Research in plant ecology and sustainable farming advocate for increasing crop diversity on farms over monocultures. Crop diversity provides many ecosystem services, but mainstream farming relies heavily on mechanical and chemical solutions known to degrade land quality to ensure optimal yields. For centuries, Indigenous peoples in North America maintained sustainable cropping systems characterized by crop diversity and minimal inputs, such as the Three Sisters system. To integrate this knowledge into current research, we collaborated with Indigenous corn growers in Wisconsin interested in growing their traditional corn varieties with cover crops seeded between the rows. Growers are interested in knowing which cover crop mixtures synergize well with their corns while suppressing aggressive weeds. Single and mixed plantings of winter wheat, clover, and chicory/plantain were sown after corn planting while establishing a hand-weeded and weedy control. From 2021 to 2023, we found the triple mixture to lower weed biomass at the end of the season while also having the highest total relative yield, indicating cover crops in this mixture accumulated more biomass than their single plantings. No corn yield was collected in 2022, but low nutrients impacted corn yield in 2021, which was lower overall compared to the 2023 corn yield. Within 2021, weed pressure played a significant role in reducing corn yield, but the single planting of clover and winter wheat had higher yields than the control left weedy and comparable to the control with no cover crops or weeds. In 2023 all cover crop treatments and controls did not differ significantly indicating these corn varieties have a potential higher tolerance from weed or cover crop competition. Indigenous growers now have data relevant to their corn varieties and their goals to preserve their traditional food systems. The trial and error from these experiments was integral to the relationship building between UW-Madison and our Indigenous partners, creating a shared learning environment to better understand sustainable farming practices. From this project, we have developed a framework to guide agricultural research with Indigenous communities centered on the principles of traditional Indigenous farming.
