Biochar and Regenerative Agriculture
One exciting way to improve soil health involves a charcoal made from excess crop residues. Let’s dive into biochar to understand why it’s such an important topic in regenerative agriculture.
Biochar 101
Biochar is essentially the charred embers left behind when biomass is burned at high temperatures with little to no oxygen in a process known as pyrolysis. The result is a “highly porous, stable, carbon-rich material,” which looks a lot like charcoal. This sturdy material can sequester carbon for hundreds of years and can be applied to agricultural or forested lands to boost soil health and produce a wide range of beneficial outcomes. Biochar is gaining popularity as a modern climate solution, but the practice can actually be traced back at least 2,000 years to Indigenous Amazonian societies. Burying smoldering biomass helped to enrich the relatively infertile soils of the Amazon basin, leaving behind “Terra Preta,” dark, productive soils that supported civilizations for thousands of years. Similar forms of biochar have long been used in many societies across the world, including in early Japanese agriculture and Indigenous North American fire management practices.
Biochar can be produced from many organic materials, or “feedstocks”, which would have otherwise decayed naturally or burned outdoors, releasing carbon into the atmosphere. Feedstocks can be sourced from crop residues (such as wheat straw), orchard trimmings, or even animal manure. With these waste materials, biochar production facilities can produce useful soil additives while reducing emissions from biomass collection programs (such as a composting and yard waste collection). The pyrolysis process and the type of feedstock will determine the properties of the biochar that is produced, such as its ability to store carbon, enrich soils, and aid plant growth.
Biochar and Climate
Because of its high stable carbon content (around 70%), biochar is a promising way to sequester carbon underground rather than letting it return to the atmosphere. Several recent studies have supported what Terra Preta suggested: that most of the carbon stored in biochar can stay in soils for hundreds or even thousands of years, which could help mitigate climate change. However, the way that biochar is produced has an impact on whether production represents a net environmental gain. Kilns and gasifiers without pollution control devices may emit excess soot and methane, overwhelming the climate benefits of the preserved carbon in the biochar. Biochar production systems also work best when they serve local producers, avoiding the emissions of transporting biomass over long distances or production of “purpose-grown” crops planted solely to be transformed to biochar. Because of these nuanced factors, Life-Cycle Assessments (LCAs) are an important tool to help biochar producers follow emerging quality standards and ensure positive impacts.
Biochar and Agriculture
Biochar fits nicely into regenerative agriculture because it enriches soils and can be produced using farm or forest waste instead of dedicated crops. When applied to soil, biochar can have a plethora of benefits such as reducing the need for synthetic fertilizers, increasing soil organic carbon (SOC) content, restoring degraded lands, holding nutrients and moisture, preventing runoff, suppressing wildfires, and promoting healthy fungal and microbial activity. These benefits can boost crop yields and help prevent surrounding ecosystems from harm. Biochar production is also eligible for carbon credits under the puro.earth reserve; this value stream could help build reciprocal systems where farms can provide waste biomass to producers whose costs are subsidized and who can in turn make affordable biochar additives available to farmers.
The bottom line: Biochar is just one among many important practices in the regenerative agriculture toolkit. When produced responsibly, it’s a strategy that could help mitigate climate change by sequestering carbon, and its numerous agricultural co-benefits should not be overlooked!