Climate Change Mitigation - Climate Resilient Agriculture for Ensuring Food Security - page 286

• The grain yields in agricultural soils are shown
to increase by the use of biochar.
• The use of locally available feedstock reduces
dependence on fossil fuel.
• Employment opportunities can be created in
the course of development of biochar
technology.
• Revenue can be generated through carbon
trading.
• Since biochar can be used as a fertilizer, alter-
native fertilizers no longer need to be pur-
chased (imported) which helps developing
countries to reduce trade and fi scal defi cits.
(iii) Contribution of the technology to protection
of the environment
(a) Reduced GHG emission : Reduced use of fer-
tilizer results in reduced emissions from pro-
duction and use of other fertilizer products.
Retention of nutrients like nitrogen in the soil
limits consequent emission of nitrous oxide
into the atmosphere. As agricultural wastes
are turned into biochar, the emission of
methane resulting from natural decomposi-
tion of biomass is reduced. By 2100, the use
of biochar can sequester 5.5-9.5 GtC/year
(Lehmann et al. 2006 ). Similarly, biochar
increases the microbial life in the soil and
increases carbon storage in the soil.
(b) Enhanced soil fertility and food security :
Biochar increases the number of soil
microbes, retains nutrients in the soil, and
hence increases the soil fertility and subse-
quently there is increased food security. In
Laos, application of biochar improved satu-
rated hydraulic conductivity of top soil.
However, biochar may not be suitable for all
situations. Derived biochar may enhance the
loss of forest humus. Therefore identifi cation
of specifi c niches for biochar application is
crucial to exploiting its benefi ts.
(c) Reduced water pollution : Groundwater and
surface water pollution through leaching,
erosion, etc., is reduced through lower use of
chemical fertilizer and reduced degradation
of soils. As the nutrients and agrochemicals
are retained in the soil due to the use of
biochar, pollutants produced through agri-

culture in water are reduced. Mizuta et al.
( 2004 ) notes that biochar can remove nitrate
and phosphate from water. Biochar also has
an affi nity for organic compounds which can
help retaining toxic organic compounds from
water (Kookana et al. 2011 ).
(d) Waste management : Biochar technology
offers a simple and sustainable solution to
waste management because agricultural
wastes are used as feedstocks. During the
pyrolysis process, no waste is produced and
by-products include syngas and bio-oils can
be recycled and used further.
(e) Reduced deforestation and increased crop-
land diversity : Since biochar technology
emphasizes the use of agricultural wastes as
feedstock, deforestation is prevented and
biodiversity inside soil can be signifi cantly
enhanced. Hence, by converting agricultural
waste into a powerful soil enhancer with sus-
tainable biochar, cropland diversity can be
preserved and deforestation discouraged.

13.1.3.3 Off-Field Crop Residue
Management
Crop residue management is an important miti-
gation technology using biomass, vermicompost,
etc. processed under aerobic conditions which is
being utilized as a commercial option to reduce
greenhouse gas emissions. Vermicomposting is a
modifi ed method of composting using earth-
worms to eat and digest farm waste and turn it
into a high-quality vermicompost in 2 months or
less. It is different from other composts due to the
presence of worms such as earthworms, red
wigglers, white worms, etc. (Satavik 2011 ).
Crop residue management is an important
component of organic farming that helps the
conservation of carbon in the rhizosphere
thereby mitigating the emissions of GHG to the
atmosphere. It includes leguminous cover crops
grown as green manure to provide a cost-effec-
tive source of N to subsequent crops. Organic
farming relies heavily on inputs of organic resi-
dues in the forms of green manure (i.e., cover
crops), plant compost, and composted animal
manures added to the soil along with integrated