As the world grapples with the twin challenges of feeding a growing population and combating climate change, innovative solutions are urdgently needed in agriculture. In this context, perennial cropping systems are gaining attention for their higher root biomass input and reduced soil disturbance compared to annual crops, potentially addressing these pressing issues. A recent study conducted over nine years in Denmark sheds light on the benefits of perennial crops in enhancing soil carbon stock and biomass yield compared to traditional annual cropping systems.

The study revealed significant findings regarding the impact of perennial cropping systems on soil carbon (C) and nitrogen (N) stocks. Unlike annual cropping systems, which showed a decrease in topsoil C stocks, perennial systems exhibited a notable increase, highlighting their ability to enhance soil fertility and contribute to climate change mitigation“.

"Benefited from their biological traits, perennial crops have the unique ability to sequester carbon in the soil over the long term, which is instrumental in mitigating the greenhouse effect and combating climate change," PhD Student Yiwei Shang from the Department of Agroecology at Aarhus University explains. "Our findings highlight the transformative potential of these cropping systems in promoting green transition."

Sustainable biomass yield

The study also highlighted the comparable biomass yield of perennial crops like miscanthus and festulolium with annual crops like maize. The produced biomass can be processed into a spectrum of bio-based products, like food, feed, biofuels, fibers, etc. Additionally, perennial crops exhibited similar yield stability levels with annuals. These findings underscored the potential of perennial crops to sustain high productivity over time.

"The comparisons of biomass yield and yield stability are highly dependent on the species of selected crops, rather than on whether they are annuals or perennials," Yiwei Shang notes. "At least, our findings demonstrate that these perennial crops can sustain high levels of biomass production while enhancing soil C, offering a win-win solution for farmers and the environment."

Promising pathway to sustainable agriculture

By promoting perennial cropping systems, which enhance soil carbon stocks while maintaining high biomass yield and stability, farmers can adopt sustainable practices that mitigate climate change and ensure food security. According to Yiwei Shang, further research is needed to understand the mechanisms behind soil carbon sequestration in perennial cropping systems and explore the stability of soil organic carbon.

"As we confront the challenges of feeding a growing global population amidst climate uncertainty, the importance of sustainable agricultural practices cannot be overstated," he remarks. "Perennial cropping systems represent a promising strategy for enhancing food security and climate change mitigation."

In other words, perennial cropping systems offer a promising pathway towards sustainable climate-smart agriculture. As policymakers and stakeholders in the agricultural sector consider strategies for long-term food security and environmental sustainability, the adoption of perennial crops may be one way to go.