Geoscience Reference
In-Depth Information
are generally expected to have the biggest decreases in agricul-
tural production. Another factor affecting agriculture with this
background is the increasing rate of microbial decomposition of
organic matter, which adversely affects soil fertility in the long
run. Also, studies analysing the effects on pests and diseases
suggest that temperature increases may extend the geographic
range of some insect pests currently limited by temperature.
The effects of increased ultraviolet-B (UV-B) radiation are
also of great concern. The increase in UV-B radiation reduces
the yield in certain agricultural crops. Olszyk and Ingram
(1993) have also discussed the potential of crop-quality reduc-
tion due to the 'Effects of UV-B and Global Climate Change
on Rice Production' in the Environmental Protection Agency
International Rice Research Institute (EPA/IRRI) cooperative
research plan (Dai et al., 1992).
In the long run, the outcome of climatic change will have the
following effects on agriculture:
•
The quality and quantity of agricultural productivity will
be adversely affected.
•
There will be changes of water use (irrigation) and
agricultural inputs such as herbicides, insecticides and
fertilisers.
•
Several environmental factors will be altered and will
have their negative impact, particularly in relation to fre-
quency and intensity of soil drainage (leading to nitrogen
leaching), soil erosion and reduction of crop diversity.
•
The cultivable land, land speculation, land renunciation
and hydraulic amenities will be at stake. There will be
less rural space available for cultivation.
•
Adaptation in organisms may lead to changes in competi-
tion levels, and humans may develop an urgency to develop
more competitive organisms, such as lood-resistant or
salt-resistant varieties of crops; also implementing various
methods and technologies so as to develop new varieties
of crops to combat the growing disease and pests.
5.3
Mitigation strategies for reducing crop
productivity losses
It is apparent that, in general, agricultural productivity will
decrease to a greater or lesser extent under increasing cli-
matic variability, particularly with rising temperatures and
fluctuating extreme precipitation. Agricultural resources and
