Decarbonizing North American soybean production

Authors: DELLA CHIESA, TOMAS - Iowa State University; MIGUEZ, FERNANDO - Iowa State University; ARCHONTOULIS, SOTIRIOS - Iowa State University; BAUM, MITCHELL - Iowa State University; NORTHRUP, DANIEL - Iowa State University; Venterea, Rodney - Rod; Emmett, Bryan; Malone, Robert - Rob; GOESER, NICHOLAS - Collaborator; JOSPE, CHRISTOPHE - Collaborator; IQBAL, JAVED - University Of Nebraska; NECPALOVA, MAGDALENA - University College Dublin; CASTELLANO, MICHAEL - Iowa State University

Submitted to: Nature Sustainability
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/18/2024
Publication Date: N/A
Citation: N/A

Interpretive Summary: Greenhouse gas emissions from upland crops are difficult to reduce because they are dominated by nitrous oxide production from biological soil processes. Strategies to reduce these emissions largely focus on improving nitrogen fertilizer management. There is a widespread assumption that leguminous crops such as soybean, which do not receive nitrogen fertilizer, emit relatively little nitrous oxide and therefore offer little opportunity for emissions reduction. Here, we show that this assumption is incorrect. Approximately 40% of nitrous oxide emissions from the most widespread cropping system in North America – the corn-soybean rotation – are attributable to the soybean phase of the system. We design a systems approach that combines cover crops and earlier planting of soybean varieties with extended growth to reduce emissions from soybean production by 30%. These practices complement nitrogen fertilizer management in corn and are widely accessible to farmers. Therefore, the proposed management changes represent an immediate opportunity to reduce the greenhouse gas impact of soybean production, which is important to producers, scientists, crop advisers, and policy makers.

Technical Abstract: Greenhouse gas emissions from upland crops are difficult to abate because they are dominated by nitrous oxide (N2O) production from biological soil processes. Strategies to reduce these emissions largely focus on improving nitrogen (N) fertilizer management; there is a widespread assumption that leguminous crops, which do not receive N fertilizer, emit relatively little N2O and offer little opportunity for emissions abatement. Here, we show that this assumption is incorrect. Approximately 40% of N2O emissions from the most widespread cropping system in North America – the maize-soybean rotation – are attributable to the soybean phase of the system. We design a systems approach that combines cover crops and earlier planting of soybean varieties with extended growth to reduce emissions from soybean production by 30%. These practices complement N fertilizer management in maize and are widely accessible to farmers therefore representing an immediate opportunity to decarbonize the soybean production system.