Smallholders in sub-Saharan Africa learn biochar production to boost soil health

Mr. David W. Kpogbeh, a farmer from Grand Bassa, Liberia, grabs a handful of a black flaky material and stirs it into the soil. “This is how we apply biochar,” he explains. “We get heavy rainfalls here in Liberia and have sandy soils. So by applying this biochar, we can ensure that our crops get the nutrients and water they need rather than having it all wash away.”

Smallholder farmers, like David, in seven sub-Saharan African countries are learning how to make and apply biochar. The RESADE project of the International Center for Biosaline Agriculture (ICBA) has been conducting a series of farmer field schools to explain how biochar can help farmers increase the production in their fields and how they can make and apply it.

“Biochar is a carbon-rich material that can be used as a soil conditioner and as a means to sequester carbon in the soils,” said Dr. Ahmed H. El-Naggar, a soil management scientist at ICBA. “As soils across sub-Saharan Africa become more degraded due to nutrient and organic matter losses, rising salinity, drought and desertification, we need to develop special management practices to conserve water, improve soil properties, and prevent nutrient loss.”

Smallholder farmers now have a sustainable way to enhance soil health using biochar, which they can produce from locally sourced farm waste and biomass. By fabricating simple and affordable units, they can induce a process called pyrolysis, which heats biomass in an oxygen-limited environment. This method carbonizes the material and creates a stable form of carbon that resists breakdown.

“This biochar acts as a carbon repository, sequestering carbon from decomposed plant material and contributing significantly to climate change mitigation,” said Dr. Ahmed H. El-Naggar. “Additionally, its use as a soil amendment is revolutionary. It protects the soils from degradation and enriches it by bolstering nutrient and water retention, essential factors for healthy crop growth.”

Under the five-year project titled “Improving Agricultural Resilience to Salinity through Development and Promotion of Pro-poor Technologies” (RESADE), ICBA is working with national agricultural research systems in Botswana, The Gambia, Liberia, Mozambique, Namibia, Sierra Leone, and Togo to improve agricultural production and productivity and increase incomes of farming communities in salt-affected agricultural areas. One of RESADE’s activities is to conduct farmer field schools about biochar.

RESADE is implemented in partnership with the International Fund for Agricultural Development (IFAD) and the Arab Bank for Economic Development in Africa (BADEA).

In many areas across West and Southern Africa, soils are characterized by carbon losses and a coarse texture, resulting in inherently low capacities for water and nutrient retention. This leads to challenges in agriculture, especially under conditions of frequent irrigation or high precipitation rates, which intensify issues such as nutrient leaching, depletion, and groundwater contamination. The region’s hot climate coupled with periodic rainfall further emphasizes the urgent need for methods to conserve water, enhance soil properties, and reduce nutrient loss.

“Our research has shown a significant increase in crop biomass when biochar is applied to sandy soils,” said Dr. Ahmed H. El-Naggar. “In a recent study conducted at ICBA’s research station, we observed a remarkable 23 to 35% increase in alfalfa biomass yield over the control, a result of integrating biochar into the soil.”

Biochar application has been found to lessen the adverse effects on yield typically seen with irrigation using saline water. “The improved plant tolerance to salinity is linked to the enhancement of soil’s physical and chemical properties by biochar,” explained Dr. Ahmed H. El-Naggar.

Moreover, studies at ICBA highlight biochar’s role in boosting soil water availability. “Our findings indicate that an application of biochar at 20 and 30 tonnes per hectare can increase the soil’s available water content by 16% and 40%, respectively, compared to untreated soils,” said Dr. Ahmed H. El-Naggar. “This significant improvement in soil moisture retention will help farmers optimize water use, particularly in regions facing water scarcity.”

The RESADE project has conducted research that suggests that biochar is a highly effective soil amendment in various countries such as Togo and Sierra Leone. “Biochar has been shown to boost crop growth, promote early maturity, increase grain yields and biomass in the RESADE countries,” said Dr. Zied Hammami, an agronomist at ICBA working on the RESADE project. “Furthermore, during dry seasons, the application of biochar has been found to significantly increase the germination rate of sorghum by 25% and pearl millet by 62.5% when irrigated with slightly saline water in The Gambia.”

The farmers of the seven countries where RESADE is working have eagerly adopted the technology. Farmers like David have become champions of biochar and are sharing their biochar experience with others in the hope that the soils in their country will once again be fertile.