Mitigating GHG emissions from agriculture
Role of sustainable agriculture
Mitigation principles
1. Reducing emissions
 reduce emissions by managing the C and N flows in
agricultural systems
 approaches would vary from region to region
 local conditions
2. Enhancing removals
 storing (sequestering) C
 methods that increase photosynthesis or slows
return of C via respiration
 soil organic matter (SOM) is a large store (sink) for
C in soils
3. Avoiding emissions
 avoiding cultivation of new lands (deforestation)
 using bioenergy feed stocks to release C (via CO2)
of recent origin rather than ancient C through
combustion of fossil fuels
Greenhouse gases : Worldwide impacts, Julie Kerr Casper, Facts On File, Inc., New York, 2010
Niggli, U., Fließbach, A., Hepperly, P. and Scialabba, N. 2009. Low Greenhouse Gas Agriculture: Mitigation
and Adaptation Potential of Sustainable Farming Systems. FAO, April 2009, Rev. 2 – 2009.
Sustainable agriculture
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Sustainable agriculture is an agriculture production
system that uses one or more practices that are
environmentally sound and socially responsible
Productivity and profit are still the focus of sustainable
agriculture, but they must be achieved with the care of
the environment and well-being of the farm household
and local community
Sustainable agriculture is not anti-technology, but
embraces any useful technology provided that they do
not cause harm to the environment
The key to sustainability is to use optimally but not
damage the environment
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Sustainable agriculture deliberately lowers artificial or
synthetic inputs and non-renewable energy sources, and
replaces them with natural materials or methods
Part of this is achieved by practicing integrated nutrient
and pest management techniques
Nutrient management
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Instead of artificial fossil fuel-based fertilisers, soil fertility
can be gradually build up by
 growing nitrogen-fixing plants/microbes together with
crops
 mulching using crop residues or animal manures
 composting
 reduce or eliminate soil tillage
 crop rotation and intercropping
 mixed (integrated) farming
 organic farming
Pest management
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Control pests (as well as diseases) by natural methods
 biopesticides (from natural resources)
 biological control
 crop rotation and intercropping
Nitrogen-fixing plants
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Nitrogen is an essential nutrient to plant growth
Two groups of herbaceous and woody plants have the
ability to fix atmospheric nitrogen in the soil
 at least 1,350 species of plants capable of nitrogen
fixation, although only about 25 are extensively used
today in agriculture and forestry
Legumes are such as beans, peas, clover and alfalfa
 legumes popular in Malaysia: Centrosema, Pueraria,
Mucuna, Calopogonium
Some plants have symbiotic relationship with Rhizobium,
Frankia and Azotobacter bacteria, which form nodules in
the roots
 Mycorrhizae fungi-root association also important
Root nodules
http://www.allposters.com
Mycorrhiza
Left plant without Mycorrhizae
Right with Mycorrhizae
Left plant without Mycorrhizae
Right with Mycorrhizae
http://www.botany.hawaii.edu/faculty/wong/Bot201/Symbiosis/Symbiosis.htm
Mulching
Rice straws
Palm fronds
Leaf litter
Empty fruit bunches (EFB)
Ecomat (made from EFB)
http://thailand.ipm-info.org/components/mulching.htm
Cover crops
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Common cover crops in Malaysia, in particular in oil
palm plantations
 Pueraria javanica/phaseoloides
 Calopogonium mucunoides
 Centrosema pubescens
 Mucuna bracteata
 Arachis pintoi
In addition to N-fixation, cover crops protect soil surface
from erosion, conserve water, increase soil fertility
through increased SOM (and biological activity) and
addition of other nutrients
