Managing Global Resources for a Secure Future

2017 Annual Meeting | Oct. 22-25 | Tampa, FL

181-2 The Influence of Winter 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 Enhance Nitrogen-Use Efficiency and Mitigate Greenhouse Gas Emissions Oral

Tuesday, October 24, 2017: 8:15 AM
Tampa Convention Center, Room 24

Neville Millar, Kellogg Biological Station, Michigan State University, Hickory Corners, MI, Dean G. Baas, Michigan State University Extension, Centreville, MI and G. Philip Robertson, W.K. Kellogg Biological Station, Michigan State University, Hickory Corners, MI
Abstract:
The practice of including winter cover crops in Midwest row-crop systems is increasing. This perennializaton of annual crop systems can provide climate stabilization through additional soil carbon storage, and perhaps nitrous oxide (N2O) mitigation.

Nitrous oxide is the largest contributor to the greenhouse gas (GHG) burden of cropping systems in the US. An increase or decrease in emissions of N2O from the soil due to management change, such as cover crop planting, can make the difference between abating or raising the overall Global Warming Impact (GWI) of the system. Limited, longer-term N2O emissions data from winter cover crops make this evaluation challenging.

Here, we will present twelve site years of N2O emissions data from a corn-soybean rotation, either with or without cover crops (grass – legume mixture) under conventional management, at the Kellogg Biological Station in SW Michigan.

Results show that including cover crops in annual crop systems did not have much affect on total N2O emissions compared to their absence. There was evidence for decreased emissions in soybean years following cover crops, but not in corn years following cover crops. N2O emissions were highest in corn (vs. soybean) years, irrespective of cover crop presence or absence. The largest N2O fluxes occurred following fertilization, soil disturbance (annual crop planting and cover crop termination), and rainfall.

See more from this Division: ASA Section: Environmental Quality
See more from this Session: Agricultural Practices to Enhance Nitrogen-Use Efficiency and Mitigate Greenhouse Gas Emissions Oral