Agriculture Reference
In-Depth Information
Climate change is widely considered to be one of the greatest chal-
lenges to modern human civilization that has profound socioeconomic
and environmental impacts. Over exploitation of fossil fuels ever since
the beginning of industrial era led to increased concentration of green
house gases (GHGs)
viz.,
carbon dioxide, methane, nitrous oxide, sul-
fur dioxide, etc. in the atmosphere. Increase in the concentration of
these GHGs is responsible for global climate change. Climate change
may be due to natural processes or external forcings, anddue to persis-
tent anthropogenic changes in the composition of the atmosphere or
inland use. The CO
2
, concentration has increased from a preindustrial
value of about 280 ppm to 395 ppm in 2012. Similarly, the global
atmospheric concentration of methane and nitrous oxides and other
important GHGs, has also increased considerably. This has resulted
in warming of the climate system by 0.74 °C between 1906 and 2005
(IPCC, 2007). Climate change is often manifested in extreme events of
precipitation, sea-level rise and temperature increase, leading to droughts,
floods, forest fires and desertification. Cashew is usually grown as a rain-
fed crop in ecologically sensitive areas such as coastal belts, hilly areas
and areas with high rainfall and humidity. Climate change therefore has a
profound impact on cashew.
6.2
CLIMATIC SUITABILITY OF CASHEW CULTIVATION
Most of the regions where it is an economically important crop are between
15°South and 15°North. Cashew thrives at temperatures up to 40 °C. Dam-
age to young trees or flowers occurs below the minimum temperature of
7 °C and above the maximum of 45 °C. Only prolonged cool temperatures
will damage mature trees; cashew can survive temperatures of about 0 °C
for a short time (Ohler, 1979). Low altitude areas with a mean rainfall of
1500 to 2000 mm are excellent for cashew. Environments with maximum
temperature ranging from 28 °C to 32 °C, minimum winter temperature
around 19 °C and 70-80% relative humidity are good for getting better
results. Frost is detrimental to the crop. Mandal (1992) attempted to rate
cashew growing environments as very good, good, fair and poor based on
variation in altitude, rainfall, proximity to sea, maximum and minimum
temperature, humidity and occurrence of frost. The ratings and the range
of these parameters are indicated in
Table 6.2.