Mucuna bracteata in oil palm
http://edmayang.com/products_mucuna_gallery.html
Compost
Hot composting
Vermicomposting
http://www.compostguy.com/composting/hot-composting-vs-vermicomposting/
http://aquirkyblog.com/tag/compostapalooza/
Minimum or zero tillage
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Soil fertility can also be improved by minimizing or
completely stopping tillage
 Ploughing is a common practice worldwide to control
weeds and aerate the soil before sowing
 Ploughing, however, disturbs the soil, leaving it
vulnerable to erosion, releases carbon dioxide as
decomposition is promoted, and, in some cases,
actually cause more, not less, weeds
 bringing up seeds closer to the soil surface for
easier germination
Crop rotation
Different season, different crop
Different field location, different crop
(always the same crops)
http://agriculture.kzntl.gov.za/publications/books/plant_diseases/disease_4.htm
http://www.baap.lt/codes_gap/lithuania/chapter_2.htm
Intercropping
Two or more crops planted together in the same plot
http://eucalyptusclones.com/eucalyptus.htm
Eucalyptus-sugar cane
http://www.environment.uwaterloo.ca/ers/faculty/moelbermann.htm
Maize-soybean
More efficient light & water use
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Compared to monoculture crops, polyculture crops also
use sunlight and water more effectively and often give
higher yields
tall & short canopies
deep & shallow roots
Pest Management
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Instead of synthetic pesticides, the practice of
polyculture helps to reduce the population of weeds and
pests
Polyculture is the culturing of two or more crops
simultaneously, as opposed to monoculture, where only
a single type crop is cultured, typical in conventional
agriculture
Monocultures produce a uniform population of a single
crop species so this encourages weeds and pests since
they are often host-specific
Polycultures, in contrast, break up the uniformity of the
crop population, and this discourages the spread and
population of weeds and pests
Control of insect pests
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Bacteria Bacillus thuringiensis exudes a harmless toxin
to humans but deadly to insects (toxin formulated as
biopesticides)
 Plutella xylostella (vegetables)
 Spodoptera sp. (vegetables, fruit and root crops)
Plant weeds?!
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In Africa, maize has two common problems: stem borers
(Chilo partellus and Busseola fusca) and a parasitic
weed known as African witchweed (Striga spp.)
By planting Napier grass (Pennisetum purpureum) and
Desmodium (Desmodium uncinatum), both weeds, along
the maize rows, these weeds help to control both pests
 Napier grass attracts and actually kills the stem borer
because the Napier grass contains a toxin deadly to
the borer
 Desmodium exude a prohibitive chemical against
Striga
Method first introduced in Kenya and saw 60-70%
increase in maize yields
Maize pests
http://www.arc.agric.za/home.asp?pid=637
stem borer
http://www.rothamsted.ac.uk/chelsea/2005/
Striga weed
Napier
http://www.arc.agric.za/home.asp?pid=637
Maize-Napier
http://abbe.mysuperblogs.in/100707/p2/
Maize-Desmodium
Beneficial fungi
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Beauveria bassiana
 Cylas formicarius (sweet potato)
 Lissorhoptrus brevirostris (rice)
Verticilium lecanii
 Bemisia tabaci (vegetables)
 Myzus persicae (fruit and root crops)
Trichoderma sp. as control of soil-borne pathogens
 Phytopthora capsici (vegetables, ornamentals)
 Rhizoctonia solani (vegetables, ornamentals)
Beneficial insects
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Trichogramma sp.
 Mocis latipes (pasture)
 Heliothis virescens (maize)
 Plutella xylostella (vegetable)
 Diaphania sp. (cucumber)
Telenomus sp.
 Spodoptera frugiperda (maize)
Encarsia sp.
 Bemisia sp. (beans)
Intercropping as a pest control
System
Pests controlled
Maize-bean
Meloidogyne sp.
