ARS | Publication request: Gas and Water Vapor Exchanges in Rainfed Corn-Soybean Systems

Submitted to: Meeting Abstract
Publication Type: Abstract
Publication Acceptance Date: January 26, 2007
Publication Date: January 22, 2007
Citation: Prueger, J.H., Hatfield, J.L., Parkin, T.B., Sauer, T.J. 2007. Gas and Water Vapor Exchanges in Rainfed Corn-Soybean Systems [abstract]. NACP Investigators Meeting, January 22-26, 2007, Colorado Springs, Colorado. CD-ROM.

Technical Abstract: Corn and soybean production in the Midwestern United States represents one of the most intensive and extensive cropping systems in the world. It is critical to understand the dynamics of CO2 (carbon dioxide) and H2O (water) vapor exchanges above corn and soybean canopies in rainfed environments in order to provide insights into how these cropping systems respond to the combination of management and meteorological conditions. The Iowa Ameriflux site encompasses year-around measurements over adjacent corn and soybean fields at a height of 5 m above the canopy. An additional site has been established at 10 m between the two fields to provide a more regional scale estimate of the fluxes across the two cropping systems. Additional within field measurements are made of the soil CO2 exchanges and within canopy CO2 and H2O vapor fluxes. Ancillary data on crop growth, yield, and management practices have been recorded for each growing season and crop. There are seasonal changes in the magnitude of the fluxes and the resulting NEE (net ecosystem exchnages) for both corn and soybean. This is well known given the differences between C3 (dicots plants) and C4 (grass plants) vegetation. A complete C (carbon) and H2O balance for the typical cropping systems provide a baseline from which comparisons can be made on the expected changes in C storage that would result from changing management practices.