Soil organic carbon assessments can be used to guide agricultural practices that promote soil health, help mitigate climate change and boost the livelihoods of farmers across the world.
Background
Agriculture is responsible for over 30% of global greenhouse gas emissions. Regenerative agricultural practices such as no-till farming, rotational grazing and mixed crop rotation have the potential to reduce emissions by 4.3-6.9 billion tons/year by sequestering carbon dioxide in soil. This would also improve soil health – an estimated 40% of soils are degraded worldwide – and boost ecosystem services vital to the livelihoods of vast numbers of people dependent on farming. This win-win scenario can be achieved by measuring and monitoring soil carbon levels in order to prioritize and quantify the impact of good agricultural practices.
WLE innovation
WLE’s support for the development and uptake of methodologies for soil spectral analysis has enabled the collection and analysis of soil samples on a massive scale. This has generated baseline data for a holistic overview of soil health centered on soil organic carbon (SOC). This process of monitoring allows an assessment of how agricultural practices affect soil health, and quantifies how soil health varies across landscapes. In turn, this helps prioritize interventions to improve soil health for the benefit of farmers and for climate mitigation, aligning with global carbon sequestration initiatives such as 4 per 1000. It has been estimated that the sequestration potential of increased SOC stocks is between 0.9 to 1.85 gigatons of carbon annually. Results vary, however, with some researchers finding SOC release rates reduced rather than reversed altogether.
WLE supported the development of the open-access Soil Organic Carbon App, which calculates a soil profile’s ability to sequester carbon, as well as the Global Soil Data Manager and the SOC Dashboard. These tools allow decision makers to assess the impact of planned climate mitigation interventions on soil health. However, the success of management practices to improve soil health depends on how they are implemented by both women and men farmers. WLE research has thus also focused on the importance of accounting for the influence of gender dynamics on the adoption of good agricultural practices.
Impact
WLE-led recommendations on SOC estimation and sequestration have been incorporated in a report by the United Nations Conference on Combating Desertification to help achieve its land degradation neutrality targets, which 122 countries have committed to. Moreover, WLE research that informed the development of a decision analysis framework to support improved planning and monitoring of land restoration initiatives has been adopted by several county governments in Kenya, while a pilot project based on the framework has been initiated in Ethiopia. WLE’s land restoration assessment and soil health mapping and monitoring tools are now being applied in a growing number of African countries.
Challenges
While there is strong scientific consensus on the positive impact of best management practices in agriculture, adoption can be constrained by a lack of supporting policy, the continued emphasis on SOC-reducing productivity, poor dissemination of knowledge to farmers and the initial costs of some practices. The capacity of countries to monitor SOC remains limited, and the long-term trials essential to the development of a multi-faceted understanding of carbon sequestration across time and space are not yet established.
Next steps
With multiple global initiatives dedicated to land degradation neutrality through best management practices, the opportunity to improve soil health monitoring has never been as favorable as it is today. It is essential that countries be supported to fulfil their commitments, including through a unified reporting framework. National policies, too, should expand funding for mapping and modelling while incentivizing farmers to adopt practices favorable to carbon sequestration.
The concept of soil health, as expressed through robust SOC levels, needs to be understood as a physical, biological and chemical totality. It is literally the ground on which we walk – a treasure-house that sustains us rather than a resource to be exploited. Equally, WLE research demonstrates that sequestration is much more than a mechanical means to draw carbon out of the atmosphere. As a boost to soil health and a public good, application depends on the commitment of those working the land, and decision makers should factor this into restoration initiatives.
