Agriculture Reference
In-Depth Information
affecting maize yield as compared to rainfall, which may not have a major
impact on winter yields as the crops in the Gangetic belt are well irrigated.
Maize yield during monsoon could be reduced by up to 35% in most of
the Southern Plateau regions and up to 55% in Mid Indo-Gangetic Plains,
whereas the Upper Indo-Gangetic Plain is expected to be relatively unaf-
fected.
19.3.2 VEGETABLES AND LEGUMES
Most of the vegetables crops are sensitive to extreme weather parameters,
thus periodic high temperature and soil moisture stress conditions are
likely to reduce yield. But research also shows that higher CO
2
concen-
tration could offset the negative effect of higher temperature especially
in the case of leafy vegetables that would benefit from increased rates of
photosynthesis. Short duration vegetables and legumes could perform bet-
ter under higher concentration of CO
2
, especially crops such as chickpeas
which have a well developed carbon sink capacity, due to their ability to
use additional photo-assimilates more effectively. Chickpeas grown under
elevated concentration of CO
2
(up to 550 ppm) showed better performance
compared to plants grown under current CO
2
concentrations of 370 ppm.
There was greater shoot elongation and leaf expansion under elevated CO
2
and an 18% increase in the number of seed in some varieties. Neverthe-
less, an increase in temperature is likely to reduce the beneficial effect
of increasing CO
2
. Elevated CO
2
(550 ppm) leads to higher number of
leaves and to larger bulb size in onions. The pseudo stem length, number
of leaves and leaf area are higher at bulb initiation and bulb development
stages than at ambient CO
2
levels (370 ppm). Plant length, number of sec-
ondary branches and leaf area increase at elevated levels of CO
2
, as com-
pared to ambient levels. The yield increase is mainly due to increase in the
number of fruits per plant with a mean of 74 fruits per plant, compared
to 56 fruits per plant under current ambient conditions (Singh, 2010; Sid-
diqui et al., 2011).
