Mohit Saini & Virendra Singh

The ill-effects of the constant dip in temperature, coupled with the fog and frost, are already visible in the rabi crops. Agriculture experts, however, say various crops like chana, arhar, potato, gourds, mustard, barley and wheat can be saved by following some simple measures.

Many states, including Punjab, Haryana, Bihar and Madhya Pradesh, are suffering from a cold wave. In Rajasthan, Jaipur has experienced the coldest winter in five years; for Jodhpur, it is the coldest in 35 years. Recently, the minimum temperature recorded in Srinagar was -5.6 degrees, the lowest this season.

Professor RS Sengar of the biotechnology department in Sardar Vallabh Bhai Patel University of Agriculture and Technology, Meerut, said, “During peak winter, when the sky is clear and it is not draughty, a dip in temperature produces frost. During the day, the earth’s surface warms up by absorbing sunlight and this heat then gets radiated to the atmosphere. At night, the temperature on the earth’s surface dips, but when the surface does not warm up during the day in winters, the night temperature goes past the freezing point turning the dew into what we call frost.”

Frost has already ruined crops in many states such as Madhya Pradesh, UP and Rajasthan. The Indian Agricultural Research Institute has forecast heavy fog and frost. If the frost continues, its maximum impact would be on the pulse crops of the rabi season, besides potato, peas and chana.

“When frost hits rabi crops, they get spoiled. To avoid this, spray 0.1% sulfuric acid solution to increase the temperature around the crop. For horticulture crops such as papaya, one may cover the plant with plastic sheets to raise the surrounding temperature and aid their growth,” said Sengar.

Barabanki’s agricultural protection expert Tareshwar Tripathi said, “Currently, the temperature has plummeted quite low, increasing the risk of fungal diseases in crops like jhulsa in potato and blight in mustard. To ward these off, one may spray mancozeb carbendazim. Besides, one may smoke the western and northern ends of the fields and do light irrigation.”

Dr Sarvesh Tripathi, senior scientist from Krishi Vigyaan Kendra, Ratlam, said, “Frost affects pulse crops and potatoes the most. Its maximum impact occurs between midnight and 2 am. So, one is advised to smoke the surrounding area, keeping in mind the wind direction, for it must be done in the same direction as the wind. Smoke elevates the temperature by 5-6 degrees Centigrade. Sulfur sprays also help save the crops from frost.”

Fencing may also help

Dr Sengar said, “Building a fence of trees and hedges around the field and crops can help protect crops from frost during extreme cold. If fencing is not possible on all sides, a border of trees on the northwestern end is a must.”

Day time irrigation through sprinklers

“Whenever there is a possibility of frost, the weather forecast department issues a warning. Farmers should then lightly irrigate their crops with sprinklers so that the surface temperature doesn’t fall beyond zero degree Celsius,” said Dr Sengar. “It must, however, be noted that if the sprinkles are put off before daybreak, the water would settle as frozen droplets above the crop, doing more harm than good.”

Frost affects plants more in nurseries

Dr Sengar said plants in nurseries get more affected by frost. It is advised to keep the plants covered with plastic sheets, which raise the temperature inside by 2-3 degrees, he said. “Straw can also be used to cover plants in villages while bearing in mind that the south-eastern part remains exposed so that plants receive sunlight during morning and noon. The cover should be removed as soon as March approaches.”