183-10 The Influence of Potential Biofuel Cover Crops on Nitrous Oxide (N2O) Emissions from Midwest Row-Crops.

See more from this Division: ASA Section: Environmental Quality
See more from this Session: Agricultural Practices to Improve Nitrogen-Use Efficiency and Mitigate Greenhouse Gas Emission: II

Tuesday, November 17, 2015: 10:30 AM
Minneapolis Convention Center, M100 C

Neville Millar, Kellogg Biological Station, Michigan State University, Hickory Corners, MI, Dean G. Baas, St. Joseph County, Michigan State University Extension, Centreville, MI and G Philip Robertson, W.K. Kellogg Biological Station, Michigan State University, Hickory Corners, MI
Abstract:
Nitrous oxide (N2O) is the largest contributor to the greenhouse gas burden of cropping systems in the US, with emissions primarily due to N fertilizer inputs and other soil management activities. The practice of including winter cover crops in corn-based row-crop systems is not widely adopted but is increasing. Perennializing annual crop systems through year-round soil cover can: reduce nutrient run-off and soil erosion; provide a cellulosic biofuel feedstock additional to the primary grain crop; provide climate stabilization through additional soil carbon storage and perhaps N2O mitigation. There is little N2O emissions data from cover crop systems. We will present four years of N2O emissions data from a corn-soybean-winter wheat rotation, either with or without cover crops (Grass, Legume and Brassica), situated at the Kellogg Biological Station in SW Michigan.

Results show that: including potential biofuel cover crops in annual crop systems affected N2O emissions differently (red clover increased total N2O emissions, whereas annual ryegrass and oilseed radish had no effect); average daily N2O emissions from biofuel cover crop treatments decreased in the order Legume > Grass ≥ Brassica; late cover crop termination time decreased N2O emissions in red clover, but not annual ryegrass; N2O emissions were highest in corn (vs. wheat and soybean), irrespective of cover crop presence or absence; highest N2O fluxes occurred following fertilization, soil disturbance (annual crop planting and cover crop termination), and rainfall. Cover crop effects on N2O emissions vary by species and cash crop: Legumes can increase N2O emissions, whereas non-legumes have no effect or can depress N2O emissions in soybean years.

See more from this Division: ASA Section: Environmental Quality
See more from this Session: Agricultural Practices to Improve Nitrogen-Use Efficiency and Mitigate Greenhouse Gas Emission: II