Soil health indicators in FMNR restoration practice

By SPACIAL | CIFOR-ICRAF

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15 April 2026

Soil health broadly refers to the capacity of soils to support plants, animals, and human beings by sustaining key ecological functions like nutrient cycling, vegetation growth, water retention, carbon storage and resilience to climate extremes.

We might refer to landscapes with poor soil health as degraded. That is - the soil’s functional capacity is impaired, leading to poor yields, limited water retention, and greater exposure to climate extremes.

When implementing restoration projects in degraded areas, we should aim to repair soil functional capacity, not just regreen the land. This can be a complex task however, and requires having a good understanding of local ecological conditions and social dynamics. So, how do we measure something so complex?

Two key indicators: SOC and erosion

There are many different kinds of indicators that can be used to assess soil health, from pH, total nitrogen, CEC, and infiltration capacity, to presence of pollutants or pathogens. Two important indicators that are often used as proxies for soil fertility and climate mitigative and adaptive potential are soil organic carbon and erosion.

Soil Organic Carbon (SOC)
SOC can be a key proxy indicator for soil fertility. It can improve water retention, nutrient availability, and microbial activity. More organic carbon generally means healthier soils, and acts as a stable reservoir of carbon for climate mitigation.

Erosion
Erosion is the loss of topsoil, the most fertile layer of soil, through wind and water. Even small increases in erosion prevalence can signal degradation of protective vegetation cover or other land management changes.

These indicators are two sides of the same coin. SOC shows what the land can store and support while erosion shows how much the land is losing. Together, they provide an idea of how land is functioning and whether it’s improving or degrading.

How do these indicators change over time?

We can examine trends in these indicators with data from a real-world restoration project.

Using data from the Regreening Africa restoration program (2017–2021), we can track SOC and erosion trends across six countries to understand whether restoration efforts are reversing degradation.

It should be noted that restoration under the Regreening Africa program was implemented at the farm-level, and data from these plots has been aggregated up to country level. For this case-study, we are looking at FMNR practice only.

SOC and erosion trends vary widely, not only between countries, but within them. Some regions show promising recovery, while others show minimal or indeed negative change, stuck in cycles of carbon loss and erosion. These patterns reflect both natural variation (climate, soils) and human management factors.

Understanding this variability is important for understanding what kinds of interventions are most effective and where. If we zoom into the Mopti and Sikasso regions in Mali, for example, we see substantial differences in soil response to intervention.

Mopti exhibits an overall loss of SOC (-2.0%), but a significant decrease in erosion (-24.5%). Sikasso on the other hand, had a slight increase in SOC (2.3%), and a near negligible impact on erosion levels (0.6%). Why two neighbouring regions exhibit such different results should be explored for adaptive management in future restoration efforts.

Trends in soil organic carbon (SOC)

SOC levels differed across the six countries between baseline and endline (2017 - 2021). Countries like Kenya and Ethiopia tended to start with higher SOC, while drier areas like Niger and Senegal began with much lower levels.

Of course, SOC accumulation is a long process and in some systems with naturally low biomass turnover (like drylands), changes are minimal over a five year monitoring window.

The changes we do see show that gains are uneven and in some places, like Senegal and Ghana, SOC even sees a decline. Where and why certain regions under restoration achieve greater SOC gains raises questions about site suitability, quality of intervention, or monitoring gaps.

Trends in erosion

Erosion change (2017 - 2021) was similarly mixed. In some locations, like Kenya and Ghana, erosion prevalence declined - a sign of improved vegetation cover or management. Elsewhere, erosion increased, suggesting ongoing land pressures and disturbances, or failed interventions.

Unlike SOC, erosion processes can happen very quickly, especially under major climate events like flooding or high-speed winds that accelerate loss of topsoil.

Some regions like Ethiopia and Senegal show substantial increases in erosion prevalence - a concerning trend and indicator of persistent land pressures and potentially climatic events, which could not have been mitigated by restoration activities.

Senegal in particular displays concerning trends of both SOC loss and increased erosion, suggesting that more targeted and intensive interventions are needed to mitigate degradation.

Why does this matter?

These findings highlight the need for high-resolution, high accuracy, multi-indicator project monitoring. By tracking changes in soil health, we get a much better understanding of how and why the landscape is changing. Useful proxies like SOC and erosion enable:

➜ Targeted interventions in areas most likely to respond

➜ Risk detection and early warning of where erosion or degradation persists

➜ Adaptive learning, where data feedback improves planning

For instance, areas that are highly responsive to restoration interventions, exhibiting strong SOC and erosion recovery from increased tree cover, might prove priority areas to scale restoration activities. Areas with little change or negative change might require more intensive or adapted restoration approaches like soil contouring or other erosion control measures before carbon recovery becomes possible.

Data-driven monitoring enables us to track landscape trends and guide adaptive management, funding priorities, and intervention design, leading to more effective long-term restoration outcomes. Understanding land health through multiple different indicators ensures projects truly restore ecosystem functioning and resilience.