Reducing the amount of nitrogen fertilisers crops require could improve the quality of water in rivers and lakes, and help protect aquatic life.
That is the purpose of research being carried out by scientists at Tohoku University in Sendai, Japan. They are producing insights into the gene and protein control systems that regulate the uptake of nitrogen by plant roots, and say their research could help develop crops that require less fertiliser to produce decent yields.
Nitrogen is a crucial nutrient for plants, and vast quantities of fertilisers containing the chemical are spread on farmland worldwide. These fertilisers mostly contain nitrogen as ammonium ions, the chemical form in which nitrogen is most readily taken up by plant roots.
"One of the key goals of modern agricultural research is to develop crops that can grow healthily without relying on so much added nitrogen."
The downside is that when excess nitrogen in soil runs off the land into rivers and lakes, it causes serious ecological imbalances and harmful algal blooms (HABs). Algae are simple plants and form the base of food webs; HABs occur when colonies of algae grow out of control, de-oxygenating water and killing fish and other aquatic life.
Soichi Kojima, a plant biochemist at Tohoku University says, "One of the key goals of modern agricultural research is to develop crops that can grow healthily without relying on so much added nitrogen."
There are also significant economic and environmental incentives behind this aim, he says.
"Energy from vast quantities of fossil fuels is currently needed to convert nitrogen in the air into ammonium for fertilisers."
The researchers worked with thale cress (Arabidopsis thaliana), a small flowering plant commonly used in botanical studies.
"Taken together, our results reveal, at the genetic level, regulatory mechanisms at work when plants utilise nitrogenous fertilisers in their roots," says Kojima.
The team's next step is to determine whether the processes they have identified in Arabidopsis are shared by other plant species, especially major crop plants such as rice and other cereals. If so, it could open an avenue for plant breeders and geneticists to generate crops that might need much less fertiliser, while still producing the yields needed to feed the world.
The study is published in the journal Frontiers in Plant Science.