Climate Change Mitigation - Climate Resilient Agriculture for Ensuring Food Security - page 272

tractors and other implements is reduced because
no-till involves fewer passes of equipment across
the fi eld.
Crop varieties that have been created by tradi-
tional plant selection methods have no barriers to
dissemination, and they are accepted worldwide.
On the other hand, plant varieties resulting from
GM crops have faced stiff opposition from con-
sumers in several parts of the world, most notably
in Europe. Moreover, the resultant seeds are often
relatively expensive so they may not be available
to the poorest farmers.
(i) Advantages
• A big advantage of biotechnology is that,
besides increasing carbon sequestration,
it can help to improve the productivity of
crop plants.
• By selecting cultivars that are more
responsive to elevated CO 2 and more
resistant to heat stress, crops will be better
adapted to future climatic conditions.
(ii) Disadvantages
• The method generally requires several
years and generations of plants to imple-
ment because yield and carbon sequestra-
tion are dependent on many abiotic and
biotic factors. The pace of variety devel-
opment may be slower than changes in
atmospheric CO 2 and climate.
• Whole new research programs are needed
for identifying varieties and traits respon-
sive to the increases in atmospheric CO 2
and global warming and their interactions
on the productivity, grain quality, water
relations, and pest resistance of crops, and
such research is expensive (Ainsworth
et al. 2008 ).
• To be successful, selection needs germ-
plasm that differs in many traits, and there
may not be enough range in variation of
crucial traits needed to adapt to climate
change.
• Many varietal crosses require the use of
growth chambers or greenhouses with
potted plants, which makes it difficult
to predict responses under field
conditions.

Traditional plant selection is used worldwide
to improve plant varieties, often with the aim of
matching them to local growing conditions.
Newer biotechnology requires specialized equip-
ment and laboratories as well as more trained
personnel; therefore, it tends to be a technology
that is confi ned to more developed countries.
Because of the high cost of facilities that can pro-
duce conditions with elevated CO 2 and tempera-
ture as expected with global change, relatively
few fi eld experiments have been conducted
(Ainsworth et al. 2008 ), and they have tended to
be in developed countries, with China and India
as exceptions. Approximately 250 million acres
of biotechnology-engineered maize, canola, cot-
ton, soybeans, papaya, sugar beets, sweet corn,
and squash crops have increased global farmer
profi ts by about US$27 billion, reduced pesti-
cides application by 224 million kg, reduced
environmental impacts of pesticides by 14 %, and
reduced GHG emissions by 960 million kg of
CO 2 (Brookes and Barfoot 2009 ). On the basis of
the above advantages of GM crops, several com-
panies such as Monsanto, Syngenta, and DuPont
Pioneer have started to use these germplasm in
their research and development pipelines.
Varieties with increased yield for whatever
reason improve the profi tability of farmers. Many
commercial seed companies are hugely success-
ful. Therefore, the economics of using improved
varieties, whether by traditional plant selection or
by biotechnology, have been very positive, and it
is very likely that they will continue to be positive
with future climate change. As mentioned above,
besides benefi ting agriculture by improving pro-
ductivity and disease resistance, improved plant
varieties have decreased GHG emissions by
reducing demand for cultivated land and fossil
fuel-based inputs. GM crops conserve over
14,200 million kg of CO 2 - the equivalent of
removing over six million cars from circulation
in 2007 alone (Brookes and Barfoot 2009 ).

13.1.1.2 Cover Crop Technology
Cover cropping is an effective method of reducing
emissions of CO 2 . These crops grow over entire
land areas or in localized spots such as grassed