Linking Plant Traits with Soil Health to Determine Optimal Cover Crop Mixtures on Organic Farms
Project Director
Jennifer Blesh
Year Funded
2019
Award Number
2019-51106-30193
Funded Institution
University of Michigan
Grant Program
ORG (Organic Transitions)
USDA NIFA Report
Project Overview
Organic producers often use cover crop mixtures for multiple purposes including nutrient retention, weed suppression, and soil organic matter (SOM). This project conducted farmer-participatory field trials with cover crop mixtures versus monocultures (rye or crimson clover) on 14 organic grain farms representing a range of soil types, management histories, and soil health conditions.
Farmer Takeaways
(1) Multispecies cover crops develop higher biomass and provide greater benefits – organic matter, N, P, weed suppression, etc – than single species cover crops.
(2) As soil health improves, biological capacity to release N from organic matter increases, and legume biomass and N fixation decreases.
(3) As soil health improves, total cover crop biomass increases, which further builds organic matter and soil health in a positive feedback loop.
(4) Switching from rye to a grass-legume-crucifer mixture can increase net returns by $65/ac on Michigan organic grain farms, compared to just $2-3/ac for crimson clover alone.