Prabhjyot Kaur and SS Gosal
CLIMATE change and its extremes have become a harsh reality today. According to the latest report of the World Meteorological Organisation, the past eight years are on track to become the eight warmest on record. The global mean temperature in 2022 is currently being estimated to be nearly 1.15°C more than the average of 1850-1900 and this warming is evident by the exceptionally high melting of glaciers. Since the start of 2022, India has witnessed extremes of climate in the form of heatwaves. The Ministry of Earth Sciences has reported that the total number of heatwave days in India this year were 203, which exceeded the 174 days of 2019.
According to the India Meteorological Department (IMD), when the temperature of a station is 4.5-6.4°C above its average value, it is considered a ‘heatwave’ condition. During March-April this year in northern and central India, the winter crops were exposed to heatwave conditions. A recent report by the Indian Council of Agricultural Research has stated that abnormally high temperatures during these months affected field crops (wheat, maize, mustard, chickpea), fruits (citrus, mango, apple, pomegranate) and vegetables (cabbage, cauliflower, cucumber, tomato and okra). The temperatures were appreciably higher in most parts of India, while the northwest and central regions experienced the hottest April in 122 years.
During March-April 2022, the maximum and minimum temperatures were often higher than the average temperatures during these months by 5-6°C. Since these two months coincide with the reproductive and grain development phase of rabi crops, the crops were induced towards forced maturity and their respective yields were reduced. In Punjab, wheat yield fell by 13.5% during 2021-22 as compared to the previous year as the heatwave led to the formation of shrivelled grains. This heatwave, coupled with scarce rainfall due to weak activity of western disturbances, increased the overall irrigation requirement of the crop. In green gram, there was increased infestation of whitefly, poor vegetative growth and poor pod setting, causing reduction in yield up to 20%. Maize yield dropped by up to 18% in Faridkot, Bathinda and Gurdaspur districts of Punjab due to retarded growth and attack of the fall armyworm. Tomato yield in Bathinda district fell by 40% due to high temperatures. Kinnow, a very important fruit crop of the state, was also hit by these high temperatures. The kinnow growers of south- western districts (Fazilka, Muktsar, Bathinda) reported that temperatures above 35-38°C adversely affected the fruit-setting period of the crop since it favoured the attack of citrus psyllid pest, leading to fruit shedding in the early period of growth. Since the start of 2022, the minimum temperatures up to November have remained above normal, though the maximum temperatures showed a slight cooling after April and were near normal thereafter.
Since weather is becoming a key player in determining agricultural productivity, Punjab Agricultural University (PAU) is disseminating weather-based agro advisories to farmers of the state. The predictions of weather for five days at the district and block levels are being given by IMD. In Punjab, there are five main Agromet Field Units, located at PAU (Ludhiana) and its four research stations at Gurdaspur, Ballowal Saunkhri, Bathinda and Faridkot. Weather experts are available at the Krishi Vigyan Kendras in Ropar, Ferozepur, Nurmahal and Moga. This network of agro-meteorologists converts the predicted weather information (temperature, rainfall, relative humidity, wind speed, wind direction, cloud cover) into a usable form of weather-based agro-advisory for the farmers by combining information from experts of allied fields of agriculture (agronomy, soil science, plant pathology, entomology, horticulture, animal husbandry, etc). This information is shared on digital platforms and through mass media.
Adaptive measures such as mulching, early/timely sowing of crops, cultivation of short-duration varieties, planting methods, spray by certain chemicals, intercropping, irrigation methods, etc. can counter the effects of climate extremes in crops.
Some climate-resilient wheat varieties having a better heat susceptibility index such as PBW 766 (Sunheri), PBW 826, PBW 824, PBW 869 and PBW 725 are good choices to tackle heatwave conditions.
Creating awareness about climate change and adaptive as well as mitigation techniques holds the key to combat climate change and its extremes. We need to explore ways to minimise depletion of our natural resources to ensure that agriculture becomes climate-resilient and sustainable.
Prabhjyot Kaur is Principal
Scientist (Agrometeorology); SS Gosal is VC, PAU, Ludhiana
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