes of terrestrial ecosystems are still not clear. We therefore conducted an experiment in the subalpine coniferous forest ecosystem of the eastern edges of the Tibetan Plateau to study roots of Picea asperata seedlings and rhizosphere soil responses to soil warming and nitrogen availability from April 2007 to December 2008. The seedlings were subjected to two levels of temperature (ambient; infrared heater warming) and two nitrogen levels (0 or 25 g m −2 year −1  N). We used a free air temperature increase from an overhead infrared heater to raise both air and soil temperature by 2.1 and 2.6°C, respectively. The results showed that warming alone significantly increased total biomass, coarse root biomass and fine root biomass of P. asperata seedlings. Both total biomass and fine root biomass were increased, but coarse root biomass was significantly decreased by nitrogen fertilization and warming combined with nitrogen fertilization. Warming induced a prominent increase in soil organic carbon (SOC) and NO 3 − -N of rhizosphere soil, while nitrogen fertilization significantly decreased SOC and NH 4 + -N of rhizosphere soil. The warming, fertilization and warming × N fertilization interaction decreased soil microbial C significantly, but substantially increased soil microbial N. These results suggest that nitrogen deposition combined with warmer temperatures under future climatic change possibly will have no effect on fine root production of P. asperata seedlings, but could enhance the nitrification process of their rhizosphere soils in subalpine coniferous forests.