In some areas of the African continent a severe environmental problem is deforestation and land degradation resulting in changes in rural land vegetation cover. These two issues overlap because, while forested areas are typically converted into agricultural lands, the latter are subsequently degraded due to poor agricultural practices. The impacts of climate change are critical for agriculture as rising temperatures, changing rainfall patterns and increased pests and diseases expose the food systems to new and bigger risks and make food security and poverty reduction in Africa a major challenge for the future. They threat the integrity of the environment and cause the loss of biodiversity, thus endangering the health of the ecosystem and the lives and livelihoods of people who depend on it.
Climate-Smart Agriculture represents an approach for transforming and reorienting agricultural systems in Africa to support food security under the new challenges posed by climate change.
Biochar is an option for Climate-Smart Agriculture as it provides a unique opportunity to improve soil fertility and increase nutrients use efficiency in the long term. When applied to soil, biochar remains for a long time, and single applications may provide benefits over many and many years. The conversion of plant residues to char was discovered in ancient land of the Brazilian Amazon region. These dark earths (terra preta de índio) form an out of place patch of fertility in an otherwise harsh environment. This practice is not alien in West Africa, since an ancient system identified as “African dark earth”, similar to Terra Preta, was discovered. This proves the existence of a climate-smart indigenous African agricultural soil enrichment system, which enduringly transformed yellowish and red infertile and carbon-poor soils into highly fertile and carbon-rich dark earths. Incorporating biochar into soil is an ancient practice used by the natives to improve soil productivity. Nowadays, research is exploring the reasons why and the conditions upon which the biochar offers such positive results in soil management systems. Studies are now confirming the benefits of biochar application, including the following:
- Reduced leaching of nitrogen into ground water;
- Decrease of nitrous oxide and methane emissions from soils;
- Increased cation exchange capacity (CEC);
- Moderation of soil acidity;
- Enhancement of water retention, filtration and infiltration;
- Increased abundance and diversity of beneficial soil microbes.
Biochar application to soil is recognized as a good practice to enhance soil productivity and contribute to address the food security issue, thus addressing UN SDG 2 “Zero hunger”. Observations under different climates have shown that a single application of approximately 10 tonnes of biochar per hectare can increase crop productivity to levels that range from 50 to 200%, depending on soil, climate and crops. When biochar is used as a soil amendment, the application rates of fertilizers such as compost, manures or mineral fertilizers can be reduced, and this is very interesting when there is a poor access to fertilizers.