Posted on April, 4, 2023 at 09:11 pm
2021-22 and 2022-23 have both seen unusual rabi (winter-spring) cropping seasons in terms of weather and yield loss, especially in wheat. But the patterns of rainfall and temperature variation — and the damage to the standing crop as a result — have been different in the two seasons.
The 2021-22 season was marked by too much rain. The country received rainfall that was way above the “normal” long period average in every month from September 2021 to January 2022. This was followed by the hottest ever March in terms of average maximum temperatures.
The unusual heat of March 2022 led to lower wheat production, as the spike in temperatures happened during the grain formation and filling stage when the kernels were accumulating starch and proteins. That stage, which determines the size and weight of the harvested grains, was cut short with maximum temperatures crossing 35 degrees Celsius by mid-March.
While the Agriculture Ministry claimed last year’s wheat output at 107.74 million tonnes (mt) — a marginal decline of 1.7% from the all-time-high 109.59 mt of 2020-21 — the private trade estimated the crop to be 10-15% lower at 93-98 mt.
This was borne out by the government’s own procurement falling to 18.79 mt, as against 43.34 mt in the previous marketing season, and wholesale wheat inflation crossing 20% year-on-year by December even after a ban on exports.
Why has 2022-23 been different?
If 2021-22 was largely wet, with five consecutive months of excess/surplus rain, 2022-23 was quite the opposite. The winter was exceptionally dry, with the four months from November 2022 to February 2023 registering deficient rainfall (see chart). February 2023 not only recorded 68.3% below-normal rain, it was also the hottest ever February in terms of the average maximum temperature, just as March was in 2022.
Given how hot and dry February was, it wasn’t unnatural to expect March 2022 to be repeated, if not exceeded. In fact, the India Meteorological Department (IMD) on February 28 forecast both maximum and minimum temperatures for March 2023 to be “above normal” over most parts of the country. Its monthly outlook for March also predicted average rainfall over the county to be normal, and “below normal” over most areas of northwest and west central India, and some parts of east and northeast India.
But March turned out to be neither hot nor dry. Last year, the maximum temperature in Delhi hit 35 degrees on March 15, 38 degrees on March 20, and 40 degrees on March 30. This year, the highest was 34 degrees on March 12 and 15, and the maximum on March 31 was 26 degrees. Contrary to initial fears, temperatures remained well within the 35-degree limit that is the most conducive for grain-filling in wheat.
The surprise element, however, was rain — a 25.8% surplus in March 2023. But while the first half of March (1-15) reported 77.6% deficient rainfall, the second half (16-31) saw a 120.5% surplus. The so-called “Ides of March”, seen in the heat wave that forced premature ripening and drying of the wheat crop last year, manifested itself in the form of unseasonal rain this year.
Will the rain affect wheat yields?
Wheat is sensitive to both heat stress and rain/ thunderstorms during the terminal grain filling and ripening period. This is the time when the crop’s earheads are heavy with grains. The more the weight accumulated from grain-filling, the more vulnerable is the crop to rain. These, when accompanied by high-velocity winds, make the stems prone to “lodging” or bending and even falling flat on the ground.
“In earlier years, we got only occasional showers in March. This time, it rained heavily not once, but at least thrice — on March 18, March 24, and March 30-31. The crop flattened by the first rain did not get a chance to revive,” said Gurmail Singh, a 30-acre farmer from Gehlan village in Punjab’s Sangrur district.
In 2021, Gurmail Singh harvested an average wheat yield of 24-25 quintals per acre. That fell to 16-18 quintals in 2022 because of the unusual heat. “I don’t know what it will be this time,” he said. Gurmail’s crop has seen 100% lodging on 10 acres, and 40-45% on another 8 acres.
Pargat Singh, who farms 22 acres in Gehri Baghi village of Bathinda district and runs a Crops Information channel on YouTube with 432,000 subscribers, said the yield losses were likely to be the highest in areas that saw waterlogging and hail.
“The water will not drain out easily in districts such as Fazilka, Firozpur, Muktsar, and Bathinda that have low-lying areas with hardly 3-4-metre water tables. The moist grains from even the fully-matured crops here may suffer discolouration and lustre loss, with poor milling quality.”
Rajbir Yadav, principal scientist at the New Delhi-based Indian Agricultural Research Institute, said the production loss in wheat this time may be more during harvesting than on account of lodging or reduced crop yields per se. “When the crop gets wet and then dries in the sun, its earheads (bearing the grains) become brittle, and tend to break from the stem. Such earheads may not be picked up by the combine harvester machines,” Yadav said.
He pointed out that lodging of wheat has taken place mostly after March 22, by which time grain-filling was nearly complete for the crop sown before mid-November in much of Punjab and Haryana.
While the wheat in Madhya Pradesh was harvest-ready by mid-March itself, the crop sown in December in eastern Uttar Pradesh and Bihar may even benefit from the current rain that has brought down temperatures and prolonged the time for grain-filling.
“I don’t expect overall yield loss to be anywhere near last year’s. There would be more of harvesting than actual crop yield loss,” Yadav told The Indian Express.
Would wheat prices go up if production falls?
It is unlikely — because wheat prices at the Chicago Board of Trade futures exchange are now at just over $254 per tonne compared to the $500-plus peaks that were scaled last March.
Source: Financial Express