Nitrogen-fixing GM crops

Could genetic engineering be used to create cereal crops that fix nitrogen from the soil?

Clover, peas and beans belong to a group of plants called legumes. Unlike other plants, they can take up nitrogen from the soil, which plants need to grow. They do this using bacteria on their roots which convert nitrogen from the air into nitrates which can be taken up by the plant roots. Thus, they do not need artificial nitrogen to be added in fertilisers. When legumes are harvested their roots return nitrogen to the soil improving its fertility and providing a natural source of fertiliser.

If genetic engineering could be used to create cereals that fix nitrogen, the use of artificial fertilisers might be reduced without resorting to traditional methods of rotating crops.

This idea was first proposed over thirty years ago by the US Office of Technology Assessment in its 1981 report. But it is very difficult to achieve in practice because the ability to fix nitrogen depends on a complex relationship between bacteria and the roots of plants. Members of the U.K. Government Office for Science's Foresight Project on Global Food and Farming Futures have written a paper (see Table 1) which predicts it will take more than 20 years' more research to create such crops. In reality it is questionable whether such promises can ever be delivered.


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