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ARS Home » Midwest Area » Columbia, Missouri » Cropping Systems and Water Quality Research » Research » Publications at this Location » Publication #396827
Research Project: Linkages Between Crop Production Management and Sustainability in the Central Mississippi River Basin

Location: Cropping Systems and Water Quality Research

Title: Quantifying the impact of no-till and cover crops on soil carbon flux in a corn-soybean rotation

Author
item Schreiner-Mcgraw, Adam
item Ransom, Curtis
item WOOD, JEFFREY - UNIVERSITY OF MISSOURI

Submitted to: American Geophysical Union
Publication Type: Abstract Only
Publication Acceptance Date: 10/4/2022
Publication Date: 12/15/2022
Citation: Schreiner-McGraw, A.P., Ransom, C.J., Wood, J.D. 2022. Quantifying the impact of no-till and cover crops on soil carbon flux in a corn-soybean rotation [abstract]. American Geophysical Union. Paper 1165448.

Interpretive Summary:

Technical Abstract: Corn (Zea mays) and soybean (Glycine max) production dominates agricultural land in the Midwestern United States and impacts the regional carbon cycle. Preserving soil carbon stocks is important both to increase crop yield and mitigate greenhouse gas emissions. Monitoring the impact of cropping practices on soil carbon stocks, however, requires long-term observations because changes to soil carbon occur over a period of years. Here, we compared carbon fluxes in two agricultural management systems: a business-as-usual (BAU) corn-soybean rotation, and an aspirational (ASP) field with a diverse crop rotation, no-tillage, and cover crops. We combined 7-years of eddy covariance measurements of net ecosystem CO2 exchange (NEE) with intensive soil sampling campaigns to quantify differences in the carbon balances of these agricultural systems. Average annual net ecosystem exchange (NEE) was negative (carbon uptake) at both agricultural sites (-305 ± 147 and -311 ± 154 gC m-2 yr-1 at ASP and BAU, respectively). Yet, when crop yield was taken into account, the BAU field had significantly less carbon uptake than the ASP field; primarily because corn, which has higher carbon removal than soybean, is planted more frequently at BAU. These values also do not include carbon that is removed from the fields in runoff. We combined measurements of soil carbon storage NEE to calculate carbon balances, and quantify the amount of carbon lost through runoff. Additionally, we evaluated the sensitivity of carbon dioxide fluxes to environmental conditions including soil water content, vapor pressure deficit, air temperature, and photosynthetic photon flux density and find that the BAU site is more sensitive to changes in environmental conditions than the ASP site. Finally, we used the eddy covariance measurements to quantify the amount of carbon uptake that can be attributed to cover crops. Results from this study illustrate the value of these conservation practices in a changing climate.