Agriculture Reference
In-Depth Information
from climate change will have a very great implication for global food pol-
itics. In these regions even moderate warming of 1°C for wheat and maize
and 2°C for rice will reduce yields significantly. It is known that many
agricultural systems are seasonally dependent and thus sensitive to climate
change. Crop and livestock production need a specific range of weather
conditions at particular times, for optimal growth. The most vulnerable ag-
ricultural systems are the arid, semiarid, and dry subhumid regions of the
developing world. In these regions high rainfall variability and recurrent
drought, flood cycles disrupt crop development. Extreme high and low
temperatures cause physical injuries like freezing and sunburn to the crop
plants and damage the grain. Temperature rise in lower latitude regions
accelerates the rate of respiration, transpiration and evapotranspiration ex-
cessively leading to sub optimal growth. The rice productivity is estimated
to decrease under climate change due to its sensitivity to temperatures
that cause damage to the plant, thus affecting yield (Chakraborty et al.,
2008). Increased temperatures have multiple impacts on crop productiv-
ity depending on the biological characteristics of the specific crop and the
time of the heat stress in relation to its growth and development. Higher
daytime temperature accelerates plant maturity and results in poor grain
filling due to pollination failure while higher night temperatures increase
yield losses due to higher rate of respiration
(Hedayetullah et al., 2014).
19.2.8 DISEASES AND PESTS
The diseases and pest infestation on crop plant is fully depend on climatic
parameters. Most of the plant disease like blast, bacterial leaf blight and
brown spot observed on paddy, wheat (
Puccinia and Septoria
) and hor-
ticultural (
Meloidogyne
) crops are affected by climate change. The trend
indicates that severity of majority of diseases is found to be higher with
elevated CO
2
levels, an off-shoot of climate change
(Mock et al., 2006).
The severity of diseases caused by fungi, bacteria, viruses, and insects are
anticipated to increase with global warming and these pest and pathogens
trying to adopt under diverse climatic condition. Elevated CO
2
may modi-
fy pathogen aggressiveness and or host susceptibility and affect the initial
establishment of the pathogen, especially fungi, on the host (Heiser et al.,
2005; Yates, et al., 2000). In most examples, host resistance has increased,
possibly due to changes in host morphology, physiology and composition.
