The incidence of drought appears to be on the rise. According to a National Crisis Management plan to tackle drought, much of the country’s farmland is prone to drought every 30 months, that is, four times in 10 years.
Rainfall data indicate that 68 per cent of the sown area is subject to drought of varying degrees.
At least 33 per cent of the farmland is chronically drought-prone, receiving less than 750 mm of rain. The situation becomes gloomier considering the depletion of groundwater and limited availability of surface water. Climate change is to blame for the erratic rainfall that is affecting about 53 per cent of the area under kharif and 55 per cent of the area under rabi, threatening to impact farm output.
Climate change
Warmer days and nights affect severely the metabolic rate of plants, significantly increasing their water intake. Scientists at the Central Research Institute for Dryland Agriculture have found that in the 10 years from 2000 to 2009 the magnitude of rise in seasonal mean temperatures has been higher during rabi, at 0.28 degrees Celsius, and lower in the kharif season, at 0.19 degrees. This trend is likely to continue and can affect crop yields, B. Venkateswarlu, Director of CRIDA, told
Increase in temperatures can severely impact farm output. “It may shorten crop duration and or increase water demand as more quantum of water may be lost through evaporation,” Venkateswarlu said.
Impact on output
Warming during rabi has serious implications for production of crops such as wheat, mustard and chickpea in the Indo-Gangetic plains.
“We have seen an increase of 0.6 degrees Celsius in the last 100 years. But what is worrying is that a good part of the increase (0. 4 degrees) has happened after 1980. The rise is more in North India,” he said. The Institute said the quantum of rainfall has not come down. But averages do not reflect the accurate picture.
“The distribution (of rainfall) has been affected and we are witnessing an increase in the frequency of extreme events, such as intense rain, heat/cold wave and frost. Except in three-four places, such as East Madhya Pradesh, Chhattisgarh and Jharkhand, there is no decrease in temperature,” he said.
There is, however, a silver lining. There has been no significant change in the net availability of natural resources such as water and soil. “What we had in the 1970s, we still have now. Only, dependence is very high now. You need to be realistic and grow crops that can be supported by the resources available,” the CRIDA Director said.