麻豆淫院

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鈥攍ike no-till treatments, cover-crop utilization and residue retention鈥攃an help promote carbon sequestration in soil and reduce greenhouse gas emissions.

in Agronomy Journal, the findings show that using a combination of models鈥攔ather than just one鈥攃an 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鈥攚ith different climates, soils and crops grown," said Debjani Sihi, the senior author of a paper describing the research and a member of NC State's Plant Sciences Initiative. "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鈥攐r world鈥攖o better generalize effects."