Creating Biochar to Sequester Carbon and Fertilize Plants
The slash-and-burn agriculture technique grows food whereby forested land is clear-cut, and any vegetation is burned. The resulting layer of ash from the burnt vegetation provides a newly cleared land with a nutrient-rich layer that helps fertilize crops. Traditionally, the area was left fallow and reverted to a secondary forest of bush. Cultivation would then shift to a new plot.
Unfortunately, as we’ve shifted towards a fast-past world, these techniques are deemed harmful to the environment as modern slash-and-burn techniques are a significant source of carbon dioxide emissions, especially when used to initiate permanent deforestation. Moreover, many of these plots do not get replanted.
On a smaller scale, farmers are turning to create biochar to sequester carbon emissions and aid in growing their crops. Biochar is similar to slash-and-burn techniques, except it is created artificially through a process called pyrolysis. It is made when biomass, such as fallen tree branches and crop residue, is heated at 200-400°C with little or no oxygen.
Various types of biomass have been used on a commercial scale to produce biochar. This includes agricultural and forestry by-products (such as straw or tree bark), industrial by-products (such as paper sludge and pulp), animal wastes (such as chicken litter) and sewage sludge. Converting biomass to biochar offers an excellent method for reducing waste and using these by-products.
This process decomposes the organic waste into a solid residue of carbon. Farmers can apply it to the field where around 50 percent of the carbon is stored in stable forms as a soil additive to improve drainage, aeration, plant health, crop yield, and water and nutrient retention. Biochar helps process things that settle on it, such as soil’s water and nutrients that the plants can access when needed. Biochar can also absorb heavy metals, reducing the plants’ risk of accessing them.
There are a number of ways that small farmers can use biochar to sequester carbon:
- Incorporate it into their soil: Biochar to sequester carbon can be added as a soil amendment. This can be done by broadcasting it on the soil’s surface or by mixing it into the soil.
- Use it as a fertilizer: Biochar can be used as a fertilizer by mixing it with compost or other organic materials. This can help to improve the nutrient content of the soil and increase crop yields.
- Use it to produce energy: Biochar can be used to produce energy by burning it in a stove or furnace. This can provide farmers with a renewable source of energy.
This process reduces emissions from organic waste that is burned or left to decompose, producing greenhouse gases. Studies have shown that only about 10 to 20 percent of the residue carbon is recycled into the soil when crop residue is left to decompose on its own.
Biochar increases soil fertility more than simple plant matter and reduces nutrients from leaching from the crop root zone, meaning they would have to use less chemical fertilizers to grow their crops. Using biochar to sequester carbon will also benefit farmers who cannot afford to buy fertilizers or invest in organic cultivation techniques that take a long time to establish. It also helps establish independence among smaller farmers as they would not have to depend on chemical fertilizer companies.
Creating biochar to sequester carbon is a sustainable way to fertilize plants and actively remove carbon from the atmosphere. According to the IPCC, biochar is one of the safest, most durable ways to remove carbon from the atmosphere. It helps create nutrient levels in the soil that are more stable and resistant to environmental degradation. This allows farmers to save money and resources, reducing their environmental impact.