Agriculture Reference
In-Depth Information
The C3 plants are likely to gain from the increasing level of CO
2
in the
atmosphere. Elevated carbon dioxide has positive effect by increasing the
productivity ranging from 24-51%. CO
2
enrichment in greenhouses (800-
2000 ppm depending on the crop) to increase the production of flower
crops is popular. It would be possible to spend less on energy to generate
CO
2
for carbon fertilization.
13.5.3.2
NEGATIVE IMPACT
The above positive effects will be counteracted by increase in tempera-
ture, reduced humidity levels, reduced water levels, increased salt levels
in water and soil. Rise in temperature will reduce crop duration, increase
respiration rate, alter photosynthate partitioning to economic product,
alter phenology, particularly flowering, fruiting and reduce chilling unit
accumulation, hasten senescence, fruit ripening and maturity. However,
the overall impact of climate change and global warming will depend on
interaction effect of elevated carbon dioxide and temperature rise.
Besides these the major impact would be on the following:
1. Drastic reduction in volatile fragrances the flowers emit;
2. deterioration of pigments leading to dull shades;
3. reduced production and productivity under open and protected en-
vironment;
4. shift in insect pest and disease outbreaks;
5. absence of winter chilling will reduce flowering in bulbous orna-
mental crops;
6.
reduced post harvest life;
7.
poor pollination and seed set due to changes in insect behavior;
8.
Similarly higher rainfall would increase anaerobic stress at the root
zone leading to yellowing, poor growth and even mortality.
13.5.4
ABIOTIC STRESS ENCOUNTERED
A number of factors induce stress in plants when the plants are grown in
adverse growing conditions. Plant encounters stress when grown under
high temperature, low temperature, high salt and heavy metal concentra-
tions. Such stresses are known as abiotic stress in comparison to biotic
stresses that the plant encounters due to pathogens. With the advent of
