Soil Organic Matter
Biochar
Biochar has received considerable scientific attention in the past decade as a possible method for carbon storage and increasing agricultural yields. Biochar is a charcoal-like material that is produced after the pyrolysis (thermal processing) of industry by-products, municipal wastes, and agricultural waste (agricultural and forest residues i.e., chaf, stover, bark, chips, and slash) at temperatures between 300 and 800 degrees C under no or low oxygen conditions. The feedstock type and pyrolysis conditions influence biochar physicochemical properties. During the process, the physical and chemical properties of the feedstocks change into a highly porous, stable, carbon-rich material known as biochar.
Potential Use of Biochar as an Amendment
Biochar enhances soil quality, increasing its moisture-holding capacity, pH, cation exchange capacity, crop yield, and encouraging the beneficial activity of fungi and microbes. In addition, it sequesters carbon from the atmosphere biosphere pool and transfers it to the soil. Biochar is rich in highly stable carbon (i.e., 98%), characterized by micro and macroporosity that decomposes more slowly than normal compost. Thus, the use of biochar in agriculture theoretically can improve plant growth.
Cost-Benefit in Using Biochar
The economic and environmental effects of making and using biochar depend on the source of the feedstock being converted to biochar, whether heat and gases produced in the process are utilized or just allowed to dissipate, the amount of available oxygen during biochar production, and the distance from where it is produced to the field where it is applied. Recent research suggests it has the potential to be used as a container substrate amendment in nursery and greenhouse production, and it may improve several soil and substrate physical, chemical, and biological properties. Currently, the prospect of using biochar to improve soils for growing cereals, fruits, and vegetables is limited given its high price point making biochar a poor investment option for farmers.
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