It is well known that nitrogen is important for plant growth. Farmers can artificially increase the amount of nitrogen in soil with fertilizer, but this can have negative environmental impacts. Fertilizer can be washed off fields and into streams or enter the groundwater. It can also enter the atmosphere as nitrogen oxides or ammonium gas that contribute to the greenhouse effect. The production of nitrogen fertilizers requires a lot of energy. The team wanted to find a way to introduce more nitrogen to plants without the artificial fertilizers.