New studies released by CIAT and partners show that, given the vast amount of carbon stored our soils, small management changes could have tremendous impacts, offsetting greenhouse gas emissions.
“We’re at the forefront of understanding how we can make the most of soils to remove carbon dioxide from the atmosphere,” said Rolf Sommer, principal soil scientist at CIAT Africa.
“But at the same time, we do need to be realistic about how much carbon our soils actually can store, and how much this would contribute to climate change mitigation.”
The five rapid assessments tested “climate-smart” soil protection and restoration practices across different farm types in Kenya, Ethiopia, Burkina Faso, India and Benin. They studied five different kinds of households, from poor female-headed households to large commercial ones.
The researchers added up the amount of calories of food produced on each farm, and GHGs emitted, comparing current with best-bet soil management techniques advocated by GIZ and development partners to sustain soil health, boost production, and improve farm resilience.
They found that, while farmers in these countries already contribute very few emissions to start with, in general, small farms emit higher quantities of GHGs per calorie of food produced compared with larger ones. They also found that livestock contribute more greenhouse gas emissions in these farming systems, especially when raised on low quality feed – the case in most smallholder systems in Africa.
While total quantities of emissions from smallholder systems pale in comparison with large commercial farms, small farms are also less efficient. At the same time, tilling the soil on a more regular basis, especially on smaller plots of land, accelerates the process of decomposing organic matter – required to move from net loss to net sinking carbon.
Room for improvement
“The bottom line is that we need more sophisticated management practices than the ones being advocated right now, because these don’t seem to sequester enough carbon – if any – to be able put a notable dent into global emission figures,” said Sommer.
“Using the best management practices available, we are still not talking sequestration yet. But whatever solutions we come up with for turning soils into carbon sinks, we must not forget that these solutions need to be compatible with the realities of farmers,” he added.
Beside carbon sequestration, management practices should boost farm productivity and efficiency without putting additional stress on farm resources, finances or workloads of men and women.
For Sommer, it’s a tall order to call on African smallholders to mitigate greenhouse gas emissions and build carbon in the soil when food security, drought and other challenges are looming.
“In smallholder farming systems in Africa, soil organic carbon sequestration is a co-benefit. In this context, we need to talk about avoiding carbon loss from agricultural soils – unfortunately currently, the best management practices we’re scientifically aware of merely slow those losses down.” he added.
Systems where soil tillage is reduced or even completely skipped over, and where significant amounts of organic matter – like crop residues, manure, or compost – are retained or returned to the soil have not yet been adopted by farmers large-scale, so soil carbon sinks are rarely found on smallholder farms.
Check in with realities on the farm
“We’re now studying what’s required to convince farmers otherwise. It may take only little incentives for a farmer to adopt soil conservation practices that significantly reduce losses of carbon from soils.”
On the other hand, research has shown that planting a few trees per hectare of agricultural land can sequester significant amounts of carbon. Likewise, drained or used peatlands lose massive amounts of carbon at a fast rate – so the bigger picture is important.
As an immediate next step, researchers are adding up the numbers, to find out how carbon loss from soils can be slowed down with the best management practices we have at hand – and what this mean in terms of climate change mitigation globally.
They are also investigating how to move towards actually sequestering carbon in soils, and how these measures compare with others like wetland conservation or afforestation for a bigger impact.
As scientists work to beat climate change, 500 experts from around the world will discuss protecting the largest carbon store we have: soils. The Global Symposium on Soil Organic Carbon (GSOC17) takes place in Rome March 21st – 23rd.
The Symposium will address, among other things, how farmers can adapt to climate change and mitigate – even decrease – harmful emissions, by making better use of soils.
This research, entitled: “Climate-smart soil protection and rehabilitation in Benin, Burkina Faso, Ethiopia, India and Kenya,” was led by CIAT with the financial support of the Federal Ministry for Economic Cooperation and Development. It was compiled together with colleagues from GIZ, national partners in the countries where the research took place, and the consultancy firm GOPA.
- Further research is needed to identify drivers of land use change at regional, national and sub-national scales, to develop policies to enhance carbon capture on agricultural land, benefiting farmers and communities.
- Ready-to-finance packages of best-bet land and soil conservation practices need to be improved, to highlight which practices are most appropriate to enhance soil organic carbon stocks in particular regions.
- Site-specific tools can be developed to present decision makers with the bigger picture of where soils are most degraded, and which areas should be prioritized for investment to improve soil carbon stocks.