China’s farmers key to cutting greenhouse gas emissions

By Tierney Smith 

Halving nitrogen fertiliser use in China could significantly decrease greenhouse gas emissions without affecting crop productivity, according to new research.

The study, published in the journal Environmental Research Letters, found that a 60% reduction in fertiliser use could significantly reduce emissions in areas that are already ‘over-fertilised’, such as the North China Plain and the middle and lower reaches of the Yangtze River Basin.

Nitrogen Dioxide (NO2) is 2-300 times more effective at trapping heat than carbon dioxide, and is the third highest contributor to climate change behind CO2 and methane. It is also widely used in China, due to generous subsidies provided to farmers by the state.

China currently meets 22% of global food demand, and as the world’s population grows to an expected nine billion in 2050 – feeding the world while addressing climate change will become an increasing problem.

Researchers say that since the 1990s the rate of crop production has slowed in these areas has slowed, suggesting the fertilizer has become less effective.

“Nitrogen fertiliser has become less efficient in recent years as the nitrogen input has surpassed nitrogen demands of plants and microbes. Excess nitrogen is not stimulating plant growth but leaving the system through leaching and nitrous gas emissions,” said report co-author, Dr Hangin Tain.

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