1. N 2 O-It’s No Laughing Matter! Leilei Ruan and Sandy Erwin

2. Introduction  Surface temperature has increased to 0.74 o C from 1906 to 2005 and are expected to rise to 1.1-6.4 o C by 2100.  The increases of greenhouse gas (CO 2, CH 4 and N 2 O) since 1750 are dramatic compared with antecedent concentrations CO 2 concentration 280 ppm 379 ppm CH 4 715 ppb 1774 ppb N 2 O 270 ppb 319 ppb

3. Biofuels Question: can biofuels really mitigate Greenhouse gas (GHG) emissions?

4. Biofuels are not 100% “GHG neutral” due to cultivation  Soil CO 2 will release when soil carbon is oxidized following cultivation  CH 4 oxidation is reduced  N 2 O is released Concentratio n Global warming potential by time horizon 20 years 100 years 500 years CO 2 379 ppm111 CH 4 1774 ppb72257.6 N2ON2O319 ppb289298153

5. Nitrogen in animals and microbes Bacteria fix N 2 NH 4 + NO 3 - NO x, N 2 O nitrificationdenitrification Nitrogen cycle Nitrogen in plants Nitrogen back to soil N2N2 N2N2 +

6.  Extra source for nitrogen cycle: http://youtu.be/6GLIzlUD-zw  Soil Safari : http://school.discoveryeducation.com/schoolad ventures/soil/down_dirty.html www.glbrc.org 6

7. The impacts of nitrogen fertilizer management on GHG emissions in switchgrass Hypothesis: The response in soil N 2 O emissions to the inputs of N fertilizer in switchgrass will be non-linear; in particular, fluxes will increase sharply after biomass yields no longer increase.

8. Objective 1 : To determine the Impacts of nitrogen fertilizer management on GHG emissions in switchgrass Hypothesis: The response in soil N 2 O emissions to the inputs of N fertilizer in switchgrass will be non-linear; in particular, fluxes will increase sharply after biomass yields no longer increase.

9. Experimental design http://lter.kbs.msu.edu/photos/index.php

10. Block 2 Block 1 Block 3 Block 4 14056196112841680281961681401128456280 11256196288416814000561961681122814084 15m 10m 4.75m N-Rate( kg ha -1 ) Block 1 Block 2

11. Experimental materials and methods Static Chamber - 4 samples taken during an hour-long closure. Gas Chromatograph: N 2 O (ECD) (CV=2.4%), CH 4 (FID), and CO 2 (IRGA) analysis

13. Field time www.glbrc.org 13

14. Data nugget and discussion www.glbrc.org 14