Biochar is defined simply as charcoal that is used for agricultural purposes. It created using a pyrolysis process, heating biomass in a low oxygen environment. Once the pyrolysis reaction has begun, it is self-sustaining, requiring no outside energy input. Byproducts of the process include syngas (H2 + CO), minor quantities of methane (CH4), tars, organic acids and excess heat.
Once it is produced, biochar is spread on agricultural fields and incorporated into the top layer of soil. Biochar has many agricultural benefits. It increases crop yields, sometimes substantially if the soil is in poor condition. It helps to prevent fertilizer runoff and leeching, allowing the use of less fertilizers and diminishing agricultural pollution to the surrounding environment. And it retains moisture, helping plants through periods of drought more easily. Most importantly, it replenishes exhausted or marginal soils with organic carbon and fosters the growth of soil microbes essential for nutrient absorption, particularly mycorrhizal fungi.
Studies have indicated that the carbon in biochar remains stable for millenia, providing a simple, sustainable means to sequester historic carbon emissions that is technologically feasible in developed or developing countries alike. The syngas and excess heat can be used directly or employed to produce a variety of biofuels.
When biochar is created from biomass, approximately 50% of the carbon that the plants absorbed as CO2 from the atmosphere is ?fixed? in the charcoal. As a material, the carbon in charcoal is largely inert, showing a relative lack of reactivity both chemically and biologically, and so it is strongly resistant to decomposition. Research scientists have found charcoal particles as old as 400 million years in sediment layers from wildfires that occurred when plant life first began on earth. (Sediment Records of Biomass Burning and Global Change, James Samuel Clark)
Of the many organic and inorganic substances that contain carbon atoms, only diamonds could potentially provide a more permanent carbon store than charcoal. Hence, biochar offers us a golden opportunity to remove excess CO2 from the atmosphere and sequester it in a virtually permanent and environmentally beneficial way.
The two main methods of pyrolysis are “fast” pyrolysis and “slow” pyrolysis. Fast pyrolysis yields 60% bio-oil, 20% bio char, and 20% syngas and can be done in seconds, whereas slow pyrolysis can be optimized to produce substantially more char (~50%), but takes on the order of hours to complete . Depending on the feedstock, bio char may look similar to potting soil or to a charred substance. The combined production and use of biochar are considered a carbon-negative process, meaning that it removes carbon from the atmosphere. Studies suggest that biochar sequester approximately 50–80% of the carbon available within the biomass feedstock being pyrolyzed depending upon the feedstock type.
- Biochar enhances soils. By converting agricultural waste into a powerful soil enhancer that holds carbon and makes soils more fertile,
- We can boost food security, discourage deforestation and preserve cropland diversity.
- Reduced leaching of nitrogen into ground water
- Possible reduced emissions of nitrous oxide
- Increased cation exchange capacity resulting in improved soil fertility
- Moderating of soil acidity
- Increased water retention
- Increased number of beneficial soil microbes
- Produces healthy tilth and structure (humus), reducing compaction so soil can breathe.
- Neutralizes and mantains pH of soil.
- Neutralizes toxins in the soil.
- Increases the water holding capacity of the soil.
- Improves germination of seedlings.
- Improves resistence to infestation by fungus, nematodes, and insects.
- Provides a rich source of carbon to build hummus/organic matter and increase productvity.
- Sequesters atmospheric carbon.
- Both repenishes and retains soil nutrients so crops will be more nutrient-dense.
- Improves cation exchange capacity for greater mineral delivery to plant roots.
- Increases microbial populations, including increased reproduction and higher retention of microorganisms
B.Sc. (Hons) Agricultural Sciences, Department of Agronomy, University of Agriculture Faisalabad, Pakistan
E-mail: [email protected], Cell no. +923347858391
Author: Imran Ramzan*, Arslan Shehroz1, Muhamamd Zunair Latif2.
Author * Department of Agronomy, University of Agriculture Faisalabad
1&2 Co-author Department of Plant pathology, University of Agriculture Faisalabad
E-mail: [email protected]