Increased plant diversity improves soil carbon sequestration

Increasing plant diversity in agricultural practices can enhance the carbon storage capacity of soils, according to recent research. How the agricultural sector is trying to reduce its carbon footprint, the implementation of wider biodiversity may be the key to more sustainable and climate-friendly food production. With the continued expansion of agriculture and intensive practices that degrade soil and release carbon into the atmosphere, it is imperative to find ways to increase carbon storage. With over 40 % of the world's land used for agriculture, it is important that agroecosystems play a leading role in mitigating climate change.

Although agreement on plant-microbe interactions has so far been limited, a team of researchers led by Luiz Domeignoz-Horta of the University of Zurich has discovered that increasing plant diversity in agriculture can significantly improve soil's ability to store carbon.

Barley together with other types of plants

In Finland, through the TwinWin experiment, the team investigated how different levels of plant diversity combined with barley affect microbial processes. Barley has been grown with up to eight other plant species, including those that fix nitrogen and have deep roots, improving soil health. The efficiency of microbial carbon utilization was measured as an indicator of the ability of microbes to convert carbon into new biomass without releasing it in the form of CO₂. The researchers tracked the movement of carbon in the soil through molecular sequencing and stable isotope tracking.

"We found that greater plant diversity strengthened positive interactions between microbes in the rhizosphere, leading to better carbon utilization efficiency," explained Luiz Domeignoz-Horta.

Improvement of plant biomass

Plant diversity also increased plant biomass production without negatively affecting barley yield, making it a practical method to maintain productivity while improving soil carbon sequestration. These results highlight the importance of plant diversity in influencing soil microbial life, promoting healthier and more resilient ecosystems and providing a sustainable method of carbon sequestration in agriculture.

"Implementing plant diversity is challenging, especially for small farmers," admits Domeignoz-Horta. “However, with the right policy support, growing diverse crops could make a significant contribution to 'carbon farming', (CO2AI)