Impact of terminal heat stress on wheat yield in India and options for adaptation
2020
The effect of climate change is being observed in India in the form of shorter winter coupled with commencement of summer quite earlier than normal. The proximity of equator and late sowing of wheat (due to late harvesting of rice) exposes the wheat crop (Triticum aestivum L.) to high temperature stress during grain filling stage leading to terminal heat stress in the crop and reduced yield. There are limited studies done till date in India to assess the long term impact of climate variability on wheat yield and to develop adaptation strategies to reduce its negative impact. Therefore, in this study, simulation model (InfoCrop) and field experiment was used to assess the impacts of terminal heat stress on growth and yield of wheat as well as to identify adaptation strategies. Simulated results showed that terminal heat stress will reduce wheat yield by 18.1%, 16.1% and 11.1%, respectively in present, 2020 and 2050 scenarios. Advancement in sowing date, application of additional dose of nitrogen and irrigation at grain filling stage were found suitable options for preventing yield loss. Among various combinations of adaptation options, early sowing by 10 days from recommended sowing date with 30 kg ha⁻¹ additional nitrogen fertilizer and one additional irrigation at grain filling stage was found most suitable. Adaptation of these strategies will help in reducing impact of heat stress by 7.5, 6.4 and 9% respectively in present, 2020 and 2050 heat stressed scenarios.
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