Suite of models shows some positive effects of climate-smart Ag practices

A study using multiple agronomic models to examine two long-term agricultural research stations in North America shows that so-called climate-smart agricultural practices – like no-till treatments, cover-crop utilization and residue retention – can help promote carbon sequestration in soil and reduce greenhouse gas emissions. 

The findings show that using a combination of models – rather than just one – can provide a more realistic range of outcomes and can highlight the shortcomings of individual models.

“We targeted open-source data from long-term agricultural experiments in Michigan and Texas that are very different – with different climates, soils and crops grown,” said Debjani Sihi, the senior author of a paper describing the research. “By utilizing these long-term studies, we wanted to see what the future might look like in terms of carbon sequestration and greenhouse gas emissions.

“We examined three different models developed by different research groups and looked at them collectively,” said Sihi, an assistant professor with joint appointments in NC State’s Department of Plant and Microbial Biology and Department of Crop and Soil Sciences. “The architecture is a little different in these models. What can we learn from each of the models, and what is the collective information?” 

The study examined data from more than three decades at the two agricultural experimental sites and calibrated it into a “model ensemble” to make future predictions. The ensemble examined both individual climate-smart agricultural practices and practices that were “stacked,” or added to each other.

The researchers then examined whether these proposed practices would, in the next 25 years or so, generate carbon sequestration in soil and a reduction of greenhouse gas emissions in two different scenarios: a baseline scenario that replicated climate-change historical data of the past three decades, and a “worst-case” scenario that envisions dramatic growth in greenhouse gas emissions.

“We tried to capture a variety of biological processes related to soil carbon sequestration and greenhouse gas (methane and nitrous oxide) emission while also accounting for climate-change effects,” Sihi said. “These processes are driven by different climate variables like temperature and precipitation.”

The model ensemble showed some positive effects in both studied locations under the baseline scenario.

“At the Michigan site, we found that no-till farming and keeping crop residues on the field increased soil carbon sequestration, while using no-till farming, some cover crops, and reducing fertilizer decreased greenhouse gas emissions,” Sihi said. “At the Texas site, most of the farming practices we tried increased soil carbon sequestration, and greenhouse gas emissions stayed about the same. However, the models indicated that not plowing alone could reverse greenhouse gas emissions.”

The worst-case scenario, however, lived up to its name in the study.

“We also found that all the climate-smart farming practices performed worse under worst-case scenario climate change, which was expected,” Sihi said.

She added that the study could provide the impetus for other researchers to try out the model ensemble approach and improve it. Future studies could be improved by using real-world data from on-farm studies and selecting other models with different strengths to broaden the insights.

“We hope others will evaluate these climate-smart practices to learn which may be more important, and what kind of experiments that we can leverage,” Sihi said. “These are two long-term examples in Michigan and Texas that we have utilized, so that others could adopt and improve and build on it.

“In this context, utilizing no-till or cover crops as a base practice and then stacking residue retention reduced future net emissions. Future work would need more study in other parts of the country – or world – to better generalize effects.” 
    
The paper appears in Agronomy Journal. Ellen Maas, a former postdoctoral researcher who worked with Sihi on this project, is the paper’s first author. 

Support for the work was primarily provided by Valent BioSciences, a subsidiary of Sumitomo Chemical Co., Ltd; with partial support from the U.S. Department of Agriculture’s National Institute of Food and Agriculture Project numbers 7009808 and 7010251. The study also drew on data supported by the National Science Foundation’s Long-term Ecological Research Program, Grant/Award Number DEB 2224712.

- kulikowski -

Note to editors: The abstract of the paper follows.

“Management alternatives for climate-smart agriculture at two long-term agricultural research sites in the U.S.: A model ensemble case study”

Authors: Ellen D. v. L. Maas, Emory University and Debjani Sihi, North Carolina State University

Published: Sept. 5, 2025 in Agronomy Journal

DOI: 10.1002/agj2.70146

Abstract: Greenhouse gas (GHG) emissions reduction efforts are underway to mitigate climate change worldwide. Climate-smart agriculture (CSA) practices have been shown to both increase soil organic carbon (SOC) inputs and reduce net greenhouse gas emissions (GHGnet). We evaluated the GHGnet of several management practices with three biogeochemical models (APSIM, Daycent, and RothC) at two sites with contrasting soils, climates, and cropping systems. Additionally, two future climate scenarios (baseline and high-emissions) provided alternative outcomes of SOC, N2O, and CH4 by 2050. In Michigan, most biochar and residue retention with no-till treatments increased SOC stocks; leguminous cover crops, no-till, and reducing fertilizer input lowered N2O emissions. The lowest biochar treatment lowered GHGnet in the baseline climate scenario, but all other management treatments increased GHGnet under both baseline and high emissions, and all management scenarios increased a mean of 8.0 Mg CO2-equivalent GHG (CO2e) ha?1 from baseline to high emissions. Conversely, in Texas, most treatments increased SOC, and N2O was relatively constant. Every no-till treatment reversed GHGnet in both the baseline and high-emissions climate scenarios but all management scenarios increased a mean of 0.6 Mg CO2e ha?1 under high emissions. At both sites under high-emissions climate change, cover crops and no-till resulted in the lowest GHGnet overall. Overall, the study showed that no-till, especially with residue retention, and cover crops are important CSA practices to lower the GHGnet of agriculture, but there remains much room to find even more effective solutions to adapt to climate change.