Modern agriculture feeds the people of the world, but it also threatens ecosystems that humanity depends on. One key player in the drama is synthetic nitrogen fertilizer.

Finding a way around the use of man-made fertilizer while keeping agricultural productivity high could be the key to a new green revolution, which explains why the National Science Foundation has given a $6.5 million grant to researchers at The Samuel Roberts Noble Foundation to study legumes.

Nitrogen is all around us, making up most of the Earth’s atmosphere, but plants can only make use of it when it’s been converted into certain forms. For the past 100 years, humans have been capturing nitrogen from the air and using it to make ammonia-based synthetic fertilizers. The process of making the stuff starts with fossil fuels and ends with agricultural runoff that kills water life, creates smog and makes people sick.

Beans know a better way. Legumes have an evolutionary alliance with bacteria, growing root nodules that provide a safe home for microorganisms known as rhizobia that are able to convert atmospheric nitrogen into ammonia. Organic farmers since pretty much the dawn of agriculture have known something about this, leading to practices like planting corn and beans together, and rotating crops to take advantage of the nitrogen that legumes build into the soil.

The Noble researchers hope to gain a deeper understanding of the way legumes do their work. Along with fellow scientists from other institutions, they will try to determine the genes responsible for legumes’ ability to pull nitrogen from the air and into the soil. They’ll also study how fungi in the soil work with plant roots to improve the uptake of phosphorus — another crucial element for plants that is typically supplied through synthetic fertilizer.

Ultimately, the researchers say they hope to find ways to improve plants’ ability to use their symbiotic relationships so that more food can be produced with sustainable practices.

Main photo credit: thebaron03/Flickr