Forced maturity in plants due to higher temperatures can result in smaller seeds
A comparatively 'warm' winter in Bihar this year could harm production of rabi crops like wheat, oil seed and pulses, agricultural scientists have predicted.
According to experts, production of winter crops may be hit by at least 30-40 per cent if the weather in the eastern state is unchanged for long.
The minimum temperature should be 10-12 degrees Celsius (°C) while the maximum temperature should be 18°C-21°C for better yield of rabi crop, said experts.
However, the minimum temperature has remained between 11°C and 18°C in Bihar. The average day temperature has gone up to 27°C over the last 10 days. Normally such kind of weather is seen in the February end or March.
“Warm weather and sudden high temperatures affect the photoperiodism of plants. If such weather continues, it will hamper tiller formation as well as grain filling of wheat crops. Sometimes, forced maturity occurs in case of high temperature in rabi crops,” RK Sohane, senior agriculture scientist at Bihar Agriculture University in Sabour (Bhagalpur), told Down to Earth.
He added low temperature is essential for vegetative growth of rabi crops.
The fluctuation in temperature would severely impact crop production, said Rajiv Kumar, a soil science specialist at Krishi Vihyan Kendra in Patna. “We are feeling March-like weather in January. If such conditions continue, the crops will suddenly be pushed into flowering stages and we will see smaller grains. This will adversely affect rabi production,” he added.
Scientists say night dew, fog and cold weather conditions keep the soil moist and boost rabi crop. “We apprehend the warmer weather could impact rabi production by 30 per cent due to improper growth of plants, smaller wheat spikes which mean fewer grains,” said Ratan Kumar Bhagat, joint director, agronomy.
Bhagat is the in-charge of Magadh division comprising five districts of Gaya, Aurangabad, Nawada, Jehanabad and Arwal.
Several farmers complained their plants have turned yellowish and require frequent irrigation because of warm winter conditions. “Previously, we could have bumper wheat yield by irrigating the crops only once. But this time, we are irrigating them for the second time as there is no moisture in the soil,” said Shivnath Singh, a farmer from East Champaran district.
He added that the warm winter has already affected their crops by around 50 per cent since the plants have turned yellowish instead of deep green despite irrigation, use of fertilizers and pest control.
A farmer from Chausa block in Madhepura, Pankaj Kumar Mehta, complained of similar symptoms in his plants. "Our labour seems to be in vain,” he said.
Kishore Jaiswal, convenor of Progressive Farmers Association, Munger, said heavy night dew and cold weather are must for rabi crops. “This is a very crucial time for flowering and pod bearing in rabi crops but we are noticing a sudden change in temperature. This will have a drastic impact on these crops, particularly wheat, oil seeds and pulses,” Jaiswal said.
The agriculture department has set a target of 71 lakh tonnes of wheat production this year.
Wheat production has never met annual targets in recent years. In 2019-20, over 60 lakh tonnes of wheat was produced in the state while in 2018-19, it was 64.66 lakh tonnes in 2018-19. In 2017-18, wheat production was recorded at 61.04 lakh tonnes and in 2016-17, the vilume was 60 lakh tonnes.
Last year, wheat crops were grown in 22.70 lakh hectares of land, maize crops in 5.5 lakh hectares, oil seeds in 1.79 lakh hectares and barley in 18,760 hectares in Bihar.
Wheat is grown in three agro-climatic zones of Bihar. Zone-1 includes 13 north Bihar districts: Saran, Siwan, Gopalganj, East-Champaran, West-Champaran, Muzaffarpur, Sitamarhi, Sheohar, Vaishali, Darbhanga, Madhubani, Samastipur and Begusarai.
Zone-2 has eight districts of north-eastern Bihar: Saharsa, Supaul, Madhepura, Purnia, Kishanganj, Araria, Katihar and Khagaria.
Zone-3 has 17 districts. They are Patna, Nalanda, Arwal, Bhojpur, Buxar, Bhabhua, Rohtas, Gaya, Jahanabad, Nawada, Aurangabad, Munger, Sheikhpura, Lakhisarai, Jamui, Bhagalpur and Banka.
Wheat is one of the most important rabi crops in Bihar. It is sown in November and harvested between March and April.
The three leading districts where the highest volume of wheat is produced are Rohtas (5.18 lakh tonnes), Muzaffarpur (3.36 lakh tonnes) and Sitamarhi (3.21 lakh tonnes) in 2017-18, according to the latest state economic survey.
Acording to the report, wheat productivity is the highest in Madhepura (3,805 kg per hectare), Begusarai (3,775 kg per hectare) and Rohtas (3,680 kg per hectare) and lowest in Sheikhpura (2,200 kg per hectare), Jamui (2,113 kg per hectare) and Madhubani (1,993 kg per hectare.
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