New Paper Points to Soil Pore Structure as Key to Carbon Storage

The findings reveal the importance of soil pore structure for stimulating soil carbon accumulation and protection. (Image: via pixabay / CC0 1.0)

Alexandra Kravchenko, Michigan State University professor in the Department of Plant, Soil and Microbial Sciences, and several of her colleagues recently discovered a new mechanism determining how carbon storage in soils takes place that could improve the climate resilience of cropping systems and also reduce their carbon footprints.

The findings, published in the scientific journal Nature Communications, reveal the importance of soil pore structure for stimulating soil carbon accumulation and protection. Phil Robertson, University Distinguished Professor of Plant, Soil and Microbial Sciences, and a co-author of the study, said:

The study was conducted through the MSU Great Lakes Bioenergy Research Center, funded by the U.S. Department of Energy, and the Kellogg Biological Station Long-term Ecological Research program funded by the National Science Foundation, or NSF, and it was supported by NSF’s Division of Earth Sciences.

Over a period of nine years, researchers studied five different cropping systems in a replicated field experiment in southwest Michigan. Of the five cropping systems, only the two with high plant diversity resulted in higher levels of soil carbon.

Kravchenko and her colleagues used X-ray micro-tomography and micro-scale enzyme mapping to show how pore structures affect microbial activity and carbon protection in these systems, and how plant diversity then impacts the development of soil pores conducive to greater carbon storage.

John Schade, from the NSF Division of Environmental Biology, said the results may transform the understanding of how carbon and climate can interact in plant and soil microbial communities:

Kravchenko added:

Stable carbon storage is the result of microbes

Scientists have traditionally believed soil aggregates, clusters of soil particles, were the principal locations for stable carbon storage. Recent evidence, however, shows that most stable carbon appears to be the result of microbes producing organic compounds that are then adsorbed onto soil mineral particles. The research further reveals that soil pores created by root systems provide an ideal habitat where this carbon storage can occur.

Of particular importance are soils from ecosystems with higher plant diversity. Soils from restored prairie ecosystems, with many different plant species, had many more pores of the right size for stable carbon storage than did a pure stand of switchgrass. Kravchenko said:

Robertson said the research may prompt farmers to focus on plant diversity when attempting to increase soil carbon storage:

Nick Haddad, director of the Kellogg Biological Station Long-term Ecological Research program, said research that builds from these findings will continue to discover ways to improve the sustainability of agricultural ecosystems and landscapes. Haddad added

Provided by: Justin Whitmore, Michigan State University [Note: Materials may be edited for content and length.]

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