Climate Change Mitigation - Climate Resilient Agriculture for Ensuring Food Security - page 309

13.1.10 Organic Agriculture

primary barriers to adoption of organic farming
are the lower productivity and consequently
higher prices, as well as lower produce quality in
the market place. Greater education of farmers
and the public needs to be done to show that the
environmental and long-term sustainability
advantages of organic agriculture are worth to the
added current costs.

Organic farming restricts the use of artifi cial
fertilizers and pesticides, and it promotes the use
of crop rotations, green manures, compost, bio-
logical pest control, and mechanical cultivation
for weed control. These measures use the natural
environment to enhance agricultural productivity.
Legumes are planted to fi x nitrogen into soil, and
natural insect predators are encouraged. Crops are
rotated to renew soil, and natural materials such
as potassium bicarbonate and mulches are used to
control diseases and weeds. Crop diversity is a
distinct feature of organic farming. However,
organic farming originated as a small-scale enter-
prise with operations from under 1 acre (4,000 m 2 )
to under 100 acres (0.40 km 2 ). Crop rotation,
cover cropping, reduced tillage, and application
of compost are varieties of methods used in
organic agriculture. Organic agriculture is one of
the important options for carbon sequestration
which can reduce greenhouse gases.
Organic farmers use several different tech-
niques. The most effective ones are fertilization
by animal manure, by composted harvest resi-
dues, and by leguminous plants such as (soil)
cover and (nitrogen) catch crops. Introducing
grass and clover into rotations for building up soil
fertility, diversifying the crop sequences, and
reducing plowing depth and frequency also aug-
ment soil fertility. All these techniques increase
carbon sequestration rates in organic fi elds,
whereas in conventional fi elds, soil organic mat-
ter is exposed to more tillage and consequent
greater losses by mineralization. The annual
sequestration rate increases up to 3.2 t of CO 2
ha −1 year −1 by organic farming (Smith et al. 2007 ).
Historically, agriculture was organic, relying
on the recycling of farm wastes and manures.
Very little or negligible amounts of external inputs
were applied. Sustainable farming practices and
cycles evolved over centuries, integrated with
livestock rearing. For instance, farmers of ancient
India are known to have evolved nature-friendly
farming techniques and practices such as mixed
cropping and crop rotation.
Besides overcoming a tradition of recently
adopted synthetic fertilizers and pesticides, the

13.1.10.1 Advantages
• Organic agriculture aims to improve soil
fertility and N supply by using leguminous
crops, crop residues, and cover crops to elimi-
nate fossil fuel used to manufacture N fertil-
izer. The addition of the crop residues and
cover crops leads to the stabilization of soil
organic matter at higher levels and increases
the sequestration of CO 2 into soils.
• Organic agriculture increases soil's water
retention capacity, which would enable a crop
to go longer into a drought cycle assuming an
initial full profi le. This should provide an
adaptation to unpredictable climatic condi-
tions. Soil C retention is more likely to with-
stand climatic challenges and soil erosion, an
important source of CO 2 losses.
• Organic agriculture can contribute to agro-
forestry production systems, which offer addi-
tional means to sequester carbon.
• Organic systems are highly adaptive to climate
change due to the application of traditional
skills and farmers' knowledge, soil fertility-
building techniques, and a high degree of
diversity.
• Organic agriculture as a water protector reduces
water pollution due to the absence of pesticides
and chemical fertilizers.
• Organic agriculture is compatible with con-
servation tillage, thereby enabling even greater
C sequestration potential by incorporating this
mitigation technology.

13.1.10.2 Disadvantages
• Organic agriculture is less productive com-
pared to intensive conventional agriculture.
Consequently, the yield of highly demanding
crops such as potatoes, grapefruits, and horti-
cultural crops is too low, and energy input