Agricultural management attenuates interannual variability in carbon fluxes but not water fluxes in the U.S. Corn Belt

Authors: Schreiner-Mcgraw, Adam; WOOD, JEFFERY - University Of Missouri; Metz, Megan; SADLER, EDWARD - Retired ARS Employee; Sudduth, Kenneth - Ken

Submitted to: Frontiers in Hydrology Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 3/31/2022
Publication Date: 6/23/2022
Citation: Schreiner-Mcgraw, A.P., Wood, J.D., Metz, M.E., Sadler, E.J., Sudduth, K.A. 2022. Agricultural management attenuates interannual variability in carbon fluxes but not water fluxes in the U.S. Corn Belt [abstract]. Frontiers in Hydrology Meeting. Paper 1032764.

Interpretive Summary:

Technical Abstract: Global food demand is expected to double by 2050, thereby increasing demands on agricultural lands. Some of the most productive agricultural land in the world is in the Corn Belt of the United States. Much of this land was originally prairie that was put into agricultural production. The cropping practices can vary greatly between individual farms, but the impact that land management practices have on water and carbon fluxes remain poorly quantified. In this study, we installed eddy covariance towers in a native tallgrass prairie, a business-as-usual corn-soybean rotation, and an aspirational, no-till cropping rotation including corn, soybean, wheat, and hay with cover crops. These land cover classes are representative of the primary historical, current, or aspirational land cover in the Corn Belt. We present a side-by-side comparison of the three sites over a 6-year period demonstrating that evapotranspiration (ET) is highest in the aspirational agricultural site (696 mm/yr) and lowest at the native prairie site (484 mm/yr). We assess the impact of environmental conditions, including soil moisture, air temperature, vapor pressure deficit, and solar radiation, on the observed ET. The ET from the native prairie has the lowest sensitivity to environmental conditions, followed by the aspirational cropping system. Results from this analysis indicate that systems with perennial vegetation are more resilient to non-optimal environmental conditions than conventional cropping systems. Finally, we assess the interannual variability of plant growth (represented by Gross Primary Productivity; GPP) and ET. We find that agricultural management attenuates interannual variability in GPP, but not ET in these (agro) ecosystems. Our findings suggest that changes in land use to aspirational cropping systems will impact the water budget of the Corn Belt by increasing the ET, leaving less water available to become streamflow.