Biochar is found in soils around the world as a result of vegetation fires and historic soil management practices. Intensive study of biochar-rich dark earths in the Amazon (terra preta), has led to a wider appreciation of biochar’s unique properties as a soil enhancer.
Biochar can be an important tool to increase food security and cropland diversity in areas with severely depleted soils, scarce organic resources, and inadequate water and chemical fertilizer supplies.
Soil degradation simply means the decline in soil quality which comes about due to aspects such as improper land use, agriculture, and pasture, urban or industrial purposes. It involves the decline of the soil’s physical, biological and chemical state.
Soil degradation examples include decline in soil fertility, adverse changes in alkalinity, acidity or salinity, extreme flooding, use of toxic soil pollutants, erosion, and deterioration of the soil’s structural condition.
These elements contribute to a significant amount of soil quality depreciation annually. Excessive soil degradation thus gives rise to immediate and long-term impacts which translate into serious global environmental headaches.
Effects of Soil Degradation:
- Increased flooding
- Loss of arable land
- Drought and aridity
- Land degradation
- Pollution and clogging of waterways
Biochar is a simple and sustainable tool for the management of agricultural wastes. It helps in waste recycling as animal and crop wastes are used in biochar manufacturing and these wastes converted into bio-energy that is quiet useful. Not only power and energy obtained in combustion process but overall volume of waste also reduce.
Conversion of organic waste into biochar decreases methane gas which is usually generated by natural decomposition of waste material. With the use of this technique, we can store 2.2 gigatones of carbon per year. Climate change mitigation is indirectly influenced through proper waste management.
This is comparatively economical, extensively applicable and readily scalable. Biochar addition to soil alters microbial populations in the rhizosphere, albeit via mechanisms not yet understood, and may cause a shift towards beneficial microorganism populations that promote plant growth and resistance to biotic and abiotic stresses.
In addition there is scant evidence for biochar-induced plant protection against soil-borne diseases; the induction of systemic resistance towards several foliar pathogens has been demonstrated.
In nutshell, using biochar as a soil amendment can help sequester stable carbon in soils and combat harmful effects of climate change. However, responses to biochar may depend on the type of feed stock used and the specific characteristics of that biochar.
Because biochar characteristics determine its suitability for specific agronomic or environmental purposes, biochar production must be tailored to address such specific needs and Pakistan biochar initiative has been setup in this regard.
The United Nations Convention to Combat Desertification (UNCCD) supports biochar as a means for combating land degradation, improving farmland and combating climate change.
There are two ways which use can counter land degradation:
1) biochar use to make farming more sustainable and productive with less harmful pollution. This would reduce pressure for clearing new land. Biochar’s use to rehabilitate degraded or naturally poor land e also helping to reduce pressures for clearing new areas.
One vital question is ‘how will degraded or desertified regions produce sufficient biochar to effectively support land rehabilitation when there is only sparse plant cover to use for feedstock?’
One solution would be to grow hardy vegetation on unfarmed biodiversity-poor areas, perhaps irrigated with water too poor to be used for food crops.
Other possibilities are algae, reeds, grasses or aquatic weeds grown in lagoons using poor quality water and effluents. Waste from towns and agricultural waste might also be used if transport were cost effective.
Strezov et al. (2008) suggest un-irrigated elephant grass grown on degraded (non-agricultural) land could produce biofuel and biochar even where growth rates are less than 40 metric tons of dry biomass per hectare per annum.
Land ruined by salts or soda, might produce biomass for biochar production and the removal of the contaminants with the biomass could help rehabilitate it as well as providing material to improve soils elsewhere.
This has been explored in Australia (Bartle, Olsen, Cooper, & Hobbs, 2007), where dry, salty land yields coppiced eucalyptus feedstock and in Sumatra where forestry and paper pulp waste has been used (Ogawa, Okimori, & Takahashi, 2006).
Urban brown field sites could be rehabilitated with biochar to support amenity planting or biofuel and timber production and at the same time lock-up carbon.
Linked to refuse treatment biochar could have much potential. Modern urban refuse in developed countries (and increasingly in developing nations) is likely to be contaminated with toxic materials and so may not make good compost; however, some studies suggest uncontaminated biochar may be produced with it.
Biochar’s could be a key component for a doubly green revolution; it could also be one of the best practical ways to counter global warming and it might be an effective way to rehabilitate degraded land and counter pollution of streams and groundwater.
However, enthusiasm needs to be backed with adequate research to establish the qualities of biochar’s and to develop the best usage and ways to promote optimum innovation.
There is a need for a broad overview of the diverse research. If biochar’s is found to have the potential its supporters claim its use must be carefully controlled to reduce problems.