Environmental and biological controls on free-living nitrogen fixation

A major goal of our research is to identify how cropping systems can be maintained at a high level of productivity and yields while, also ensuring soil and system sustainability. A key, but often overlooked, component to balancing productivity and sustainability is N and the factors controlling its availability. Nitrogen typically limits plant growth, but N additions can have detrimental impacts on the environment (e.g. NO3- leaching; N2O efflux) and hinder sustainability. Finding ways to optimize cropping systems such that  biological N-fixation is a significant N-source would be an ideal method for jointly maximizing productivity and sustainability. Our research seeks to address gaps in our knowledge regarding N dynamics and sustainability, taking an integrated approach to plant-soil-microbiome systems with experimental work that spans the lab to the field and uses multiple -omics technologies to assess system function.

We are particularly interested developing a better understanding of the controls on in free-living N-fixation in various food and bioenergy cropping systems. Please see more information about our research on these project websites:



Also, check out a project press release here:


Our new nitrogenase gene database – NFixDB – and other information can be found here: