Early Heatwave And Wheat Production In Punjab: Time For Action Is Now

Punjab is one of the major wheat-producing states in India, accounting for a significant share of the country's total wheat production. The estimated wheat production in Punjab in the 2020–21 crop year was 139.92 lakh metric tons, or around 17% of the total wheat production in India, according to the Ministry of Agriculture and Farmers' Welfare. In comparison to other states in India, Uttar Pradesh is the largest wheat-producing state, with an estimated production of 353.09 lakh metric tonnes in the 2020–21 crop year, accounting for around 43% of the total wheat production in India. Other major wheat-producing states include Madhya Pradesh, Haryana, Rajasthan, and Bihar. It is important to note that these estimates can vary yearly based on various factors, such as weather conditions, pest infestations, and other agricultural practices. However, Punjab consistently ranks among the top wheat-producing states in India.

Climate change has been affecting agriculture in Punjab as it is experiencing changes in temperature, rainfall, and other weather patterns that impact wheat production. The question is, how does rising temperature impact wheat production? The rising temperature leads to heatwaves, which affect crop yields and quality. High temperatures cause heat stress in crops, reducing growth and yield.

Also, crops like wheat need to grow in a certain range of cold temperatures, and rising temperatures can disrupt their growth cycle. Data on wheat production in Punjab from 2015 to 2020 show a slight average decline. The data shows that the area under production has increased only slightly.

B Pateriya, director of the Punjab Remote Sensing Centre, provides evidence for this change. His team analysed the impact of heat stress on wheat phenology in Punjab for two normal years (2003 and 2013) and two heat-stressed years (2010 and 2022) using satellite data. The rate of decrease in the Normalised Difference Vegetation Index, a spectral index to measure the change in crop phenology, was higher during March 2004 and 2022 than 2003 and 2013. The average decrease in wheat yield in Punjab due to heat stress was approximately 5-7% during 2010 and 10–20% during 2022.

This shows that high temperatures during the grain development stage affect wheat yield. To support these findings, these studies required more detailed scientific analysis and research using more data using AI-based data analytics.

"For 2023, it is a bit early to estimate the impact of heat stress on wheat yield due to farm advisories issued by agricultural universities and agriculture departments encouraging the adoption of improved management practices to minimise the negative impact of heat stress on wheat yield and an assured irrigation system in Punjab," Pateriya said. "Indeed, it may impact the farmers' input cost and other soil and crop parameters depending on climatic conditions that may prevail in the region require micro level detail analysis."

Early heatwaves can significantly impact crop production, data from other regions showed. Wheat is a cool-season crop, and an early heatwave can decrease its yield and quality in Punjab, one of the country's significant wheat-producing states.

The question is, how does it happen?

During an early heatwave, the temperature can rise above the optimal temperature range for wheat growth, around 15-25 degree celsius. When the temperature rises above this range, it can reduce photosynthesis, which is essential for plant growth and grain development. This can result in a decrease in the number of grains per spike and a reduction in the grain weight, ultimately reducing the overall yield.

"Wheat crops are sensitive to higher temperatures particularly at two critical stages—tillering and grain-filling (formation). For normal tillering of the crop, the minimum night temperatures need around 5-10°C, and the maximum day temperatures need around 13-24°C, said Surinder Singh Kukal, member of Punjab Water Regulation and Development Authority. "Similarly, during grain filling, the normal minimum and maximum temperatures should be around 5-9°C and 19-25°C, respectively."

In last 10 days, the maximum temperatures have been about 3°C above normal, averaged over a week, whereas on a daily basis still higher 4-6°C, he said. The timely sown crop by Nov. 15 is now at reproductive stage and shall soon within seven days be in grain filling stage, he said. "If the temperatures continue soaring like this, the wheat crop yield will be affected, as happened during 2021-22 wheat season, when we lost 10-15% of crop yield."

Going by the predictions of India Meteorological Department, both minimum and maximum temperatures are expected to remain above normal by 0-2 and 2-4°C, respectively, Kukal said. "In case this happens, the crop yield may be affected. On the other hand, the late sown crop (after Nov 15) is expected to lose to a greater extent”

In recent years, Punjab has been facing a decline in wheat production. The cause of this decline is attributed to climate changes, which are wreaking havoc on the state's agrarian economy. The alarming trend calls for immediate attention and action from the government, policymakers, and farmers alike.

“Punjab is a relatively low risk state for wheat production, and that is one of the reasons Punjab never implemented the PM crop insurance scheme since the inception of the scheme," said Sukhpal Singh, professor at the Center for Management in Agriculture, who has been researching on agriculture in Punjab for past four decades. "But the change in climate in 2022 led to shriveling of grain and, therefore, lower and poor-quality wheat yield. This is likely to happen again this year if the temperature keeps rising abnormally and before the crop is at the grain formation stage. This can lead to sterility and early maturation of grains which will affect quality of produce, if not yield."

"Therefore, the IMD agrometeorological advisory for the state includes wheat farmers giving light irrigation to the crop, two sprays of potassium chloride, and monitoring the crop for yellow rust. Additionally, the number of wheat varieties grown in the state is very small, which makes the whole of the crop prone to such impact," he said.

To adapt to these changes, farmers may need to adopt new crop varieties, change agricultural practices, and adopt new technologies to conserve water, manage soil health, and prevent pest and disease outbreaks. Additionally, efforts to mitigate climate change, such as reducing greenhouse gas emissions and promoting sustainable agriculture, are critical to protect the region's agricultural productivity and food security.

Furthermore, the state's groundwater level is rapidly depleting, adversely affecting the fields' productivity. Many farmers are relying on tube wells to irrigate their land, which is leading to a decline in water quality, and in turn, negatively impacting the yield. The alarming drop in wheat production has also led to increased costs of production, which can make farming an unprofitable venture for many small-scale farmers.

In sum, the declining wheat production in Punjab is a pressing issue that needs to be addressed immediately. The government and all stakeholders involved in agriculture must work together to find a viable solution to ensure that the state's farmers are not left vulnerable to the effects of climate change. The situation calls for urgent action, and we must all act now to ensure that the state's agricultural sector thrives and contributes to the country's overall food security.