PRJNA255542
Soil bacterial community in temperate grassland
Anthropogenic disturbance and global climate change are greatly affecting ecosystems worldwide by ways such as widespread nitrogen (N) deposition and changing precipitation regimes. It is predicted that the mean annual precipitation and N deposition in North China will continue to increase in future. Although much of work has been focus on the response of above-ground plant community to presumed climate change, the effects of nitrogen and water addition on the soil microbial community has not yet been systematically surveyed. Given the important role of soil microbial communities in nutrient cycling in terrestrial ecosystem, the effects of nitrogen and water addition and their interaction on soil microbial communities increased our attention. The specific aims of this project are: (1) to analyze the response of soil microbial diversity and community structure to the increase of soil N inputs and soil moisture; (2) to reveal the relationship between the variation of microbial communities and the above-ground plant community. The study sites were located in Duolun county, Inner Mongolia (E 116°17’20”, N 42°2’29”). A field experiment with a constant increase in precipitation and three Nitrogen supply levels was established in 2005 to examine the potential effects of N deposition and changes in precipitation regime on the ecological processes. A split-plot experimental design was employed in this study. The block was divided into two main plots with water treatment (ambient precipitation and water addition). Each main plot was divided into twenty-eight 8 m × 8 m subplots with a 1-m wide buffer zone. Four levels of Nitrogen treatment (N0 (control), N5 (5 g N m-2 yr-1), N10 (10 g N m-2 yr-1), N15 (15 g N m-2 yr-1), each including seven replicates, were randomly assigned to each subplot within main plot. In the middle growing season from June to August, the water addition plots received 15 mm of precipitation weekly by sprinkling irrigation. A total of 180 mm precipitation, approximately 50% of mean annual rainfall, was added yearly during the growing season from 2005 to 2013.