What is Biochar and How Does It Work

What is Biochar and How Does it Work

Biochar is fine-grained charcoal made by pyrolysis (pī-rä’-la-sis), the process of heating biomass (wood, manure, crop residues, solid waste, etc.) with limited to no oxygen in a specially designed furnace capturing all emissions, gases, and oils for reuse as energy.

Biochar has been used in agriculture for more than 2,500 years and is becoming increasingly popular in modern agriculture and horticulture as a safe, sustainable soil amendment. 

Biochar outshines all other organic soil material in its ability to attract and retain water and nutrients, as well as hold phosphorous and agrochemicals. Plants are healthier and less fertilizer runs off into surface water and leaches into groundwater.

This is the microscopic view of (biochar) charcoal porous characteristics. These pores are responsible for retaining water, micronutrients, and a very natural habitat for microorganisms.

Biochar is relatively inert and therefore persists in soil far longer than any other organic soil additives. Because biochar lasts 100's thousands of years, its benefits of nutrient and water retention and overall soil porosity keep working, unlike common fertilizers and conditioners.

When added to soil, biochar improves plant growth and crop yields while reducing the total fertilizer required. Nitrous oxide (N2O), a greenhouse gas, released from certain fertilizers is 310 times more potent than carbon dioxide CO2. Biochar-conditioned soils reduce N2O off-gassing by 50-80%. 

Biochar approach 47 allows the agricultural industry to reduce its carbon footprint by storing pyrolyzed biomass in soil 48 with an estimated residence time ranging from 5-29 years to 1,300-2,600 years depending on references cited 3, 4 49. In addition, there are other benefits from the study of biochar properties. For 50 examples, biochar is a by-product of biofuel production and mechanistic knowledge of biochar 51 formations can be invaluable in understanding the chemical pathways of biofuel production. 

Biochar Mitigates Climate Change

Decaying or burning biomass releases CO2 into the atmosphere and plants reabsorb it; this active carbon cycle has been in balance for millennia. Burning fossil fuels puts excessive CO2 into the air, more than can be absorbed naturally. This traps heat in the Earth’s atmosphere. Reducing atmospheric CO2 is critical to combat climate change. 

Burning biomass through pyrolysis to produce energy (heat and power) instead of burning fossil fuels is a carbon-neutral process; it neither adds to the climate-change problem nor reverses it.

Biochar retains approximately 50% of the carbon from the raw biomass. When applied to soil, it sequesters that carbon for centuries, reducing the overall amount of atmospheric CO2 by removing it from the active cycle. Biochar also enhances plant growth which, in turn, absorbs more CO2 from the atmosphere. Overall, these benefits make the biochar process carbon negative when biomass production is managed sustainably. 

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