Land management could make Africa a carbon sink

Cattle farmers are potentially sitting on a carbon sink gold mine. Large areas covered with grass, especially used for animal grazing, can boost the capacity of soils as carbon sinks and help countries reach their climate goals, according to a new report by the Food and Agriculture Organization of the United Nations (FAO).

After oceans, soils are the secondlargest carbon pool on earth and play an important role in global climate change due to the large amount of carbon stored in soil organic matter. By improving management practices in grasslands, farmers can boost the carbon sequestration ability of their soils.

The first FAO global assessment of soil carbon in grasslands measured the baseline of stocks of soil organic carbon (SOC) in both semi-natural and managed grasslands and estimated their potential of SOC sequestration. (SOC is the carbon held within the soil that is measurable, and is expressed as a percentage by weight (gC/kg soil.))

The study found that if the SOC content in the first 30cm layer of grasslands increased by 0,3% after 20 years of favourable management practices, 0,3t/C/ha/year could be sequestered.

Thanawat Tiensin, director of FAO’s Animal Production and Health division, said that the research was key in understanding the benefits of grassland services for food security, biodiversity conservation and climate change mitigation.

“Estimates of global soil carbon stock are still quite uncertain, however. To improve the accuracy of input data, such as soil, animal and vegetation properties, and C exchange information, it’s crucial to generate local datasets, especially from underrepresented regions like Africa, and explore differences among existing datasets.”

The report showed that Africa south of the equator had a negative carbon balance, meaning that current SOC stocks were likely to be decreasing due to human activity stresses combined with climatic conditions. This trend could be reversed by stimulating plant growth, capturing carbon in the soil, and protecting carbon in highly organic soils, such as semi-natural (non-human-managed) grasslands.

In livestock management, this could mean implementing rotational, planned or adaptative grazing measures.

Sub-Saharan Africa and South Asia show the highest potential for carbon storage on a perhectare basis: 0,41t/C/Ȳha/Ȳyear and 0,33t/C/ha/year respectively.

Stressing the importance of the correct human interventions to increase carbon storage, Tiensin said: “Soils can act as both sources and sinks of carbon.” –