‘Temperature rise impacts farm output’

Increase in atmospheric temperature due to climate change adversely impacts the growth of the various agricultural crops, an assessment study conducted by Indian Council of Agricultural Research (ICAR) has said.

?Rise in temperature reduces crop duration, increases crop respiration rates, affects the equilibrium between crops and pests, hastens nutrient mineralisation in soils, decreases fertilizer use efficiencies, and increases evapo-transpiration,? an ICAR statement on Wednesday said.

However, the study said increase in carbon dioxide is ?beneficial? for several crops such as wheat, rice, legumes and oilseeds.

Crops such as maize, jowar, bajra and sugarcane do not benefit from increased carbon dioxide in the atmosphere.

According to the ICAR assessment, a study conducted on onion crop in Maharashtra indicated that the crop failed in 1997 rabi due to high temperatures in bulb formation stage and in 1998 kharif due to Purple ?Blotch and Stemphylium Blight diseases which were induced by high rainfall.

The report also said that the apple belt was shifting upwards in the apple growing areas of Himachal Pradesh due to decreasing chilling hours and increasing temperature during November ? March.

?New areas of apple cultivation have appeared in Lahaul and Spiti and upper reaches of Kinnaur district of Himachal Pradesh,? the study showed.

The analysis of data for the period 1901 to 2005 indicates increase in the annual mean temperature by 0.50C. The long-term variation of the mean annual temperature of the country for the period 1875 to 2004 was in the order of 0.030C per decade while for the period 1971 to 2004 it was around 0.220C per decade indicating greater warming in the recent decades.

?Analysis of long-term (1952-2007) mean annual temperature trends of 47 locations across the country indicated increasing trend in the central and southern parts and north eastern region. Decreasing trend in temperature is observed in some parts of Gujarat, Konkan Region, north-west parts of MP and Eastern Rajasthan,? the assessment observed.