242-1 Nitrous Oxide (N2O) Emisisons On Conversion of Conservation Reserve Program (CRP) Land to Biofuel Crops Under till and No-till Practices.



Tuesday, October 18, 2011: 8:05 AM
Henry Gonzalez Convention Center, Room 207A, Concourse Level

Leilei Ruan and G. Philip Robertson, W. K Kellogg Biological Station and Crop & Soil Sciences, Hickory Corners, MI
Returning land enrolled in the Conservation Reserve Program (CRP) to crop land can be an option to meet the demand for expanding biofuel production. However, failing to consider GHG emissions caused by crop activities such as tillage and fertilization will overestimate the ability of biofuels to reduce GHG emissions. We studied the impacts of tillage and fertilization on N2O emissions during the first two years of CRP conversion to either corn, switchgrass, or restored prairie. Soybean was planted as the conversion year crop on all three sites in southwestern Michigan in 2009. For 2009 total emissions of N2O were three times higher under conventional tillage (CT) than under no-till (NT) (6.69 vs. 2.72 kg N2O-N ha-1; p<0.01). In 2010 N2O fluxes were also higher under CT across all three plants corn, switchgrass, and prairie (3.77 vs. 1.45 kg N2O-N ha-1; p<0.01). Among corn, switchgrass, and prairie plantings, averaged cumulative soil N2O emissions from corn (4.58 kg N2O-N ha-1), which was fertilized, were three times larger than emissions from the two unfertilized cellulosic crops (1.63 kg N2O-N ha-1; p<0.05); there were no significant differences between the switchgrass and prairie plots. Using no-till practices during the conversion year can substantially reduce the N2O cost of CRP conversion to biofuel crops, as can converting to perennial cellulosic crops rather than corn.
See more from this Division: S01 Soil Physics
See more from this Session: Symposium--Emission of Regulated and Greenhouse Gases: Measurement Technology, Monitoring and Policy: I