Cabbage-tomatosorghum-sesame
Plutella xylostella
Maize-cassavacucumber
Spodoptera frugiperda
Cassava-bean
Cassava-maize
Erinnyis ello
Lonchaea chalybea
Mixed (or integrated) farming
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An agricultural system that consists of both crop and
animal
 minimizes external inputs
 recycles all wastes within the system
 saves energy and money
 more stable income
 depending on more than one type of activitiy
Fossil reserve
Wasteland
biomass
Sun, soil, rain
Straw
Brans, cakes
Losses
Losses
Leys, fodder
CROPS
ANIMALS
Draught
Solid excreta
Urine
Labour
Labour
HUMANS
Food, etc
Food, etc
Rice-fish culture
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Rice-fish culture is the cultivation of wetland rice with fish
 practised with almost no external chemical fertilisers
Besides fish providing an additional income to farmers,
the wastes from these fishes (such as tilapia and carp)
also help to increase the amount of organic fertiliser in
the fields and the movement of these fishes help to
spread the organic fertiliser more evenly than the farmer
can
http://www.fao.org/docrep/005/x3185e/X3185e3.htm
CIPAV mixed farming system
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Developed by the Foundation Center for the
Investigation in Sustainable Systems of Agricultural
Production (CIPAV), typifies the success of integrating
and using local natural resources to produce several
commodities
The system consists of the simultaneous cultivation of
sugar cane, food crops (like corn or rice) and tree fodder
(trees or shrubs used for animal feed), together with the
raising of sheep, pigs, ducks and fish
CIPAV mixed farming system
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The system works by minimising external inputs so that
each component in the CIPAV system sustains one
another
Essentially, the crop residues serve as feed to the
livestock and fish, and in turn, the wastes from the
livestock and fish serve as fertiliser to the crops
Moreover, their wastes, together with crop residues, are
digested in a biodigester to produce fuel for household
cooking and electricity
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This mixed farming system recycles all wastes so that
little is thrown away: one’s waste is indeed another’s
food
Reduces dependency on fossil fuels because of its selfsufficient system means little external input is required;
in fact, by being able to generate its own fuel from
wastes means even less depedency on fossil fuels
This mixed farming system recycles all wastes so that
little is thrown away: one’s waste is indeed another’s
food
Reduces dependency on fossil fuels because of its selfsufficient system means little external input is required;
in fact, by being able to generate its own fuel from
wastes means even less depedency on fossil fuels
Cows and sheep
Food and Agriculture organization. 2001. Mixed crop-livestock farming. A review of traditional technologies based on literature
and field experience. Series title: FAO Animal Production and Health Paper - 152. Rome, Italy
Chicken and fish
Food and Agriculture organization. 2001. Mixed crop-livestock farming. A review of traditional technologies based on literature
and field experience. Series title: FAO Animal Production and Health Paper - 152. Rome, Italy
Livestock and crop
Food and Agriculture organization. 2001. Mixed crop-livestock farming. A review of traditional technologies based on literature
and field experience. Series title: FAO Animal Production and Health Paper - 152. Rome, Italy
Crop-livestock farming in Malaysia
Oil palm and sheep
Rubber and sheep
But problem of damaged
trunks with cattle-rubber or
goat-rubber
http://www.fao.org/DOCREP/004/X6543E/X6543E04.htm
http://www.fao.org/docrep/005/af298e/af298E21.htm
Organic farming
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Agriculture production that excludes (completely
prohibits) the use of any
 synthetic agrochemicals
 plant and animal growth regulators
 livestock feed additives
 GM organisms
Organic farming relies on, among others, crop rotation,
green manure, compost, biological pest control, and
mechanical cultivation to maintain soil productivity and
control pests
Organic farming acreage
http://www.organic-world.net/
Distribution of organic land by continent
http://www.organic-world.net/
In 2001, Malaysia only
had 131 hectares of
organic land.
But in 2006, the
Ministry of Agriculture and
Agro-based Industry said
that Malaysia then had
2,367 hectares of organic
land (an 18x expansion or
3.6x increase per year).
Those could include noncertified organic lands.
http://www.organic-world.net/
http://www.freshplaza.com/news_detail.asp?id=39955
Can sustainable agriculture deliver?
