By Anders Lorenzen
China’s bread basket, the province of Henan, is becoming increasingly concerned that climate impacts could seriously weaken its wheat yields.
Henan, ‘China’s granary’, is worried about diminishing wheat yields
Henan, the 5th largest Chinese provincial economy and, if it were a country, the 18th in the world, accounts for 28% of Chinese wheat production and is known as China’s granary, is warning that dry and hot winds threaten wheat crop development.
The warning comes as this and next week (11th to 13th of May) temperatures are expected to exceed 35 degrees C.
How vulnerable is wheat production to extreme heat?
The flowering and pollination stage
During this growing stage, extreme heat can cause pollen sterility and reduce grain set.
Temperatures above 30-35 °c during this stage severely impair fertilisation.
The grain-filling stage
During this crucial stage, high temperatures accelerate maturity and shorten the grain-filling.
During this process, the plant transfers nutrients into developing grains, determining both the yield and the quality of the grains.
Heat stress during this stage leads to smaller and lighter grains.
Temperatures above the optimal threshold between 15-25 °c reduce starch deposition.
Henan is concerned about several wheat-growing areas
A local government statement from Henan specifically voiced concerns about Anyang, Puyang and Zhengzhou.
How significant is wheat production in China?
China is the world’s largest wheat producer. In 2024, the country produced 140 million metric tonnes.
This accounts for 18% of the world’s wheat supply.
One-third of this is produced in Henan, where the typical harvest time is between late May and mid-June.
Broader Chinese concerns about wheat production
The region’s warning comes against the backdrop of the Chinese government’s resources minister’s warning last month about worsening drought conditions in the northern wheat belt due to decreasing short-term rainfall.
Rainfall deficit in China’s northern wheat belt
Weather maps have shown a 90-day rainfall deficit across the key growing regions of Hebei, Henan, Anhui, and Jiangsu. Combined, those regions account for 61% of the winter wheat crop.
China has been significantly increasing its wheat production in recent years, but a drop in domestic production could ramp up wheat imports again after they have dropped in the last few years.
The global picture: heat is making a significant dent in global crop yields
A study published this week by researchers at Stanford University in the US found that heat significantly reduces crop yields globally.
It further outlined that the global yields of barley, maise and wheat are 4% to 13% lower than they would have been without warming.
Anders Lorenzen is the founding Editor of A greener life, a greener world.
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