Response to nitrogen addition reveals metabolic and ecological strategies of soil bacteria

We used soil microcosms to test the impact of nitrogen deposition on microbial communities. Using repacked soil cores (1.1 mg m-3) in tension tables we mimicked a urine-N deposition event for over 60 days by applying urea under two different moisture contents: near saturated (-1.0 kPa) and field conditions (-10 kPa). Simultaneous measurements of soil chemistry, gas kinetics, microbial community composition and functional gene abundance (for nitrification and denitrification) at DNA (gene) and RNA (transcript) levels were performed to determine the active populations and pathways during the urine cascade.