Although drylands are not intensive carbon sinks, their vast extent (>40% of global land area) makes them globally significant in the carbon cycle, with biocrusts – the “living skin of the drylands” – accounting for 5% of total global carbon fixation. Very little work has assessed the carbon sequestration potential of restored biocrusts; with the support of the CO2 Foundation, the DIRT Lab team at Northern Arizona University aims to change this.

DIRT Lab’s goal is to heal the living skin of the drylands by restoring the thin, protective and biologically-rich layer on dryland soil surfaces made by tiny plants and microbes which protect the soil from erosion, dictate the water supply, store fertility, and draw CO2 from the atmosphere. Without these biocrusts, drylands are degraded, shedding resources and less able to provide a healthy life support system for people. DIRT Lab farms biocrusts so they can be added back where they are lost, restoring photosynthesis to the soil surface and boosting carbon storage in dry ecosystems. But by how much?

Dr. Matthew Bowker leads the team that is seeking to understand the potential of biocrust restoration to serve as an effective carbon removal approach while also mitigating societal risks due to fire. In this novel drawdown technique, suitable for water-limited ecosystems, biocrust “sods” are farmed in thin soil layers over biodegradable plant-derived fabrics and applied to degraded drylands, where they maintain themselves and store carbon – fast-tracking biocrust growth to months (compared to natural rates of years to decades). Sod variations are optimized for native plant growth or excluding flammable weeds, determined by site conditions and restoration goals, increasing the residence time of carbon in drylands by reducing wildfire risk.

DIRT Lab’s restoration work is already occurring at a sod farm and a handful of 2-6 year old experimental application sites across the southwest US, in settings including vehicle tracks, burned areas, solar installations, and overgrazed rangelands. These test plots are pursuing landscape-scale impacts through strategic small-area treatment: creating fire breaks that constrain exotic-grass fueled wildfires, lengthening carbon residence time, and serving as “restoration islands” from which productive biocrusts spread, improving ecosystem carbon cycling.

But beneficial uses for biocrust restoration and sods are not confined to desert wildlands. They could be incorporated into green roofs to boost biodiversity and dampen unwanted runoff and cool the human environment; used to protect and conserve cultural sites and objects, like earthen sections of the Great Wall of China; immobilize pollutant metals and plausibly reclaim brownfields; provide an alternative water-smart cover crop in agricultural field; and help keep wildfire out of the wildland-urban interface. All of these examples produce benefits for society in natural systems, agro-ecosystems or the built environment while conferring the ability to a surface to draw down carbon.

During this research period, the team will extend experimental monitoring to understand longer-term fate of biocrust-fixed carbon, and how sod use could be expanded to new settings, ultimately building public capacity for carbon dioxide removal (CDR). Methods are transferable to communities for local-scale production, application, citizen science, education or pioneering new uses in the built environment; future users may include land managers (public or private), policymakers, ecological engineers and even urban planners, landscape architects, and farmers. As the research yields results, the team will help leverage that knowledge to do effective climate action and transfer knowledge so that it can catalyze community climate resilience.

DIRT Lab operates under the guiding principle “Humans welcome: diversity is strength;” the researchers’ guiding principles include: the goal of science is the truth, minimize environmental degradation, science is for the people (not just scientists), and collaboration not competition. The lab will publish its results in peer-reviewed scientific publications as well as non-technical, accessible resources like its biocrust restoration manual. The team ultimately hopes to launch a non-profit service lab that produces biocrust sods for various users.