Biochar Farming for Soil Amendment and Sustainable Energy in Africa

The increasing population of many African countries, the continuous depletion of the soil in African farmlands, food and energy shortage in the continent has necessitated the adoption of sustainable agricultural technologies that can solve these problems.

Biochar technology can be used to increase food security and cropland diversity in areas with severely depleted soils, scarce organic resources, and inadequate water and chemical fertilizer supplies.

In addition to creating a soil enhancer, sustainable biochar practices can produce oil and gas by-products that can be used as fuel, providing clean and renewable energy.

The addition of biochar to soil has been found to accelerate the mineralization of the existing soil organic matter and enhance agricultural productivity.

It has been found to be more effective than other organic matters in retaining nutrients and keeping them available to plants as observed with phosphorus which is not retained by normal soil organic matter, and has increased yields of a range of crops of up to 324%.

It is more important as a conditioner and driver of nutrient transformations and less as a primary source of nutrients. It improves water quality and quantity in soil by increasing soil retention of nutrients and agrochemicals for plant and crop utilization, enabling more nutrients to stay in the soil instead of leaching into groundwater and causing pollution.

This 2,000-year-old practice can be used to improve the life of by smallholder farmers in Africa if they are empowered to be able to turn their agricultural waste into a soil enhancer and energy.

Biochar, which is a fine-grained, highly porous type charcoal is made in the same manner as other charcoal by heating biomass in the absence or under limited oxygen, in a process called pyrolysis or gasification; but unlike charcoal which is a fuel that is used for cooking and other heat generating applications biochar is intended for utilization as a soil amendment.

Basically, the key is the end use of the material. It is common charcoal if it is intended to be used as a fuel; hence it is manufactured with optimal fuel properties. In contrast, if the intended use is as a soil amendment, then its soil nutrient improving properties are optimized.

Biochar is not oxidized by soil micro-organisms as compared with charcoal which eventually is degraded by soil microbes to carbon dioxide. The chemical structure of biochar is characterized by the presence of poly-condensed aromatic moieties that are responsible for its stability against microbial degradation.

In addition to creating a soil enhancer, sustainable biochar practices can produce oil and gas by-products that can be used as fuel, providing clean and renewable energy.

Agricultural waste typically worthless but costly to get rid of, is now a valuable resource for biochar production. Depending on size and capacity of the pyrolysis furnace, heat and power are generated and available as an alternative clean energy source for family-sized residential, commercial, industrial and community applications.

Biochar is not the only valuable bio energy and bio-products produced during pyrolysis.  The process burns or captures all of the emissions better known as air pollution and greenhouse gases and typically associated with burning biomass. Volatile gases (methane, carbon monoxide and other combustible gases) and other hydrocarbons are captured and condensed into liquid bio-fuels that can be used for energy production.

The technology can also be used to reduce carbon emissions for the carbon in biochar resists degradation so can hold carbon in soils for hundreds to thousands of years. Biochar and bio-energy co-production can help combat global climate change by displacing fossil fuel use and by sequestering carbon in stable soil carbon pools.

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