Kozhikode: The drastic fall in water levels and fissures in fields have literally shocked the people in Wayanad, especially farmers. The temperature in the district has risen to more than 28 degrees Celcius days after the continuous rain and floods. However, experts point out that the change in temperature is not unusual and it has been increasing gradually for the past three years and the spike is very much discernible in the months of September over the last few years if weather data is considered.
Data available with Onmanorama from the Regional Agricultural Research Station (RARS), Ambalavayal, points at rise in average temperature from 2015 to 2016. The mean temperature is showing a gradual increase in the next years, especially when comparing the September data.
While the average range of minimum-maximum temperature in September 2015 ranged from 18.2 degrees to 21.3, the average temperature range in September 2016, was 18.0 to 26.2 degrees, i.e., a sudden increase of 5 degrees in a year. Coming to 2017 in the same period, the average temperature ranged from 19.2 to 26.3 degrees. This year, till September, the maximum temperature recorded in the district is 29.4 degrees, the minimum was 16.9 degrees on an average.
“The temperature has increased considerably, resulting in dip in the water level. In some areas, it was also reported that earthworms were found dead in large numbers. Considering global warming, there could be a difference of a maximum .2 degrees in a year. A difference of 5 degrees in mean temperature range is a huge change and that will definitely have an adverse impact on the soil and living conditions. Rain stopped just 15 days ago, and the temperature is showing a sudden shift. This situation is something mysterious. There is a drought-like situation in the district soon after the rain,” said RARS associate director Dr P Rajendran.
Loss of humus another worry
Drought-like conditions worsen the delicate condition of the land in an agrarian region. Soil loses humus, the essential organic component, as the top soil gets eroded in high intensity rains.The velocity of water infiltration increases as humus, which is formed by the decomposition of leaves and other bio materials. is lost. Soil moisture is balanced when organic carbon in it is present within 1.5 feet of the top soil, said soil conservation specialist PU Das.
However, Wayanad has no relief on this count too as it received exceptionally high rain this monsoon. “The rain intensity is calculated according to the amount of rain received in 24 hours. Red alert is issued when the rain is marked 20 cm and above. In Wayanad this year, the rain marked 36 to 40 cm, which comes under high intensity rain. When the top soil is washed out, the pore spaces are open and the infiltration rate increases. This will lead to drying up of the springs and lowering of the water level,” he said.
The infiltration rate is the velocity or speed at which water enters into the soil.
The loss of humus also results in the destruction of micro-organisms and crops supported by them. “When valuable cash crops like pepper are affected even the agrarian economy is affected. More studies into the high intensity rain and the rise in temperature have to carried out by the Biodiversity board,” Das stated.
Wayanad, Idukki on the same boat
Experts from the Centre for Water Resources Development and Management (CWRDM) noticed that Idukki also shares similar concerns as Wayanad. Both the districts are facing a sudden decrease in rainfall over the past few years. Incidents of heatstroke in Wayanad, that too during south west monsoon, is a matter of concern, they said. Though the scientists point finger at the global warming, they could not establish it yet.
Usually, places like Vythiri in Wayanad receives rain for 130 days in a year, but this fell to 100 in the last three years, indicating a significant decrease. The scientists estimated that the decrease in temperature as well as the rise in temperature are indications of global warming. They added that the impact is more visible in India, where natural calamities have apparently increased in a decade.
(NB: Mean Temperature Range is the average of the maximum and minimum temperatures.)
