TRACE GAS EXCHANGES IN MIDWEST CROPPING SYSTEMS
Location: Soil, Water, and Air Resources Research Unit
Project Number: 3625-11000-005-00
Start Date: Dec 15, 2009
End Date: Jun 02, 2010
Project objectives are 1) develop infrastructure for long-term monitoring of spatial and temporal variation of CO2/H2O vapor exchange and C storage in corn/soybean systems, 2) evaluate the effects of alternative agricultural practices on net greenhouse gas exchange, 3) investigate biophysical interactions that regulate greenhouse gas exchange, water use, and energy transfer to enhance predictive capabilities of emission and soil C sequestration, and 4) develop infrastructure to conduct year-round measurements of nitrous oxide emissions as a function of agronomic and nitrogen management practices.
A long-term measurement site will be located and maintained in central Iowa, near the center of the Upper Midwest Corn Belt. The area is intensively cultivated in corn and soybeans. Three instrument towers will be installed in two adjacent fields with crops alternating every season. Each tower will be instrumented to measure energy balance parameters, evaporation, and CO2 fluxes. Another field site will be used to evaluate tillage, rotation, cover crop, crop residue, and N fertilization management on CO2, nitrous oxide, and methane fluxes. Chamber techniques will be utilized on replicated plots for the various treatments. These studies are part of the ARS multi-location Greenhouse Gas Reduction through Agricultural Carbon Enhancement Network (GRACEnet). Observed greenhouse gas fluxes and soil C sequestration will be coupled with supporting biophysical data to allow testing of simulation models for the prediction of climate changes.