Ground-level air pollution in China is leading to lower crop yields

Emission levels are having a tangible impact on farming in the world’s leading country for cereal, cotton, fruit, vegetable, meat, poultry, egg and fish production.

China has long been notorious for problems with air quality, with the capital, Beijing, only meeting national standards for the first time since records began earlier this month. Now a new study conducted by researchers at Nanjing University of Information Science and Technology has identified a correlation between falling agricultural yields and atmospheric pollution.

Key to the problem is ground-level ozone, which forms when nitrogen oxides react with certain organic compounds while in the presence of sunlight. This is predominantly caused by the burning of fossil fuels, and although there has been a gradual reduction in the overall quantity of air pollutants in China’s atmosphere, data shows the pollution is actually increasing at ground-level.

As a result, wheat cultivation decreased by around 33% as a result of noxious gases, although this figure fluctuates depending on the specific type of crop. High-yield hybrid rice wheat varieties, which account for around half of China’s overall rice output, for example, have fallen by around 30%. In comparison, regular rice yields dropped by just 12%. This is because higher yield varieties are known to have greater photosynthetic capacity, which in turn means increased gas exchange with the environment.

It’s also worth noting that ozone levels are particularly high around the North China Plain, which covers part of seven provinces including Henan and Shandong, both of which are known for wheat production. The study also identified evidence of a relationship between air pollution and agricultural yields in other East Asian locations, including South Korea and Japan. In December, figures were released showing that ozone-depleting emissions in China had doubled in the last decade, with a prior study suggesting air quality in the country could still be under-reported.  

Photo credit: Matt Briney