Geoscience Reference
In-Depth Information
inundation on coastal areas gives rise to potential acid sulphate
soil layers.
Experts are unsure how global warming will affect agricul-
ture. CO
2
increases the efficiency of photosynthesis, only if the
temperature increases by less than a few degrees; for example,
2°C in wheat and soya bean yields 10-15%; maize and rice 8%,
at 4°C yields decrease. CO
2
increases water use efficiency (anti-
transpiration effect) as temperatures rise. The increase in pre-
cipitation results in a rise in the sea level and leads to flooding
and loss of cropping area. The drainage problems and seawater
intrusion into fresh water may become too arid and are decrease
the production. Other arid areas may get more rainfall and start
to produce. The growing season is likely to extend where north-
ern regions may benefit, but there is little benefit for the tropics.
15.10
Climate change impact on Indian agriculture
Global climatic change has its own paradigm shift in its
research methodologies and developmental aspects. India
being an agri-economy-based country, it is quite obvious that
we depend heavily upon the agricultural sector and its pro-
ductivity. On the other hand, agriculture and environment are
mutually interlinked with each other in its entire operation and
execution towards the economy regeneration of any country.
The impact of climate change on Indian agriculture is being
studied to a limited extent. For the Indian subcontinent, it is
predicted that the mean atmospheric temperature will increase
by 1-40°C (Sinha and Swaminathan, 1991). Although the solar
radiation received at the surface will vary geographically, on
an average, it is expected to decrease by about 1% (Hume and
Cattle, 1990). Rice and wheat are the two most important cere-
als that fill the Indian breadbasket. While rice and wheat con-
stitute the major cropping system of the Indo-Gangetic plains
of northern India, the southern peninsula comprising Godavari
and Kauvery delta exclusively depend on rice. For India as a
whole, rice may become even more important in the national
food security system, since rice can give higher yields than
wheat under a wider range of growing conditions. In the subse-
quent paragraphs, discussion will be centred on the impact of
climate change on rice production.
Rice is cultivated in diverse ecologies that differ from each
other in water availability and depth of standing water during
growth. It is grown over a wide geographic range from 45°N
to 40°S to elevations of more than 2500 m but with average
