How much carbon can Kenyan grasslands store in their soils? Insights from the CarboGrass Project

In Kenya, a team of researchers is working to assess the impact of grassland management on soil health, nutrient cycling, and carbon sequestration through a study forming part of the CarboGrass project that is investigating the health of grasslands and soils globally.

Grasslands are critical for ecosystem resilience, carbon storage, and combating the climate crisis.

As one of the largest ecosystems globally, grasslands also support diverse plant and animal species, sustain livestock, and provide livelihoods for millions of pastoralists and other livestock keepers.

At the same time, they face growing threats from overgrazing, urbanization, invasive species, and recurring severe droughts.

When grasslands degrade, the balance tips: soil loses its ability to retain carbon, leading to high greenhouse gas emissions.

Moreover, degraded soil cannot retain water well, leading to soil erosion and landslides, and making the grassland more susceptible to drought.

There is very little information on the carbon storage potential of dryland soils in African grasslands, and what role wildlife and livestock grazing play for their functioning.

This limits our ability to make recommendations to livestock keepers and land managers for maintaining soil health in these semi-arid rangelands.

Research solutions

Researchers are carefully measuring soil and vegetation characteristics in paired grassland sites inside and outside of protected areas, including the Kapiti Research Station and Wildlife Conservancy in Machakos, the Mukutan Conservancy in Laikipia, and Meru National Park in Meru, along their fence lines.

The protected grasslands have wildlife grazing but no or very little livestock grazing. They represent the ‘natural baseline’, a healthy ecosystem, where the densities of grazing animals (like zebras, wildebeest, and gazelles) are controlled by predators and stay within numbers that the land can sustain.

Communal grazing lands outside the protected area can show signs of overgrazing and degradation.

Samples from these areas show how soil health is being affected, and how much soil carbon is being lost.

This also indicates the natural carbon sequestration potential of the soil, or in other words, how much additional carbon the degraded lands could take up if they were restored back to their natural, healthy state.

Photo: Dorper and Red Maasai sheep at the ILRI Kapiti Research Station south of Nairobi (ILRI/Paul Karaimu)