Agriculture Reference
In-Depth Information
ity of a shortfall. We have seen already that basmati varieties of rice are
particularly vulnerable to temperature induced pollen sterility, and thus to
lower grain formation. Many determinants of crop yield like rate of pho-
tosynthesis, biomass production, leaf area index, number and test weight
of grains were reduced by elevated O
3
level up to 14%. According to pro-
jections, ozone pollution may cause rice yield losses up to 16% with no
change in agricultural practices, which would put food security in Asia at
substantial risk
(Wissuwa, 2008; Vanja et al., 2009). Rainfall pattern is a
very important limiting factor for rain-fed rice production. Higher vari-
ability in distribution and a likely decrease in precipitation will adversely
impact rice production and complete crop failure if severe drought takes
place during the reproductive stages. In upland fields, if the rice crop re-
ceives up to 200 mm of precipitation in 1 day and then receives no rainfall
for the next 20 days, the moisture stress will severely damage final yields.
Assessments predict a decrease in the rice production in tropical regions,
but an increase of rice production outside tropical regions. This shift is of
particular concern to India because lower rice production will immedi-
ately create a hunger situation on a large scale. Studies on the impact of
night time temperature rise on rice yield indicate that the warmer nights
have an extensive impact on the yield of rice; every 1°C increase in night
time temperature led to a 10% reduction in yield. The eastern region of
India has diverse physiographic and agro-climatic land which supports ge-
netic resources. According to a study conducted by the Indian Agriculture
Research Institute (IARI) that the impact of climate change with increased
temperature and decreased radiation which will ultimately lead to decrease
in productivity of rice in the North Eastern region.
19.3.1.3 MAIZE
Maize (
Zea mays
L) is the third most important cereal crop in India and
has a major role to play in food security. Maize production in arid and semi
arid tropical regions is particularly sensitive to weather conditions, espe-
cially rainfall. Therefore, variation in the rainfall as well as maximum and
minimum temperature during the south-west and north-east monsoon pe-
riod will negatively impact maize crops. The Upper Indo-Gangetic Plain
characterized by low winter temperature, the maize yield can increase up
to a 2.7°C rise in temperature. High temperatures plays a greater role in
