Perennial grain-legume intercrops

Collaborators: Ali Nord, University of Michigan; Jeremy Moghtader, University of Michigan Campus Farm

Funding: USDA AFRI Foundational Program

Integrating perennial species into agroecosystems is central to an ecological management approach that can avoid surpassing critical planetary thresholds for sustainability. The greater vulnerability of annual cropping systems in a changing climate make perennial crops increasingly appealing to farmers. Intermediate wheatgrass (Thinopyrum intermedium; IWG) is the most advanced perennial grain crop, which has been selected for increased yield. Grain from these improved lines is now sold as Kernza® to restaurants, bakeries, and other businesses for use in value-added products. A particularly promising, and novel, system for increasing ecosystem services is intercropping perennial grains with legumes to supply an organic nitrogen (N) source. However, there remains a need to optimize these intercrops for resource use efficiency and productivity, which requires understanding their ecological interactions.

This project will address three research gaps related to perennial grain-legume intercrops through the following objectives: (i) understand how two perennial legumes (alfalfa and white clover) impact IWG yield, grain quality, and soil health; (ii) determine the relative contribution of above- and below-ground alfalfa biomass to fixed N inputs and soil N cycling capacity by simulating forage removal; and (iii) improve mechanistic understanding of interactions between intercropped species – including N fixation rates, transfer of fixed N to IWG, and changes in root functional traits – that increase ecosystem services. This project will establish the foundation for long-term, interdisciplinary research on perennial grain agroecosystems at UM and extend the limited body of research on perennial grains by applying ecological science to identify generalizable mechanisms that can inform more sustainable crop production.