INTA research found that production systems incorporating the perennial crop accumulated 25% more soil organic carbon than continuous cropping systems.
Researchers from INTA San Luis and local producers are studying how perennial crops could build soil carbon reserves in the central semiarid region of Argentina, where limited rainfall and sandy soils constrain crop production.
Juan Cruz Colazo, a researcher at INTA San Luis, says agricultural systems can partially offset their emissions by removing carbon dioxide from the atmosphere and storing it within the soil profile, according to a press release.
Field assessments conducted on sandy soils near Villa Mercedes identified alfalfa as a potentially important crop for increasing long-term carbon storage.
“After several measurement cycles, the systems that include these perennial pastures accumulate 25% more organic carbon in the soil compared to continuous agriculture approaches,” Colazo said and added: “This would be due to the greater contribution of their roots, both in depth and in time.”
Deep Roots Support Carbon Storage
As a perennial crop, alfalfa maintains its root system for longer than annual crops and contributes plant material at greater soil depths. Researchers believe these root characteristics are responsible for the higher soil organic carbon levels recorded in diversified production systems.
The work suggests that integrating alfalfa into crop rotations could help producers improve soil health and strengthen the resilience of farming systems exposed to water scarcity and environmental variability.
Nitrous Oxide Emissions Remain Low
Maria Laura Guzmán, a researcher at INTA San Luis, reported that nitrous oxide emissions remained low, with no significant differences among the production systems evaluated.
Researchers attributed these results to the region’s dry conditions, which limit the soil microbial processes responsible for producing and releasing nitrous oxide.
“The integration of alfalfa under the principles of climate-intelligent agriculture allows the transformation of semi-arid production systems into carbon sinks, achieving greater resilience to environmental variability and guaranteeing the conservation of the soil resource in the long term,” Colazo pondered.