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In 2006, the world’s largest study on sustainable
agriculture was published
This study covered 286 projects in 57 countries,
involving 12.6 million farmers on 37 million hectares
(about the size of Japan)
Dr. Jules Pretty
Uni. of Essex, UK
Increased yields
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Reported that farms adopting sustainable agriculture
technologies saw an average yield increase of 79 per
cent across a wide variety of crop types, including grain
crops
 Wetland rice, for instance, saw a yield increase of
over 20 per cent
Furthermore, these farms helped to sequester (store) an
annual average of 1.3 tonnes of carbon dioxide per
hectare, totalling about 48 million tonnes of carbon
dioxide a year
Land use change
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Reversion of cropland to another, preferably closer to the
original native vegetation
 convert to grassland
 less C removal from harvested material
 lesser soil disturbance
 revert drained cropland to wetland
 rapid C accumulation
 planting trees (agroforestry)
 reduce C emission
 C sequestation
Drawback: loss of agricultural productivity
 good only for marginal land or have surplus
agricultural land
Second generation biofuel
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Use of non-food plant parts as biofuel
 such as stem, leaves and stalk of maize plant
Non food crops
 like jatropha (Jatropha curcas), Elephant grass
(Miscanthus giganteus), and switchgrass (Panicum
virgatum), hemp (Cannabis sativa)
 which grow well in poor fertile soils
No competition with food
Drawbacks:
 have to do life cycle analysis to determine mitigation
benefits
 may have positive net CO2 emissions
 non food plant parts have lower ethanol yield
Reducing methane emission from rice fields
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Reduction in the CH4 efflux from rice fields can be made
either by reducing the methane production, increasing
methane oxidation, or reducing methane transport
through plants
Reduce CH4 emissions by
 mid-season drainage
 avoid year long flooding, no 3 times planting a year
 plant with wider spacing
 use sulfate-based fertilizers (ammonium sulfate and
sodium sulfate)
 crop rotation: wetland rice – upland rice
 new rice cultivars
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Rice plants influence the methane dynamics in paddy
soils by
 (1) providing substrate in the form of root exudates to
methanogens to enhance the production of CH4
 (2) transporting CH4 from soil to atmosphere (conduit
effect)
 (3) creating aerobic microhabitat in rhizosphere,
which is suitable for growth and multiplication of
methanotropic bacteria responsible for CH4
consumption
Singh, S.N. 2009. Climate change and crops. Springer,-Verlag, Berlin
Animal feed management
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Livestock sources of CH4 are predominantly enteric (i.e.,
from the breath of ruminants and flatus of monogastric
animals) as a result of feed digestion
 responsible for about 30% of global methane
emission
Replace fodder with
 feed concentrates
 adding oils to the diet
 improving pasture quality
 optimizing protein intake
 increase legume intake
Biochar
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Biochar is a carbon-rich product obtained when biomass,
such as wood, manure or leaves, is heated in a closed
container with little or no available air
Biochar is produced by heating the organic material
under limited supply of oxygen and at high temperatures
(<700°C)
 process called pyrolisis
Like producing charcoal, but biochar is not used as field
but placed into the soil to improve soil properties
(increase soil nutrients, water retention, and infiltration)
and sequester C
http://www.cef-environmental.co.uk/BioChar.htm
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Plant biomass that is formed on an annual basis typically
decomposes rapidly
 this decomposition releases the CO2 that was fixed by
the plants back to the atmosphere
 but by transforming this biomass into biochar that
decomposes much more slowly diverts C from the
rapid biological cycle into a much slower biochar
cycle
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Drawbacks: source of energy for heat is from burning of
biofuels
To be justified as a carbon storage strategy, the amount
sequestered must exceed that produced in moving it
between its site of production, burning, and application
In the case of crop residues, it must be ensured that
biochar addition provides a similar carbon gain to the
simple return of these materials at the site of production
 does not cause nutrient depletion